feat(core): port App/Surface and wire up the runnable ghostty binary

This is the integration step that turns the ported crates into a working
terminal: `cargo run` now opens a GTK window running the user's shell.

ghostty-core ports App.zig, Surface.zig (split into keyboard, mouse,
binding, clipboard and config submodules), surface_mouse.zig and
global.zig, and implements the runtime traits. perform_binding_action
handles every binding action.

Cross-crate integration:
- The core<->runtime traits (CoreApp, CoreSurface, RtApp, RtSurface,
  Waker) move from apprt-gtk into ghostty_apprt::runtime_api so the core
  stays runtime-agnostic; Scrollbar/RendererHealth stand-ins are replaced
  by the real terminal/renderer types.
- termio now uses ghostty_renderer::state::{State, SharedState}; the
  renderer calls kitty_update; image-storage-limit is applied at init
  and on config change.
- The search thread locks the terminal through a TerminalLock trait so
  it can share the render state mutex; termio's Wakeup gained a hook to
  wake the renderer thread.
- apprt-gtk: GL proc addresses are resolved through libepoxy's
  epoxy_glFoo pointer variables (plain glFoo symbols resolved to null),
  default DPI fixed to 96, libadwaita version read without GTK init so
  --version works headless.

The root binary dispatches +actions to ghostty-cli (list-fonts,
show-face and new-window are now wired) and otherwise runs the GTK app
with the real core.

Verified at runtime on Wayland and X11: shell prompt and colored output
render, child exit closes the window cleanly. Not yet verified: keyboard
and mouse input, clipboard, IME, tabs and splits (no key injection was
possible in this environment). GHOSTTY_DEBUG_SCREENSHOT=<png> dumps the
renderer's last frame for headless checks.

Test Plan:
- cargo test --workspace (2890 passed)
- cargo clippy --workspace --all-targets -- -D warnings
- GSETTINGS_BACKEND=memory GHOSTTY_RESOURCES_DIR=/usr/share/ghostty \
  cargo run

crates/ghostty-core/src/surface/binding.rs

@@ -0,0 +1,1327 @@
+//! `performBindingAction`, search, and screen file dumps (Zig `Surface.zig`:
+//! `Search`, `searchCallback`, `dumpText`, `performBindingAction`,
+//! `closingAction`, `writeScreenFile`).
+
+use std::io::Write as _;
+use std::sync::Arc;
+use std::thread::JoinHandle;
+
+use ghostty_apprt::action::{
+    Action as RtAction, CloseTabMode as RtCloseTabMode, FloatWindow, Fullscreen,
+    GotoSplit as RtGotoSplit, GotoTab, GotoWindow as RtGotoWindow, Inspector as RtInspector,
+    KeyTable, MoveTab, OpenUrl, OpenUrlKind, PromptTitle, Readonly, ReloadConfig,
+    ResizeSplit as RtResizeSplit, ResizeSplitDirection, SecureInput, SetTitle,
+    SplitDirection as RtSplit, StartSearch, Target,
+};
+use ghostty_apprt::runtime_api::{CoreError, RtApp, SurfaceId};
+use ghostty_apprt::structs::{Clipboard, ClipboardRequest};
+use ghostty_apprt::surface::Message as SurfaceMessage;
+use ghostty_config::types_a::NonNativeFullscreen;
+use ghostty_datastruct::blocking_queue::Timeout;
+use ghostty_input::binding::{
+    Action, AdjustSelection, CloseTabMode, CrashThread, InspectorMode, NavigateSearch, Scope,
+    SplitDirection, SplitFocusDirection, SplitResizeDirection, WriteScreen, WriteScreenAction,
+    WriteScreenFormat,
+};
+use ghostty_renderer::message::Message as RendererMessage;
+use ghostty_renderer::state::SharedState;
+use ghostty_renderer::thread::Handle as RendererHandle;
+use ghostty_terminal::formatter::{self, Content, Format, ScreenFormatter};
+use ghostty_terminal::point::Tag;
+use ghostty_terminal::screen::Scroll;
+use ghostty_terminal::search::screen::Select;
+use ghostty_terminal::search::thread::{
+    Event, Message as SearchMessage, Options as SearchOptions, TerminalLock, TerminalRef,
+    Thread as SearchThread,
+};
+use ghostty_terminal::selection::{Adjustment, Order, Selection};
+use ghostty_terminal::terminal::{ScrollViewport, Terminal};
+use ghostty_termio::message::Message as IoMessage;
+use ghostty_termio::{SharedStateExt, TerminalGuard};
+
+use super::Surface;
+use crate::app::Mailbox as AppMailbox;
+
+/// The maximum number of key tables that can be active at any given time
+/// (Zig: `max_active_key_tables`). Enforced by the keyboard module.
+pub const MAX_ACTIVE_KEY_TABLES: usize = 8;
+
+// ----------------------------------------------------------------------
+// Search
+
+/// The search state for the surface (Zig: `Surface.Search`).
+pub struct Search {
+    handle: ghostty_terminal::search::thread::Handle,
+    thread: Option<JoinHandle<()>>,
+}
+
+/// Lets the search thread lock the terminal inside the shared render state.
+struct StateLock(SharedState);
+
+impl TerminalLock for StateLock {
+    fn lock_terminal(&self) -> Box<dyn TerminalRef + '_> {
+        Box::new(self.0.lock_terminal())
+    }
+}
+
+// `TerminalGuard` derefs mutably to the terminal.
+fn _assert_guard(g: TerminalGuard<'_>) -> impl TerminalRef + '_ {
+    g
+}
+
+impl Search {
+    /// Start the search thread (nothing is searched until a needle is sent).
+    fn start(surface: &Surface) -> Result<Search, CoreError> {
+        let renderer = surface.renderer_handle.clone();
+        let mailbox = surface.surface_mailbox();
+        let cb = Arc::new(move |event: Event| search_callback(&renderer, &mailbox, event));
+        let (handle, thread) = SearchThread::spawn(SearchOptions {
+            terminal: Arc::new(StateLock(Arc::clone(&surface.renderer_state))),
+            event_cb: Some(cb),
+        })?;
+        Ok(Search {
+            handle,
+            thread: Some(thread),
+        })
+    }
+
+    /// Stop the search thread and free the state.
+    pub fn deinit(mut self) {
+        // Notify the thread to stop
+        self.handle.stop();
+
+        // Wait for the OS thread to quit
+        if let Some(t) = self.thread.take()
+            && t.join().is_err()
+        {
+            log::warn!("search thread panicked");
+        }
+    }
+}
+
+/// Events from the search thread (Zig: `searchCallback_`).
+///
+/// IMPORTANT: this runs on the SEARCH THREAD! It must only touch things that
+/// are safe from any thread.
+fn search_callback(
+    renderer: &RendererHandle,
+    mailbox: &ghostty_apprt::surface::Mailbox<SurfaceId, AppMailbox>,
+    event: Event,
+) {
+    match event {
+        Event::ViewportMatches(matches) => {
+            renderer.send(RendererMessage::SearchViewportMatches(matches));
+        }
+
+        Event::SelectedMatch(selected) => {
+            if let Some(sel) = selected {
+                renderer.send(RendererMessage::SearchSelectedMatch(Some(sel.highlight)));
+
+                // Send the selected index to the surface mailbox
+                mailbox.push(
+                    SurfaceMessage::SearchSelected(Some(sel.idx)),
+                    Timeout::Forever,
+                );
+            } else {
+                // Reset our selected match
+                renderer.send(RendererMessage::SearchSelectedMatch(None));
+
+                // Reset the selected index
+                mailbox.push(SurfaceMessage::SearchSelected(None), Timeout::Forever);
+            }
+        }
+
+        Event::TotalMatches(total) => {
+            mailbox.push(SurfaceMessage::SearchTotal(Some(total)), Timeout::Forever);
+        }
+
+        // When we quit, tell our renderer to reset any search state.
+        Event::Quit => {
+            renderer.send(RendererMessage::SearchSelectedMatch(None));
+            renderer.send(RendererMessage::SearchViewportMatches(Vec::new()));
+
+            // Reset search totals in the surface
+            mailbox.push(SurfaceMessage::SearchTotal(None), Timeout::Forever);
+            mailbox.push(SurfaceMessage::SearchSelected(None), Timeout::Forever);
+        }
+
+        // Unhandled, so far.
+        Event::Complete => {}
+    }
+}
+
+// ----------------------------------------------------------------------
+// Text dumping
+
+/// Represents text read from the terminal and some metadata about it that is
+/// often useful to apprts (Zig: `Surface.Text`).
+#[derive(Debug, Clone, PartialEq)]
+pub struct Text {
+    /// The text that was read from the terminal.
+    pub text: String,
+
+    /// The viewport information about this text, if it is visible in the
+    /// viewport.
+    pub viewport: Option<TextViewport>,
+}
+
+/// See [`Text::viewport`].
+#[derive(Debug, Clone, Copy, PartialEq)]
+pub struct TextViewport {
+    /// The top-left corner of the selection in pixels within the viewport.
+    pub tl_px_x: f64,
+    pub tl_px_y: f64,
+
+    /// The linear offset of the start of the selection and the length. This
+    /// is "linear" in the sense that it is the offset in the flattened
+    /// viewport as a single array of text.
+    ///
+    /// Note: these values are currently wrong if there is a partially
+    /// visible selection in the viewport (i.e. the top-left or bottom-right
+    /// of the selection is outside the viewport). The wrong values will
+    /// always be within the text bounds so we aren't risking an overflow.
+    pub offset_start: u32,
+    pub offset_len: u32,
+}
+
+/// Pixel metrics needed to place a text selection within the viewport.
+#[derive(Debug, Clone, Copy)]
+pub struct ViewportMetrics {
+    pub cell_width: u32,
+    pub cell_height: u32,
+    pub cell_baseline: u32,
+    pub padding_left: u32,
+    pub padding_top: u32,
+    pub scale_x: f32,
+    pub scale_y: f32,
+}
+
+/// The viewport placement of `sel` (the second half of Zig's
+/// `dumpTextLocked`).
+#[must_use]
+pub fn text_viewport(t: &Terminal, sel: Selection, m: ViewportMetrics) -> Option<TextViewport> {
+    let screen = t.screen();
+    let pages = &screen.pages;
+
+    // If our bottom right pin is before the viewport, then we can't
+    // possibly have this text be within the viewport.
+    let vp_tl_pin = pages.get_top_left(Tag::Viewport)?;
+    let br_pin = sel.bottom_right(pages);
+    if br_pin.before(pages, vp_tl_pin) {
+        return None;
+    }
+
+    // If our top-left pin is after the viewport, then we can't possibly have
+    // this text be within the viewport.
+    let Some(vp_br_pin) = pages.get_bottom_right(Tag::Viewport) else {
+        log::warn!("viewport bottom-right pin not found, bug?");
+        return None;
+    };
+    let tl_pin = sel.top_left(pages);
+    if vp_br_pin.before(pages, tl_pin) {
+        return None;
+    }
+
+    // We established that our top-left somewhere before the viewport
+    // bottom-right and that our bottom-right is somewhere after the
+    // top-left. This means that at least some portion of our selection is
+    // within the viewport.
+
+    // Our top-left point. If it doesn't exist in the viewport it must be
+    // before and we can return (0,0).
+    let tl_coord = pages
+        .point_from_pin(Tag::Viewport, tl_pin)
+        .map_or((0u32, 0u32), |p| {
+            let c = p.coord();
+            (u32::from(c.x), c.y)
+        });
+
+    // Our bottom-right point. If it doesn't exist in the viewport it must be
+    // the bottom-right of the viewport.
+    let br_coord = pages
+        .point_from_pin(Tag::Viewport, br_pin)
+        .or_else(|| pages.point_from_pin(Tag::Viewport, vp_br_pin))
+        .map(|p| {
+            let c = p.coord();
+            (u32::from(c.x), c.y)
+        })?;
+
+    // Our sizes are all scaled so we need to send the unscaled values back.
+    let x = {
+        // Simple x * cell width gives the left
+        let mut x = f64::from(tl_coord.0 * m.cell_width);
+        // Add padding
+        x += f64::from(m.padding_left);
+        // Scale
+        x / f64::from(m.scale_x)
+    };
+    let y = {
+        // Simple y * cell height gives the top
+        let mut y = f64::from(tl_coord.1 * m.cell_height);
+        // We want the text baseline
+        y += f64::from(m.cell_height);
+        y -= f64::from(m.cell_baseline);
+        // Add padding
+        y += f64::from(m.padding_top);
+        // Scale
+        y / f64::from(m.scale_y)
+    };
+
+    // Utilize viewport sizing to convert to offsets
+    let cols = u32::from(pages.cols);
+    let start = tl_coord.1 * cols + tl_coord.0;
+    let end = br_coord.1 * cols + br_coord.0;
+
+    Some(TextViewport {
+        tl_px_x: x,
+        tl_px_y: y,
+        offset_start: start,
+        offset_len: end.saturating_sub(start),
+    })
+}
+
+// ----------------------------------------------------------------------
+// Screen files
+
+/// The portion of the screen to write for `writeScreenFile`.
+#[derive(Debug, Clone, Copy, PartialEq, Eq)]
+pub enum WriteScreenLoc {
+    /// Full screen
+    Screen,
+    /// History (scrollback)
+    History,
+    /// Selected text
+    Selection,
+}
+
+impl WriteScreenLoc {
+    fn name(self) -> &'static str {
+        match self {
+            WriteScreenLoc::Screen => "screen",
+            WriteScreenLoc::History => "history",
+            WriteScreenLoc::Selection => "selection",
+        }
+    }
+}
+
+/// The file name used for a screen dump.
+#[must_use]
+pub fn screen_file_name(loc: WriteScreenLoc, emit: WriteScreenFormat) -> String {
+    format!(
+        "{}.{}",
+        loc.name(),
+        match emit {
+            WriteScreenFormat::Plain | WriteScreenFormat::Vt => "txt",
+            WriteScreenFormat::Html => "html",
+        }
+    )
+}
+
+/// Format the requested portion of the active screen. Returns `None` when
+/// there is no data (no selection, no history, ...).
+pub fn screen_file_contents(
+    t: &Terminal,
+    loc: WriteScreenLoc,
+    emit: WriteScreenFormat,
+) -> Result<Option<String>, CoreError> {
+    // We only dump history if we have history. We still keep the file and
+    // write the empty file to the pty so that this command always works on
+    // the primary screen.
+    let screen = t.screen();
+    let pages = &screen.pages;
+    let sel = match loc {
+        WriteScreenLoc::History => {
+            // We do not support this for alternate screens because they
+            // don't have scrollback anyways.
+            if t.screens.active_key == ghostty_terminal::screen_set::Key::Alternate {
+                None
+            } else {
+                match (
+                    pages.get_top_left(Tag::History),
+                    pages.get_bottom_right(Tag::History),
+                ) {
+                    (Some(tl), Some(br)) => Some(Selection::new(tl, br, false)),
+                    _ => None,
+                }
+            }
+        }
+
+        WriteScreenLoc::Screen => match (
+            pages.get_top_left(Tag::Screen),
+            pages.get_bottom_right(Tag::Screen),
+        ) {
+            (Some(tl), Some(br)) => Some(Selection::new(tl, br, false)),
+            _ => None,
+        },
+
+        WriteScreenLoc::Selection => screen.selection,
+    };
+
+    // If we have no selection we have no data so we do nothing.
+    let Some(sel) = sel else {
+        return Ok(None);
+    };
+
+    let mut opts = formatter::Options::new(match emit {
+        WriteScreenFormat::Plain => Format::Plain,
+        WriteScreenFormat::Vt => Format::Vt,
+        WriteScreenFormat::Html => Format::Html,
+    });
+    opts.unwrap = true;
+    opts.trim = false;
+    opts.background = t.colors.background.get();
+    opts.foreground = t.colors.foreground.get();
+    opts.palette = Some(t.colors.palette.current);
+    let mut f = ScreenFormatter::new(screen, opts);
+    f.content = Content::Selection(Some(sel.ordered(pages, Order::Forward)));
+    Ok(Some(
+        f.format_string()
+            .map_err(|e| format!("error formatting screen: {e:?}"))?,
+    ))
+}
+
+/// Write `contents` to `<tempdir>/<loc>.<ext>` (mode 0600) and return the
+/// canonical path. The temporary directory is intentionally left behind so
+/// the file stays around for the user (Zig does not delete it either).
+pub fn write_screen_temp_file(
+    contents: &str,
+    loc: WriteScreenLoc,
+    emit: WriteScreenFormat,
+) -> Result<String, CoreError> {
+    use std::os::unix::fs::OpenOptionsExt as _;
+
+    // Create a temporary directory to store our scrollback.
+    let tmp_dir = ghostty_os::temp_dir::TempDir::init()?;
+    let filename = screen_file_name(loc, emit);
+    let file_path = tmp_dir.path().join(&filename);
+
+    let result = (|| -> Result<String, CoreError> {
+        let mut file = std::fs::OpenOptions::new()
+            .write(true)
+            .create(true)
+            .truncate(true)
+            .mode(0o600)
+            .open(&file_path)?;
+        file.write_all(contents.as_bytes())?;
+        file.flush()?;
+        Ok(std::fs::canonicalize(&file_path)?
+            .to_string_lossy()
+            .into_owned())
+    })();
+
+    match result {
+        Ok(path) => {
+            // Keep the directory (and thus the file) on disk.
+            std::mem::forget(tmp_dir);
+            Ok(path)
+        }
+        Err(err) => {
+            tmp_dir.deinit();
+            Err(err)
+        }
+    }
+}
+
+/// Returns true if performing the given action result in closing the
+/// surface. This is used to determine if our self pointer is still valid
+/// after performing some binding action.
+#[must_use]
+#[allow(dead_code)]
+pub(crate) fn closing_action(action: &Action) -> bool {
+    matches!(
+        action,
+        Action::CloseSurface | Action::CloseWindow | Action::CloseTab(_)
+    )
+}
+
+/// The number of rows to scroll for `scroll_page_fractional`.
+#[must_use]
+pub fn fractional_scroll_delta(fraction: f32, rows: u16) -> isize {
+    (fraction * f32::from(rows)).trunc() as isize
+}
+
+/// Clamp a font size delta like Zig (`@max(0, @min(255, delta))`).
+#[must_use]
+pub fn clamp_font_delta(delta: f32) -> f32 {
+    delta.clamp(0.0, 255.0)
+}
+
+fn adjustment_for(a: AdjustSelection) -> Adjustment {
+    match a {
+        AdjustSelection::Left => Adjustment::Left,
+        AdjustSelection::Right => Adjustment::Right,
+        AdjustSelection::Up => Adjustment::Up,
+        AdjustSelection::Down => Adjustment::Down,
+        AdjustSelection::PageUp => Adjustment::PageUp,
+        AdjustSelection::PageDown => Adjustment::PageDown,
+        AdjustSelection::Home => Adjustment::Home,
+        AdjustSelection::End => Adjustment::End,
+        AdjustSelection::BeginningOfLine => Adjustment::BeginningOfLine,
+        AdjustSelection::EndOfLine => Adjustment::EndOfLine,
+    }
+}
+
+/// Adjust the selection of the active screen and scroll the endpoint into
+/// view. Returns false if there is no selection (the action isn't
+/// performed).
+pub fn adjust_selection(t: &mut Terminal, direction: AdjustSelection) -> bool {
+    let screen = t.screen_mut();
+    let Some(mut sel) = screen.selection else {
+        // If we don't have a selection we do not perform this action,
+        // allowing the keybind to fall through to the terminal.
+        return false;
+    };
+    sel.adjust(&mut screen.pages, adjustment_for(direction));
+    screen.selection = Some(sel);
+
+    // If the selection endpoint is outside of the current viewpoint, scroll
+    // it in to view. Note we always specifically use sel.end because that is
+    // what adjust modifies.
+    'scroll: {
+        let viewport_tl = screen
+            .pages
+            .get_top_left(Tag::Viewport)
+            .expect("viewport top left");
+        let Some(viewport_br) = screen.pages.get_bottom_right(Tag::Viewport) else {
+            break 'scroll;
+        };
+        let end = sel.end(&screen.pages);
+        if end.is_between(&screen.pages, viewport_tl, viewport_br) {
+            break 'scroll;
+        }
+
+        // Our end point is not within the viewport. If the end point is
+        // after the br then we need to adjust the end so that it is at the
+        // bottom right of the viewport.
+        let target = if end.before(&screen.pages, viewport_tl) {
+            end
+        } else {
+            let rows = usize::from(screen.pages.rows);
+            end.up(&screen.pages, rows - 1).unwrap_or(end)
+        };
+
+        screen.scroll(Scroll::Pin(target));
+    }
+
+    // Queue a render so its shown
+    screen.dirty.selection = true;
+    true
+}
+
+/// Perform an app-scoped binding action (Zig: `App.performAction`).
+fn perform_app_action(rt: &dyn RtApp, action: &Action) {
+    let a = match action {
+        Action::Ignore => return,
+        Action::Unbind => {
+            log::warn!("unbind action reached the app");
+            return;
+        }
+        Action::Quit => RtAction::Quit,
+        Action::NewWindow => RtAction::NewWindow,
+        Action::OpenConfig => RtAction::OpenConfig,
+        Action::ReloadConfig => RtAction::ReloadConfig(ReloadConfig::default()),
+        Action::CloseAllWindows => RtAction::CloseAllWindows,
+        Action::ToggleQuickTerminal => RtAction::ToggleQuickTerminal,
+        Action::ToggleVisibility => RtAction::ToggleVisibility,
+        Action::CheckForUpdates => RtAction::CheckForUpdates,
+        Action::ShowGtkInspector => RtAction::ShowGtkInspector,
+        Action::Undo => RtAction::Undo,
+        Action::Redo => RtAction::Redo,
+        _ => return,
+    };
+    rt.perform_action(Target::App, a);
+}
+
+impl Surface {
+    /// Grab the value of text at the given selection point. Note that the
+    /// selection structure is used as a way to determine the area of the
+    /// screen to read from, it doesn't have to match the user's current
+    /// selection state (Zig: `dumpText`).
+    pub fn dump_text(&self, sel: Selection) -> Result<Text, CoreError> {
+        let t = self.lock_terminal();
+        self.dump_text_locked(&t, sel)
+    }
+
+    /// Same as [`Surface::dump_text`] but assumes the renderer state mutex
+    /// is already held.
+    pub fn dump_text_locked(&self, t: &Terminal, sel: Selection) -> Result<Text, CoreError> {
+        // Read out the text
+        let text = t
+            .screen()
+            .selection_string(ghostty_terminal::screen::SelectionString { sel, trim: false });
+
+        let scale = self.rt_surface.get_content_scale();
+        let size = self.size.get();
+        let baseline = self.font.borrow().metrics.cell_baseline;
+        let viewport = text_viewport(
+            t,
+            sel,
+            ViewportMetrics {
+                cell_width: size.cell.width,
+                cell_height: size.cell.height,
+                cell_baseline: baseline,
+                padding_left: size.padding.left,
+                padding_top: size.padding.top,
+                scale_x: scale.x,
+                scale_y: scale.y,
+            },
+        );
+
+        Ok(Text { text, viewport })
+    }
+
+    /// Open a URL through the runtime, falling back to the default opener
+    /// (Zig: `openUrl`).
+    pub(crate) fn open_url_with_fallback(&self, action: OpenUrl) {
+        // If the apprt handles it then we're done.
+        let kind = action.kind;
+        let url = action.url.clone();
+        if self.perform(RtAction::OpenUrl(action)) {
+            return;
+        }
+
+        // apprt didn't handle it, fallback to our simple cross-platform URL
+        // opener. We log a warning because we want well-behaved apprts to
+        // handle this themselves.
+        log::warn!("apprt did not handle open URL action, falling back to default opener");
+        let kind = match kind {
+            OpenUrlKind::Unknown => ghostty_os::open::OpenUrlKind::Unknown,
+            OpenUrlKind::Text => ghostty_os::open::OpenUrlKind::Text,
+            OpenUrlKind::Html => ghostty_os::open::OpenUrlKind::Html,
+        };
+        if let Err(err) = ghostty_os::open::open(kind, &url) {
+            log::warn!("failed to open url err={err}");
+        }
+    }
+
+    /// Write the screen/history/selection to a temp file and paste/copy/open
+    /// the path (Zig: `writeScreenFile`).
+    fn write_screen_file(
+        &self,
+        loc: WriteScreenLoc,
+        write_screen: WriteScreen,
+    ) -> Result<(), CoreError> {
+        // Write the scrollback contents. This requires a lock.
+        let contents = {
+            let t = self.lock_terminal();
+            screen_file_contents(&t, loc, write_screen.emit)?
+        };
+        let Some(contents) = contents else {
+            return Ok(());
+        };
+
+        let path = write_screen_temp_file(&contents, loc, write_screen.emit)?;
+
+        match write_screen.action {
+            WriteScreenAction::Copy => {
+                self.rt_surface.set_clipboard(
+                    Clipboard::Standard,
+                    &[("text/plain".to_owned(), path)],
+                    false,
+                );
+            }
+            WriteScreenAction::Open => self.open_url_with_fallback(OpenUrl {
+                kind: match write_screen.emit {
+                    WriteScreenFormat::Plain | WriteScreenFormat::Vt => OpenUrlKind::Text,
+                    WriteScreenFormat::Html => OpenUrlKind::Html,
+                },
+                url: path,
+            }),
+            WriteScreenAction::Paste => self.queue_io(IoMessage::write_req(path.as_bytes())),
+        }
+        Ok(())
+    }
+
+    /// Update `mouse-reporting` on this surface's config (Zig mutates the
+    /// derived config in place).
+    fn toggle_mouse_reporting(&self) {
+        let mut config = (*self.cfg().config).clone();
+        config.mouse_reporting = !config.mouse_reporting;
+        log::debug!("mouse reporting toggled: {}", config.mouse_reporting);
+        match super::config::DerivedConfig::new(Arc::new(config)) {
+            Ok(d) => *self.config.borrow_mut() = std::rc::Rc::new(d),
+            Err(err) => log::warn!("failed to toggle mouse reporting err={err}"),
+        }
+    }
+
+    /// Adjust the font size and mark whether it was manually adjusted.
+    fn adjust_font_size(
+        &self,
+        f: impl FnOnce(f32, f32) -> f32,
+        adjusted: bool,
+    ) -> Result<(), CoreError> {
+        let mut size = self.font.borrow().size;
+        size.points = f(size.points, self.cfg().original_font_size);
+        self.set_font_size(size)?;
+        self.font.borrow_mut().adjusted = adjusted;
+        Ok(())
+    }
+
+    /// Perform a binding action. A binding is a keybinding. This function
+    /// must be called from the GUI thread.
+    ///
+    /// This function returns true if the binding action was performed. This
+    /// may return false if the binding action is not supported or if the
+    /// binding action would do nothing (i.e. previous tab with no tabs).
+    ///
+    /// NOTE: At the time of writing this comment, only previous/next tab
+    /// will ever return false. We can expand this in the future if it
+    /// becomes useful. We did previous/next tab so we could implement #498.
+    pub fn perform_binding_action(&self, action: &Action) -> Result<bool, CoreError> {
+        // Forward app-scoped actions to the app. Some app-scoped actions are
+        // special-cased here because they do some special things when
+        // performed from the surface.
+        if action.scope() == Scope::App {
+            match action {
+                // The new window has this surface as its parent.
+                Action::NewWindow => {
+                    self.rt_app
+                        .perform_action(Target::Surface(self.id), RtAction::NewWindow);
+                }
+
+                // Undo and redo both support both surface and app targeting.
+                // If we are triggering on a surface then we perform the
+                // action with the surface target.
+                Action::Undo => return Ok(self.perform(RtAction::Undo)),
+                Action::Redo => return Ok(self.perform(RtAction::Redo)),
+
+                _ => perform_app_action(self.rt_app.as_ref(), action),
+            }
+            return Ok(true);
+        }
+
+        match action {
+            Action::Csi(data) | Action::Esc(data) => {
+                // We need to send the CSI/ESC sequence as a single write
+                // request. If you split it across two then the shell can
+                // interpret it as two literals.
+                let full = if matches!(action, Action::Csi(_)) {
+                    format!("\x1b[{data}")
+                } else {
+                    format!("\x1b{data}")
+                };
+                self.queue_io(IoMessage::write_req(full.as_bytes()));
+
+                // CSI/ESC triggers a scroll.
+                self.scroll_to_bottom(&mut self.lock_terminal());
+            }
+
+            Action::Text(data) => {
+                let text = match ghostty_config::string::parse(data) {
+                    Ok(t) => t,
+                    Err(err) => {
+                        log::warn!("error parsing text binding text={data} err={err:?}");
+                        return Ok(true);
+                    }
+                };
+                self.queue_io(IoMessage::write_req(text.as_bytes()));
+
+                // Text triggers a scroll.
+                self.scroll_to_bottom(&mut self.lock_terminal());
+            }
+
+            Action::CursorKey(ck) => {
+                // We send a different sequence depending on if we're in
+                // cursor keys mode. We're in "normal" mode if cursor keys
+                // mode is NOT set.
+                let normal = {
+                    let mut t = self.lock_terminal();
+
+                    // With the lock held, we must scroll to the bottom. We
+                    // always scroll to the bottom for these inputs.
+                    self.scroll_to_bottom(&mut t);
+
+                    !t.modes.get(ghostty_vt::modes::Mode::CursorKeys)
+                };
+
+                if normal {
+                    self.queue_io(IoMessage::write_req(ck.normal.as_bytes()));
+                } else {
+                    self.queue_io(IoMessage::write_req(ck.application.as_bytes()));
+                }
+            }
+
+            Action::Reset => {
+                self.lock_terminal().full_reset();
+            }
+
+            Action::StartSearch => {
+                // To save resources, we don't actually start a search here,
+                // we just notify the apprt. The real thread will start when
+                // the first needles are set.
+                return Ok(self.perform(RtAction::StartSearch(StartSearch {
+                    needle: String::new(),
+                })));
+            }
+
+            Action::SearchSelection => {
+                let Some(selection) = self.selection_string() else {
+                    return Ok(false);
+                };
+                return Ok(self.perform(RtAction::StartSearch(StartSearch { needle: selection })));
+            }
+
+            Action::EndSearch => {
+                // We only return that this was performed if we actually
+                // stopped a search, but we also send the apprt end_search so
+                // that GUIs can clean up stale stuff.
+                let search = self.search.borrow_mut().take();
+                let performed = search.is_some();
+                if let Some(s) = search {
+                    s.deinit();
+                }
+
+                self.perform(RtAction::EndSearch);
+                return Ok(performed);
+            }
+
+            Action::Search(text) => {
+                if self.search.borrow().is_none() {
+                    // If we're stopping the search and we had no prior
+                    // search, then there is nothing to do.
+                    if text.is_empty() {
+                        return Ok(false);
+                    }
+
+                    let s = Search::start(self)?;
+                    *self.search.borrow_mut() = Some(s);
+                }
+
+                // Zero-length text means stop searching.
+                if text.is_empty() {
+                    let s = self.search.borrow_mut().take();
+                    if let Some(s) = s {
+                        s.deinit();
+                    }
+                } else if let Some(s) = self.search.borrow().as_ref() {
+                    s.handle
+                        .send(SearchMessage::ChangeNeedle(text.as_bytes().to_vec()));
+                    s.handle.wakeup();
+                }
+            }
+
+            Action::NavigateSearch(nav) => {
+                let search = self.search.borrow();
+                let Some(s) = search.as_ref() else {
+                    return Ok(false);
+                };
+                s.handle.send(SearchMessage::Select(match nav {
+                    NavigateSearch::Next => Select::Next,
+                    NavigateSearch::Previous => Select::Prev,
+                }));
+                s.handle.wakeup();
+            }
+
+            Action::CopyToClipboard(format) => {
+                let cfg = self.cfg();
+                let mut t = self.lock_terminal();
+
+                if let Some(sel) = t.screen().selection {
+                    self.copy_selection_to_clipboards(&t, sel, &[Clipboard::Standard], *format);
+
+                    // Clear the selection if configured to do so.
+                    if cfg.selection_clear_on_copy {
+                        if let Err(err) = self.set_selection(&mut t, None) {
+                            log::warn!("failed to clear selection after copy err={err}");
+                        } else {
+                            self.queue_render();
+                        }
+                    }
+
+                    return Ok(true);
+                }
+
+                return Ok(false);
+            }
+
+            Action::CopyUrlToClipboard => {
+                // If the mouse isn't over a link, nothing we can do.
+                let Some(url) = self.link_url_at_cursor() else {
+                    return Ok(false);
+                };
+                self.rt_surface.set_clipboard(
+                    Clipboard::Standard,
+                    &[("text/plain".to_owned(), url)],
+                    false,
+                );
+                return Ok(true);
+            }
+
+            Action::CopyTitleToClipboard => {
+                return Ok(self.perform(RtAction::CopyTitleToClipboard));
+            }
+
+            Action::PasteFromClipboard => {
+                return Ok(
+                    self.start_clipboard_request(Clipboard::Standard, ClipboardRequest::Paste)
+                );
+            }
+
+            Action::PasteFromSelection => {
+                return Ok(
+                    self.start_clipboard_request(Clipboard::Selection, ClipboardRequest::Paste)
+                );
+            }
+
+            Action::IncreaseFontSize(delta) => {
+                // Max delta is somewhat arbitrary.
+                let clamped = clamp_font_delta(*delta);
+                log::debug!("increase font size={clamped}");
+
+                // Max point size is somewhat arbitrary.
+                self.adjust_font_size(|p, _| (p + clamped).min(255.0), true)?;
+            }
+
+            Action::DecreaseFontSize(delta) => {
+                // Max delta is somewhat arbitrary.
+                let clamped = clamp_font_delta(*delta);
+                log::debug!("decrease font size={clamped}");
+
+                self.adjust_font_size(|p, _| (p - clamped).max(1.0), true)?;
+            }
+
+            Action::ResetFontSize => {
+                log::debug!("reset font size");
+
+                // Reset font size also resets the manual adjustment state
+                self.adjust_font_size(|_, original| original, false)?;
+            }
+
+            Action::SetFontSize(points) => {
+                log::debug!("set font size={points}");
+
+                let points = *points;
+                self.adjust_font_size(|_, _| points.clamp(1.0, 255.0), true)?;
+            }
+
+            Action::PromptSurfaceTitle => {
+                return Ok(self.perform(RtAction::PromptTitle(PromptTitle::Surface)));
+            }
+
+            Action::PromptTabTitle => {
+                return Ok(self.perform(RtAction::PromptTitle(PromptTitle::Tab)));
+            }
+
+            Action::SetSurfaceTitle(v) => {
+                return Ok(self.perform(RtAction::SetTitle(SetTitle { title: v.clone() })));
+            }
+
+            Action::SetTabTitle(v) => {
+                return Ok(self.perform(RtAction::SetTabTitle(SetTitle { title: v.clone() })));
+            }
+
+            Action::ClearScreen => {
+                // This is a duplicate of some of the logic in
+                // termio.clearScreen but we need to do this here so we can
+                // know the answer before we send the message. If the
+                // currently active screen is on the alternate screen then
+                // clear screen does nothing so we want to return false so
+                // the keybind can be unconsumed.
+                if self.lock_terminal().screens.active_key
+                    == ghostty_terminal::screen_set::Key::Alternate
+                {
+                    return Ok(false);
+                }
+
+                self.queue_io(IoMessage::ClearScreen { history: true });
+            }
+
+            Action::ScrollToTop => {
+                self.queue_io(IoMessage::ScrollViewport(ScrollViewport::Top));
+            }
+
+            Action::ScrollToBottom => {
+                self.queue_io(IoMessage::ScrollViewport(ScrollViewport::Bottom));
+            }
+
+            Action::ScrollToRow(n) => {
+                self.lock_terminal().screen_mut().scroll(Scroll::Row(*n));
+                self.queue_render();
+            }
+
+            Action::ScrollToSelection => {
+                {
+                    let mut t = self.lock_terminal();
+                    let screen = t.screen_mut();
+                    let Some(sel) = screen.selection else {
+                        return Ok(false);
+                    };
+                    let tl = sel.top_left(&screen.pages);
+                    screen.scroll(Scroll::Pin(tl));
+                }
+
+                self.queue_render();
+            }
+
+            Action::ScrollPageUp => {
+                let rows = self.size.get().grid().rows as isize;
+                self.queue_io(IoMessage::ScrollViewport(ScrollViewport::Delta(-rows)));
+            }
+
+            Action::ScrollPageDown => {
+                let rows = self.size.get().grid().rows as isize;
+                self.queue_io(IoMessage::ScrollViewport(ScrollViewport::Delta(rows)));
+            }
+
+            Action::ScrollPageFractional(fraction) => {
+                let delta = fractional_scroll_delta(*fraction, self.size.get().grid().rows);
+                self.queue_io(IoMessage::ScrollViewport(ScrollViewport::Delta(delta)));
+            }
+
+            Action::ScrollPageLines(lines) => {
+                self.queue_io(IoMessage::ScrollViewport(ScrollViewport::Delta(
+                    isize::from(*lines),
+                )));
+            }
+
+            Action::JumpToPrompt(delta) => {
+                self.queue_io(IoMessage::JumpToPrompt(isize::from(*delta)));
+            }
+
+            Action::WriteScreenFile(v) => self.write_screen_file(WriteScreenLoc::Screen, *v)?,
+            Action::WriteScrollbackFile(v) => {
+                self.write_screen_file(WriteScreenLoc::History, *v)?;
+            }
+            Action::WriteSelectionFile(v) => {
+                self.write_screen_file(WriteScreenLoc::Selection, *v)?;
+            }
+
+            Action::NewTab => return Ok(self.perform(RtAction::NewTab)),
+
+            Action::CloseTab(v) => {
+                return Ok(self.perform(RtAction::CloseTab(match v {
+                    CloseTabMode::This => RtCloseTabMode::This,
+                    CloseTabMode::Other => RtCloseTabMode::Other,
+                    CloseTabMode::Right => RtCloseTabMode::Right,
+                })));
+            }
+
+            Action::PreviousTab => return Ok(self.perform(RtAction::GotoTab(GotoTab::Previous))),
+            Action::NextTab => return Ok(self.perform(RtAction::GotoTab(GotoTab::Next))),
+            Action::LastTab => return Ok(self.perform(RtAction::GotoTab(GotoTab::Last))),
+            Action::GotoTab(v) => {
+                return Ok(self.perform(RtAction::GotoTab(GotoTab::Index(*v as i32))));
+            }
+
+            Action::MoveTab(position) => {
+                return Ok(self.perform(RtAction::MoveTab(MoveTab { amount: *position })));
+            }
+
+            Action::NewSplit(direction) => {
+                let size = self.size.get();
+                return Ok(self.perform(RtAction::NewSplit(match direction {
+                    SplitDirection::Right => RtSplit::Right,
+                    SplitDirection::Left => RtSplit::Left,
+                    SplitDirection::Down => RtSplit::Down,
+                    SplitDirection::Up => RtSplit::Up,
+                    SplitDirection::Auto => {
+                        if size.screen.width > size.screen.height {
+                            RtSplit::Right
+                        } else {
+                            RtSplit::Down
+                        }
+                    }
+                })));
+            }
+
+            Action::GotoSplit(direction) => {
+                return Ok(self.perform(RtAction::GotoSplit(match direction {
+                    SplitFocusDirection::Previous => RtGotoSplit::Previous,
+                    SplitFocusDirection::Next => RtGotoSplit::Next,
+                    SplitFocusDirection::Up => RtGotoSplit::Up,
+                    SplitFocusDirection::Left => RtGotoSplit::Left,
+                    SplitFocusDirection::Down => RtGotoSplit::Down,
+                    SplitFocusDirection::Right => RtGotoSplit::Right,
+                })));
+            }
+
+            Action::GotoWindow(direction) => {
+                return Ok(self.perform(RtAction::GotoWindow(match direction {
+                    ghostty_input::binding::GotoWindow::Previous => RtGotoWindow::Previous,
+                    ghostty_input::binding::GotoWindow::Next => RtGotoWindow::Next,
+                })));
+            }
+
+            Action::ResizeSplit(value) => {
+                return Ok(self.perform(RtAction::ResizeSplit(RtResizeSplit {
+                    amount: value.1,
+                    direction: match value.0 {
+                        SplitResizeDirection::Up => ResizeSplitDirection::Up,
+                        SplitResizeDirection::Down => ResizeSplitDirection::Down,
+                        SplitResizeDirection::Left => ResizeSplitDirection::Left,
+                        SplitResizeDirection::Right => ResizeSplitDirection::Right,
+                    },
+                })));
+            }
+
+            Action::EqualizeSplits => return Ok(self.perform(RtAction::EqualizeSplits)),
+            Action::ToggleSplitZoom => return Ok(self.perform(RtAction::ToggleSplitZoom)),
+
+            Action::ToggleReadonly => {
+                let ro = !self.readonly.get();
+                self.readonly.set(ro);
+                self.perform(RtAction::Readonly(if ro {
+                    Readonly::On
+                } else {
+                    Readonly::Off
+                }));
+                return Ok(true);
+            }
+
+            Action::ResetWindowSize => return Ok(self.perform(RtAction::ResetWindowSize)),
+            Action::ToggleMaximize => return Ok(self.perform(RtAction::ToggleMaximize)),
+
+            Action::ToggleFullscreen => {
+                return Ok(self.perform(RtAction::ToggleFullscreen(
+                    match self.cfg().macos_non_native_fullscreen {
+                        NonNativeFullscreen::False => Fullscreen::Native,
+                        NonNativeFullscreen::True => Fullscreen::MacosNonNative,
+                        NonNativeFullscreen::VisibleMenu => Fullscreen::MacosNonNativeVisibleMenu,
+                        NonNativeFullscreen::PaddedNotch => Fullscreen::MacosNonNativePaddedNotch,
+                    },
+                )));
+            }
+
+            Action::ToggleWindowDecorations => {
+                return Ok(self.perform(RtAction::ToggleWindowDecorations));
+            }
+            Action::ToggleTabOverview => return Ok(self.perform(RtAction::ToggleTabOverview)),
+            Action::ToggleWindowFloatOnTop => {
+                return Ok(self.perform(RtAction::FloatWindow(FloatWindow::Toggle)));
+            }
+            Action::ToggleSecureInput => {
+                return Ok(self.perform(RtAction::SecureInput(SecureInput::Toggle)));
+            }
+
+            Action::ToggleMouseReporting => self.toggle_mouse_reporting(),
+
+            Action::ToggleCommandPalette => {
+                return Ok(self.perform(RtAction::ToggleCommandPalette));
+            }
+            Action::ToggleBackgroundOpacity => {
+                return Ok(self.perform(RtAction::ToggleBackgroundOpacity));
+            }
+            Action::ShowOnScreenKeyboard => {
+                return Ok(self.perform(RtAction::ShowOnScreenKeyboard));
+            }
+
+            Action::SelectAll => {
+                let mut t = self.lock_terminal();
+                let sel = t.screen().select_all();
+                if let Some(s) = sel {
+                    self.set_selection(&mut t, Some(s))?;
+                    self.queue_render();
+                }
+            }
+
+            Action::Inspector(mode) => {
+                return Ok(self.perform(RtAction::Inspector(match mode {
+                    InspectorMode::Toggle => RtInspector::Toggle,
+                    InspectorMode::Show => RtInspector::Show,
+                    InspectorMode::Hide => RtInspector::Hide,
+                })));
+            }
+
+            Action::CloseSurface => self.close(),
+
+            Action::CloseWindow => return Ok(self.perform(RtAction::CloseWindow)),
+
+            Action::ActivateKeyTable(name) => return self.activate_key_table(name, false),
+            Action::ActivateKeyTableOnce(name) => return self.activate_key_table(name, true),
+
+            Action::DeactivateKeyTable => return Ok(self.deactivate_key_table()),
+
+            Action::DeactivateAllKeyTables => return Ok(self.deactivate_all_key_tables()),
+
+            Action::EndKeySequence => {
+                // End the key sequence and flush queued keys to the
+                // terminal, but don't encode the key that triggered this
+                // action. This will do that because leaf keys (keys with
+                // bindings) aren't in the queued encoding list.
+                self.end_key_sequence(
+                    super::keyboard::SequenceAction::Flush,
+                    super::keyboard::SequenceFree::Retain,
+                );
+            }
+
+            Action::Crash(location) => match location {
+                CrashThread::Main => panic!("crash binding action, crashing intentionally"),
+
+                CrashThread::Render => {
+                    self.renderer_handle.send(RendererMessage::Crash);
+                    self.queue_render();
+                }
+
+                CrashThread::Io => self.queue_io(IoMessage::Crash),
+            },
+
+            Action::AdjustSelection(direction) => {
+                let performed = adjust_selection(&mut self.lock_terminal(), *direction);
+                if !performed {
+                    return Ok(false);
+                }
+                self.queue_render();
+            }
+
+            // App-scoped actions were handled above.
+            Action::Ignore
+            | Action::Unbind
+            | Action::NewWindow
+            | Action::OpenConfig
+            | Action::ReloadConfig
+            | Action::CloseAllWindows
+            | Action::ToggleQuickTerminal
+            | Action::ToggleVisibility
+            | Action::CheckForUpdates
+            | Action::ShowGtkInspector
+            | Action::Undo
+            | Action::Redo
+            | Action::Quit => unreachable!("app-scoped actions are handled above"),
+        }
+
+        Ok(true)
+    }
+
+    /// Notify the runtime that a key table was activated (used by the
+    /// keyboard module when it implements `activate_key_table`).
+    #[allow(dead_code)]
+    pub(crate) fn notify_key_table(&self, kt: KeyTable) {
+        self.perform(RtAction::KeyTable(kt));
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+    use ghostty_terminal::terminal::Options;
+
+    fn term(cols: u16, rows: u16) -> Terminal {
+        Terminal::new(Options::new(cols, rows)).unwrap()
+    }
+
+    #[test]
+    fn closing_action_table() {
+        assert!(closing_action(&Action::CloseSurface));
+        assert!(closing_action(&Action::CloseWindow));
+        assert!(closing_action(&Action::CloseTab(CloseTabMode::This)));
+        assert!(!closing_action(&Action::NewTab));
+        assert!(!closing_action(&Action::Reset));
+    }
+
+    #[test]
+    fn scroll_and_font_math() {
+        assert_eq!(fractional_scroll_delta(0.5, 24), 12);
+        assert_eq!(fractional_scroll_delta(-0.5, 25), -12);
+        assert_eq!(fractional_scroll_delta(1.0, 10), 10);
+        assert!((clamp_font_delta(-3.0) - 0.0).abs() < f32::EPSILON);
+        assert!((clamp_font_delta(300.0) - 255.0).abs() < f32::EPSILON);
+    }
+
+    #[test]
+    fn screen_file_names() {
+        assert_eq!(
+            screen_file_name(WriteScreenLoc::Screen, WriteScreenFormat::Plain),
+            "screen.txt"
+        );
+        assert_eq!(
+            screen_file_name(WriteScreenLoc::History, WriteScreenFormat::Vt),
+            "history.txt"
+        );
+        assert_eq!(
+            screen_file_name(WriteScreenLoc::Selection, WriteScreenFormat::Html),
+            "selection.html"
+        );
+    }
+
+    #[test]
+    fn screen_file_contents_and_write() {
+        let mut t = term(20, 3);
+        t.print_string("hello\r\nworld").unwrap();
+        let s = screen_file_contents(&t, WriteScreenLoc::Screen, WriteScreenFormat::Plain)
+            .unwrap()
+            .unwrap();
+        assert!(s.contains("hello"));
+        assert!(s.contains("world"));
+
+        // No selection and no history: nothing to write.
+        assert!(
+            screen_file_contents(&t, WriteScreenLoc::Selection, WriteScreenFormat::Plain)
+                .unwrap()
+                .is_none()
+        );
+
+        let path =
+            write_screen_temp_file(&s, WriteScreenLoc::Screen, WriteScreenFormat::Plain).unwrap();
+        assert!(path.ends_with("screen.txt"));
+        let read = std::fs::read_to_string(&path).unwrap();
+        assert_eq!(read, s);
+        let mode = std::os::unix::fs::PermissionsExt::mode(
+            &std::fs::metadata(&path).unwrap().permissions(),
+        );
+        assert_eq!(mode & 0o777, 0o600);
+        let _ = std::fs::remove_dir_all(std::path::Path::new(&path).parent().unwrap());
+    }
+
+    #[test]
+    fn adjust_selection_without_selection() {
+        let mut t = term(10, 3);
+        assert!(!adjust_selection(&mut t, AdjustSelection::Left));
+    }
+
+    #[test]
+    fn adjust_selection_moves_end() {
+        let mut t = term(10, 3);
+        t.print_string("abcdef").unwrap();
+        let sel = {
+            let pages = &t.screen().pages;
+            let a = pages
+                .pin(ghostty_terminal::point::Point::Active(
+                    ghostty_terminal::point::Coordinate { x: 0, y: 0 },
+                ))
+                .unwrap();
+            let b = pages
+                .pin(ghostty_terminal::point::Point::Active(
+                    ghostty_terminal::point::Coordinate { x: 2, y: 0 },
+                ))
+                .unwrap();
+            Selection::new(a, b, false)
+        };
+        t.screen_mut().select(Some(sel)).unwrap();
+        assert!(adjust_selection(&mut t, AdjustSelection::Right));
+        let s = t.screen();
+        let end = s.selection.unwrap().end(&s.pages);
+        assert_eq!(end.x, 3);
+        assert!(s.dirty.selection);
+    }
+
+    #[test]
+    fn text_viewport_placement() {
+        let mut t = term(10, 3);
+        t.print_string("abcdef").unwrap();
+        let (a, b) = {
+            let pages = &t.screen().pages;
+            let p = |x| {
+                pages
+                    .pin(ghostty_terminal::point::Point::Active(
+                        ghostty_terminal::point::Coordinate { x, y: 0 },
+                    ))
+                    .unwrap()
+            };
+            (p(1), p(3))
+        };
+        let m = ViewportMetrics {
+            cell_width: 10,
+            cell_height: 20,
+            cell_baseline: 4,
+            padding_left: 2,
+            padding_top: 3,
+            scale_x: 2.0,
+            scale_y: 1.0,
+        };
+        let v = text_viewport(&t, Selection::new(a, b, false), m).unwrap();
+        assert!((v.tl_px_x - 6.0).abs() < 1e-9); // (10 + 2) / 2
+        assert!((v.tl_px_y - 19.0).abs() < 1e-9); // 0 + 20 - 4 + 3
+        assert_eq!(v.offset_start, 1);
+        assert_eq!(v.offset_len, 2);
+    }
+}

crates/ghostty-core/src/surface/clipboard.rs

@@ -0,0 +1,401 @@
+//! Clipboard handling for a surface (Zig `Surface.zig`: `clipboardWrite`,
+//! `copySelectionToClipboards`, clipboard requests, paste, OSC 52 and
+//! desktop notifications).
+
+use std::hash::{Hash, Hasher};
+use std::rc::Rc;
+use std::sync::Arc;
+use std::time::{Duration, Instant};
+
+use base64::Engine as _;
+use base64::engine::general_purpose::STANDARD;
+use ghostty_apprt::action::{Action as RtAction, DesktopNotification};
+use ghostty_apprt::runtime_api::ClipboardError;
+use ghostty_apprt::structs::{Clipboard, ClipboardRequest};
+use ghostty_config::types_b::ClipboardAccess;
+use ghostty_input::binding::CopyToClipboard;
+use ghostty_input::paste;
+use ghostty_terminal::formatter::{self, Format, ScreenFormatter};
+use ghostty_terminal::selection::Selection;
+use ghostty_terminal::terminal::Terminal;
+use ghostty_termio::message::Message as IoMessage;
+use ghostty_vt::modes::Mode;
+
+use super::Surface;
+use super::config::DerivedConfig;
+
+/// `input.paste.Options.fromTerminal`.
+#[must_use]
+pub fn paste_options_from_terminal(t: &Terminal) -> paste::Options {
+    paste::Options {
+        bracketed: t.modes.get(Mode::BracketedPaste),
+    }
+}
+
+impl Surface {
+    /// Handle an OSC 52 write: `data` is base64 (Zig `clipboardWrite`).
+    pub(crate) fn clipboard_write(&self, data: &[u8], loc: Clipboard) {
+        let cfg = self.cfg();
+        if cfg.clipboard_write == ClipboardAccess::Deny {
+            log::info!(
+                "application attempted to write clipboard, but 'clipboard-write' is set to deny"
+            );
+            return;
+        }
+
+        // Decode. Zig tolerates a missing-padding error ("It is possible to
+        // actually have valid data and get this error, so we allow it"), so
+        // decode leniently without requiring padding.
+        let lenient = base64::engine::GeneralPurpose::new(
+            &base64::alphabet::STANDARD,
+            base64::engine::GeneralPurposeConfig::new()
+                .with_decode_padding_mode(base64::engine::DecodePaddingMode::Indifferent),
+        );
+        let Ok(decoded) = lenient.decode(data) else {
+            log::info!("application sent invalid base64 data for OSC 52");
+            return;
+        };
+        let text = String::from_utf8_lossy(&decoded).into_owned();
+
+        // When clipboard-write is "ask" a prompt is displayed to the user
+        // asking them to confirm the clipboard access. Each app runtime
+        // handles this differently.
+        let confirm = cfg.clipboard_write == ClipboardAccess::Ask;
+        self.rt_surface
+            .set_clipboard(loc, &[("text/plain".to_owned(), text)], confirm);
+    }
+
+    /// Format the selection and put it on the given clipboards (Zig
+    /// `copySelectionToClipboards`). The caller holds the terminal lock.
+    pub(crate) fn copy_selection_to_clipboards(
+        &self,
+        t: &Terminal,
+        sel: Selection,
+        clipboards: &[Clipboard],
+        format: CopyToClipboard,
+    ) {
+        let cfg = self.cfg();
+
+        // The options we'll use for all formatting. We'll just override the
+        // emit format.
+        let codepoint_map: Vec<formatter::CodepointMap> = cfg
+            .clipboard_codepoint_map
+            .map
+            .list
+            .iter()
+            .map(|e| formatter::CodepointMap {
+                range: e.range,
+                replacement: match &e.replacement {
+                    ghostty_config::clipboard_codepoint_map::Replacement::Codepoint(c) => {
+                        formatter::Replacement::Codepoint(*c)
+                    }
+                    ghostty_config::clipboard_codepoint_map::Replacement::String(s) => {
+                        formatter::Replacement::String(s.clone())
+                    }
+                },
+            })
+            .collect();
+        let opts = formatter::Options {
+            emit: Format::Plain, // We'll override this below
+            unwrap: true,
+            trim: cfg.clipboard_trim_trailing_spaces,
+            codepoint_map: Some(codepoint_map),
+            background: t.colors.background.get(),
+            foreground: t.colors.foreground.get(),
+            palette: Some(t.colors.palette.current),
+        };
+
+        let run = |opts: formatter::Options| -> Option<String> {
+            let mut f = ScreenFormatter::new(t.screen(), opts);
+            f.content = formatter::Content::Selection(Some(sel));
+            match f.format_string() {
+                Ok(s) => Some(s),
+                Err(err) => {
+                    log::error!("error formatting selection for clipboard err={err:?}");
+                    None
+                }
+            }
+        };
+
+        let mut contents: Vec<(String, String)> = Vec::new();
+        match format {
+            CopyToClipboard::Plain => {
+                let Some(s) = run(opts) else { return };
+                contents.push(("text/plain".to_owned(), s));
+            }
+
+            CopyToClipboard::Vt => {
+                let mut o = opts;
+                o.emit = Format::Vt;
+                // Note: We don't apply codepoint mappings to VT format since
+                // it contains escape sequences that should be preserved
+                // as-is
+                let Some(s) = run(o) else { return };
+                contents.push(("text/plain".to_owned(), s));
+            }
+
+            CopyToClipboard::Html => {
+                let mut o = opts;
+                o.emit = Format::Html;
+                // Note: We don't apply codepoint mappings to HTML format
+                // since HTML has its own character encoding and entity
+                // system
+                let Some(s) = run(o) else { return };
+                contents.push(("text/html".to_owned(), s));
+            }
+
+            CopyToClipboard::Mixed => {
+                // First, generate plain text with codepoint mappings applied
+                let Some(plain) = run(opts.clone()) else {
+                    return;
+                };
+                contents.push(("text/plain".to_owned(), plain));
+
+                // Second, generate HTML without codepoint mappings
+                let mut o = opts;
+                o.emit = Format::Html;
+                // We purposely don't emit background/foreground for mixed
+                // mode because the HTML contents is often used for rich text
+                // input and with trimmed spaces it looks pretty bad.
+                o.background = None;
+                o.foreground = None;
+                let Some(html) = run(o) else { return };
+                contents.push(("text/html".to_owned(), html));
+            }
+        }
+
+        for clipboard in clipboards {
+            self.rt_surface.set_clipboard(*clipboard, &contents, false);
+        }
+    }
+
+    /// Start a clipboard request, with some basic validation. For example,
+    /// an OSC 52 request is not actually requested if OSC 52 is disabled.
+    ///
+    /// Returns true if the request was started, false if it was not (e.g.,
+    /// clipboard doesn't contain text for paste requests). This allows
+    /// performable keybinds to pass through when the action cannot be
+    /// performed.
+    pub(crate) fn start_clipboard_request(&self, loc: Clipboard, req: ClipboardRequest) -> bool {
+        match req {
+            ClipboardRequest::Paste => {} // always allowed
+            ClipboardRequest::Osc52Read(_) => {
+                if self.cfg().clipboard_read == ClipboardAccess::Deny {
+                    log::info!(
+                        "application attempted to read clipboard, but 'clipboard-read' is set to deny"
+                    );
+                    return false;
+                }
+            }
+
+            // No clipboard write code paths travel through this function
+            ClipboardRequest::Osc52Write(_) => unreachable!(),
+        }
+
+        self.rt_surface.clipboard_request(loc, req)
+    }
+
+    /// The runtime answers a clipboard request (Zig:
+    /// `completeClipboardRequest`).
+    pub fn complete_clipboard_request(
+        &self,
+        req: ClipboardRequest,
+        data: &str,
+        confirmed: bool,
+    ) -> Result<(), ClipboardError> {
+        match req {
+            ClipboardRequest::Paste => self.complete_clipboard_paste(data.as_bytes(), confirmed),
+
+            ClipboardRequest::Osc52Read(clipboard) => {
+                self.complete_clipboard_read_osc52(data.as_bytes(), clipboard, confirmed)
+            }
+
+            ClipboardRequest::Osc52Write(clipboard) => {
+                self.rt_surface.set_clipboard(
+                    clipboard,
+                    &[("text/plain".to_owned(), data.to_owned())],
+                    !confirmed,
+                );
+                Ok(())
+            }
+        }
+    }
+
+    /// Paste text (also the target of `text_callback`).
+    pub(crate) fn complete_clipboard_paste(
+        &self,
+        data: &[u8],
+        allow_unsafe: bool,
+    ) -> Result<(), ClipboardError> {
+        if data.is_empty() {
+            return Ok(());
+        }
+
+        let cfg = self.cfg();
+        let encode_opts = {
+            let mut t = self.lock_terminal();
+            let opts = paste_options_from_terminal(&t);
+
+            // If we have paste protection enabled, we detect unsafe pastes
+            // and return an error. The error approach allows apprt to
+            // attempt to complete the paste before falling back to
+            // requesting confirmation.
+            //
+            // We do not do this for bracketed pastes because bracketed
+            // pastes are by definition safe since they're framed.
+            let unsafe_paste = 'unsafe_paste: {
+                // If we've disabled paste protection then we always allow
+                // the paste.
+                if !cfg.clipboard_paste_protection {
+                    break 'unsafe_paste false;
+                }
+
+                // If we're allowed to paste unsafe data then we always allow
+                // the paste. This is set during confirmation usually.
+                if allow_unsafe {
+                    break 'unsafe_paste false;
+                }
+
+                if opts.bracketed {
+                    // If we're bracketed and the paste contains and ending
+                    // bracket then something naughty might be going on and
+                    // we never trust it.
+                    if data.windows(6).any(|w| w == b"\x1b[201~") {
+                        break 'unsafe_paste true;
+                    }
+
+                    // If we are bracketed and configured to trust that then
+                    // the paste is not unsafe.
+                    if cfg.clipboard_paste_bracketed_safe {
+                        break 'unsafe_paste false;
+                    }
+                }
+
+                !paste::is_safe(data)
+            };
+
+            if unsafe_paste {
+                log::info!("potentially unsafe paste detected, rejecting until confirmation");
+                return Err(ClipboardError::UnsafePaste);
+            }
+
+            // With the lock held, we must scroll to the bottom. We always
+            // scroll to the bottom for these inputs.
+            self.scroll_to_bottom(&mut t);
+
+            opts
+        };
+
+        // Encode the data. In most cases this doesn't require any copies,
+        // so we optimize for that case.
+        let mut data_duped: Vec<u8>;
+        let vecs = match paste::encode(data, encode_opts) {
+            Ok(v) => v,
+            Err(paste::Error::MutableRequired) => {
+                data_duped = data.to_vec();
+                paste::encode_mut(&mut data_duped, encode_opts)
+            }
+        };
+
+        for vec in vecs {
+            if !vec.is_empty() {
+                self.queue_io(IoMessage::write_req(vec));
+            }
+        }
+        Ok(())
+    }
+
+    fn complete_clipboard_read_osc52(
+        &self,
+        data: &[u8],
+        clipboard_type: Clipboard,
+        confirmed: bool,
+    ) -> Result<(), ClipboardError> {
+        let cfg = self.cfg();
+
+        // We should never get here if clipboard-read is set to deny
+        debug_assert_ne!(cfg.clipboard_read, ClipboardAccess::Deny);
+
+        // If clipboard-read is set to ask and we haven't confirmed with the
+        // user, do that now
+        if cfg.clipboard_read == ClipboardAccess::Ask && !confirmed {
+            return Err(ClipboardError::UnauthorizedPaste);
+        }
+
+        // Even if the clipboard data is empty we reply, since presumably the
+        // client app is expecting a reply.
+        let kind = match clipboard_type {
+            Clipboard::Standard => 'c',
+            Clipboard::Selection => 's',
+            Clipboard::Primary => 'p',
+        };
+
+        // Wrap our data with the OSC code
+        let mut buf = format!("\x1b]52;{kind};").into_bytes();
+        buf.extend_from_slice(STANDARD.encode(data).as_bytes());
+        buf.extend_from_slice(b"\x1b\\");
+
+        self.queue_io(IoMessage::write_req(&buf));
+        Ok(())
+    }
+
+    /// Set `clipboard-read` / `clipboard-write` to a fixed value for this
+    /// surface (the runtime calls this after the user chose "remember").
+    pub(crate) fn set_config_clipboard(&self, read: bool, access: ClipboardAccess) {
+        let mut config = (*self.cfg().config).clone();
+        if read {
+            config.clipboard_read = access;
+        } else {
+            config.clipboard_write = access;
+        }
+        match DerivedConfig::new(Arc::new(config)) {
+            Ok(d) => *self.config.borrow_mut() = Rc::new(d),
+            Err(err) => log::warn!("failed to update clipboard access err={err}"),
+        }
+    }
+
+    /// Show a desktop notification, rate limited (Zig
+    /// `showDesktopNotification`).
+    pub(crate) fn show_desktop_notification(&self, title: &str, body: &str) {
+        let now = Instant::now();
+
+        // Set a limit of one desktop notification per second so that the OS
+        // doesn't kill us when we run out of resources.
+        let last = self.app.last_notification_time.get();
+        if let Some(last) = last
+            && now.duration_since(last) < Duration::from_secs(1)
+        {
+            log::warn!("rate limiting desktop notifications");
+            return;
+        }
+
+        let new_digest = {
+            let mut hash = std::collections::hash_map::DefaultHasher::new();
+            title.hash(&mut hash);
+            body.hash(&mut hash);
+            hash.finish()
+        };
+
+        // Set a limit of one notification per five seconds for desktop
+        // notifications with identical content.
+        if let Some(last) = last
+            && self.app.last_notification_digest.get() == new_digest
+            && now.duration_since(last) < Duration::from_secs(5)
+        {
+            log::warn!("suppressing identical desktop notification");
+            return;
+        }
+
+        self.app.last_notification_time.set(Some(now));
+        self.app.last_notification_digest.set(new_digest);
+        self.perform(RtAction::DesktopNotification(DesktopNotification {
+            title: title.to_owned(),
+            body: body.to_owned(),
+        }));
+    }
+
+    /// `textCallback`: text input that is pasted verbatim.
+    pub fn text_callback(&self, text: &str) -> Result<(), ClipboardError> {
+        self.complete_clipboard_paste(text.as_bytes(), true)
+    }
+}

crates/ghostty-core/src/surface/config.rs

@@ -0,0 +1,87 @@
+//! The configuration a surface has (Zig: `Surface.DerivedConfig`).
+//!
+//! Zig copies a subset of the main config so no pointer to it needs to stay
+//! alive. In Rust the whole (conditional-state-applied) [`Config`] is kept
+//! behind an `Arc`, which is the same thing, and `DerivedConfig` derefs to
+//! it so the fields keep their Zig names (`cfg.copy_on_select`, ...). The
+//! few values that are *computed* in Zig live as fields of this struct.
+
+use std::ops::Deref;
+use std::sync::Arc;
+
+use ghostty_config::config::Config;
+use ghostty_input::link::{Action as LinkAction, Highlight};
+use onig::Regex;
+
+use ghostty_renderer::size::Padding;
+
+/// A link with its compiled regex (Zig: `DerivedConfig.Link`).
+pub struct Link {
+    pub regex: Regex,
+    pub action: LinkAction,
+    pub highlight: Highlight,
+}
+
+/// See the module docs.
+pub struct DerivedConfig {
+    /// The config this was derived from (conditional state already applied).
+    pub config: Arc<Config>,
+
+    /// `font-size`.
+    pub original_font_size: f32,
+
+    /// `click-repeat-interval` in nanoseconds (the config is in ms).
+    pub mouse_interval: u64,
+
+    /// `abnormal-command-exit-runtime` (ms).
+    pub abnormal_command_exit_runtime_ms: u32,
+
+    /// `selection-word-chars` codepoints.
+    pub selection_word_chars: Vec<u32>,
+
+    /// The compiled `link` entries.
+    pub links: Vec<Link>,
+}
+
+impl Deref for DerivedConfig {
+    type Target = Config;
+    fn deref(&self) -> &Config {
+        &self.config
+    }
+}
+
+impl DerivedConfig {
+    /// Derive the surface configuration. Fails if a link regex is invalid.
+    pub fn new(config: Arc<Config>) -> Result<DerivedConfig, onig::Error> {
+        // Build all of our links
+        let mut links = Vec::with_capacity(config.link.links.len());
+        for link in &config.link.links {
+            links.push(Link {
+                regex: Regex::new(&link.regex)?,
+                action: link.action,
+                highlight: link.highlight,
+            });
+        }
+
+        Ok(DerivedConfig {
+            original_font_size: config.font_size,
+            mouse_interval: u64::from(config.click_repeat_interval) * 1_000_000, // 500ms
+            abnormal_command_exit_runtime_ms: config.abnormal_command_exit_runtime,
+            selection_word_chars: config.selection_word_chars.codepoints.clone(),
+            links,
+            config,
+        })
+    }
+
+    /// Padding scaled by the DPI (Zig: `scaledPadding`).
+    #[must_use]
+    pub fn scaled_padding(&self, x_dpi: f32, y_dpi: f32) -> Padding {
+        let scale = |v: u32, dpi: f32| -> u32 { (v as f32 * dpi / 72.0).floor() as u32 };
+        Padding {
+            top: scale(self.window_padding_y.top_left, y_dpi),
+            bottom: scale(self.window_padding_y.bottom_right, y_dpi),
+            left: scale(self.window_padding_x.top_left, x_dpi),
+            right: scale(self.window_padding_x.bottom_right, x_dpi),
+        }
+    }
+}

crates/ghostty-core/src/surface/keyboard.rs

@@ -0,0 +1,1138 @@
+//! Keyboard input for a surface (Zig `Surface.zig`: `keyEventIsBinding`,
+//! `keyCallback`, `maybeHandleBinding`, key sequences/tables, `encodeKey`,
+//! the key-table binding actions and the key release on focus loss).
+//!
+//! # Deviations from Zig
+//!
+//! Zig keeps raw pointers into the config (`*const Binding.Set`) for the
+//! current sequence and the key table stack. Here the sequence is stored as
+//! a *path* (where it started plus the triggers pressed so far) and tables
+//! are stored by name; both are resolved against the current config each
+//! time. A config change drops them anyway (`update_config` calls
+//! [`Surface::end_key_sequence`] and [`Surface::deactivate_all_key_tables`]).
+
+use ghostty_apprt::action::{Action as RtAction, KeySequence, KeyTable};
+use ghostty_apprt::runtime_api::{CoreError, InputEffect};
+use ghostty_input::binding::set::Value;
+use ghostty_input::binding::{Action as BindingAction, Flags, Scope, Set, Trigger, TriggerKey};
+use ghostty_input::key_encode;
+use ghostty_input::{Action as KeyAction, Key, KeyEvent, Mods};
+use ghostty_terminal::terminal::{MouseEvents, ScrollViewport, Terminal};
+use ghostty_termio::message::Message as IoMessage;
+use ghostty_vt::modes::Mode;
+use ghostty_vt::mouse_shape::MouseShape;
+
+use super::Surface;
+use super::config::DerivedConfig;
+
+/// The maximum number of key tables that can be active at any given time.
+/// `activate_key_table` calls after this are ignored.
+pub const MAX_ACTIVE_KEY_TABLES: usize = 8;
+
+/// Where a sequence (or a lookup) is rooted.
+#[derive(Debug, Clone, PartialEq, Eq)]
+pub enum SetRoot {
+    /// The root keybinding set.
+    Root,
+    /// A named key table.
+    Table(String),
+}
+
+/// The currently active key sequence: the set it started in plus the
+/// triggers (leader keys) pressed so far.
+#[derive(Debug, Clone, PartialEq)]
+pub struct SequencePath {
+    pub root: SetRoot,
+    pub path: Vec<Trigger>,
+}
+
+/// An entry of the key table stack.
+#[derive(Debug, Clone, PartialEq, Eq)]
+pub struct TableEntry {
+    pub name: String,
+    pub once: bool,
+}
+
+/// Keyboard state for the surface (Zig: `Surface.Keyboard`).
+#[derive(Default)]
+pub struct Keyboard {
+    /// The currently active key sequence for the surface. If this is `None`
+    /// then we're not currently in a key sequence.
+    pub sequence: Option<SequencePath>,
+
+    /// The queued keys when we're in the middle of a sequenced binding.
+    /// These are flushed when the sequence is completed and unconsumed or
+    /// invalid. Naturally bounded by the configuration maximum sequence
+    /// length.
+    pub sequence_queued: Vec<IoMessage>,
+
+    /// The stack of tables that is currently active. The first value in this
+    /// is the first activated table (NOT the default keybinding set).
+    /// Bounded by [`MAX_ACTIVE_KEY_TABLES`].
+    pub table_stack: Vec<TableEntry>,
+
+    /// The hash value of the last keybinding trigger that we performed. Only
+    /// set if the last key input matched a keybinding, consumed it, and
+    /// performed it. Used to prevent sending release/repeat events for
+    /// handled bindings.
+    pub last_trigger: Option<u64>,
+}
+
+/// An owned copy of a [`KeyEvent`] (the `utf8` text is owned). Used for the
+/// "currently pressed key" so a release can be sent on focus loss.
+#[derive(Debug, Clone, PartialEq, Eq)]
+pub struct OwnedKeyEvent {
+    pub action: KeyAction,
+    pub key: Key,
+    pub mods: Mods,
+    pub consumed_mods: Mods,
+    pub composing: bool,
+    pub utf8: String,
+    pub unshifted_codepoint: u32,
+}
+
+impl Default for OwnedKeyEvent {
+    fn default() -> Self {
+        Self::from_event(&KeyEvent::default())
+    }
+}
+
+impl OwnedKeyEvent {
+    /// Copy an event.
+    #[must_use]
+    pub fn from_event(e: &KeyEvent<'_>) -> Self {
+        OwnedKeyEvent {
+            action: e.action,
+            key: e.key,
+            mods: e.mods,
+            consumed_mods: e.consumed_mods,
+            composing: e.composing,
+            utf8: e.utf8.to_owned(),
+            unshifted_codepoint: e.unshifted_codepoint,
+        }
+    }
+
+    /// Borrow as a [`KeyEvent`].
+    #[must_use]
+    pub fn as_event(&self) -> KeyEvent<'_> {
+        KeyEvent {
+            action: self.action,
+            key: self.key,
+            mods: self.mods,
+            consumed_mods: self.consumed_mods,
+            composing: self.composing,
+            utf8: &self.utf8,
+            unshifted_codepoint: self.unshifted_codepoint,
+        }
+    }
+}
+
+/// What to do with queued sequence inputs (Zig: `KeySequenceQueued`).
+#[derive(Debug, Clone, Copy, PartialEq, Eq)]
+pub enum SequenceAction {
+    Drop,
+    Flush,
+}
+
+/// Memory handling of the queue afterwards (Zig: `KeySequenceMemory`). Both
+/// release the queued entries in Rust; kept for parity with the Zig API.
+#[derive(Debug, Clone, Copy, PartialEq, Eq)]
+pub enum SequenceFree {
+    Free,
+    Retain,
+}
+
+/// `key_encode.Options.fromTerminal`. The macOS option-as-alt value can't be
+/// known from the terminal state.
+#[must_use]
+pub fn encode_options_from_terminal(t: &Terminal) -> key_encode::Options {
+    key_encode::Options {
+        alt_esc_prefix: t.modes.get(Mode::AltEscPrefix),
+        cursor_key_application: t.modes.get(Mode::CursorKeys),
+        keypad_key_application: t.modes.get(Mode::KeypadKeys),
+        ignore_keypad_with_numlock: t.modes.get(Mode::IgnoreKeypadWithNumlock),
+        modify_other_keys_state_2: t.flags.modify_other_keys_2,
+        kitty_flags: t.screens.active().kitty_keyboard.current(),
+        macos_option_as_alt: ghostty_input::OptionAsAlt::False,
+    }
+}
+
+/// Resolve a set by root (Zig pointer) against a config.
+fn root_set<'a>(cfg: &'a DerivedConfig, root: &SetRoot) -> Option<&'a Set> {
+    match root {
+        SetRoot::Root => Some(&cfg.keybind.set),
+        SetRoot::Table(name) => cfg
+            .keybind
+            .tables
+            .iter()
+            .find(|(n, _)| n == name)
+            .map(|(_, s)| s),
+    }
+}
+
+/// Resolve the set a sequence path points at.
+fn sequence_set<'a>(cfg: &'a DerivedConfig, seq: &SequencePath) -> Option<&'a Set> {
+    let mut set = root_set(cfg, &seq.root)?;
+    for trigger in &seq.path {
+        match set.get_entry(*trigger)?.1 {
+            Value::Leader(next) => set = next,
+            _ => return None,
+        }
+    }
+    Some(set)
+}
+
+/// What a lookup found, with everything borrowed copied out.
+enum Found {
+    /// A leader key: the new sequence path.
+    Leader(Trigger, SequencePath),
+    /// A leaf (possibly chained).
+    Leaf {
+        actions: Vec<BindingAction>,
+        flags: Flags,
+    },
+}
+
+fn found_from(trigger: Trigger, value: &Value, origin: SetRoot, parent_path: &[Trigger]) -> Found {
+    match value {
+        Value::Leader(_) => {
+            let mut path = parent_path.to_vec();
+            path.push(trigger);
+            Found::Leader(trigger, SequencePath { root: origin, path })
+        }
+        Value::Leaf(l) => Found::Leaf {
+            actions: vec![l.action.clone()],
+            flags: l.flags,
+        },
+        Value::LeafChained(l) => Found::Leaf {
+            actions: l.actions.clone(),
+            flags: l.flags,
+        },
+    }
+}
+
+/// `SurfaceMouse.keyToMouseShape` (surface_mouse.zig), needed for the
+/// cursor shape update when modifier keys change.
+fn key_to_mouse_shape(
+    physical_key: Key,
+    mouse_event: MouseEvents,
+    mods: Mods,
+    over_link: bool,
+    hidden: bool,
+) -> Option<MouseShape> {
+    let eligible = physical_key.ctrl_or_super()
+        || physical_key.left_or_right_shift()
+        || physical_key.left_or_right_alt();
+    if !eligible {
+        return None;
+    }
+
+    // Link hover or hidden state overrides any other shape processing.
+    if over_link || hidden {
+        return None;
+    }
+
+    let rect_select = mods.ctrl_or_super() && mods.alt;
+    if mouse_event == MouseEvents::None {
+        // Default terminal mode: text
+        Some(if rect_select {
+            MouseShape::Crosshair
+        } else {
+            MouseShape::Text
+        })
+    } else if mods.shift && rect_select {
+        // Mouse tracking mode, overriding with shift + rectangle select.
+        Some(MouseShape::Crosshair)
+    } else if mods.shift {
+        Some(MouseShape::Text)
+    } else {
+        Some(MouseShape::Default)
+    }
+}
+
+fn closing_action(action: &BindingAction) -> bool {
+    matches!(
+        action,
+        BindingAction::CloseSurface | BindingAction::CloseWindow | BindingAction::CloseTab(_)
+    )
+}
+
+impl Surface {
+    /// Apply key remappings (Zig: at the top of `keyEventIsBinding` and
+    /// `keyCallback`). Returns the event with remapped mods.
+    fn remap_event<'a>(cfg: &DerivedConfig, event: &KeyEvent<'a>) -> KeyEvent<'a> {
+        let mut event = event.clone();
+        if cfg.key_remap.is_remapped(event.mods) {
+            event.mods = cfg.key_remap.apply(event.mods);
+        }
+        event
+    }
+
+    /// Returns the flags of the binding the given key event would trigger,
+    /// if any. This is useful for determining if a key event should be sent
+    /// to the terminal or not.
+    ///
+    /// Note that this function does not check if the binding itself is
+    /// performable, only if the key event would trigger a binding.
+    pub fn key_event_is_binding(&self, event: &KeyEvent<'_>) -> Option<Flags> {
+        let cfg = self.cfg();
+
+        // Apply key remappings for consistency with key_callback
+        let event = Self::remap_event(&cfg, event);
+
+        match event.action {
+            KeyAction::Release => return None,
+            KeyAction::Press | KeyAction::Repeat => {}
+        }
+
+        let (seq, tables) = {
+            let kb = self.keyboard.borrow();
+            (kb.sequence.clone(), kb.table_stack.clone())
+        };
+
+        let value = 'entry: {
+            // If we're in a sequence, check the sequence set
+            if let Some(seq) = &seq {
+                let set = sequence_set(&cfg, seq)?;
+                break 'entry set.get_event(&event)?.1;
+            }
+
+            // Check active key tables (inner-most to outer-most)
+            for t in tables.iter().rev() {
+                if let Some(set) = root_set(&cfg, &SetRoot::Table(t.name.clone()))
+                    && let Some((_, v)) = set.get_event(&event)
+                {
+                    break 'entry v;
+                }
+            }
+
+            // Check the root set
+            cfg.keybind.set.get_event(&event)?.1
+        };
+
+        Some(match value {
+            Value::Leader(_) => Flags {
+                // Zig: `.{}` which are the struct defaults.
+                ..Flags::default()
+            },
+            Value::Leaf(l) => l.flags,
+            Value::LeafChained(l) => l.flags,
+        })
+    }
+
+    /// Called for any key events. This handles keybindings, encoding and
+    /// sending to the terminal, etc.
+    #[allow(clippy::needless_pass_by_value)]
+    pub fn key_callback(&self, event_orig: KeyEvent<'_>) -> Result<InputEffect, CoreError> {
+        let cfg = self.cfg();
+
+        // Apply key remappings to transform modifiers before any
+        // processing. This allows users to remap modifier keys at the app
+        // level.
+        let event = Self::remap_event(&cfg, &event_orig);
+
+        // Handle keybindings first. We need to handle this on all events
+        // (press, repeat, release) because a press may perform a binding but
+        // a release should not encode if we consumed the press.
+        if let Some(v) = self.maybe_handle_binding(&cfg, &event) {
+            return Ok(v);
+        }
+
+        // If we allow KAM and KAM is enabled then we do nothing.
+        if cfg.vt_kam_allowed && self.lock_terminal().modes.get(Mode::DisableKeyboard) {
+            return Ok(InputEffect::Consumed);
+        }
+
+        // If this input event has text, then we hide the mouse if
+        // configured. We only do this on pressed events to avoid hiding the
+        // mouse when we change focus due to a keybinding (i.e. switching
+        // tabs).
+        if cfg.mouse_hide_while_typing
+            && event.action == KeyAction::Press
+            && !self.mouse.borrow().hidden
+            && !event.utf8.is_empty()
+        {
+            self.hide_mouse();
+        }
+
+        // If our mouse modifiers change we may need to change our link
+        // highlight state.
+        let mouse_mods = self.mouse.borrow().mods;
+        if !mouse_mods.equal(event.mods) {
+            self.refresh_mouse_for_mods_change(&event);
+        }
+
+        // Process the cursor state logic. This will update the cursor shape
+        // if needed, depending on the key state.
+        let shape = {
+            let mouse_event = self.lock_terminal().flags.mouse_event;
+            let m = self.mouse.borrow();
+            key_to_mouse_shape(event.key, mouse_event, m.mods, m.over_link, m.hidden)
+        };
+        if let Some(shape) = shape {
+            self.perform(RtAction::MouseShape(shape));
+        }
+
+        // We've processed a key event that produced some data so we want to
+        // track the last pressed key.
+        {
+            let mut pressed = self.pressed_key.borrow_mut();
+            let prev = pressed.take();
+            *pressed = 'event: {
+                // We need to unset the allocated fields that will become
+                // invalid
+                let mut copy = OwnedKeyEvent::from_event(&event);
+                copy.utf8.clear();
+
+                // If we have a previous pressed key and we're releasing it
+                // then we set it to invalid to prevent repeating the
+                // release event.
+                if event.action == KeyAction::Release {
+                    // if we didn't have a previous event and this is a
+                    // release event then we just want to set it to null.
+                    let Some(prev) = prev else {
+                        break 'event None;
+                    };
+                    if prev.key == copy.key {
+                        copy.key = Key::Unidentified;
+                    }
+                }
+
+                // If our key is invalid and we have no mods, then we're
+                // done! This helps catch the state that we naturally
+                // released all keys.
+                if copy.key == Key::Unidentified && copy.mods.empty() {
+                    break 'event None;
+                }
+
+                Some(copy)
+            };
+        }
+
+        // Encode and send our key. If we didn't encode anything, then we
+        // return the effect as ignored.
+        let Some(write_req) = self.encode_key(&event) else {
+            // No valid request means that we didn't encode anything.
+            return Ok(InputEffect::Ignored);
+        };
+
+        // If our process is exited and we press a key that results in an
+        // encoded value, we close the surface. We want to eventually move
+        // this behavior to the apprt probably.
+        if self.child_exited.get() {
+            self.close();
+            return Ok(InputEffect::Closed);
+        }
+
+        self.queue_io(write_req);
+
+        // If our event is any keypress that isn't a modifier and we
+        // generated some data to send to the pty, then we move the viewport
+        // down to the bottom. We also clear the selection for any key other
+        // then modifiers.
+        if !event.key.modifier() {
+            {
+                let mut t = self.lock_terminal();
+                if cfg.selection_clear_on_typing || event.key == Key::Escape {
+                    let _ = self.set_selection(&mut t, None);
+                }
+
+                if cfg.scroll_to_bottom.keystroke {
+                    t.scroll_viewport(ScrollViewport::Bottom);
+                }
+            }
+            self.queue_render();
+        }
+
+        Ok(InputEffect::Consumed)
+    }
+
+    /// The modifier-change block of `keyCallback` (`mouse_mods` label).
+    fn refresh_mouse_for_mods_change(&self, event: &KeyEvent<'_>) {
+        // Update our modifiers, this will update mouse mods too
+        self.mods_changed(event.mods);
+
+        let (mouse_event, mouse_shape) = {
+            let t = self.lock_terminal();
+            (t.flags.mouse_event, t.mouse_shape)
+        };
+        let shift = self.mouse.borrow().mods.shift;
+
+        // We only refresh links if
+        // 1. mouse reporting is off
+        // OR
+        // 2. mouse reporting is on and we are not reporting shift to the
+        //    terminal
+        if mouse_event == MouseEvents::None
+            || (shift && !self.mouse_shift_capture(&self.lock_terminal()))
+        {
+            // Refresh our link state
+            let pos = self.rt_surface.get_cursor_pos();
+            let over_link = self.mouse.borrow().over_link;
+            let vp = self.pos_to_viewport(f64::from(pos.x), f64::from(pos.y));
+            if let Err(err) = self.mouse_refresh_links(pos, vp, over_link) {
+                log::warn!("failed to refresh links err={err}");
+            }
+        } else if mouse_event != MouseEvents::None && !shift {
+            // If we have mouse reports on and we don't have shift pressed,
+            // we reset state
+            self.perform(RtAction::MouseShape(mouse_shape));
+            self.perform(RtAction::MouseOverLink(
+                ghostty_apprt::action::MouseOverLink { url: String::new() },
+            ));
+            self.queue_render();
+        }
+    }
+
+    /// Maybe handles a binding for a given event and if so returns the
+    /// effect. Returns `None` if the event is not handled in any way and
+    /// processing should continue.
+    fn maybe_handle_binding(
+        &self,
+        cfg: &DerivedConfig,
+        event: &KeyEvent<'_>,
+    ) -> Option<InputEffect> {
+        match event.action {
+            // Release events never trigger a binding but we need to check
+            // if we consumed the press event so we don't encode the
+            // release.
+            KeyAction::Release => {
+                if let Some(last) = self.keyboard.borrow().last_trigger
+                    && last == event.binding_hash()
+                {
+                    // We don't reset the last trigger on release because an
+                    // apprt may send multiple release events for a single
+                    // press event.
+                    return Some(InputEffect::Consumed);
+                }
+
+                return None;
+            }
+
+            // Carry on processing.
+            KeyAction::Press | KeyAction::Repeat => {}
+        }
+
+        let (seq, tables) = {
+            let kb = self.keyboard.borrow();
+            (kb.sequence.clone(), kb.table_stack.clone())
+        };
+
+        // Find an entry in the keybind set that matches our event.
+        let found = 'entry: {
+            // Handle key sequences first.
+            if let Some(seq) = &seq {
+                // Get our entry from the set for the given event.
+                if let Some(set) = sequence_set(cfg, seq)
+                    && let Some((t, v)) = set.get_event(event)
+                {
+                    break 'entry found_from(*t, v, seq.root.clone(), &seq.path);
+                }
+
+                // No entry found. We need to encode everything up to this
+                // point and send to the pty since we're in a sequence.
+
+                // We ignore modifiers so that nested sequences such as
+                // ctrl+a>ctrl+b>c work.
+                if event.key.modifier() {
+                    return None;
+                }
+
+                // If we have a catch-all of ignore, then we special case
+                // our invalid sequence handling to ignore it.
+                if self.catch_all_is_ignore(cfg) {
+                    self.end_key_sequence(SequenceAction::Drop, SequenceFree::Retain);
+                    return Some(InputEffect::Ignored);
+                }
+
+                // Encode everything up to this point
+                self.end_key_sequence(SequenceAction::Flush, SequenceFree::Retain);
+
+                return None;
+            }
+
+            // No currently active sequence, move on to tables. For tables,
+            // we search inner-most table to outer-most. The table stack
+            // does NOT include the root set.
+            for (i, table) in tables.iter().rev().enumerate() {
+                let root = SetRoot::Table(table.name.clone());
+                if let Some(set) = root_set(cfg, &root)
+                    && let Some((t, v)) = set.get_event(event)
+                {
+                    // If this is a one-shot activation AND its the
+                    // currently active table, then we deactivate it after
+                    // this. Note: we may want to change the semantics here
+                    // to remove this table no matter where it is in the
+                    // stack, maybe.
+                    let f = found_from(*t, v, root, &[]);
+                    if table.once && i == 0 {
+                        self.deactivate_key_table();
+                    }
+                    break 'entry f;
+                }
+            }
+
+            // No table, use our default set
+            let (t, v) = cfg.keybind.set.get_event(event)?;
+            found_from(*t, v, SetRoot::Root, &[])
+        };
+
+        // Determine if this entry has an action or if its a leader key.
+        let (actions, flags) = match found {
+            Found::Leader(trigger, path) => {
+                // Setup the next set we'll look at.
+                self.keyboard.borrow_mut().sequence = Some(path);
+
+                // Store this event so that we can drain and encode on
+                // invalid. We don't need to cap this because it is
+                // naturally capped by the config validation.
+                if let Some(req) = self.encode_key(event) {
+                    self.keyboard.borrow_mut().sequence_queued.push(req);
+                }
+
+                // Start or continue our key sequence
+                self.perform(RtAction::KeySequence(KeySequence::Trigger(trigger)));
+
+                return Some(InputEffect::Consumed);
+            }
+            Found::Leaf { actions, flags } => (actions, flags),
+        };
+
+        // consumed determines if the input is consumed or if we continue
+        // encoding the key (if we have a key to encode).
+        //
+        // If the consumed flag is explicitly set, then we are consumed. If
+        // the global or all flag is set, we always consume.
+        let consumed = flags.consumed || flags.global || flags.all;
+
+        // We have an action, so at this point we're handling SOMETHING so we
+        // reset the last trigger to null. We only set this if we actually
+        // perform an action (below). An action also always resets the
+        // sequence set.
+        {
+            let mut kb = self.keyboard.borrow_mut();
+            kb.last_trigger = None;
+            kb.sequence = None;
+        }
+
+        // Attempt to perform the action
+        log::debug!("key event binding flags={flags:?} action={actions:?}");
+        let performed = 'performed: {
+            // If this is a global or all action, then we perform it on the
+            // app and it applies to every surface.
+            if flags.global || flags.all {
+                self.perform_all_chained_action(&actions);
+
+                // "All" actions are always performed since they are global.
+                break 'performed true;
+            }
+
+            // Perform each action. We are performed if ANY of the chained
+            // actions perform.
+            let mut performed = false;
+            for action in &actions {
+                match self.perform_binding_action(action) {
+                    Ok(v) => performed = performed || v,
+                    Err(err) => log::info!(
+                        "key binding action failed action={} err={err}",
+                        action.key().name()
+                    ),
+                }
+            }
+
+            performed
+        };
+
+        if performed {
+            // If we performed an action and it was a closing action, our
+            // "self" is not safe to use anymore so we need to just exit
+            // immediately.
+            if actions.iter().any(closing_action) {
+                log::debug!("key binding is a closing binding, halting key event processing");
+                return Some(InputEffect::Closed);
+            }
+
+            // If our action was "ignore" then we return the special input
+            // effect of "ignored".
+            if actions.iter().any(|a| matches!(a, BindingAction::Ignore)) {
+                // If we're in a sequence, clear it.
+                self.end_key_sequence(SequenceAction::Drop, SequenceFree::Retain);
+
+                return Some(InputEffect::Ignored);
+            }
+        }
+
+        // If we have the performable flag and the action was not performed,
+        // then we act as though a binding didn't exist.
+        if flags.performable && !performed {
+            // If we're in a sequence, we treat this as if we pressed a key
+            // that doesn't exist in the sequence. Reset our sequence and
+            // flush any queued events.
+            self.end_key_sequence(SequenceAction::Flush, SequenceFree::Retain);
+
+            return None;
+        }
+
+        // If we consume this event, then we are done. If we don't consume
+        // it, we processed the action but we still want to process our
+        // encodings, too.
+        if consumed {
+            // If we had queued events, we deinit them since we consumed
+            self.end_key_sequence(SequenceAction::Drop, SequenceFree::Retain);
+
+            // Store our last trigger so we don't encode the release event
+            self.keyboard.borrow_mut().last_trigger = Some(event.binding_hash());
+
+            return Some(InputEffect::Consumed);
+        }
+
+        // If we didn't perform OR we didn't consume, then we want to encode
+        // any queued events for a sequence.
+        self.end_key_sequence(SequenceAction::Flush, SequenceFree::Retain);
+
+        None
+    }
+
+    /// Perform actions on the app and every surface (Zig:
+    /// `App.performAllChainedAction`; reimplemented here because the app
+    /// handle isn't reachable from a surface).
+    fn perform_all_chained_action(&self, actions: &[BindingAction]) {
+        for action in actions {
+            match action.scope() {
+                Scope::App => self.perform_app_action(action),
+                Scope::Surface => {
+                    for surface in self.app.surfaces() {
+                        if let Err(err) = surface.perform_binding_action(action) {
+                            log::warn!(
+                                "error performing chained action action={} err={err}",
+                                action.key().name()
+                            );
+                        }
+                    }
+                }
+            }
+        }
+    }
+
+    /// `App.performAction` for app-scoped binding actions.
+    fn perform_app_action(&self, action: &BindingAction) {
+        use ghostty_apprt::action::{ReloadConfig, Target};
+        let rt = match action {
+            BindingAction::Quit => RtAction::Quit,
+            BindingAction::NewWindow => RtAction::NewWindow,
+            BindingAction::OpenConfig => RtAction::OpenConfig,
+            BindingAction::ReloadConfig => RtAction::ReloadConfig(ReloadConfig::default()),
+            BindingAction::CloseAllWindows => RtAction::CloseAllWindows,
+            BindingAction::ToggleQuickTerminal => RtAction::ToggleQuickTerminal,
+            BindingAction::ToggleVisibility => RtAction::ToggleVisibility,
+            BindingAction::CheckForUpdates => RtAction::CheckForUpdates,
+            BindingAction::ShowGtkInspector => RtAction::ShowGtkInspector,
+            BindingAction::Undo => RtAction::Undo,
+            BindingAction::Redo => RtAction::Redo,
+            _ => return,
+        };
+        let target = if matches!(rt, RtAction::NewWindow) {
+            Target::Surface(self.id)
+        } else {
+            Target::App
+        };
+        self.rt_app.perform_action(target, rt);
+    }
+
+    /// Deactivate every key table. Returns whether any was active.
+    pub(crate) fn deactivate_all_key_tables(&self) -> bool {
+        {
+            let mut kb = self.keyboard.borrow_mut();
+            // No key table active. This does nothing.
+            if kb.table_stack.is_empty() {
+                return false;
+            }
+
+            // Clear the entire table stack.
+            kb.table_stack.clear();
+        }
+
+        // Notify the UI.
+        self.perform(RtAction::KeyTable(KeyTable::DeactivateAll));
+        true
+    }
+
+    /// Activate a key table by name (Zig: `activate_key_table[_once]`).
+    /// Returns whether the table was activated.
+    #[allow(dead_code, clippy::unnecessary_wraps)] // used by the binding-actions module
+    pub(crate) fn activate_key_table(&self, name: &str, once: bool) -> Result<bool, CoreError> {
+        let cfg = self.cfg();
+
+        // Look up the table in our config
+        if root_set(&cfg, &SetRoot::Table(name.to_owned())).is_none() {
+            log::debug!("key table not found: {name}");
+            return Ok(false);
+        }
+
+        {
+            let mut kb = self.keyboard.borrow_mut();
+
+            // If this is the same table as is currently active, then do
+            // nothing.
+            if kb.table_stack.last().is_some_and(|t| t.name == name) {
+                log::debug!("ignoring duplicate activate table: {name}");
+                return Ok(false);
+            }
+
+            // If we're already at the max, ignore it.
+            if kb.table_stack.len() >= MAX_ACTIVE_KEY_TABLES {
+                log::info!("ignoring activate table, max depth reached: {name}");
+                return Ok(false);
+            }
+
+            // Add the table to the stack.
+            kb.table_stack.push(TableEntry {
+                name: name.to_owned(),
+                once,
+            });
+        }
+
+        // Notify the UI.
+        self.perform(RtAction::KeyTable(KeyTable::Activate(name.to_owned())));
+
+        log::debug!("key table activated: {name}");
+        Ok(true)
+    }
+
+    /// Deactivate the inner-most key table (Zig: `deactivate_key_table`).
+    /// Returns whether a table was active.
+    pub(crate) fn deactivate_key_table(&self) -> bool {
+        {
+            let mut kb = self.keyboard.borrow_mut();
+            // No key table active. This does nothing.
+            if kb.table_stack.pop().is_none() {
+                return false;
+            }
+        }
+
+        // Notify the UI.
+        self.perform(RtAction::KeyTable(KeyTable::Deactivate));
+        true
+    }
+
+    /// This checks if the current keybinding sets have a catch_all binding
+    /// with `ignore`. This is used to determine some special input cases.
+    fn catch_all_is_ignore(&self, cfg: &DerivedConfig) -> bool {
+        let trigger = Trigger {
+            key: TriggerKey::CatchAll,
+            mods: Mods::default(),
+        };
+
+        let tables = self.keyboard.borrow().table_stack.clone();
+        let mut value = None;
+        for t in tables.iter().rev() {
+            if let Some(set) = root_set(cfg, &SetRoot::Table(t.name.clone()))
+                && let Some(v) = set.get(trigger)
+            {
+                value = Some(v);
+                break;
+            }
+        }
+        let Some(value) = value.or_else(|| cfg.keybind.set.get(trigger)) else {
+            return false;
+        };
+
+        // We have a catch-all entry, see if its an ignore
+        match value {
+            Value::Leader(_) => false,
+            Value::Leaf(l) => matches!(l.action, BindingAction::Ignore),
+            Value::LeafChained(l) => l.actions.iter().any(|a| matches!(a, BindingAction::Ignore)),
+        }
+    }
+
+    /// End a key sequence. Safe to call if no key sequence is active.
+    ///
+    /// `action` and `free` determine the behavior of the queued inputs up
+    /// to this point.
+    pub(crate) fn end_key_sequence(&self, action: SequenceAction, _free: SequenceFree) {
+        // Notify apprt key sequence ended
+        self.perform(RtAction::KeySequence(KeySequence::End));
+
+        // No matter what we clear our current sequence set. This restores
+        // the set we look at to the root set.
+        let queued = {
+            let mut kb = self.keyboard.borrow_mut();
+            kb.sequence = None;
+            std::mem::take(&mut kb.sequence_queued)
+        };
+
+        // If we have no queued data, there is nothing else to do. Run the
+        // proper action otherwise.
+        if action == SequenceAction::Flush {
+            for req in queued {
+                self.queue_io(req);
+            }
+        }
+    }
+
+    /// Encodes the key event into a write request. Returns `None` if
+    /// nothing was encoded.
+    fn encode_key(&self, event: &KeyEvent<'_>) -> Option<IoMessage> {
+        // Build our encoding options, which requires the lock.
+        let opts = {
+            let t = self.lock_terminal();
+            encode_options_from_terminal(&t)
+        };
+
+        let mut data: Vec<u8> = Vec::with_capacity(64);
+        if let Err(err) = key_encode::encode(&mut data, event, &opts) {
+            log::warn!("error encoding key event err={err}");
+            return None;
+        }
+
+        // Special-case: we did nothing.
+        if data.is_empty() {
+            return None;
+        }
+
+        Some(IoMessage::write_req(&data))
+    }
+
+    /// Called from `focus_callback` when focus is lost: if we have a
+    /// pressed key, send a key release event for it (and for all
+    /// modifiers). Depending on the apprt, this CAN result in duplicate key
+    /// release events, but that is better than not sending a key release
+    /// event at all.
+    pub(crate) fn release_pressed_key_on_unfocus(&self) {
+        let Some(mut pressed_key) = self.pressed_key.borrow_mut().take() else {
+            return;
+        };
+
+        // All our actions will be releases
+        pressed_key.action = KeyAction::Release;
+
+        // Release the full key first
+        if pressed_key.key != Key::Unidentified {
+            let ev = pressed_key.as_event();
+            match self.key_callback(ev) {
+                Ok(InputEffect::Closed) => return,
+                Ok(_) => {}
+                Err(err) => log::warn!("error releasing key on focus loss err={err}"),
+            }
+        }
+
+        // Release any modifiers if set
+        if pressed_key.mods.empty() {
+            return;
+        }
+
+        // Go through all the modifiers and if they're set, release both the
+        // left and right sides of the modifier. This may not match the exact
+        // input event but it ensures a full reset.
+        let original_key = pressed_key.key;
+        let release =
+            |pk: &mut OwnedKeyEvent, which: fn(&mut Mods) -> &mut bool, keys: [Key; 2]| {
+                if !*which(&mut pk.mods) {
+                    return true;
+                }
+                *which(&mut pk.mods) = false;
+                for key in keys {
+                    pk.key = key;
+                    if pk.key != original_key {
+                        let ev = pk.as_event();
+                        match self.key_callback(ev) {
+                            Ok(InputEffect::Closed) => return false,
+                            Ok(_) => {}
+                            Err(err) => log::warn!("error releasing key on focus loss err={err}"),
+                        }
+                    }
+                }
+                true
+            };
+        if !release(
+            &mut pressed_key,
+            |m| &mut m.shift,
+            [Key::ShiftRight, Key::ShiftLeft],
+        ) {
+            return;
+        }
+        if !release(
+            &mut pressed_key,
+            |m| &mut m.ctrl,
+            [Key::ControlRight, Key::ControlLeft],
+        ) {
+            return;
+        }
+        if !release(
+            &mut pressed_key,
+            |m| &mut m.alt,
+            [Key::AltRight, Key::AltLeft],
+        ) {
+            return;
+        }
+        release(
+            &mut pressed_key,
+            |m| &mut m.super_,
+            [Key::MetaRight, Key::MetaLeft],
+        );
+    }
+}
+
+#[cfg(test)]
+#[allow(clippy::unwrap_used)]
+mod tests {
+    use super::*;
+    use ghostty_config::cli_args::ConfigField;
+    use ghostty_config::config::Config;
+    use ghostty_terminal::terminal::Options;
+
+    fn cfg_with(binds: &[&str]) -> DerivedConfig {
+        let mut c = Config::default();
+        for b in binds {
+            c.keybind.parse_cli(Some(b)).unwrap();
+        }
+        DerivedConfig::new(std::sync::Arc::new(c)).unwrap()
+    }
+
+    #[test]
+    fn owned_key_event_round_trip() {
+        let e = KeyEvent {
+            action: KeyAction::Press,
+            key: Key::KeyA,
+            mods: Mods {
+                ctrl: true,
+                ..Mods::default()
+            },
+            utf8: "a",
+            unshifted_codepoint: 'a' as u32,
+            ..KeyEvent::default()
+        };
+        let o = OwnedKeyEvent::from_event(&e);
+        assert_eq!(o.as_event(), e);
+    }
+
+    #[test]
+    fn closing_actions() {
+        assert!(closing_action(&BindingAction::CloseSurface));
+        assert!(closing_action(&BindingAction::CloseWindow));
+        assert!(!closing_action(&BindingAction::Ignore));
+    }
+
+    #[test]
+    fn sequence_path_resolution() {
+        let cfg = cfg_with(&["ctrl+a>b=new_window", "ctrl+a>c>d=quit"]);
+        let a = Trigger {
+            key: TriggerKey::Unicode('a' as u32),
+            mods: Mods {
+                ctrl: true,
+                ..Mods::default()
+            },
+        };
+        let seq = SequencePath {
+            root: SetRoot::Root,
+            path: vec![a],
+        };
+        let set = sequence_set(&cfg, &seq).expect("leader set");
+        let b = Trigger {
+            key: TriggerKey::Unicode('b' as u32),
+            mods: Mods::default(),
+        };
+        assert!(matches!(set.get(b), Some(Value::Leaf(_))));
+        let c = Trigger {
+            key: TriggerKey::Unicode('c' as u32),
+            mods: Mods::default(),
+        };
+        let seq2 = SequencePath {
+            root: SetRoot::Root,
+            path: vec![a, c],
+        };
+        assert!(sequence_set(&cfg, &seq2).is_some());
+        // A path through a leaf is invalid
+        let seq3 = SequencePath {
+            root: SetRoot::Root,
+            path: vec![a, b],
+        };
+        assert!(sequence_set(&cfg, &seq3).is_none());
+    }
+
+    #[test]
+    fn root_set_tables() {
+        let cfg = cfg_with(&["foo/x=new_window"]);
+        assert!(root_set(&cfg, &SetRoot::Table("foo".into())).is_some());
+        assert!(root_set(&cfg, &SetRoot::Table("bar".into())).is_none());
+    }
+
+    #[test]
+    fn found_from_leader_extends_path() {
+        let cfg = cfg_with(&["ctrl+a>b=new_window"]);
+        let (t, v) = cfg
+            .keybind
+            .set
+            .bindings
+            .iter()
+            .find(|(_, v)| matches!(v, Value::Leader(_)))
+            .unwrap();
+        match found_from(t.0, v, SetRoot::Root, &[]) {
+            Found::Leader(_, p) => assert_eq!(p.path.len(), 1),
+            Found::Leaf { .. } => panic!("expected leader"),
+        }
+    }
+
+    #[test]
+    fn encode_options_follow_terminal_modes() {
+        let mut t = Terminal::new(Options::new(10, 5)).unwrap();
+        let o = encode_options_from_terminal(&t);
+        assert!(!o.cursor_key_application);
+        t.modes.set(Mode::CursorKeys, true);
+        t.modes.set(Mode::AltEscPrefix, false);
+        t.flags.modify_other_keys_2 = true;
+        let o = encode_options_from_terminal(&t);
+        assert!(o.cursor_key_application);
+        assert!(!o.alt_esc_prefix);
+        assert!(o.modify_other_keys_state_2);
+        assert_eq!(o.kitty_flags.int(), 0);
+    }
+
+    #[test]
+    fn mouse_shape_for_keys() {
+        let none = Mods::default();
+        // No specific key pressed
+        assert_eq!(
+            key_to_mouse_shape(Key::Unidentified, MouseEvents::None, none, false, false),
+            None
+        );
+        // Over a link
+        assert_eq!(
+            key_to_mouse_shape(Key::ShiftLeft, MouseEvents::None, none, true, false),
+            None
+        );
+        // Hidden
+        assert_eq!(
+            key_to_mouse_shape(Key::ShiftLeft, MouseEvents::None, none, false, true),
+            None
+        );
+        // Shift in mouse tracking mode -> text
+        let shift = Mods {
+            shift: true,
+            ..Mods::default()
+        };
+        assert_eq!(
+            key_to_mouse_shape(Key::ShiftLeft, MouseEvents::Normal, shift, false, false),
+            Some(MouseShape::Text)
+        );
+        // Released in tracking mode -> default
+        assert_eq!(
+            key_to_mouse_shape(Key::ShiftLeft, MouseEvents::Normal, none, false, false),
+            Some(MouseShape::Default)
+        );
+        // ctrl+alt in text mode -> crosshair
+        let ca = Mods {
+            ctrl: true,
+            alt: true,
+            ..Mods::default()
+        };
+        assert_eq!(
+            key_to_mouse_shape(Key::AltLeft, MouseEvents::None, ca, false, false),
+            Some(MouseShape::Crosshair)
+        );
+        assert_eq!(
+            key_to_mouse_shape(Key::AltLeft, MouseEvents::None, none, false, false),
+            Some(MouseShape::Text)
+        );
+    }
+}

crates/ghostty-core/src/surface/mod.rs

@@ -0,0 +1,1941 @@
+//! Surface represents a single terminal "surface" (port of `Surface.zig`).
+//!
+//! A terminal surface is a minimal "widget" where the terminal is drawn and
+//! responds to events such as keyboard and mouse. Each surface also creates
+//! and owns its pty session.
+//!
+//! The word "surface" is used because it is left to the higher level
+//! application runtime to determine if the surface is a window, a tab, a
+//! split, a preview pane in a larger window, etc. This struct doesn't care:
+//! it just draws and responds to events. The events come from the
+//! application runtime so the runtime can determine when and how those are
+//! delivered (i.e. with focus, without focus, and so on).
+//!
+//! # Structure
+//!
+//! The Zig file is split into several Rust modules that all add `impl
+//! Surface` blocks:
+//!
+//! * this file: the struct, creation/teardown (threads), the message
+//!   handler, config updates, sizing, fonts, focus, preedit, selection and
+//!   the [`CoreSurface`] implementation;
+//! * [`clipboard`]: OSC 52, paste (safety, bracketed), desktop notifications;
+//! * [`keyboard`]: key events, bindings, sequences, key tables, key encoding;
+//! * [`mouse`]: mouse buttons/motion/scroll, mouse reporting, selection by
+//!   mouse, links;
+//! * [`binding`]: `performBindingAction`, search, screen file dumps;
+//! * [`config`]: the derived configuration.
+//!
+//! # Threading and interior mutability
+//!
+//! Every method runs on the runtime's main thread. Other threads (renderer,
+//! IO, search) talk to the surface through the app [`Mailbox`]. Methods take
+//! `&self`; state lives in `Cell`/`RefCell`. **Never hold a `RefCell` borrow
+//! or the terminal lock across a call into the runtime** (`rt_app`,
+//! `rt_surface`): the runtime may call straight back into this surface.
+
+pub mod binding;
+pub mod clipboard;
+pub mod config;
+pub mod keyboard;
+pub mod mouse;
+
+use std::cell::{Cell, RefCell};
+use std::rc::Rc;
+use std::sync::Arc;
+use std::thread::JoinHandle;
+use std::time::{Duration as StdDuration, Instant};
+
+use ghostty_apprt::action::{
+    Action as RtAction, CellSize as ActionCellSize, ColorChange, ColorKind, CommandFinished,
+    ConfigChange, InitialSize, MouseVisibility, Pwd, ReloadConfig, SecureInput, SetTitle,
+    SizeLimit, Target,
+};
+use ghostty_apprt::runtime_api::{
+    ClipboardError, CoreError, CoreSurface, DesiredFontSize, InputEffect, RtApp, RtSurface,
+    SurfaceId,
+};
+use ghostty_apprt::structs::{
+    ClipboardRequest, ColorScheme, ContentScale, CursorPos, ImePos, SurfaceSize,
+};
+use ghostty_apprt::surface::{Mailbox as SurfaceMailboxImpl, Message};
+use ghostty_config::conditional;
+use ghostty_config::config::Config;
+use ghostty_config::types_a::ConfirmCloseSurface;
+use ghostty_datastruct::blocking_queue::Timeout;
+use ghostty_font::face::DesiredSize;
+use ghostty_font::metrics::Metrics;
+use ghostty_font::shared_grid_set::{DerivedConfig as FontDerivedConfig, Key as FontGridKey};
+use ghostty_input::{Mods, MouseButton, MouseButtonState, ScrollMods};
+use ghostty_renderer::generic::Host as RendererHost;
+use ghostty_renderer::message::{FontGridChange, Message as RendererMessage};
+use ghostty_renderer::opengl::OpenGL;
+use ghostty_renderer::options::Options as RendererOptions;
+use ghostty_renderer::size::{CellSize, Coordinate, Padding, ScreenSize, Size};
+use ghostty_renderer::state::{Preedit, PreeditCodepoint, State as RenderStateData};
+use ghostty_renderer::thread::{Handle as RendererHandle, Running as RendererRunning};
+use ghostty_renderer::{Health, Renderer};
+use ghostty_terminal::page_list::Scrollbar;
+use ghostty_terminal::point::Coordinate as PointCoordinate;
+use ghostty_terminal::selection::Selection;
+use ghostty_termio::exec;
+use ghostty_termio::message::Message as IoMessage;
+use ghostty_termio::{
+    Backend, DerivedConfig as IoDerivedConfig, Exec, Mailbox as IoMailbox, Options as IoOptions,
+    RendererMailbox, SharedState, SharedStateExt, TerminalGuard, Termio, Thread as IoThread,
+    Wakeup,
+};
+
+use crate::app::{AppState, Mailbox, Message as AppMessage};
+use crate::global;
+use config::DerivedConfig;
+
+/// Minimum window size in cells (Zig: `min_window_width_cells`).
+pub const MIN_WINDOW_WIDTH_CELLS: u32 = ghostty_apprt::runtime_api::MIN_WINDOW_WIDTH_CELLS;
+/// See [`MIN_WINDOW_WIDTH_CELLS`].
+pub const MIN_WINDOW_HEIGHT_CELLS: u32 = ghostty_apprt::runtime_api::MIN_WINDOW_HEIGHT_CELLS;
+
+/// The default DPI (Zig: `font.face.default_dpi`).
+pub const DEFAULT_DPI: f32 = 96.0;
+
+/// The effect of an input event (Zig: `Surface.InputEffect`).
+pub type InputEffectT = InputEffect;
+
+/// Mouse button count (Zig: `input.MouseButton.max`).
+pub const MOUSE_BUTTON_COUNT: usize = 12;
+
+/// The surface mailbox type termio and the renderer use to message us.
+type SurfaceMailboxT = SurfaceMailboxImpl<SurfaceId, Mailbox>;
+
+/// Bridge from termio to the renderer thread's mailbox. The IO side is
+/// created before the renderer thread exists (the renderer needs the shared
+/// terminal state which termio creates), so the handle is filled in later.
+#[derive(Default)]
+struct RendererLink {
+    handle: std::sync::OnceLock<RendererHandle>,
+}
+
+impl RendererMailbox for RendererLink {
+    fn push(&self, msg: RendererMessage, timeout: Timeout) -> usize {
+        match self.handle.get() {
+            Some(h) => usize::from(h.push(msg, timeout)),
+            None => 0,
+        }
+    }
+}
+
+/// What the renderer needs from us (thread-safe, non-blocking).
+struct HostImpl {
+    id: SurfaceId,
+    mailbox: Mailbox,
+}
+
+impl RendererHost for HostImpl {
+    fn scrollbar(&self, scrollbar: Scrollbar) -> bool {
+        self.mailbox.push(
+            AppMessage::SurfaceMessage {
+                surface: self.id,
+                message: Message::Scrollbar(scrollbar),
+            },
+            Timeout::Instant,
+        ) > 0
+    }
+
+    fn renderer_health(&self, health: Health) {
+        self.mailbox.push(
+            AppMessage::SurfaceMessage {
+                surface: self.id,
+                message: Message::RendererHealth(health),
+            },
+            Timeout::Forever,
+        );
+    }
+
+    fn redraw_surface(&self) -> bool {
+        self.mailbox
+            .push(AppMessage::RedrawSurface(self.id), Timeout::Instant)
+            > 0
+    }
+}
+
+/// Font state of the surface.
+pub struct FontState {
+    /// The key of the font grid we hold a reference on.
+    pub grid_key: FontGridKey,
+    /// The desired size (points + DPI).
+    pub size: DesiredSize,
+    /// The metrics of the current grid.
+    pub metrics: Metrics,
+    /// This keeps track of if the font size was ever modified. If it wasn't,
+    /// then config reloading will change the font. If it was manually
+    /// adjusted, we don't change it on config reload since we assume the
+    /// user wants a specific size.
+    pub adjusted: bool,
+}
+
+/// A single terminal surface. See the module docs.
+pub struct Surface {
+    /// The identifier the runtime gave us (Zig: the `*Surface` pointer).
+    pub(crate) id: SurfaceId,
+
+    /// The app that this surface is attached to.
+    pub(crate) app: Rc<AppState>,
+
+    /// The windowing system surface and app.
+    pub(crate) rt_app: Rc<dyn RtApp>,
+    pub(crate) rt_surface: Rc<dyn RtSurface>,
+
+    /// The font structures.
+    pub(crate) font: RefCell<FontState>,
+
+    /// The renderer for this surface. It is created and destroyed on the
+    /// main thread (GL context current) and drawn from the main thread.
+    pub(crate) renderer: Arc<Renderer>,
+
+    /// The render state (terminal + preedit + mouse) behind the renderer
+    /// mutex (`renderer_state.mutex` in Zig).
+    pub(crate) renderer_state: SharedState,
+
+    /// The renderer thread.
+    pub(crate) renderer_handle: RendererHandle,
+    renderer_thread: RefCell<Option<RendererRunning>>,
+
+    /// The IO thread and the mailbox used to send it messages.
+    pub(crate) io_mailbox: IoMailbox,
+    io_stop: Wakeup,
+    io_thread: RefCell<Option<JoinHandle<()>>>,
+
+    /// The command arguments the IO backend was started with (for the
+    /// abnormal exit message).
+    command_args: Vec<String>,
+
+    /// Mouse state.
+    pub(crate) mouse: RefCell<mouse::Mouse>,
+
+    /// Keyboard input state.
+    pub(crate) keyboard: RefCell<keyboard::Keyboard>,
+
+    /// A currently pressed key. This is used so that we can send a keyboard
+    /// release event when the surface is unfocused. See Zig docs.
+    pub(crate) pressed_key: RefCell<Option<keyboard::OwnedKeyEvent>>,
+
+    /// All our sizing information.
+    pub(crate) size: Cell<Size>,
+
+    /// The configuration derived from the main config.
+    config: RefCell<Rc<DerivedConfig>>,
+
+    /// The conditional state of the configuration.
+    pub(crate) config_conditional_state: Cell<conditional::State>,
+
+    /// This is set to true if our IO thread notifies us our child exited.
+    pub(crate) child_exited: Cell<bool>,
+
+    /// We maintain our focus state and assume we're focused by default.
+    pub(crate) focused: Cell<bool>,
+
+    /// Used to determine whether to continuously scroll.
+    pub(crate) selection_scroll_active: Cell<bool>,
+
+    /// True if the surface is in read-only mode. When read-only, no input is
+    /// sent to the PTY but terminal-level operations like selections,
+    /// (native) scrolling, and copy keybinds still work.
+    pub(crate) readonly: Cell<bool>,
+
+    /// Used to send notifications that long running commands have finished.
+    command_timer: Cell<Option<Instant>>,
+
+    /// Search state.
+    pub(crate) search: RefCell<Option<binding::Search>>,
+
+    /// Used to rate limit BEL handling.
+    last_bell_time: Cell<Option<Instant>>,
+
+    /// Debug screenshot state (see `debug_screenshot`).
+    created: Instant,
+    debug_shot_done: Cell<bool>,
+}
+
+impl Surface {
+    /// Create a new surface (Zig: `Surface.init`). This must be called from
+    /// the main thread with the GL context current.
+    pub fn new(
+        id: SurfaceId,
+        app: Rc<AppState>,
+        config_original: Arc<Config>,
+        rt_app: Rc<dyn RtApp>,
+        rt_surface: Rc<dyn RtSurface>,
+    ) -> Result<Rc<Surface>, CoreError> {
+        // Apply our conditional state. If we fail to apply the conditional
+        // state then we log and attempt to move forward with the old config.
+        let config: Arc<Config> =
+            match config_original.change_conditional_state(app.config_conditional_state.get()) {
+                Ok(Some(mut c)) => {
+                    // We want to preserve our original working directory. We
+                    // preserve this so directory inheritance works.
+                    c.working_directory = config_original.working_directory.clone();
+                    Arc::new(c)
+                }
+                Ok(None) => Arc::clone(&config_original),
+                Err(err) => {
+                    log::warn!("failed to apply conditional state to config err={err}");
+                    Arc::clone(&config_original)
+                }
+            };
+
+        // Get our configuration
+        let derived_config = Rc::new(DerivedConfig::new(Arc::clone(&config))?);
+
+        // Initialize our renderer with our initialized surface (Zig:
+        // `Renderer.surfaceInit`): load the GL functions for the current
+        // context.
+        let mut api = OpenGL::init(config.alpha_blending);
+        {
+            let rt = Rc::clone(&rt_surface);
+            api.prepare_context(|name| rt.gl_proc_address(name))
+                .map_err(|e| format!("failed to prepare the OpenGL context: {e}"))?;
+        }
+
+        // Determine our DPI configurations so we can properly configure
+        // font points to pixels and handle other high-DPI scaling factors.
+        let content_scale = rt_surface.get_content_scale();
+        let x_dpi = content_scale.x * DEFAULT_DPI;
+        let y_dpi = content_scale.y * DEFAULT_DPI;
+        log::debug!(
+            "xscale={} yscale={} xdpi={x_dpi} ydpi={y_dpi}",
+            content_scale.x,
+            content_scale.y
+        );
+
+        // The font size we desire along with the DPI determined for the
+        // surface.
+        let font_size = DesiredSize {
+            points: config.font_size,
+            xdpi: x_dpi as u16,
+            ydpi: y_dpi as u16,
+        };
+
+        // Setup our font group. This will reuse an existing font group if it
+        // was already loaded.
+        let font_derived = FontDerivedConfig::new(&config);
+        let (font_grid_key, font_grid) = app.font_grid_set.ref_(&font_derived, font_size)?;
+
+        // Build our size struct which has all the sizes we need.
+        let size = {
+            let surface_size = rt_surface.get_size();
+            let mut size = Size {
+                screen: ScreenSize {
+                    width: surface_size.width,
+                    height: surface_size.height,
+                },
+                cell: {
+                    let c = font_grid.cell_size();
+                    CellSize {
+                        width: c.width,
+                        height: c.height,
+                    }
+                },
+                padding: Padding::default(),
+            };
+
+            let explicit = derived_config.scaled_padding(x_dpi, y_dpi);
+            if derived_config.window_padding_balance {
+                size.balance_padding(explicit);
+            } else {
+                size.padding = explicit;
+            }
+            size
+        };
+
+        let app_mailbox = app.mailbox.clone();
+        let host: Arc<dyn RendererHost> = Arc::new(HostImpl {
+            id,
+            mailbox: app_mailbox.clone(),
+        });
+
+        // The renderer itself.
+        let renderer = Arc::new(Renderer::new(
+            RendererOptions {
+                config: ghostty_renderer::DerivedConfig::new(&config)?,
+                font_grid: Arc::clone(&font_grid),
+                size,
+                host: Arc::clone(&host),
+            },
+            api,
+        )?);
+
+        // The command we're going to execute
+        let command = if app.first.get() {
+            config
+                .initial_command
+                .clone()
+                .or_else(|| config.command.clone())
+        } else {
+            config.command.clone()
+        };
+
+        // Start our IO implementation
+        let renderer_link = Arc::new(RendererLink::default());
+        let renderer_wakeup = {
+            let link = Arc::clone(&renderer_link);
+            Wakeup::with_hook(Arc::new(move || {
+                if let Some(h) = link.handle.get() {
+                    h.wakeup();
+                }
+            }))?
+        };
+        let io_mailbox = IoMailbox::new()?;
+        let surface_mailbox: Arc<dyn ghostty_termio::SurfaceMailbox> = Arc::new(SurfaceMailboxT {
+            surface: id,
+            app: app_mailbox.clone(),
+        });
+
+        let (termio, command_args) = {
+            let mut env = rt_surface_env(rt_surface.as_ref());
+            // don't leak GHOSTTY_LOG to any subprocesses
+            env.remove("GHOSTTY_LOG");
+
+            let mut ecfg = exec::Config::new(env, config.term.clone());
+            ecfg.command = command.clone();
+            ecfg.env_override = config.env.clone();
+            ecfg.shell_integration = config.shell_integration;
+            ecfg.shell_integration_features = config.shell_integration_features;
+            ecfg.cursor_blink = config.cursor_style_blink;
+            ecfg.working_directory = config
+                .working_directory
+                .as_ref()
+                .and_then(|wd| wd.value())
+                .map(str::to_owned);
+            ecfg.resources_dir = global::state().resources_dir.host().map(str::to_owned);
+            ecfg.rt_pre_exec_info = ghostty_termio::command::RtPreExecInfo::init(&config);
+            ecfg.rt_post_fork_info = ghostty_termio::command::RtPostForkInfo::init(&config);
+            ecfg.create_scope = rt_surface.create_scope_fn();
+            ecfg.restore_rlimit = global::state().rlimits.nofile;
+
+            let exec = Exec::new(ecfg)?;
+            let args = exec.args().to_vec();
+            let termio = Termio::init(IoOptions {
+                size,
+                full_config: &config,
+                config: IoDerivedConfig::new(&config),
+                backend: Backend::Exec(exec),
+                mailbox: io_mailbox.clone(),
+                renderer_wakeup,
+                renderer_mailbox: Arc::clone(&renderer_link) as Arc<dyn RendererMailbox>,
+                surface_mailbox: Arc::clone(&surface_mailbox),
+            })?;
+            (termio, args)
+        };
+        let renderer_state = Arc::clone(termio.renderer_state());
+
+        // Create the renderer thread
+        let render_thread = ghostty_renderer::Thread::new(
+            &config,
+            Arc::clone(&renderer),
+            Arc::clone(&renderer_state),
+            host,
+        );
+        let renderer_handle = render_thread.handle();
+        let _ = renderer_link.handle.set(renderer_handle.clone());
+
+        // Create the IO thread
+        let io_thread = IoThread::new()?;
+        let io_stop = io_thread.stop_handle();
+
+        let surface = Rc::new(Surface {
+            id,
+            app: Rc::clone(&app),
+            rt_app: Rc::clone(&rt_app),
+            rt_surface: Rc::clone(&rt_surface),
+            font: RefCell::new(FontState {
+                grid_key: font_grid_key,
+                size: font_size,
+                metrics: font_grid.metrics(),
+                adjusted: false,
+            }),
+            renderer,
+            renderer_state,
+            renderer_handle,
+            renderer_thread: RefCell::new(None),
+            io_mailbox,
+            io_stop,
+            io_thread: RefCell::new(None),
+            command_args,
+            mouse: RefCell::new(mouse::Mouse::default()),
+            keyboard: RefCell::new(keyboard::Keyboard::default()),
+            pressed_key: RefCell::new(None),
+            size: Cell::new(size),
+            config: RefCell::new(derived_config),
+            config_conditional_state: Cell::new(app.config_conditional_state.get()),
+            child_exited: Cell::new(false),
+            focused: Cell::new(true),
+            selection_scroll_active: Cell::new(false),
+            readonly: Cell::new(false),
+            command_timer: Cell::new(None),
+            search: RefCell::new(None),
+            last_bell_time: Cell::new(None),
+            created: Instant::now(),
+            debug_shot_done: Cell::new(false),
+        });
+
+        // Report initial cell size on surface creation
+        rt_app.perform_action(
+            Target::Surface(id),
+            RtAction::CellSize(ActionCellSize {
+                width: size.cell.width,
+                height: size.cell.height,
+            }),
+        );
+
+        rt_app.perform_action(
+            Target::Surface(id),
+            RtAction::SizeLimit(SizeLimit {
+                min_width: size.cell.width * MIN_WINDOW_WIDTH_CELLS,
+                min_height: size.cell.height * MIN_WINDOW_HEIGHT_CELLS,
+                // No max:
+                max_width: 0,
+                max_height: 0,
+            }),
+        );
+
+        // Call our size callback which handles all our retina setup
+        // Note: this shouldn't be necessary and when we clean up the surface
+        // init stuff we should get rid of this. But this is required because
+        // sizeCallback does retina-aware stuff we don't do here and don't
+        // want to duplicate.
+        surface.resize(size.screen);
+
+        // Start our renderer thread
+        *surface.renderer_thread.borrow_mut() = Some(render_thread.spawn()?);
+
+        // Start our IO thread
+        *surface.io_thread.borrow_mut() = Some(
+            std::thread::Builder::new()
+                .name("io".into())
+                .spawn(move || io_thread.thread_main(termio))?,
+        );
+
+        // Determine our initial window size if configured. We need to do
+        // this quite late in the process because our height/width are in
+        // grid dimensions, so we need to know our cell sizes first.
+        //
+        // Note: it is important to do this after the renderer is setup
+        // above. This allows the apprt to fully initialize the surface
+        // before we start messing with the window.
+        surface.recompute_initial_size();
+
+        if let Some(title) = &config.title {
+            rt_app.perform_action(
+                Target::Surface(id),
+                RtAction::SetTitle(SetTitle {
+                    title: title.clone(),
+                }),
+            );
+        } else if config.xdg_terminal_exec
+            && let Some(cmd) = &command
+        {
+            // For xdg-terminal-exec execution we special-case and set the
+            // window title to the command being executed. This allows window
+            // managers to set custom styling based on the command being
+            // executed.
+            rt_app.perform_action(
+                Target::Surface(id),
+                RtAction::SetTitle(SetTitle {
+                    title: cmd.string(),
+                }),
+            );
+        } else if let Some(cmd) = &command {
+            // If a user specifies a command it is appropriate to set the
+            // title as argv[0]. We know in the case of a direct command it
+            // has been supplied by the user. We won't set the title in the
+            // case the shell expands the command as that should typically be
+            // used to launch a shell which should set its own titles.
+            if let ghostty_config::command::Command::Direct(args) = cmd
+                && let Some(first) = args.first()
+                && !first.is_empty()
+            {
+                rt_app.perform_action(
+                    Target::Surface(id),
+                    RtAction::SetTitle(SetTitle {
+                        title: first.clone(),
+                    }),
+                );
+            }
+        }
+
+        // We are no longer the first surface
+        app.first.set(false);
+
+        Ok(surface)
+    }
+
+    // ------------------------------------------------------------------
+    // Small shared helpers used by every submodule
+
+    /// The runtime-assigned id of this surface.
+    #[must_use]
+    pub fn id(&self) -> SurfaceId {
+        self.id
+    }
+
+    /// The current derived config (cheap `Rc` clone; no borrow is kept).
+    #[must_use]
+    pub fn cfg(&self) -> Rc<DerivedConfig> {
+        Rc::clone(&self.config.borrow())
+    }
+
+    /// Lock the renderer state and borrow the terminal (the Zig
+    /// `renderer_state.mutex.lock()` + `io.terminal`). Do not hold across
+    /// calls into the runtime.
+    pub fn lock_terminal(&self) -> TerminalGuard<'_> {
+        self.renderer_state.lock_terminal()
+    }
+
+    /// Lock the full render state (terminal + preedit + mouse).
+    pub fn lock_state(&self) -> std::sync::MutexGuard<'_, RenderStateData> {
+        self.renderer_state
+            .lock()
+            .unwrap_or_else(std::sync::PoisonError::into_inner)
+    }
+
+    /// Perform a runtime action targeted at this surface, ignoring the
+    /// result (most callers only log failures in Zig).
+    pub(crate) fn perform(&self, action: RtAction) -> bool {
+        self.rt_app.perform_action(Target::Surface(self.id), action)
+    }
+
+    /// Returns a mailbox that can be used to send messages to this surface.
+    pub(crate) fn surface_mailbox(&self) -> SurfaceMailboxT {
+        SurfaceMailboxT {
+            surface: self.id,
+            app: self.app.mailbox.clone(),
+        }
+    }
+
+    /// Queue a message for the IO thread.
+    ///
+    /// We centralize all our logic into this spot so we can intercept
+    /// messages for example in readonly mode. Do NOT call this while holding
+    /// the terminal lock (use [`Surface::queue_io_locked`]).
+    pub(crate) fn queue_io(&self, msg: IoMessage) {
+        if self.readonly.get() && matches!(msg, IoMessage::Write(_)) {
+            return;
+        }
+        self.io_mailbox.send(msg);
+        self.io_mailbox.notify();
+    }
+
+    #[allow(dead_code)]
+    /// Like [`Surface::queue_io`] for callers holding the renderer lock: if
+    /// the queue is full the lock is released while blocking.
+    pub(crate) fn queue_io_locked<'a>(
+        &'a self,
+        msg: IoMessage,
+        guard: std::sync::MutexGuard<'a, RenderStateData>,
+    ) -> std::sync::MutexGuard<'a, RenderStateData> {
+        if self.readonly.get() && matches!(msg, IoMessage::Write(_)) {
+            return guard;
+        }
+        let guard = self
+            .io_mailbox
+            .send_locked(msg, &self.renderer_state, guard);
+        self.io_mailbox.notify();
+        guard
+    }
+
+    /// This queues a render operation with the renderer thread. The render
+    /// isn't guaranteed to happen immediately but it will happen as soon as
+    /// practical.
+    pub(crate) fn queue_render(&self) {
+        self.renderer_handle.wakeup();
+    }
+
+    #[allow(dead_code)]
+    /// Push a message to the renderer thread (blocking if full) and wake it.
+    pub(crate) fn send_renderer(&self, msg: RendererMessage) {
+        self.renderer_handle.send(msg);
+    }
+
+    /// Current sizes.
+    #[must_use]
+    pub fn size(&self) -> Size {
+        self.size.get()
+    }
+
+    /// Convert surface-relative pixel coordinates to a viewport cell
+    /// (Zig: `posToViewport`).
+    #[must_use]
+    pub fn pos_to_viewport(&self, xpos: f64, ypos: f64) -> PointCoordinate {
+        // Get our grid cell
+        let coord = Coordinate::Surface(ghostty_renderer::size::SurfaceCoord { x: xpos, y: ypos });
+        match coord.convert(ghostty_renderer::size::CoordinateTag::Grid, self.size.get()) {
+            Coordinate::Grid(g) => PointCoordinate {
+                x: g.x,
+                y: u32::from(g.y),
+            },
+            _ => PointCoordinate { x: 0, y: 0 },
+        }
+    }
+
+    /// Scroll to the bottom of the viewport. The caller holds the terminal
+    /// lock.
+    pub(crate) fn scroll_to_bottom(&self, t: &mut ghostty_terminal::terminal::Terminal) {
+        t.scroll_viewport(ghostty_terminal::terminal::ScrollViewport::Bottom);
+        self.queue_render();
+    }
+
+    pub(crate) fn hide_mouse(&self) {
+        {
+            let mut m = self.mouse.borrow_mut();
+            if m.hidden {
+                return;
+            }
+            m.hidden = true;
+        }
+        self.perform(RtAction::MouseVisibility(MouseVisibility::Hidden));
+    }
+
+    pub(crate) fn show_mouse(&self) {
+        {
+            let mut m = self.mouse.borrow_mut();
+            if !m.hidden {
+                return;
+            }
+            m.hidden = false;
+        }
+        self.perform(RtAction::MouseVisibility(MouseVisibility::Visible));
+    }
+
+    // ------------------------------------------------------------------
+    // Lifecycle
+
+    /// Close this surface. This will trigger the runtime to start the close
+    /// process, which should ultimately deinitialize this surface.
+    pub fn close(&self) {
+        self.rt_surface.close(self.needs_confirm_quit());
+    }
+
+    /// True if the surface requires confirmation to quit. This should be
+    /// called by apprt to determine if the surface should confirm before
+    /// quitting.
+    #[must_use]
+    pub fn needs_confirm_quit(&self) -> bool {
+        // If the surface is in read-only mode, always require confirmation
+        if self.readonly.get() {
+            return true;
+        }
+
+        // If the child has exited, then our process is certainly not alive.
+        // We check this first to avoid the locking overhead below.
+        if self.child_exited.get() {
+            return false;
+        }
+
+        // Check the configuration for confirming close behavior.
+        match self.cfg().confirm_close_surface {
+            ConfirmCloseSurface::Always => true,
+            ConfirmCloseSurface::False => false,
+            ConfirmCloseSurface::True => !self.lock_terminal().cursor_is_at_prompt(),
+        }
+    }
+
+    /// Forces the surface to render (Zig: `draw`). Renderers are required
+    /// to support `draw_frame` being called from the main thread.
+    pub fn draw(&self) -> Result<(), CoreError> {
+        self.renderer.draw_frame(true)?;
+        Ok(())
+    }
+
+    // ------------------------------------------------------------------
+    // Messages (called from the app thread)
+
+    /// Called from the app thread to handle mailbox messages to our specific
+    /// surface.
+    pub fn handle_message(&self, msg: Message) -> Result<(), CoreError> {
+        match msg {
+            Message::ChangeConfig(config) => self.update_config(&config)?,
+
+            Message::SetTitle(buf) => {
+                // We ignore the message in case the title was set via config.
+                if self.cfg().title.is_some() {
+                    log::debug!(
+                        "ignoring title change request since static title is set via config"
+                    );
+                    return Ok(());
+                }
+
+                let end = buf.iter().position(|&b| b == 0).unwrap_or(buf.len());
+                let title = String::from_utf8_lossy(&buf[..end]).into_owned();
+                log::debug!("changing title \"{title}\"");
+                self.perform(RtAction::SetTitle(SetTitle { title }));
+            }
+
+            Message::ReportTitle(style) => {
+                if !self.cfg().title_report {
+                    log::info!("report_title requested, but disabled via config");
+                    return Ok(());
+                }
+
+                let title = self.rt_surface.get_title();
+                let data = match style {
+                    ghostty_apprt::surface::ReportTitleStyle::Csi21T => {
+                        format!("\x1b]l{}\x1b\\", title.unwrap_or_default())
+                    }
+                };
+                self.queue_io(IoMessage::write_req(data.as_bytes()));
+            }
+
+            Message::ColorChange(change) => {
+                // Notify our apprt, but don't send a mode 2031 DSR report
+                // because VT sequences were used to change the color.
+                use ghostty_vt::color::Dynamic as D;
+                use ghostty_vt::osc::color::Target;
+                let kind = match change.target {
+                    Target::Palette(v) => ColorKind::Palette(i32::from(v)),
+                    Target::Dynamic(dyn_) => match dyn_ {
+                        D::Foreground => ColorKind::Foreground,
+                        D::Background => ColorKind::Background,
+                        D::Cursor => ColorKind::Cursor,
+                        // Unsupported dynamic color change notification type
+                        _ => return Ok(()),
+                    },
+                    // Special colors aren't supported for change notification
+                    Target::Special(_) => return Ok(()),
+                };
+                self.perform(RtAction::ColorChange(ColorChange {
+                    kind,
+                    r: change.color.r,
+                    g: change.color.g,
+                    b: change.color.b,
+                }));
+            }
+
+            Message::SetMouseShape(shape) => {
+                log::debug!("changing mouse shape: {shape:?}");
+                self.perform(RtAction::MouseShape(shape));
+            }
+
+            Message::ClipboardRead(clipboard) => {
+                if self.cfg().clipboard_read == ghostty_config::types_b::ClipboardAccess::Deny {
+                    log::info!(
+                        "application attempted to read clipboard, but 'clipboard-read' is set to deny"
+                    );
+                    return Ok(());
+                }
+
+                self.start_clipboard_request(
+                    ghostty_apprt::structs::Clipboard::Standard,
+                    ClipboardRequest::Osc52Read(clipboard),
+                );
+            }
+
+            Message::ClipboardWrite {
+                clipboard_type,
+                req,
+            } => {
+                self.clipboard_write(req.slice(), clipboard_type);
+            }
+
+            Message::PwdChange(w) => {
+                let pwd = String::from_utf8_lossy(w.slice()).into_owned();
+                self.perform(RtAction::Pwd(Pwd { pwd }));
+            }
+
+            Message::Close => self.close(),
+
+            Message::ChildExited(info) => self.child_exited(info),
+
+            Message::DesktopNotification(notification) => {
+                if !self.cfg().desktop_notifications {
+                    log::info!(
+                        "application attempted to display a desktop notification, but 'desktop-notifications' is disabled"
+                    );
+                    return Ok(());
+                }
+
+                let title = String::from_utf8_lossy(notification.title()).into_owned();
+                let body = String::from_utf8_lossy(notification.body()).into_owned();
+                self.show_desktop_notification(&title, &body);
+            }
+
+            Message::RendererHealth(health) => self.update_renderer_health(health),
+
+            Message::Scrollbar(scrollbar) => self.update_scrollbar(scrollbar),
+
+            Message::PresentSurface => {
+                self.perform(RtAction::PresentTerminal);
+            }
+
+            Message::PasswordInput(v) => self.password_input(v),
+
+            Message::RingBell => {
+                let now = Instant::now();
+                if let Some(last) = self.last_bell_time.get()
+                    && now.duration_since(last) < StdDuration::from_millis(100)
+                {
+                    return Ok(());
+                }
+                self.last_bell_time.set(Some(now));
+                self.perform(RtAction::RingBell);
+            }
+
+            Message::ProgressReport(v) => {
+                self.perform(RtAction::ProgressReport(v));
+            }
+
+            Message::SelectionScrollTick(active) => {
+                self.selection_scroll_active.set(active);
+                self.selection_scroll_tick()?;
+            }
+
+            Message::StartCommand => {
+                self.command_timer.set(Some(Instant::now()));
+            }
+
+            Message::StopCommand(code) => {
+                let end = Instant::now();
+                let Some(start) = self.command_timer.take() else {
+                    return Ok(());
+                };
+
+                let duration = ghostty_config::types_b::Duration {
+                    duration: end.duration_since(start).as_nanos() as u64,
+                };
+                log::debug!("command took {duration:?}");
+
+                self.perform(RtAction::CommandFinished(CommandFinished {
+                    exit_code: code,
+                    duration,
+                }));
+            }
+
+            Message::SearchTotal(v) => {
+                self.perform(RtAction::SearchTotal(ghostty_apprt::action::SearchTotal {
+                    total: v,
+                }));
+            }
+
+            Message::SearchSelected(v) => {
+                self.perform(RtAction::SearchSelected(
+                    ghostty_apprt::action::SearchSelected { selected: v },
+                ));
+            }
+        }
+        Ok(())
+    }
+
+    /// The child process exited.
+    fn child_exited(&self, info: ghostty_apprt::surface::ChildExited) {
+        // Mark our flag that we exited immediately
+        self.child_exited.set(true);
+
+        // If our runtime was below some threshold then we assume that this
+        // was an abnormal exit and we show an error message.
+        if info.runtime_ms <= u64::from(self.cfg().abnormal_command_exit_runtime_ms) {
+            // If the exit code is 0 then it was a good exit.
+            if info.exit_code != 0 {
+                log::warn!("abnormal process exit detected, showing error message");
+
+                // Try and show a GUI message. If it returns true, don't do
+                // anything else.
+                if self.perform(RtAction::ShowChildExited(info)) {
+                    return;
+                }
+
+                // If a native GUI notification was not shown, update our
+                // terminal to note the abnormal exit.
+                if let Err(err) = self.child_exited_abnormally(info) {
+                    log::error!("error handling abnormal child exit err={err}");
+                }
+
+                return;
+            }
+        }
+
+        // We output a message so that the user knows what's going on and
+        // doesn't think their terminal just froze. We show this
+        // unconditionally on close even if `wait_after_command` is false and
+        // the surface closes immediately because if a user does an `undo` to
+        // restore a closed surface then they will see this message and know
+        // the process has completed.
+        //
+        // First try and show a native GUI message. If the native GUI can't
+        // be shown, display a text message in the terminal.
+        if !self.perform(RtAction::ShowChildExited(info)) {
+            let mut t = self.lock_terminal();
+            t.carriage_return();
+            let ok = t.linefeed().is_ok()
+                && t.print_string("Process exited. Press any key to close the terminal.")
+                    .is_ok();
+            if ok {
+                t.modes.set(ghostty_vt::modes::Mode::CursorVisible, false);
+
+                // We also want to ensure that normal keyboard encoding is on
+                // so that we can close the terminal. We close the terminal
+                // on any key press that encodes a character.
+                t.modes.set(ghostty_vt::modes::Mode::DisableKeyboard, false);
+                t.screen_mut().kitty_keyboard.set(
+                    ghostty_vt::kitty::key::SetMode::Set,
+                    ghostty_vt::kitty::key::Flags::DISABLED,
+                );
+            }
+        }
+
+        // Waiting after command we stop here. The terminal is updated, our
+        // state is updated, and now its up to the user to decide what to do.
+        if self.cfg().wait_after_command {
+            return;
+        }
+
+        // If we aren't waiting after the command, then we exit immediately
+        // with no confirmation.
+        self.close();
+    }
+
+    /// Called when the child process exited abnormally.
+    fn child_exited_abnormally(
+        &self,
+        info: ghostty_apprt::surface::ChildExited,
+    ) -> Result<(), ghostty_terminal::page::Error> {
+        use ghostty_vt::sgr::Attribute;
+
+        // Build up our command for the error message
+        let command = self.command_args.join(" ");
+        let runtime_str = format!("{} ms", info.runtime_ms);
+
+        let mut t = self.lock_terminal();
+
+        // No matter what move the cursor back to the column 0.
+        t.carriage_return();
+
+        // Reset styles
+        t.set_attribute(Attribute::Unset)?;
+
+        // If there is data in the viewport, we want to scroll down a little
+        // bit and write a horizontal rule before writing our message. This
+        // lets the use see the error message the command may have output.
+        let viewport_str = t.plain_string()?;
+        if !viewport_str.is_empty() {
+            t.linefeed()?;
+            for _ in 0..t.cols {
+                t.print(0x2501)?;
+            }
+            t.carriage_return();
+            t.linefeed()?;
+            t.linefeed()?;
+        }
+
+        // Output our error message
+        t.set_attribute(Attribute::Fg8(ghostty_vt::color::Name::BRIGHT_RED))?;
+        t.set_attribute(Attribute::Bold)?;
+        t.print_string("Ghostty failed to launch the requested command:")?;
+        t.set_attribute(Attribute::Unset)?;
+
+        t.carriage_return();
+        t.linefeed()?;
+        t.linefeed()?;
+        t.print_string(&command)?;
+        t.set_attribute(Attribute::Unset)?;
+
+        t.carriage_return();
+        t.linefeed()?;
+        t.linefeed()?;
+        t.print_string("Runtime: ")?;
+        t.set_attribute(Attribute::Fg8(ghostty_vt::color::Name::RED))?;
+        t.print_string(&runtime_str)?;
+        t.set_attribute(Attribute::Unset)?;
+
+        let exit_code_str = info.exit_code.to_string();
+        t.carriage_return();
+        t.linefeed()?;
+        t.print_string("Exit Code: ")?;
+        t.set_attribute(Attribute::Fg8(ghostty_vt::color::Name::RED))?;
+        t.print_string(&exit_code_str)?;
+        t.set_attribute(Attribute::Unset)?;
+
+        t.carriage_return();
+        t.linefeed()?;
+        t.linefeed()?;
+        t.print_string("Press any key to close the window.")?;
+
+        // Hide the cursor
+        t.modes.set(ghostty_vt::modes::Mode::CursorVisible, false);
+        Ok(())
+    }
+
+    /// Called when the terminal detects there is a password input prompt.
+    fn password_input(&self, v: bool) {
+        {
+            let mut t = self.lock_terminal();
+
+            // If our password input state is unchanged then we don't waste
+            // time doing anything more.
+            if t.flags.password_input == v {
+                return;
+            }
+
+            t.flags.password_input = v;
+        }
+
+        // Notify our apprt so it can do whatever it wants.
+        self.perform(RtAction::SecureInput(if v {
+            SecureInput::On
+        } else {
+            SecureInput::Off
+        }));
+
+        self.queue_render();
+    }
+
+    /// Called when our renderer health state changes.
+    fn update_renderer_health(&self, health: Health) {
+        log::warn!("renderer health status change status={health:?}");
+        self.perform(RtAction::RendererHealth(health));
+    }
+
+    /// Called when the scrollbar state changes.
+    fn update_scrollbar(&self, scrollbar: Scrollbar) {
+        self.perform(RtAction::Scrollbar(scrollbar));
+    }
+
+    /// This should be called anytime `config_conditional_state` changes so
+    /// that the apprt can reload the configuration.
+    fn notify_config_conditional_state(&self) {
+        self.perform(RtAction::ReloadConfig(ReloadConfig { soft: true }));
+    }
+
+    // ------------------------------------------------------------------
+    // Configuration
+
+    /// Update our configuration at runtime. This can be called by the apprt
+    /// to set a surface-specific configuration that differs from the app or
+    /// other surfaces.
+    pub fn update_config(&self, original: &Arc<Config>) -> Result<(), CoreError> {
+        // Apply our conditional state. If we fail to apply the conditional
+        // state then we log and attempt to move forward with the old config.
+        let config: Arc<Config> =
+            match original.change_conditional_state(self.config_conditional_state.get()) {
+                Ok(Some(c)) => Arc::new(c),
+                Ok(None) => Arc::clone(original),
+                Err(err) => {
+                    log::warn!("failed to apply conditional state to config err={err}");
+                    Arc::clone(original)
+                }
+            };
+
+        // Update our new derived config immediately
+        let derived = match DerivedConfig::new(Arc::clone(&config)) {
+            Ok(d) => Rc::new(d),
+            Err(err) => {
+                // If the derivation fails then we just log and return. We
+                // don't hard fail in this case because we don't want to
+                // error the surface when config fails we just want to keep
+                // using the old config.
+                log::error!("error updating configuration err={err}");
+                return Ok(());
+            }
+        };
+        *self.config.borrow_mut() = Rc::clone(&derived);
+
+        // If our mouse is hidden but we disabled mouse hiding, then show it
+        // again.
+        if !derived.mouse_hide_while_typing && self.mouse.borrow().hidden {
+            self.show_mouse();
+        }
+
+        // If we are in the middle of a key sequence, clear it.
+        self.end_key_sequence(keyboard::SequenceAction::Drop, keyboard::SequenceFree::Free);
+
+        // Deactivate all key tables since they may have changed. Importantly,
+        // we store references into the config as part of our table stack so
+        // we can't keep them active across config changes. But this behavior
+        // also matches key sequences.
+        self.deactivate_all_key_tables();
+
+        // Before sending any other config changes, we give the renderer a
+        // new font grid. We could check to see if there was an actual change
+        // to the font, but this is easier and pretty rare so it's not a
+        // performance concern.
+        //
+        // (Calling set_font_size builds and sends a new font grid to the
+        // renderer.)
+        let font_size = {
+            let f = self.font.borrow();
+            // If we have manually adjusted the font size, keep it that way.
+            if f.adjusted {
+                log::info!(
+                    "font size manually adjusted, preserving previous size on config reload"
+                );
+                f.size
+            } else {
+                // If we haven't, then we update to the configured font size.
+                // This allows config changes to update the font size.
+                let mut size = f.size;
+                size.points = config.font_size.clamp(1.0, 255.0);
+                size
+            }
+        };
+        self.set_font_size(font_size)?;
+
+        // We need to store our configs in a heap-allocated pointer so that
+        // our messages aren't huge.
+        let renderer_message = RendererMessage::init_change_config(&config)?;
+        self.renderer_handle.send(renderer_message);
+        self.queue_io(IoMessage::ChangeConfig(Box::new(IoDerivedConfig::new(
+            &config,
+        ))));
+
+        // With mailbox messages sent, we have to wake them up so they
+        // process it.
+        self.queue_render();
+
+        // If we have a title set then we update our window to have the newly
+        // configured title.
+        if let Some(title) = &config.title {
+            self.perform(RtAction::SetTitle(SetTitle {
+                title: title.clone(),
+            }));
+        }
+
+        // Notify the window
+        self.perform(RtAction::ConfigChange(ConfigChange { config }));
+        Ok(())
+    }
+
+    /// Recalculate the initial size of the window based on the
+    /// configuration and invoke the apprt `initial_size` action if
+    /// necessary.
+    fn recompute_initial_size(&self) {
+        let cfg = self.cfg();
+
+        // Both width and height must be set for this to work, as documented
+        // on the config options.
+        if cfg.window_height == 0 || cfg.window_width == 0 {
+            return;
+        }
+
+        let scale = self.rt_surface.get_content_scale();
+        let size = self.size.get();
+        let height = cfg.window_height.max(MIN_WINDOW_HEIGHT_CELLS) * size.cell.height;
+        let width = cfg.window_width.max(MIN_WINDOW_WIDTH_CELLS) * size.cell.width;
+        let width_f32 = width as f32;
+        let height_f32 = height as f32;
+
+        // The final values are affected by content scale and we need to
+        // account for the padding so we get the exact correct grid size.
+        let final_width =
+            (width_f32 / scale.x).ceil() as u32 + size.padding.left + size.padding.right;
+        let final_height =
+            (height_f32 / scale.y).ceil() as u32 + size.padding.top + size.padding.bottom;
+
+        self.perform(RtAction::InitialSize(InitialSize {
+            width: final_width,
+            height: final_height,
+        }));
+    }
+
+    // ------------------------------------------------------------------
+    // Text access
+
+    /// Returns true if the terminal has a selection.
+    #[must_use]
+    pub fn has_selection(&self) -> bool {
+        self.lock_terminal().screen().selection.is_some()
+    }
+
+    /// Returns the selected text.
+    #[must_use]
+    pub fn selection_string(&self) -> Option<String> {
+        let t = self.lock_terminal();
+        let sel = t.screen().selection?;
+        Some(
+            t.screen()
+                .selection_string(ghostty_terminal::screen::SelectionString { sel, trim: false }),
+        )
+    }
+
+    /// Returns the pwd of the terminal, if any. This is always copied
+    /// because the pwd can change at any point from termio.
+    #[must_use]
+    pub fn pwd(&self) -> Option<String> {
+        let t = self.lock_terminal();
+        let pwd = t.get_pwd()?;
+        Some(String::from_utf8_lossy(pwd).into_owned())
+    }
+
+    /// Returns the x/y coordinate of where the IME (Input Method Editor)
+    /// keyboard should be rendered.
+    #[must_use]
+    pub fn ime_point(&self) -> ImePos {
+        let (cursor_x, cursor_y, preedit_width) = {
+            let st = self.lock_state();
+            let cursor = &st.terminal.screen().cursor;
+            (
+                u32::from(cursor.x),
+                u32::from(cursor.y),
+                st.preedit.as_ref().map_or(0, Preedit::width) as u32,
+            )
+        };
+
+        // TODO: need to handle when scrolling and the cursor is not in the
+        // visible portion of the screen.
+
+        // Our sizes are all scaled so we need to send the unscaled values
+        // back.
+        let content_scale = self.rt_surface.get_content_scale();
+        let size = self.size.get();
+
+        // Simple x * cell width gives the top-left corner, then add padding
+        // offset
+        let mut x = f64::from(cursor_x * size.cell.width + size.padding.left);
+        // We want the midpoint
+        x += f64::from(size.cell.width) / 2.0;
+        // And scale it
+        x /= f64::from(content_scale.x);
+
+        // Simple y * cell height gives the top-left corner, then add padding
+        // offset
+        let mut y = f64::from(cursor_y * size.cell.height + size.padding.top);
+        // We want the bottom
+        y += f64::from(size.cell.height);
+        // And scale it
+        y /= f64::from(content_scale.y);
+
+        // Our height for now is always just the cell height because our
+        // preedit rendering only renders in a single line.
+        let height = f64::from(size.cell.height) / f64::from(content_scale.y);
+
+        let mut width = f64::from(preedit_width * size.cell.width);
+
+        // Our max width is the remaining screen width after the cursor. We
+        // don't have to deal with wrapping because the preedit doesn't wrap
+        // right now.
+        let screen_width = f64::from(size.terminal().width);
+        let x_offset = f64::from((cursor_x + 1) * size.cell.width);
+        let max = screen_width - x_offset;
+        width = width.min(max);
+
+        ImePos {
+            x,
+            y,
+            width,
+            height,
+        }
+    }
+
+    // ------------------------------------------------------------------
+    // Selection
+
+    /// Set the selection contents. This must be called with the renderer
+    /// mutex held (pass the locked terminal). Copy-on-select clipboard
+    /// writes happen here too.
+    pub(crate) fn set_selection(
+        &self,
+        t: &mut ghostty_terminal::terminal::Terminal,
+        sel: Option<Selection>,
+    ) -> Result<(), ghostty_terminal::page::Error> {
+        let prev = t.screen().selection;
+        t.screen_mut().select(sel)?;
+
+        let cfg = self.cfg();
+
+        // If copy on select is false then exit early.
+        use ghostty_config::types_b::CopyOnSelect;
+        if cfg.copy_on_select == CopyOnSelect::False {
+            return Ok(());
+        }
+
+        // Set our selection clipboard. If the selection is cleared we do not
+        // clear the clipboard. If the selection is set, we only set the
+        // clipboard again if it changed, since setting the clipboard can be
+        // an expensive operation.
+        let Some(sel) = sel else {
+            return Ok(());
+        };
+        if let Some(prev) = prev
+            && sel.eql(&t.screen().pages, &prev)
+        {
+            return Ok(());
+        }
+
+        use ghostty_apprt::structs::Clipboard;
+        match cfg.copy_on_select {
+            CopyOnSelect::False => unreachable!("handled above with an early exit"),
+
+            // Both standard and selection clipboards are set.
+            CopyOnSelect::Clipboard => self.copy_selection_to_clipboards(
+                t,
+                sel,
+                &[Clipboard::Standard, Clipboard::Selection],
+                ghostty_input::binding::CopyToClipboard::Mixed,
+            ),
+
+            // The selection clipboard is set if supported, otherwise the
+            // standard.
+            CopyOnSelect::True => {
+                let clipboard = if self.rt_surface.supports_clipboard(Clipboard::Selection) {
+                    Clipboard::Selection
+                } else {
+                    Clipboard::Standard
+                };
+                self.copy_selection_to_clipboards(
+                    t,
+                    sel,
+                    &[clipboard],
+                    ghostty_input::binding::CopyToClipboard::Mixed,
+                );
+            }
+        }
+        Ok(())
+    }
+
+    // ------------------------------------------------------------------
+    // Fonts and sizes
+
+    /// Change the cell size for the terminal grid. This can happen as a
+    /// result of changing the font size at runtime.
+    fn set_cell_size(&self, size: CellSize) {
+        // Update our cell size within our size struct
+        let mut s = self.size.get();
+        s.cell = size;
+        self.size.set(s);
+        self.balance_padding_if_needed();
+
+        // Notify the terminal
+        self.queue_io(IoMessage::Resize(self.size.get()));
+
+        // Update our terminal default size if necessary.
+        self.recompute_initial_size();
+
+        // Notify the window
+        self.perform(RtAction::CellSize(ActionCellSize {
+            width: size.width,
+            height: size.height,
+        }));
+    }
+
+    /// Change the font size. This can only be called from the main thread.
+    pub fn set_font_size(&self, size: DesiredSize) -> Result<(), CoreError> {
+        log::debug!("set font size size={}", size.points);
+
+        // Update our font size so future changes work
+        self.font.borrow_mut().size = size;
+
+        // We need to build up a new font stack for this font size.
+        let derived = FontDerivedConfig::new(&self.cfg().config);
+        let (font_grid_key, font_grid) = self.app.font_grid_set.ref_(&derived, size)?;
+
+        // Set our cell size
+        let metrics = font_grid.metrics();
+        self.set_cell_size(CellSize {
+            width: metrics.cell_width,
+            height: metrics.cell_height,
+        });
+
+        // Notify our render thread of the new font stack. The renderer MUST
+        // accept the new font grid and deref the old.
+        let old_key = {
+            let mut f = self.font.borrow_mut();
+            let old = std::mem::replace(&mut f.grid_key, font_grid_key.clone());
+            f.metrics = metrics;
+            old
+        };
+        self.renderer_handle
+            .send(RendererMessage::FontGrid(Box::new(FontGridChange {
+                grid: font_grid,
+                set: Arc::clone(&self.app.font_grid_set),
+                new_key: font_grid_key,
+                old_key,
+            })));
+
+        // Schedule render which also drains our mailbox
+        self.queue_render();
+        Ok(())
+    }
+
+    /// The current font size (points + dpi) for runtime queries.
+    #[must_use]
+    pub fn font_size(&self) -> DesiredSize {
+        self.font.borrow().size
+    }
+
+    /// Called when the runtime's surface size changes.
+    pub fn size_callback(&self, size: SurfaceSize) -> Result<(), CoreError> {
+        let new_screen_size = ScreenSize {
+            width: size.width,
+            height: size.height,
+        };
+
+        // Update our screen size, but only if it actually changed. And if
+        // the screen size didn't change, then our grid size could not have
+        // changed, so we just return.
+        if self.size.get().screen.equals(new_screen_size) {
+            return Ok(());
+        }
+
+        self.resize(new_screen_size);
+        Ok(())
+    }
+
+    fn resize(&self, size: ScreenSize) {
+        // Save our screen size
+        let mut s = self.size.get();
+        s.screen = size;
+        self.size.set(s);
+        self.balance_padding_if_needed();
+        let s = self.size.get();
+
+        // Recalculate our grid size. Because Ghostty supports fluid
+        // resizing, its possible the grid doesn't change at all even if the
+        // screen size changes. We have to update the IO thread no matter
+        // what because we send pixel-level sizing to the subprocess.
+        let grid_size = s.grid();
+        if grid_size.columns < 5 && (s.padding.left > 0 || s.padding.right > 0) {
+            log::warn!(
+                "WARNING: very small terminal grid detected with padding set. Is your padding reasonable?"
+            );
+        }
+        if grid_size.rows < 2 && (s.padding.top > 0 || s.padding.bottom > 0) {
+            log::warn!(
+                "WARNING: very small terminal grid detected with padding set. Is your padding reasonable?"
+            );
+        }
+
+        // Mail the IO thread
+        self.queue_io(IoMessage::Resize(s));
+    }
+
+    /// Recalculate the balanced padding if needed.
+    fn balance_padding_if_needed(&self) {
+        let cfg = self.cfg();
+        if !cfg.window_padding_balance {
+            return;
+        }
+        let content_scale = self.rt_surface.get_content_scale();
+        let x_dpi = content_scale.x * DEFAULT_DPI;
+        let y_dpi = content_scale.y * DEFAULT_DPI;
+        let mut s = self.size.get();
+        s.balance_padding(cfg.scaled_padding(x_dpi, y_dpi));
+        self.size.set(s);
+    }
+
+    /// Called to set the preedit state for character input. Preedit is used
+    /// with dead key states, for example, when typing an accent character.
+    /// This should be called with `None` to reset the preedit state.
+    ///
+    /// The core surface will NOT reset the preedit state on charCallback or
+    /// keyCallback and we rely completely on the apprt implementation to
+    /// track the preedit state correctly.
+    pub fn preedit_callback(&self, preedit: Option<&str>) -> Result<(), CoreError> {
+        let cfg = self.cfg();
+        let mut st = self.lock_state();
+
+        // We clear our selection when ANY OF:
+        // 1. We have an existing preedit
+        // 2. We have preedit text
+        if (st.preedit.is_some() || preedit.is_some()) && cfg.selection_clear_on_typing {
+            let _ = self.set_selection(&mut st.terminal, None);
+        }
+
+        // We always clear our prior preedit
+        st.preedit = None;
+
+        // Mark preedit dirty flag
+        st.terminal.flags.dirty.preedit = true;
+
+        // If we have no text, we're done. We queue a render in case we
+        // cleared a prior preedit (likely).
+        let Some(text) = preedit else {
+            drop(st);
+            self.queue_render();
+            return Ok(());
+        };
+
+        // We convert the UTF-8 text to codepoints.
+        let mut codepoints: Vec<PreeditCodepoint> = Vec::new();
+        for cp in text.chars() {
+            let width = usize::from(ghostty_unicode::table().get(u32::from(cp)).width);
+
+            // I've never seen a preedit text with a zero-width character. In
+            // theory its possible but we can't really handle it right now.
+            // Let's just ignore it.
+            if width == 0 {
+                continue;
+            }
+
+            codepoints.push(PreeditCodepoint {
+                codepoint: u32::from(cp),
+                wide: width >= 2,
+            });
+        }
+
+        if !codepoints.is_empty() {
+            st.preedit = Some(Preedit { codepoints });
+        }
+        drop(st);
+        self.queue_render();
+        Ok(())
+    }
+
+    /// Callback for when the surface is fully visible or not, regardless of
+    /// focus state.
+    pub fn occlusion_callback(&self, visible: bool) -> Result<(), CoreError> {
+        self.renderer_handle.send(RendererMessage::Visible(visible));
+        self.queue_render();
+        Ok(())
+    }
+
+    /// Called when the surface gains or loses focus.
+    pub fn focus_callback(&self, focused: bool) -> Result<(), CoreError> {
+        // If our focus state is the same we do nothing.
+        if self.focused.get() == focused {
+            return Ok(());
+        }
+        self.focused.set(focused);
+
+        // Notify our render thread of the new state
+        self.renderer_handle.send(RendererMessage::Focus(focused));
+
+        if focused {
+            // Notify our app if we gained focus.
+            self.app.focus_surface(self.id);
+        } else {
+            // If we lost focus and we have a keypress, then we want to send
+            // a key release event for it.
+            self.release_pressed_key_on_unfocus();
+        }
+
+        // Schedule render which also drains our mailbox
+        self.queue_render();
+
+        // Whenever our focus changes we unhide the mouse. The mouse will be
+        // hidden again if the user starts typing. This helps alleviate some
+        // buggy behavior upstream in macOS with the mouse never becoming
+        // visible again when tabbing between programs (see #2525).
+        self.show_mouse();
+
+        // Update the focus state and notify the terminal
+        self.lock_terminal().flags.focused = focused;
+        self.queue_io(IoMessage::Focused(focused));
+        Ok(())
+    }
+
+    /// Schedule a render (Zig: `refreshCallback`).
+    pub fn refresh_callback(&self) -> Result<(), CoreError> {
+        // The point of this callback is to schedule a render, so do that.
+        self.queue_render();
+        Ok(())
+    }
+
+    /// The content scale (DPI) of the surface changed.
+    pub fn content_scale_callback(&self, content_scale: ContentScale) -> Result<(), CoreError> {
+        // Calculate the new DPI
+        let x_dpi = content_scale.x * DEFAULT_DPI;
+        let y_dpi = content_scale.y * DEFAULT_DPI;
+
+        // Update our font size which is dependent on the DPI
+        let current = self.font.borrow().size;
+        let mut size = current;
+        size.xdpi = x_dpi as u16;
+        size.ydpi = y_dpi as u16;
+
+        // If our DPI didn't actually change, save a lot of work by doing
+        // nothing.
+        if size.xdpi == current.xdpi && size.ydpi == current.ydpi {
+            return Ok(());
+        }
+
+        self.set_font_size(size)?;
+
+        // Update our padding which is dependent on DPI. We only do this for
+        // unbalanced padding since balanced padding is not dependent on DPI.
+        let cfg = self.cfg();
+        if !cfg.window_padding_balance {
+            let mut s = self.size.get();
+            s.padding = cfg.scaled_padding(x_dpi, y_dpi);
+            self.size.set(s);
+        }
+
+        // Force a resize event because the change in padding will affect
+        // pixel-level changes to the renderer and viewport.
+        self.resize(self.size.get().screen);
+        Ok(())
+    }
+
+    /// The system color scheme changed.
+    pub fn color_scheme_callback(&self, scheme: ColorScheme) -> Result<(), CoreError> {
+        let new_scheme = match scheme {
+            ColorScheme::Light => conditional::Theme::Light,
+            ColorScheme::Dark => conditional::Theme::Dark,
+        };
+
+        // If our scheme didn't change, then we don't do anything.
+        let mut state = self.config_conditional_state.get();
+        if state.theme == new_scheme {
+            return Ok(());
+        }
+
+        // Setup our conditional state which has the current color theme.
+        state.theme = new_scheme;
+        self.config_conditional_state.set(state);
+        self.notify_config_conditional_state();
+
+        // If mode 2031 is on, then we report the change live.
+        self.queue_io(IoMessage::ColorSchemeReport { force: false });
+        Ok(())
+    }
+
+    /// Tell the surface to present itself to the user.
+    pub fn present_surface(&self) {
+        self.perform(RtAction::PresentTerminal);
+    }
+
+    // ------------------------------------------------------------------
+    // Renderer display lifecycle (GTK GLArea realize/unrealize)
+
+    /// Developer aid: if `GHOSTTY_DEBUG_SCREENSHOT=<path.png>` is set, write
+    /// the last presented frame to that path once, `GHOSTTY_DEBUG_SCREENSHOT_MS`
+    /// (default 2500) after the surface was created. Must be called with the
+    /// GL context current (from `draw_frame`).
+    fn debug_screenshot(&self) {
+        let Some(path) = std::env::var_os("GHOSTTY_DEBUG_SCREENSHOT") else {
+            return;
+        };
+        let delay = std::env::var("GHOSTTY_DEBUG_SCREENSHOT_MS")
+            .ok()
+            .and_then(|v| v.parse::<u64>().ok())
+            .unwrap_or(2500);
+        if self.debug_shot_done.get() || self.created.elapsed().as_millis() < u128::from(delay) {
+            return;
+        }
+        let Some((w, h, mut px)) = self.renderer.last_frame_pixels() else {
+            return;
+        };
+        self.debug_shot_done.set(true);
+        // Bottom-up RGBA -> top-down.
+        let stride = w * 4;
+        let mut flipped = Vec::with_capacity(px.len());
+        for row in px.chunks_exact_mut(stride).rev() {
+            flipped.extend_from_slice(row);
+        }
+        let write = || -> Result<(), Box<dyn std::error::Error>> {
+            let file = std::io::BufWriter::new(std::fs::File::create(&path)?);
+            let mut enc = png::Encoder::new(file, w as u32, h as u32);
+            enc.set_color(png::ColorType::Rgba);
+            enc.set_depth(png::BitDepth::Eight);
+            enc.write_header()?.write_image_data(&flipped)?;
+            Ok(())
+        };
+        match write() {
+            Ok(()) => log::info!("wrote debug screenshot to {}", path.to_string_lossy()),
+            Err(err) => log::warn!("debug screenshot failed: {err}"),
+        }
+    }
+
+    /// The GLArea was (re)realized; the GL context is current.
+    pub fn renderer_realized(&self) -> Result<(), CoreError> {
+        let rt = Rc::clone(&self.rt_surface);
+        self.renderer
+            .display_realized(|name| rt.gl_proc_address(name))?;
+        Ok(())
+    }
+
+    /// The GLArea is being unrealized; the GL context is current.
+    pub fn renderer_unrealized(&self) {
+        self.renderer.display_unrealized();
+    }
+}
+
+impl Drop for Surface {
+    /// Zig: `Surface.deinit`.
+    fn drop(&mut self) {
+        // Stop search thread
+        if let Some(s) = self.search.get_mut().take() {
+            s.deinit();
+        }
+
+        // Stop rendering thread
+        if let Some(running) = self.renderer_thread.get_mut().take() {
+            running.stop_and_join();
+        }
+
+        // Stop our IO thread
+        if let Err(err) = self.io_stop.notify() {
+            log::error!("error notifying io thread to stop, may stall err={err}");
+        }
+        if let Some(join) = self.io_thread.get_mut().take()
+            && join.join().is_err()
+        {
+            log::warn!("io thread panicked");
+        }
+
+        // Clean up our font grid
+        let key = self.font.get_mut().grid_key.clone();
+        self.app.font_grid_set.deref(&key);
+
+        log::info!("surface closed id={}", self.id);
+    }
+}
+
+/// The environment for the child: whatever the runtime wants plus the
+/// process environment (Zig: `rt_surface.defaultTermioEnv()` falling back to
+/// `getEnvMap`).
+fn rt_surface_env(rt: &dyn RtSurface) -> std::collections::HashMap<String, String> {
+    let mut env = ghostty_os::env::get_env_map();
+    for (k, v) in rt.default_termio_env() {
+        env.insert(k, v);
+    }
+    env
+}
+
+// ----------------------------------------------------------------------
+// CoreSurface (what the runtime calls)
+
+impl CoreSurface for Surface {
+    fn config(&self) -> Arc<Config> {
+        Arc::clone(&self.cfg().config)
+    }
+
+    fn key_callback(&self, event: ghostty_input::KeyEvent<'_>) -> Result<InputEffect, CoreError> {
+        Surface::key_callback(self, event)
+    }
+
+    fn preedit_callback(&self, text: Option<&str>) -> Result<(), CoreError> {
+        Surface::preedit_callback(self, text)
+    }
+
+    fn focus_callback(&self, focused: bool) -> Result<(), CoreError> {
+        Surface::focus_callback(self, focused)
+    }
+
+    fn mouse_button_callback(
+        &self,
+        state: MouseButtonState,
+        button: MouseButton,
+        mods: Mods,
+    ) -> Result<bool, CoreError> {
+        Surface::mouse_button_callback(self, state, button, mods)
+    }
+
+    fn cursor_pos_callback(&self, pos: CursorPos, mods: Option<Mods>) -> Result<(), CoreError> {
+        Surface::cursor_pos_callback(self, pos, mods)
+    }
+
+    fn scroll_callback(&self, xoff: f64, yoff: f64, mods: ScrollMods) -> Result<(), CoreError> {
+        Surface::scroll_callback(self, xoff, yoff, mods)
+    }
+
+    fn mouse_pressure_callback(&self, stage: ghostty_input::MousePressureStage, pressure: f64) {
+        Surface::mouse_pressure_callback(self, stage, pressure);
+    }
+
+    fn size_callback(&self, size: SurfaceSize) -> Result<(), CoreError> {
+        Surface::size_callback(self, size)
+    }
+
+    fn content_scale_callback(&self, scale: ContentScale) -> Result<(), CoreError> {
+        Surface::content_scale_callback(self, scale)
+    }
+
+    fn ime_point(&self) -> ImePos {
+        Surface::ime_point(self)
+    }
+
+    fn has_selection(&self) -> bool {
+        Surface::has_selection(self)
+    }
+
+    fn color_scheme_callback(&self, scheme: ColorScheme) -> Result<(), CoreError> {
+        Surface::color_scheme_callback(self, scheme)
+    }
+
+    fn update_config(&self, config: &Arc<Config>) -> Result<(), CoreError> {
+        Surface::update_config(self, config)
+    }
+
+    fn perform_binding_action(
+        &self,
+        action: &ghostty_input::binding::Action,
+    ) -> Result<bool, CoreError> {
+        Surface::perform_binding_action(self, action)
+    }
+
+    fn complete_clipboard_request(
+        &self,
+        req: ClipboardRequest,
+        data: &str,
+        confirmed: bool,
+    ) -> Result<(), ClipboardError> {
+        Surface::complete_clipboard_request(self, req, data, confirmed)
+    }
+
+    fn set_clipboard_read_allowed(&self, allow: bool) {
+        use ghostty_config::types_b::ClipboardAccess;
+        self.set_config_clipboard(
+            true,
+            if allow {
+                ClipboardAccess::Allow
+            } else {
+                ClipboardAccess::Deny
+            },
+        );
+    }
+
+    fn set_clipboard_write_allowed(&self, allow: bool) {
+        use ghostty_config::types_b::ClipboardAccess;
+        self.set_config_clipboard(
+            false,
+            if allow {
+                ClipboardAccess::Allow
+            } else {
+                ClipboardAccess::Deny
+            },
+        );
+    }
+
+    fn needs_confirm_quit(&self) -> bool {
+        Surface::needs_confirm_quit(self)
+    }
+
+    fn child_exited(&self) -> bool {
+        self.child_exited.get()
+    }
+
+    fn renderer_realized(&self) -> Result<(), CoreError> {
+        Surface::renderer_realized(self)
+    }
+
+    fn renderer_unrealized(&self) {
+        Surface::renderer_unrealized(self);
+    }
+
+    fn draw_frame(&self, _default_framebuffer: u32) -> Result<(), CoreError> {
+        // GTK's GLArea binds its own FBO before `render`; the renderer
+        // queries GL_FRAMEBUFFER_BINDING itself.
+        self.renderer.draw_frame(false)?;
+        self.debug_screenshot();
+        Ok(())
+    }
+
+    fn id(&self) -> Option<SurfaceId> {
+        Some(self.id)
+    }
+
+    fn readonly(&self) -> bool {
+        self.readonly.get()
+    }
+
+    fn grid_size(&self) -> (u32, u32) {
+        let g = self.size.get().grid();
+        (u32::from(g.columns), u32::from(g.rows))
+    }
+
+    fn font_size(&self) -> DesiredFontSize {
+        let s = self.font.borrow().size;
+        DesiredFontSize {
+            points: s.points,
+            xdpi: s.xdpi,
+            ydpi: s.ydpi,
+        }
+    }
+}

crates/ghostty-core/src/surface/mouse.rs

@@ -0,0 +1,2472 @@
+//! Mouse handling for a surface (Zig `Surface.zig`: mouse reporting, button,
+//! cursor position, scroll, selection by mouse, links).
+//!
+//! Locking rules: the renderer-state lock is only held while touching the
+//! terminal. Anything that calls into the runtime (actions, clipboard
+//! requests, opening URLs) and any message for the IO thread is collected in
+//! a [`Deferred`] and executed after the lock is released.
+
+use std::time::Instant;
+
+use ghostty_apprt::action::{Action as RtAction, MouseOverLink, OpenUrl, OpenUrlKind};
+use ghostty_apprt::runtime_api::CoreError;
+use ghostty_apprt::structs::{Clipboard, ClipboardRequest, CursorPos};
+use ghostty_config::types_a::LinkPreviews;
+use ghostty_config::types_b::{
+    CopyOnSelect, MouseShiftCapture as ConfigShiftCapture, RightClickAction,
+};
+use ghostty_input::link::{Action as LinkAction, Highlight};
+use ghostty_input::{Mods, MouseButton, MouseButtonState, MousePressureStage, ScrollMods};
+use ghostty_renderer::size::{Coordinate as SizeCoordinate, CoordinateTag, Size, SurfaceCoord};
+use ghostty_renderer::state::State as RenderStateData;
+use ghostty_terminal::page_list::{Direction, PageList, Pin, TrackedPin};
+use ghostty_terminal::point::{Coordinate as PointCoordinate, Point};
+use ghostty_terminal::screen::{Screen, SelectLine, SelectionString, SemanticClick};
+use ghostty_terminal::screen_set::Key as ScreenKey;
+use ghostty_terminal::selection::Selection;
+use ghostty_terminal::terminal::{
+    MouseEvents, MouseFormat, MouseShiftCapture as TerminalShiftCapture, ScrollViewport, Terminal,
+};
+use ghostty_termio::message::Message as IoMessage;
+use ghostty_vt::modes::Mode;
+
+use super::{MOUSE_BUTTON_COUNT, Surface};
+use crate::surface_mouse;
+
+/// Mouse state for the surface (Zig: `Surface.Mouse`).
+pub struct Mouse {
+    /// The last tracked mouse button state by button.
+    pub click_state: [MouseButtonState; MOUSE_BUTTON_COUNT],
+
+    /// The last mods state when the last mouse button (whatever it was) was
+    /// pressed or release.
+    pub mods: Mods,
+
+    /// The point at which the left mouse click happened. This is in screen
+    /// coordinates so that scrolling preserves the location. Tracked in the
+    /// page list of `left_click_screen`.
+    pub left_click_pin: Option<TrackedPin>,
+    pub left_click_screen: ScreenKey,
+
+    /// The starting xpos/ypos of the left click. Note that if scrolling
+    /// occurs, these will point to different "cells", but the xpos/ypos will
+    /// stay stable during scrolling relative to the surface.
+    pub left_click_xpos: f64,
+    pub left_click_ypos: f64,
+
+    /// The count of clicks to count double and triple clicks and so on. The
+    /// left click time was the last time the left click was done. This is
+    /// always set on the first left click.
+    pub left_click_count: u8,
+    pub left_click_time: Option<Instant>,
+
+    /// The last x/y sent for mouse reports.
+    pub event_point: Option<PointCoordinate>,
+
+    /// The pressure stage for the mouse. This should always be none if the
+    /// mouse is not pressed.
+    pub pressure_stage: MousePressureStage,
+
+    /// Pending scroll amounts for high-precision scrolls
+    pub pending_scroll_x: f64,
+    pub pending_scroll_y: f64,
+
+    /// True if the mouse is hidden
+    pub hidden: bool,
+
+    /// True if the mouse position is currently over a link.
+    pub over_link: bool,
+
+    /// The last x/y in the cursor position for links. We use this to only
+    /// process link hover events when the mouse actually moves cells.
+    pub link_point: Option<PointCoordinate>,
+}
+
+impl Default for Mouse {
+    fn default() -> Self {
+        Mouse {
+            click_state: [MouseButtonState::Release; MOUSE_BUTTON_COUNT],
+            mods: Mods::default(),
+            left_click_pin: None,
+            left_click_screen: ScreenKey::Primary,
+            left_click_xpos: 0.0,
+            left_click_ypos: 0.0,
+            left_click_count: 0,
+            left_click_time: None,
+            event_point: None,
+            pressure_stage: MousePressureStage::None,
+            pending_scroll_x: 0.0,
+            pending_scroll_y: 0.0,
+            hidden: false,
+            over_link: false,
+            link_point: None,
+        }
+    }
+}
+
+/// The type of action to report for a mouse event.
+#[derive(Debug, Clone, Copy, PartialEq, Eq)]
+enum MouseReportAction {
+    Press,
+    Release,
+    Motion,
+}
+
+/// The amount to scroll. This structure is always normalized so that
+/// negative is down, left and positive is up, right. Note that INTERNALLY,
+/// vertical scroll on our terminal uses positive for down.
+#[derive(Debug, Clone, Copy, Default)]
+struct ScrollAmount {
+    delta: isize,
+}
+
+impl ScrollAmount {
+    fn up_right(self) -> bool {
+        self.delta >= 0
+    }
+
+    fn magnitude(self) -> usize {
+        self.delta.unsigned_abs()
+    }
+}
+
+/// A link found under the mouse.
+#[derive(Debug, Clone, Copy)]
+struct Link {
+    action: LinkAction,
+    selection: Selection,
+}
+
+/// Work that must happen after the renderer lock is released.
+#[derive(Default)]
+struct Deferred {
+    actions: Vec<RtAction>,
+    io: Vec<IoMessage>,
+    render: bool,
+}
+
+impl Deferred {
+    fn run(self, s: &Surface) {
+        for m in self.io {
+            s.queue_io(m);
+        }
+        for a in self.actions {
+            s.perform(a);
+        }
+        if self.render {
+            s.queue_render();
+        }
+    }
+}
+
+// ----------------------------------------------------------------------
+// Pure selection logic
+
+/// Calculates the appropriate selection given pins and pixel x positions for
+/// the click point and the drag point, as well as mouse mods and screen size.
+#[must_use]
+pub fn mouse_selection(
+    list: &PageList,
+    click_pin: Pin,
+    drag_pin: Pin,
+    click_x: u32,
+    drag_x: u32,
+    mods: Mods,
+    size: Size,
+) -> Option<Selection> {
+    // Explanation:
+    //
+    // # Normal selections
+    //
+    // ## Left-to-right selections
+    // - The clicked cell is included if it was clicked to the left of its
+    //   threshold point and the drag location is right of the threshold
+    //   point.
+    // - The cell under the cursor (the "drag cell") is included if the drag
+    //   location is right of its threshold point.
+    //
+    // ## Right-to-left selections
+    // - The clicked cell is included if it was clicked to the right of its
+    //   threshold point and the drag location is left of the threshold
+    //   point.
+    // - The cell under the cursor (the "drag cell") is included if the drag
+    //   location is left of its threshold point.
+    //
+    // # Rectangular selections
+    //
+    // Rectangular selections are handled similarly, except that entire
+    // columns are considered rather than individual cells.
+
+    // We only include cells in the selection if the threshold point lies
+    // between the start and end points of the selection. A threshold of 60%
+    // of the cell width was chosen empirically because it felt good.
+    let threshold_point = (f64::from(size.cell.width) * 0.6).round() as u32;
+
+    // We use this to clamp the pixel positions below.
+    let max_x = (u32::from(size.grid().columns) * size.cell.width).saturating_sub(1);
+
+    // We need to know how far across in the cell the drag pos is, so we
+    // subtract the padding and then take it modulo the cell width.
+    let drag_x_frac = max_x.min(drag_x.saturating_sub(size.padding.left)) % size.cell.width;
+
+    // We figure out the fractional part of the click x position similarly.
+    let click_x_frac = max_x.min(click_x.saturating_sub(size.padding.left)) % size.cell.width;
+
+    // Whether or not this is a rectangular selection.
+    let rectangle_selection = surface_mouse::is_rectangle_select_state(mods);
+
+    // Whether the click pin and drag pin are equal.
+    let same_pin = drag_pin.eql(click_pin);
+
+    // Whether or not the end point of our selection is before the start
+    // point.
+    let end_before_start = if same_pin {
+        drag_x_frac < click_x_frac
+    } else if rectangle_selection {
+        // Special handling for rectangular selections, we only use x
+        // position.
+        match drag_pin.x.cmp(&click_pin.x) {
+            std::cmp::Ordering::Equal => drag_x_frac < click_x_frac,
+            std::cmp::Ordering::Less => true,
+            std::cmp::Ordering::Greater => false,
+        }
+    } else {
+        drag_pin.before(list, click_pin)
+    };
+
+    // Whether or not the the click pin cell should be included in the
+    // selection.
+    let include_click_cell = if end_before_start {
+        click_x_frac >= threshold_point
+    } else {
+        click_x_frac < threshold_point
+    };
+
+    // Whether or not the the drag pin cell should be included in the
+    // selection.
+    let include_drag_cell = if end_before_start {
+        drag_x_frac < threshold_point
+    } else {
+        drag_x_frac >= threshold_point
+    };
+
+    // If the click cell should be included in the selection then it's the
+    // start, otherwise we get the previous or next cell to it depending on
+    // the type and direction of the selection.
+    let start_pin = if include_click_cell {
+        click_pin
+    } else if end_before_start {
+        if rectangle_selection {
+            click_pin.left_clamp(1)
+        } else {
+            click_pin.left_wrap(list, 1).unwrap_or(click_pin)
+        }
+    } else if rectangle_selection {
+        click_pin.right_clamp(list, 1)
+    } else {
+        click_pin.right_wrap(list, 1).unwrap_or(click_pin)
+    };
+
+    // Likewise for the end pin with the drag cell.
+    let end_pin = if include_drag_cell {
+        drag_pin
+    } else if end_before_start {
+        if rectangle_selection {
+            drag_pin.right_clamp(list, 1)
+        } else {
+            drag_pin.right_wrap(list, 1).unwrap_or(drag_pin)
+        }
+    } else if rectangle_selection {
+        drag_pin.left_clamp(1)
+    } else {
+        drag_pin.left_wrap(list, 1).unwrap_or(drag_pin)
+    };
+
+    // If the click cell is the same as the drag cell and the click cell
+    // shouldn't be included, or if the cells are adjacent such that the
+    // start or end pin becomes the other cell, and that cell should not be
+    // included, then we have no selection, so we set it to null.
+    //
+    // If in rectangular selection mode, we compare columns as well.
+    if (!include_click_cell && same_pin)
+        || (!include_click_cell && rectangle_selection && click_pin.x == drag_pin.x)
+        || (!include_click_cell && end_pin.eql(click_pin))
+        || (!include_click_cell && rectangle_selection && end_pin.x == click_pin.x)
+        || (!include_drag_cell && start_pin.eql(drag_pin))
+        || (!include_drag_cell && rectangle_selection && start_pin.x == drag_pin.x)
+    {
+        return None;
+    }
+
+    // TODO: Clamp selection to the screen area, don't let it extend past the
+    // last written row.
+
+    Some(Selection::new(start_pin, end_pin, rectangle_selection))
+}
+
+/// Double-click dragging moves the selection one "word" at a time. Returns
+/// `None` when the selection should be cleared.
+fn drag_left_click_double_selection(
+    screen: &Screen,
+    click_pin: Pin,
+    drag_pin: Pin,
+    word_chars: &[u32],
+) -> Option<Selection> {
+    let list = &screen.pages;
+
+    // Get the word closest to our starting click.
+    let word_start = screen.select_word_between(click_pin, drag_pin, word_chars)?;
+
+    // Get the word closest to our current point.
+    let word_current = screen.select_word_between(drag_pin, click_pin, word_chars)?;
+
+    // If our current mouse position is before the starting position, then
+    // the selection start is the word nearest our current position.
+    if drag_pin.before(list, click_pin) {
+        Some(Selection::new(
+            word_current.start(list),
+            word_start.end(list),
+            false,
+        ))
+    } else {
+        Some(Selection::new(
+            word_start.start(list),
+            word_current.end(list),
+            false,
+        ))
+    }
+}
+
+/// Triple-click dragging moves the selection one "line" at a time. `None`
+/// means do nothing.
+fn drag_left_click_triple_selection(
+    screen: &Screen,
+    click_pin: Pin,
+    drag_pin: Pin,
+) -> Option<Selection> {
+    let list = &screen.pages;
+
+    // Get the line selection under our current drag point. If there isn't a
+    // line, do nothing.
+    let line = screen.select_line(SelectLine::new(drag_pin))?;
+
+    // Get the selection under our click point. We first try to trim
+    // whitespace if we've selected a word. But if no word exists then we
+    // select the blank line.
+    let sel = screen.select_line(SelectLine::new(click_pin)).or_else(|| {
+        screen.select_line(SelectLine {
+            whitespace: None,
+            ..SelectLine::new(click_pin)
+        })
+    })?;
+
+    if drag_pin.before(list, click_pin) {
+        Some(Selection::new(
+            line.start(list),
+            sel.end(list),
+            sel.rectangle,
+        ))
+    } else {
+        Some(Selection::new(
+            sel.start(list),
+            line.end(list),
+            sel.rectangle,
+        ))
+    }
+}
+
+/// Resolve a relative file path to an absolute path using `pwd` (Zig
+/// `resolvePathForOpening`). Returns `None` for absolute paths (use as-is),
+/// when there's no pwd, or when the resolved path doesn't exist.
+fn resolve_path_for_opening(pwd: Option<&str>, path: &str) -> Option<String> {
+    use std::path::{Component, Path, PathBuf};
+
+    if Path::new(path).is_absolute() {
+        return None;
+    }
+
+    let pwd = pwd?;
+    let joined = Path::new(pwd).join(path);
+
+    // Lexically normalize (std.fs.path.resolve).
+    let mut out = PathBuf::new();
+    for c in joined.components() {
+        match c {
+            Component::ParentDir => {
+                out.pop();
+            }
+            Component::CurDir => {}
+            other => out.push(other.as_os_str()),
+        }
+    }
+
+    if !out.exists() {
+        return None;
+    }
+    Some(out.to_string_lossy().into_owned())
+}
+
+impl Surface {
+    // ------------------------------------------------------------------
+    // Helpers
+
+    /// Returns true if mouse reporting is enabled both in the config and
+    /// the terminal state.
+    fn is_mouse_reporting(&self, t: &Terminal) -> bool {
+        self.cfg().mouse_reporting && t.flags.mouse_event != MouseEvents::None
+    }
+
+    /// Returns true if the shift modifier is allowed to be captured by
+    /// modifier events. It is up to the caller to still verify it is a
+    /// situation in which shift capture makes sense (i.e. left button, mouse
+    /// click, etc.)
+    pub(crate) fn mouse_shift_capture(&self, t: &Terminal) -> bool {
+        let cfg = self.cfg();
+
+        // Handle our never/always case where we don't need the terminal.
+        match cfg.mouse_shift_capture {
+            ConfigShiftCapture::Never => return false,
+            ConfigShiftCapture::Always => return true,
+            ConfigShiftCapture::False | ConfigShiftCapture::True => {}
+        }
+
+        // If the terminal explicitly requests it then we always allow it
+        // since we processed never/always at this point.
+        match t.flags.mouse_shift_capture {
+            TerminalShiftCapture::False => return false,
+            TerminalShiftCapture::True => return true,
+            TerminalShiftCapture::Null => {}
+        }
+
+        // Otherwise, go with the user's preference
+        matches!(cfg.mouse_shift_capture, ConfigShiftCapture::True)
+    }
+
+    /// Returns true if the mouse is currently captured by the terminal
+    /// (i.e. reporting events).
+    pub fn mouse_captured(&self) -> bool {
+        self.lock_terminal().flags.mouse_event != MouseEvents::None
+    }
+
+    /// This returns the mouse mods to consider for link highlighting or
+    /// other purposes taking into account when shift is pressed for
+    /// releasing the mouse from capture. Takes the renderer lock.
+    #[allow(dead_code)]
+    pub(crate) fn mouse_mods_with_capture(&self, mods: Mods) -> Mods {
+        let t = self.lock_terminal();
+        self.mouse_mods_with_capture_locked(&t, mods)
+    }
+
+    fn mouse_mods_with_capture_locked(&self, t: &Terminal, mods: Mods) -> Mods {
+        // In any of these scenarios, whatever mods are set (even shift) are
+        // preserved.
+        if t.flags.mouse_event == MouseEvents::None {
+            return mods;
+        }
+        if !mods.shift {
+            return mods;
+        }
+        if self.mouse_shift_capture(t) {
+            return mods;
+        }
+
+        // We have mouse capture, shift set, and we're not allowed to
+        // capture shift, so we can clear shift.
+        let mut final_ = mods;
+        final_.shift = false;
+        final_
+    }
+
+    /// Call this when modifiers change. This is safe to call even if
+    /// modifiers match the previous state.
+    ///
+    /// The renderer state mutex MUST NOT be held.
+    pub(crate) fn mods_changed(&self, mods: Mods) {
+        // The only place we keep track of mods currently is on the mouse.
+        let new_mods = {
+            let mut m = self.mouse.borrow_mut();
+            if m.mods.equal(mods) {
+                return;
+            }
+
+            // The mouse mods only contain binding modifiers since we don't
+            // want caps/num lock or sided modifiers to affect the mouse.
+            m.mods = mods.binding();
+            m.mods
+        };
+
+        // We also need to update the renderer so it knows if it should
+        // highlight links. Additionally, mark the screen as dirty so that
+        // the highlight state of all links is properly updated.
+        {
+            let mut st = self.lock_state();
+            let capture = self.mouse_mods_with_capture_locked(&st.terminal, new_mods);
+            st.mouse.mods = capture;
+
+            // We use the clear screen dirty flag to force a rebuild of all
+            // rows because changing mouse mods can affect the highlight
+            // state of a link. If there is no link this seems very wasteful
+            // but its really only one frame so it's not so bad.
+            st.terminal.flags.dirty.clear = true;
+        }
+
+        self.queue_render();
+    }
+
+    // ------------------------------------------------------------------
+    // Mouse reporting
+
+    /// Build the bytes for a mouse report (Zig `mouseReport`). Returns
+    /// `None` if nothing should be sent. The caller holds the terminal
+    /// lock and `m` is the (borrowed) mouse state.
+    fn mouse_report(
+        &self,
+        t: &Terminal,
+        m: &mut Mouse,
+        button: Option<MouseButton>,
+        action: MouseReportAction,
+        mods: Mods,
+        pos: CursorPos,
+    ) -> Option<Vec<u8>> {
+        // Mouse reporting must be enabled by both config and terminal state
+        debug_assert!(self.cfg().mouse_reporting);
+        debug_assert_ne!(t.flags.mouse_event, MouseEvents::None);
+
+        // Depending on the event, we may do nothing at all.
+        match t.flags.mouse_event {
+            MouseEvents::None => return None,
+
+            // X10 only reports clicks with mouse button 1, 2, 3. We verify
+            // the button later.
+            MouseEvents::X10 => {
+                if action != MouseReportAction::Press
+                    || !matches!(
+                        button,
+                        Some(MouseButton::Left | MouseButton::Right | MouseButton::Middle)
+                    )
+                {
+                    return None;
+                }
+            }
+
+            // Doesn't report motion
+            MouseEvents::Normal => {
+                if action == MouseReportAction::Motion {
+                    return None;
+                }
+            }
+
+            // Button must be pressed
+            MouseEvents::Button => {
+                button?;
+            }
+
+            // Everything
+            MouseEvents::Any => {}
+        }
+
+        let size = self.size.get();
+
+        // Handle scenarios where the mouse position is outside the
+        // viewport. We always report release events no matter where they
+        // happen.
+        if action != MouseReportAction::Release {
+            let max_x = size.screen.width as f32;
+            let max_y = size.screen.height as f32;
+            let pos_out_viewport = pos.x < 0.0 || pos.y < 0.0 || pos.x > max_x || pos.y > max_y;
+            if pos_out_viewport {
+                // If we don't have a motion-tracking event mode, do nothing.
+                if !t.flags.mouse_event.motion() {
+                    return None;
+                }
+
+                // If any button is pressed, we still do the report.
+                // Otherwise, we do not do the report.
+                if m.click_state
+                    .iter()
+                    .all(|s| *s == MouseButtonState::Release)
+                {
+                    return None;
+                }
+            }
+        }
+
+        // This format reports X/Y
+        let viewport_point = self.pos_to_viewport(f64::from(pos.x), f64::from(pos.y));
+
+        // Record our new point. We only want to send a mouse event if the
+        // cell changed, unless we're tracking raw pixels.
+        if action == MouseReportAction::Motion
+            && t.flags.mouse_format != MouseFormat::SgrPixels
+            && let Some(last) = m.event_point
+            && last == viewport_point
+        {
+            return None;
+        }
+        m.event_point = Some(viewport_point);
+
+        let format = t.flags.mouse_format;
+
+        // Get the code we'll actually write
+        let button_code: u8 = {
+            // Determine our initial button value
+            let mut acc: u8 = match button {
+                // Null button means motion without a button pressed
+                None => 3,
+                // Release is 3. It is NOT 3 in SGR mode because SGR can tell
+                // the application what button was released.
+                Some(_)
+                    if action == MouseReportAction::Release
+                        && format != MouseFormat::Sgr
+                        && format != MouseFormat::SgrPixels =>
+                {
+                    3
+                }
+                Some(b) => match b {
+                    MouseButton::Left => 0,
+                    MouseButton::Middle => 1,
+                    MouseButton::Right => 2,
+                    MouseButton::Four => 64,
+                    MouseButton::Five => 65,
+                    MouseButton::Six => 66,
+                    MouseButton::Seven => 67,
+                    MouseButton::Eight => 128,
+                    MouseButton::Nine => 129,
+                    _ => return None, // unsupported
+                },
+            };
+
+            // X10 doesn't have modifiers
+            if t.flags.mouse_event != MouseEvents::X10 {
+                if mods.shift {
+                    acc += 4;
+                }
+                if mods.alt {
+                    acc += 8;
+                }
+                if mods.ctrl {
+                    acc += 16;
+                }
+            }
+
+            // Motion adds another bit
+            if action == MouseReportAction::Motion {
+                acc += 32;
+            }
+
+            acc
+        };
+
+        let x = u32::from(viewport_point.x);
+        let y = viewport_point.y;
+
+        match format {
+            MouseFormat::X10 => {
+                if x > 222 || y > 222 {
+                    log::info!("X10 mouse format can only encode X/Y up to 223");
+                    return None;
+                }
+
+                // + 1 below is because our x/y is 0-indexed and the protocol
+                // wants 1
+                Some(vec![
+                    0x1b,
+                    b'[',
+                    b'M',
+                    32 + button_code,
+                    32 + x as u8 + 1,
+                    32 + y as u8 + 1,
+                ])
+            }
+
+            MouseFormat::Utf8 => {
+                let mut data = vec![0x1b, b'[', b'M', 32 + button_code];
+
+                // UTF-8 encode the x/y
+                let mut buf = [0u8; 4];
+                for v in [32 + x + 1, 32 + y + 1] {
+                    let c = char::from_u32(v)?;
+                    data.extend_from_slice(c.encode_utf8(&mut buf).as_bytes());
+                }
+                Some(data)
+            }
+
+            MouseFormat::Sgr => {
+                // Final character to send in the CSI
+                let final_ = if action == MouseReportAction::Release {
+                    'm'
+                } else {
+                    'M'
+                };
+                Some(format!("\x1b[<{button_code};{};{}{final_}", x + 1, y + 1).into_bytes())
+            }
+
+            MouseFormat::Urxvt => Some(
+                format!("\x1b[{};{};{}M", 32 + u32::from(button_code), x + 1, y + 1).into_bytes(),
+            ),
+
+            MouseFormat::SgrPixels => {
+                // Final character to send in the CSI
+                let final_ = if action == MouseReportAction::Release {
+                    'm'
+                } else {
+                    'M'
+                };
+
+                // The position has to be adjusted to the terminal space.
+                let coord = SizeCoordinate::Surface(SurfaceCoord {
+                    x: f64::from(pos.x),
+                    y: f64::from(pos.y),
+                })
+                .convert(CoordinateTag::Terminal, size);
+                let (cx, cy) = match coord {
+                    SizeCoordinate::Terminal(c) => (c.x, c.y),
+                    _ => (0.0, 0.0),
+                };
+
+                Some(
+                    format!(
+                        "\x1b[<{button_code};{};{}{final_}",
+                        cx.round() as i32,
+                        cy.round() as i32
+                    )
+                    .into_bytes(),
+                )
+            }
+        }
+    }
+
+    // ------------------------------------------------------------------
+    // Scrolling
+
+    /// Mouse scroll event. Negative is down, left. Positive is up, right.
+    ///
+    /// "Natural scrolling" is a macOS term for inverting the scroll
+    /// direction. This should be handled by the apprt implementation. At
+    /// this layer, negative is always down, left.
+    pub fn scroll_callback(
+        &self,
+        xoff: f64,
+        yoff: f64,
+        scroll_mods: ScrollMods,
+    ) -> Result<(), CoreError> {
+        // Always show the mouse again if it is hidden
+        let hidden = self.mouse.borrow().hidden;
+        if hidden {
+            self.show_mouse();
+        }
+
+        let cfg = self.cfg();
+        let size = self.size.get();
+
+        let (y, x) = {
+            let mut m = self.mouse.borrow_mut();
+
+            let y = if yoff == 0.0 {
+                ScrollAmount::default()
+            } else {
+                // We use cell_size to determine if we have accumulated
+                // enough to trigger a scroll
+                let cell_size = f64::from(size.cell.height);
+
+                // If we have precision scroll, yoff is the number of pixels
+                // to scroll. In non-precision scroll, yoff is the number of
+                // wheel ticks. Some mice are capable of reporting fractional
+                // wheel ticks, which don't necessarily get reported as
+                // precision scrolls. We normalize all scroll events to
+                // pixels by multiplying the wheel tick value and the cell
+                // size. This means that a wheel tick of 1 results in single
+                // scroll event.
+                let yoff_adjusted = if scroll_mods.precision {
+                    yoff * cfg.mouse_scroll_multiplier.precision
+                } else {
+                    // Round out the yoff to an absolute minimum of 1. macos
+                    // tries to simulate precision scrolling with non
+                    // precision events by ramping up the magnitude of the
+                    // offsets as it detects faster scrolling. Single click
+                    // (very slow) scrolls are reported with a magnitude of
+                    // 0.1 which would normally require a few clicks before
+                    // we register an actual scroll event (depending on cell
+                    // height and the mouse_scroll_multiplier setting).
+                    let yoff_max = if yoff > 0.0 {
+                        yoff.max(1.0)
+                    } else {
+                        yoff.min(-1.0)
+                    };
+
+                    yoff_max * cell_size * cfg.mouse_scroll_multiplier.discrete
+                };
+
+                // Add our previously saved pending amount to the offset to
+                // get the new offset value. The signs of the pending and
+                // yoff should match so that we move further away from zero,
+                // but we don't assert this because in theory a user could
+                // scroll in the opposite direction and undo a pending
+                // scroll.
+                let poff = m.pending_scroll_y + yoff_adjusted;
+
+                // If the new offset is less than a single unit of scroll,
+                // we save the new pending value and do not scroll yet.
+                if poff.abs() < cell_size {
+                    m.pending_scroll_y = poff;
+                    ScrollAmount::default()
+                } else {
+                    // We scroll by the number of rows in the offset and save
+                    // the remainder
+                    let amount = poff / cell_size;
+                    m.pending_scroll_y = poff - (amount * cell_size);
+
+                    // Round towards zero.
+                    ScrollAmount {
+                        delta: amount.trunc() as isize,
+                    }
+                }
+            };
+
+            // For detailed comments see the y calculation above.
+            let x = if xoff == 0.0 {
+                ScrollAmount::default()
+            } else if !scroll_mods.precision {
+                ScrollAmount {
+                    delta: xoff.round() as isize,
+                }
+            } else {
+                let poff = m.pending_scroll_x + xoff;
+                let cell_size = f64::from(size.cell.width);
+                if poff.abs() < cell_size {
+                    m.pending_scroll_x = poff;
+                    ScrollAmount::default()
+                } else {
+                    let amount = poff / cell_size;
+                    m.pending_scroll_x = poff - (amount * cell_size);
+                    ScrollAmount {
+                        delta: amount.trunc() as isize,
+                    }
+                }
+            };
+
+            (y, x)
+        };
+
+        // The cursor position is only needed when reporting; fetch it before
+        // taking the lock.
+        let pos = self.rt_surface.get_cursor_pos();
+
+        let mut writes: Vec<IoMessage> = Vec::new();
+        {
+            let mut t = self.lock_terminal();
+
+            // If we have an active mouse reporting mode, clear the
+            // selection. The selection can occur if the user uses the shift
+            // mod key to override mouse grabbing from the window.
+            if self.is_mouse_reporting(&t) {
+                let _ = self.set_selection(&mut t, None);
+            }
+
+            // If we're in alternate screen with alternate scroll enabled,
+            // then we convert to cursor keys. This only happens if we're:
+            // (1) alt screen (2) no explicit mouse reporting and (3)
+            // alt scroll mode enabled.
+            if t.screens.active_key == ScreenKey::Alternate
+                && t.flags.mouse_event == MouseEvents::None
+                && t.modes.get(Mode::MouseAlternateScroll)
+            {
+                if y.delta != 0 {
+                    // When we send mouse events as cursor keys we always
+                    // clear the selection.
+                    let _ = self.set_selection(&mut t, None);
+
+                    let seq: &'static [u8] = if t.modes.get(Mode::CursorKeys) {
+                        // cursor key: application mode
+                        if y.up_right() { b"\x1bOA" } else { b"\x1bOB" }
+                    } else {
+                        // cursor key: normal mode
+                        if y.up_right() { b"\x1b[A" } else { b"\x1b[B" }
+                    };
+                    for _ in 0..y.magnitude() {
+                        writes.push(IoMessage::write_stable(seq));
+                    }
+                }
+                drop(t);
+                for w in writes {
+                    self.queue_io(w);
+                }
+                return Ok(());
+            }
+
+            // We have mouse events, are not in an alternate scroll buffer,
+            // or have alternate scroll disabled. In this case, we just run
+            // the normal logic.
+
+            // If we're scrolling up or down, then send a mouse event.
+            if self.is_mouse_reporting(&t) {
+                let mods = self.mouse.borrow().mods;
+                for _ in 0..y.magnitude() {
+                    let button = if y.up_right() {
+                        MouseButton::Four
+                    } else {
+                        MouseButton::Five
+                    };
+                    let mut m = self.mouse.borrow_mut();
+                    if let Some(b) = self.mouse_report(
+                        &t,
+                        &mut m,
+                        Some(button),
+                        MouseReportAction::Press,
+                        mods,
+                        pos,
+                    ) {
+                        writes.push(IoMessage::write_req(&b));
+                    }
+                }
+
+                for _ in 0..x.magnitude() {
+                    let button = if x.up_right() {
+                        MouseButton::Six
+                    } else {
+                        MouseButton::Seven
+                    };
+                    let mut m = self.mouse.borrow_mut();
+                    if let Some(b) = self.mouse_report(
+                        &t,
+                        &mut m,
+                        Some(button),
+                        MouseReportAction::Press,
+                        mods,
+                        pos,
+                    ) {
+                        writes.push(IoMessage::write_req(&b));
+                    }
+                }
+
+                // If mouse reporting is on, we do not want to scroll the
+                // viewport.
+                drop(t);
+                for w in writes {
+                    self.queue_io(w);
+                }
+                return Ok(());
+            }
+
+            if y.delta != 0 {
+                // Modify our viewport, this requires a lock since it affects
+                // rendering. We have to switch signs here because our delta
+                // is negative down but our viewport is positive down.
+                t.scroll_viewport(ScrollViewport::Delta(-y.delta));
+            }
+        }
+
+        self.queue_render();
+        Ok(())
+    }
+
+    // ------------------------------------------------------------------
+    // Button
+
+    /// Called for mouse button press/release events. This will return true
+    /// if the mouse event was consumed in some way (i.e. the program is
+    /// capturing mouse events). If the event was not consumed, then false is
+    /// returned.
+    pub fn mouse_button_callback(
+        &self,
+        action: MouseButtonState,
+        button: MouseButton,
+        mods: Mods,
+    ) -> Result<bool, CoreError> {
+        let cfg = self.cfg();
+
+        // Always record our latest mouse state
+        let hidden = {
+            let mut m = self.mouse.borrow_mut();
+            let idx = button as usize;
+            if idx < MOUSE_BUTTON_COUNT {
+                m.click_state[idx] = action;
+            }
+            m.hidden
+        };
+
+        // Always show the mouse again if it is hidden
+        if hidden {
+            self.show_mouse();
+        }
+
+        // Update our modifiers if they changed
+        self.mods_changed(mods);
+
+        // This is set to true if the terminal is allowed to capture the
+        // shift modifier. Note we can do this more efficiently probably with
+        // less locking/unlocking but clicking isn't that frequent enough to
+        // be a bottleneck.
+        let shift_capture = {
+            let t = self.lock_terminal();
+            self.mouse_shift_capture(&t)
+        };
+
+        // Shift-click continues the previous mouse state if we have a
+        // selection. cursorPosCallback will also do a mouse report so we
+        // don't need to do any of the logic below.
+        if button == MouseButton::Left && action == MouseButtonState::Press {
+            let click_count = self.mouse.borrow().left_click_count;
+            if mods.shift && click_count > 0 && !shift_capture && self.has_selection() {
+                // If we are within the interval that the click would
+                // register an increment then we do not extend the selection.
+                let within_interval = self
+                    .mouse
+                    .borrow()
+                    .left_click_time
+                    .is_some_and(|t| t.elapsed().as_nanos() as u64 <= cfg.mouse_interval);
+
+                if !within_interval {
+                    let pos = self.rt_surface.get_cursor_pos();
+                    self.cursor_pos_callback(pos, None)?;
+                    return Ok(true);
+                }
+            }
+        }
+
+        if button == MouseButton::Left && action == MouseButtonState::Release {
+            // Stop selection scrolling when releasing the left mouse button
+            // but only when selection scrolling is active.
+            if self.selection_scroll_active.get() {
+                self.queue_io(IoMessage::SelectionScroll(false));
+            }
+
+            // The selection clipboard is only updated for left-click drag
+            // when the left button is released. This is to avoid the
+            // clipboard being updated on every mouse move which would be
+            // noisy.
+            if cfg.copy_on_select != CopyOnSelect::False {
+                let mut t = self.lock_terminal();
+                if let Some(prev) = t.screen().selection {
+                    let list = &t.screen().pages;
+                    let sel = Selection::new(prev.start(list), prev.end(list), prev.rectangle);
+                    self.copy_on_select(&mut t, sel);
+                }
+            }
+
+            // Handle link clicking. We want to do this before we do mouse
+            // reporting or any other mouse handling because a successfully
+            // clicked link will swallow the event.
+            let over_link = self.mouse.borrow().over_link;
+            if over_link {
+                let pos = self.rt_surface.get_cursor_pos();
+                match self.process_links(pos) {
+                    Ok(true) => return Ok(true),
+                    Ok(false) => {}
+                    Err(err) => log::warn!("error processing links err={err}"),
+                }
+            }
+
+            // Handle prompt clicking. If we released our mouse on a prompt
+            // and we support some kind of click events, then we need to move
+            // to it.
+            if self.maybe_prompt_click() {
+                return Ok(true);
+            }
+        }
+
+        // Report mouse events if enabled
+        {
+            let mut t = self.lock_terminal();
+            if self.is_mouse_reporting(&t) {
+                // If we have shift-pressed and we aren't allowed to capture
+                // it, then we do not do a mouse report.
+                if !(mods.shift && !shift_capture) {
+                    // In any other mouse button scenario without shift
+                    // pressed we clear the selection since the underlying
+                    // application can handle that in any way (i.e.
+                    // "scrolling").
+                    let _ = self.set_selection(&mut t, None);
+
+                    // We also set the left click count to 0 so that if mouse
+                    // reporting is disabled in the middle of press (before
+                    // release) we don't suddenly start selecting text.
+                    let pos = self.rt_surface.get_cursor_pos();
+                    let report_action = match action {
+                        MouseButtonState::Press => MouseReportAction::Press,
+                        MouseButtonState::Release => MouseReportAction::Release,
+                    };
+
+                    let bytes = {
+                        let mut m = self.mouse.borrow_mut();
+                        m.left_click_count = 0;
+                        let mods = m.mods;
+                        self.mouse_report(&t, &mut m, Some(button), report_action, mods, pos)
+                    };
+                    drop(t);
+                    if let Some(b) = bytes {
+                        self.queue_io(IoMessage::write_req(&b));
+                    }
+
+                    // If we're doing mouse reporting, we do not support any
+                    // other selection or highlighting.
+                    return Ok(true);
+                }
+            }
+        }
+
+        // For left button clicks we always record some information for
+        // selection/highlighting purposes.
+        if button == MouseButton::Left && action == MouseButtonState::Press {
+            self.left_press(mods, &cfg);
+        }
+
+        // Middle-click pastes from our selection clipboard
+        if button == MouseButton::Middle && action == MouseButtonState::Press {
+            let clipboard = if self.rt_surface.supports_clipboard(Clipboard::Selection) {
+                Clipboard::Selection
+            } else {
+                Clipboard::Standard
+            };
+            self.start_clipboard_request(clipboard, ClipboardRequest::Paste);
+        }
+
+        // Right-click down selects word for context menus. If the apprt
+        // doesn't implement context menus this can be a bit weird but they
+        // are supported by our two main apprts so we always do this. If we
+        // want to be careful in the future we can add a function to apprts
+        // that let's us know.
+        if button == MouseButton::Right
+            && action == MouseButtonState::Press
+            && let Some(consumed) = self.right_press(&cfg)
+        {
+            return Ok(consumed);
+        }
+
+        Ok(false)
+    }
+
+    /// Copy the selection per `copy-on-select` (the clipboard half of Zig
+    /// `setSelection`) without changing the selection.
+    fn copy_on_select(&self, t: &mut Terminal, sel: Selection) {
+        let cfg = self.cfg();
+        let format = ghostty_input::binding::CopyToClipboard::Mixed;
+        match cfg.copy_on_select {
+            CopyOnSelect::False => {}
+            CopyOnSelect::Clipboard => self.copy_selection_to_clipboards(
+                t,
+                sel,
+                &[Clipboard::Standard, Clipboard::Selection],
+                format,
+            ),
+            CopyOnSelect::True => {
+                let clipboard = if self.rt_surface.supports_clipboard(Clipboard::Selection) {
+                    Clipboard::Selection
+                } else {
+                    Clipboard::Standard
+                };
+                self.copy_selection_to_clipboards(t, sel, &[clipboard], format);
+            }
+        }
+    }
+
+    /// Left button press: record click state and start/extend selection by
+    /// click count.
+    fn left_press(&self, mods: Mods, cfg: &super::config::DerivedConfig) {
+        let pos = self.rt_surface.get_cursor_pos();
+        let (xpos, ypos) = (f64::from(pos.x), f64::from(pos.y));
+        let size = self.size.get();
+        let vp = self.pos_to_viewport(xpos, ypos);
+
+        let mut t = self.lock_terminal();
+        let active_key = t.screens.active_key;
+
+        let Some(pin) = t.screen().pages.pin(Point::Viewport(vp)) else {
+            // Weird... our viewport x/y that we just converted isn't found in
+            // our pages. This is probably a bug but we don't want to crash
+            // in releases because its harmless.
+            debug_assert!(false, "viewport pin not found");
+            return;
+        };
+        let Ok(tracked) = t.screen_mut().pages.track_pin(pin) else {
+            return;
+        };
+
+        let count = {
+            let mut m = self.mouse.borrow_mut();
+
+            // If we move our cursor too much between clicks then we reset
+            // the multi-click state.
+            if m.left_click_count > 0 {
+                let max_distance = f64::from(size.cell.width);
+                let distance = ((xpos - m.left_click_xpos).powi(2)
+                    + (ypos - m.left_click_ypos).powi(2))
+                .sqrt();
+
+                if distance > max_distance {
+                    m.left_click_count = 0;
+                }
+            }
+
+            if let Some(prev) = m.left_click_pin.take() {
+                let key = m.left_click_screen;
+                if let Some(pin_screen) = t.screens.get_mut(key) {
+                    pin_screen.pages.untrack_pin(prev);
+                }
+            }
+
+            // Store it
+            m.left_click_pin = Some(tracked);
+            m.left_click_screen = active_key;
+            m.left_click_xpos = xpos;
+            m.left_click_ypos = ypos;
+
+            // Setup our click counter and timer. If we have mouse clicks,
+            // then we check if the time elapsed is less than and our
+            // interval and if so, increase the count.
+            let now = Instant::now();
+            if m.left_click_count > 0 {
+                let since = m
+                    .left_click_time
+                    .map_or(u64::MAX, |t| now.duration_since(t).as_nanos() as u64);
+                if since > cfg.mouse_interval {
+                    m.left_click_count = 0;
+                }
+            }
+
+            m.left_click_time = Some(now);
+            m.left_click_count += 1;
+
+            // We only support up to triple-clicks.
+            if m.left_click_count > 3 {
+                m.left_click_count = 1;
+            }
+            m.left_click_count
+        };
+
+        // In all cases below, we set the selection directly rather than use
+        // `set_selection` because we want to avoid copying the selection to
+        // the selection clipboard. For left mouse clicks we only set the
+        // clipboard on release.
+        match count {
+            // Single click
+            1 => {
+                // If we have a selection, clear it. This always happens.
+                if t.screen().selection.is_some() {
+                    let _ = t.screen_mut().select(None);
+                    self.queue_render();
+                }
+            }
+
+            // Double click, select the word under our mouse. First try to
+            // detect if we're clicking on a URL to select the entire URL.
+            2 => {
+                // Try link detection without requiring modifier keys
+                let sel = self
+                    .link_at_pin(t.screen(), pin, None)
+                    .map(|l| l.selection)
+                    .or_else(|| t.screen().select_word(pin, &cfg.selection_word_chars));
+                if let Some(sel) = sel {
+                    let _ = t.screen_mut().select(Some(sel));
+                    self.queue_render();
+                }
+            }
+
+            // Triple click, select the line under our mouse
+            3 => {
+                let screen = t.screen();
+                let sel = if mods.ctrl_or_super() {
+                    screen.select_output(pin)
+                } else {
+                    screen.select_line(SelectLine::new(pin))
+                };
+                if let Some(sel) = sel {
+                    let _ = t.screen_mut().select(Some(sel));
+                    self.queue_render();
+                }
+            }
+
+            // We should be bounded by 1 to 3
+            _ => unreachable!(),
+        }
+    }
+
+    /// Right button press. Returns `Some(consumed)` if the event is
+    /// finished, `None` to fall through.
+    fn right_press(&self, cfg: &super::config::DerivedConfig) -> Option<bool> {
+        let pos = self.rt_surface.get_cursor_pos();
+        let vp = self.pos_to_viewport(f64::from(pos.x), f64::from(pos.y));
+
+        let mut paste = false;
+        let consumed;
+        {
+            let mut t = self.lock_terminal();
+
+            // Get our viewport pin
+            let Some(pin) = t.screen().pages.pin(Point::Viewport(vp)) else {
+                debug_assert!(false, "viewport pin not found");
+                return None;
+            };
+
+            match cfg.right_click_action {
+                RightClickAction::Ignore => consumed = true,
+                RightClickAction::ContextMenu => {
+                    // If we already have a selection and the selection
+                    // contains where we clicked then we don't want to modify
+                    // the selection.
+                    if let Some(prev_sel) = t.screen().selection
+                        && prev_sel.contains(&t.screen().pages, pin)
+                    {
+                        return None;
+                    }
+
+                    // The selection doesn't contain our pin, so we
+                    // create a new word selection where we clicked.
+
+                    // If there is a link at this position, we want to select
+                    // the link. Otherwise, select the word.
+                    let link = {
+                        let mods = self.mouse.borrow().mods;
+                        let mods = self.mouse_mods_with_capture_locked(&t, mods);
+                        self.link_at_pos(&t, vp, mods)
+                    };
+                    if let Some(link) = link {
+                        let _ = self.set_selection(&mut t, Some(link.selection));
+                    } else {
+                        let Some(sel) = t.screen().select_word(pin, &cfg.selection_word_chars)
+                        else {
+                            return None;
+                        };
+                        let _ = self.set_selection(&mut t, Some(sel));
+                    }
+                    drop(t);
+                    self.queue_render();
+
+                    // Don't consume so that we show the context menu in
+                    // apprt.
+                    return Some(false);
+                }
+                RightClickAction::Copy => {
+                    if let Some(sel) = t.screen().selection {
+                        self.copy_selection_to_clipboards(
+                            &t,
+                            sel,
+                            &[Clipboard::Standard],
+                            ghostty_input::binding::CopyToClipboard::Mixed,
+                        );
+                    }
+
+                    let _ = self.set_selection(&mut t, None);
+                    self.queue_render();
+                    consumed = true;
+                }
+                RightClickAction::CopyOrPaste => {
+                    if let Some(sel) = t.screen().selection {
+                        self.copy_selection_to_clipboards(
+                            &t,
+                            sel,
+                            &[Clipboard::Standard],
+                            ghostty_input::binding::CopyToClipboard::Mixed,
+                        );
+                        let _ = self.set_selection(&mut t, None);
+                        self.queue_render();
+                    } else {
+                        // We don't need to clear selection because we didn't
+                        // have one to begin with.
+                        paste = true;
+                    }
+                    consumed = true;
+                }
+                RightClickAction::Paste => {
+                    // Before we yield the lock, clear our selection if we
+                    // have one.
+                    let _ = self.set_selection(&mut t, None);
+                    self.queue_render();
+                    paste = true;
+                    consumed = true;
+                }
+            }
+        }
+
+        // Pasting can trigger a lock grab in complete clipboard request so
+        // we must not hold the lock.
+        if paste {
+            self.start_clipboard_request(Clipboard::Standard, ClipboardRequest::Paste);
+        }
+
+        // Consume the event such that the context menu is not displayed.
+        Some(consumed)
+    }
+
+    /// Handle a click on the prompt (Zig `maybePromptClick`). Returns true
+    /// if handled.
+    fn maybe_prompt_click(&self) -> bool {
+        let cfg = self.cfg();
+        let pos = self.rt_surface.get_cursor_pos();
+        let pos_vp = self.pos_to_viewport(f64::from(pos.x), f64::from(pos.y));
+
+        let t = self.lock_terminal();
+        let screen = t.screen();
+
+        // If our screen doesn't handle any prompt clicks, then we never do
+        // anything.
+        if screen.semantic_prompt.click == SemanticClick::None {
+            return false;
+        }
+
+        // If cursor-click-to-move is disabled, we don't do any prompt
+        // clicking.
+        if !cfg.cursor_click_to_move {
+            return false;
+        }
+
+        // If our cursor isn't currently at a prompt then we don't handle
+        // prompt clicks because we can't move if we're not in a prompt!
+        if !t.cursor_is_at_prompt() {
+            return false;
+        }
+
+        // If we have a selection currently, then releasing the mouse
+        // completes the selection and we don't do prompt moving.
+        if screen.selection.is_some() {
+            return false;
+        }
+
+        // Get the pin for our mouse click.
+        let Some(click_pin) = screen.pages.pin(Point::Viewport(pos_vp)) else {
+            debug_assert!(false, "viewport pin not found");
+            return false;
+        };
+
+        // Get our cursor's most current prompt.
+        let Some(cursor_pin) = screen.pages.tracked_pin(screen.cursor.page_pin) else {
+            return false;
+        };
+        let Some(prompt_pin) = cursor_pin
+            .prompt_iterator(&screen.pages, Direction::LeftUp, None)
+            .next()
+        else {
+            // This shouldn't be possible because we asserted we're at a
+            // prompt above, so we MUST find some prompt in a left_up search.
+            log::warn!("cursor is at prompt but no prompt found");
+            return false;
+        };
+
+        // If our mouse click is before the prompt, we don't move. We DO
+        // ALLOW clicks AFTER the prompt, specifically with Kitty's
+        // click_events=1 since we rely on the shell to validate out of
+        // bounds clicks. This matches Kitty's logic as best I can tell.
+        if click_pin.before(&screen.pages, prompt_pin) {
+            return false;
+        }
+
+        // At this point we've established:
+        // - Screen supports prompt clicks
+        // - Cursor is at a prompt
+        // - Click is at or below our prompt
+        let mut writes: Vec<IoMessage> = Vec::new();
+        match screen.semantic_prompt.click {
+            // Guarded at the start of this function
+            SemanticClick::None => unreachable!(),
+
+            SemanticClick::ClickEvents => {
+                // For the event, we always send a left-click press event.
+                // This matches what Kitty sends.
+                let resp = format!("\x1b[<0;{};{}M", u32::from(pos_vp.x) + 1, pos_vp.y + 1);
+
+                // Not that noisy since this only happens on prompt clicks.
+                log::debug!("sending click_events=1 event=ESC{}", &resp[1..]);
+                writes.push(IoMessage::write_req(resp.as_bytes()));
+            }
+
+            SemanticClick::Cl(_) => {
+                let app = t.modes.get(Mode::CursorKeys);
+                let left_arrow: &'static [u8] = if app { b"\x1bOD" } else { b"\x1b[D" };
+                let right_arrow: &'static [u8] = if app { b"\x1bOC" } else { b"\x1b[C" };
+
+                let mv = screen.prompt_click_move(click_pin);
+                for _ in 0..mv.left {
+                    writes.push(IoMessage::write_stable(left_arrow));
+                }
+                for _ in 0..mv.right {
+                    writes.push(IoMessage::write_stable(right_arrow));
+                }
+            }
+        }
+        drop(t);
+        for w in writes {
+            self.queue_io(w);
+        }
+
+        true
+    }
+
+    // ------------------------------------------------------------------
+    // Links
+
+    /// Returns the link at the given viewport point, if any. Requires the
+    /// renderer lock (pass the locked terminal) and the capture-adjusted
+    /// mods.
+    fn link_at_pos(&self, t: &Terminal, vp: PointCoordinate, mouse_mods: Mods) -> Option<Link> {
+        // Convert our cursor position to a screen point.
+        let screen = t.screen();
+        let Some(mouse_pin) = screen.pages.pin(Point::Viewport(vp)) else {
+            log::warn!("failed to get pin for clicked point");
+            return None;
+        };
+
+        // If we have the proper modifiers set then we can check for OSC8
+        // links.
+        if mouse_mods.equal(ghostty_input::ctrl_or_super(Mods::default()))
+            && let Some((_, cell)) = mouse_pin.row_and_cell(&screen.pages)
+            && cell.hyperlink()
+        {
+            let sel = Selection::new(mouse_pin, mouse_pin, false);
+            return Some(Link {
+                action: LinkAction::_OpenOsc8,
+                selection: sel,
+            });
+        }
+
+        // Fall back to configured links
+        self.link_at_pin(screen, mouse_pin, Some(mouse_mods))
+    }
+
+    /// Detects if a link is present at the given pin.
+    ///
+    /// If mouse mods is `None` then mouse mod requirements are ignored (all
+    /// configured links are checked).
+    fn link_at_pin(
+        &self,
+        screen: &Screen,
+        mouse_pin: Pin,
+        mouse_mods: Option<Mods>,
+    ) -> Option<Link> {
+        let cfg = self.cfg();
+        if cfg.links.is_empty() {
+            return None;
+        }
+
+        let line = screen.select_line(SelectLine {
+            pin: mouse_pin,
+            whitespace: None,
+            semantic_prompt_boundary: false,
+        })?;
+
+        let strmap = screen.selection_string_map(SelectionString {
+            sel: line,
+            trim: false,
+        });
+
+        for link in &cfg.links {
+            // Skip highlight/mods check when mouse_mods is None
+            // (double-click mode)
+            if let Some(mods) = mouse_mods {
+                match link.highlight {
+                    Highlight::Always | Highlight::Hover => {}
+                    Highlight::AlwaysMods(v) | Highlight::HoverMods(v) => {
+                        if !v.equal(mods) {
+                            continue;
+                        }
+                    }
+                }
+            }
+
+            let mut it = strmap.search_iterator(&link.regex);
+            while let Some(m) = it.next_match() {
+                let sel = m.selection();
+                if !sel.contains(&screen.pages, mouse_pin) {
+                    continue;
+                }
+                return Some(Link {
+                    action: link.action,
+                    selection: sel,
+                });
+            }
+        }
+
+        None
+    }
+
+    /// Return the URI for an OSC8 hyperlink at the given position or `None`
+    /// if there is no hyperlink.
+    fn osc8_uri(screen: &Screen, pin: Pin) -> Option<String> {
+        let node = screen.pages.node(pin.node)?;
+        let page = &node.data;
+        let idx = page
+            .cell_index(usize::from(pin.x), usize::from(pin.y))
+            .ok()?;
+        let id = page.lookup_hyperlink(idx)?;
+        let entry = page.hyperlink_set.get(id)?;
+        Some(String::from_utf8_lossy(&entry.uri).into_owned())
+    }
+
+    /// The URL of the link (`open` regex link or OSC8) under the current
+    /// cursor position, if the mouse is over a link (Zig
+    /// `copy_url_to_clipboard`). Takes the renderer lock.
+    pub(crate) fn link_url_at_cursor(&self) -> Option<String> {
+        // If the mouse isn't over a link, nothing we can do.
+        if !self.mouse.borrow().over_link {
+            return None;
+        }
+        let pos = self.rt_surface.get_cursor_pos();
+        let vp = self.pos_to_viewport(f64::from(pos.x), f64::from(pos.y));
+        let trim = self.cfg().clipboard_trim_trailing_spaces;
+
+        let t = self.lock_terminal();
+        let mods = self.mouse.borrow().mods;
+        let mods = self.mouse_mods_with_capture_locked(&t, mods);
+        let link = self.link_at_pos(&t, vp, mods)?;
+        let screen = t.screen();
+        match link.action {
+            LinkAction::Open => Some(screen.selection_string(SelectionString {
+                sel: link.selection,
+                trim,
+            })),
+            LinkAction::_OpenOsc8 => {
+                let uri = Self::osc8_uri(screen, link.selection.start(&screen.pages));
+                if uri.is_none() {
+                    log::warn!("failed to get URI for OSC8 hyperlink");
+                }
+                uri
+            }
+        }
+    }
+
+    /// Attempt to invoke the action of any link that is under the given
+    /// position. Takes the renderer lock.
+    fn process_links(&self, pos: CursorPos) -> Result<bool, CoreError> {
+        let vp = self.pos_to_viewport(f64::from(pos.x), f64::from(pos.y));
+        let url = {
+            let t = self.lock_terminal();
+            let mods = self.mouse.borrow().mods;
+            let mods = self.mouse_mods_with_capture_locked(&t, mods);
+            let Some(link) = self.link_at_pos(&t, vp, mods) else {
+                return Ok(false);
+            };
+            let screen = t.screen();
+            match link.action {
+                LinkAction::Open => {
+                    let str = screen.selection_string(SelectionString {
+                        sel: link.selection,
+                        trim: false,
+                    });
+                    let pwd = t.get_pwd().map(|p| String::from_utf8_lossy(p).into_owned());
+                    resolve_path_for_opening(pwd.as_deref(), &str).unwrap_or(str)
+                }
+
+                LinkAction::_OpenOsc8 => {
+                    let start = link.selection.start(&screen.pages);
+                    let Some(uri) = Self::osc8_uri(screen, start) else {
+                        log::warn!("failed to get URI for OSC8 hyperlink");
+                        return Ok(false);
+                    };
+                    uri
+                }
+            }
+        };
+
+        self.open_url(OpenUrl {
+            kind: OpenUrlKind::Unknown,
+            url,
+        })?;
+        Ok(true)
+    }
+
+    fn open_url(&self, action: OpenUrl) -> Result<(), CoreError> {
+        // If the apprt handles it then we're done.
+        let kind = action.kind;
+        let url = action.url.clone();
+        if self.perform(RtAction::OpenUrl(action)) {
+            return Ok(());
+        }
+
+        // apprt didn't handle it, fallback to our simple cross-platform URL
+        // opener. We log a warning because we want well-behaved apprts to
+        // handle this themselves.
+        log::warn!("apprt did not handle open URL action, falling back to default opener");
+        let kind = match kind {
+            OpenUrlKind::Unknown => ghostty_os::open::OpenUrlKind::Unknown,
+            OpenUrlKind::Text => ghostty_os::open::OpenUrlKind::Text,
+            OpenUrlKind::Html => ghostty_os::open::OpenUrlKind::Html,
+        };
+        ghostty_os::open::open(kind, &url)?;
+        Ok(())
+    }
+
+    /// Call this whenever the mouse moves or mods changed. Takes the
+    /// renderer lock; must not be called with it held.
+    pub(crate) fn mouse_refresh_links(
+        &self,
+        pos: CursorPos,
+        pos_vp: PointCoordinate,
+        over_link: bool,
+    ) -> Result<(), CoreError> {
+        let mut deferred = Deferred::default();
+        {
+            let mut st = self.lock_state();
+            self.mouse_refresh_links_locked(&mut st, pos, pos_vp, over_link, &mut deferred);
+        }
+        deferred.run(self);
+        Ok(())
+    }
+
+    fn mouse_refresh_links_locked(
+        &self,
+        st: &mut RenderStateData,
+        pos: CursorPos,
+        pos_vp: PointCoordinate,
+        over_link: bool,
+        out: &mut Deferred,
+    ) {
+        // If the position is outside our viewport, do nothing
+        if pos.x < 0.0 || pos.y < 0.0 {
+            return;
+        }
+
+        let cfg = self.cfg();
+
+        // Update the last point that we checked for links so we don't
+        // recheck if the mouse moves some pixels to the same point.
+        self.mouse.borrow_mut().link_point = Some(pos_vp);
+
+        // Get our link at the current position. This returns None if there
+        // isn't a link OR if we shouldn't be showing links for some reason
+        // (see further comments for cases).
+        let (link, preview): (Option<MouseOverLink>, bool) = 'link: {
+            // If we clicked and our mouse moved cells then we never
+            // highlight links until the mouse is unclicked. This follows
+            // standard macOS and Linux behavior where a click and drag
+            // cancels mouse actions.
+            {
+                let m = self.mouse.borrow();
+                if m.click_state[MouseButton::Left as usize] == MouseButtonState::Press
+                    && let Some(h) = m.left_click_pin
+                {
+                    let screen = st.terminal.screen();
+                    if let Some(pin) = screen.pages.tracked_pin(h)
+                        && let Some(pt) = screen
+                            .pages
+                            .point_from_pin(ghostty_terminal::point::Tag::Viewport, pin)
+                        && pt.coord() != pos_vp
+                    {
+                        log::debug!("mouse moved while left click held, ignoring link hover");
+                        break 'link (None, false);
+                    }
+                }
+            }
+
+            let mods = self.mouse.borrow().mods;
+            let mods = self.mouse_mods_with_capture_locked(&st.terminal, mods);
+            let Some(link) = self.link_at_pos(&st.terminal, pos_vp, mods) else {
+                break 'link (None, false);
+            };
+            let screen = st.terminal.screen();
+            match link.action {
+                LinkAction::Open => {
+                    let str = screen.selection_string(SelectionString {
+                        sel: link.selection,
+                        trim: false,
+                    });
+                    (
+                        Some(MouseOverLink { url: str }),
+                        cfg.link_previews == LinkPreviews::True,
+                    )
+                }
+
+                LinkAction::_OpenOsc8 => {
+                    // Show the URL in the status bar
+                    let pin = link.selection.start(&screen.pages);
+                    let Some(uri) = Self::osc8_uri(screen, pin) else {
+                        log::warn!("failed to get URI for OSC8 hyperlink");
+                        break 'link (None, false);
+                    };
+                    (
+                        Some(MouseOverLink { url: uri }),
+                        cfg.link_previews != LinkPreviews::False,
+                    )
+                }
+            }
+        };
+
+        // If we found a link, setup our internal state and notify the apprt
+        // so it can highlight it.
+        if let Some(link) = link {
+            st.mouse.point = Some(pos_vp);
+            self.mouse.borrow_mut().over_link = true;
+            st.terminal.screen_mut().dirty.hyperlink_hover = true;
+            out.actions.push(RtAction::MouseShape(
+                ghostty_vt::mouse_shape::MouseShape::Pointer,
+            ));
+
+            if preview {
+                out.actions.push(RtAction::MouseOverLink(link));
+            }
+
+            out.render = true;
+            return;
+        }
+
+        // No link, if we're previously over a link then we need to clear the
+        // over-link apprt state.
+        if over_link {
+            out.actions
+                .push(RtAction::MouseShape(st.terminal.mouse_shape));
+            out.actions.push(RtAction::MouseOverLink(MouseOverLink {
+                url: String::new(),
+            }));
+            out.render = true;
+        }
+    }
+
+    // ------------------------------------------------------------------
+    // Pressure
+
+    /// Mouse pressure (force click) callback.
+    pub fn mouse_pressure_callback(&self, stage: MousePressureStage, _pressure: f64) {
+        // We don't currently use the pressure value for anything. In the
+        // future, we could report this to applications using new mouse
+        // events or utilize it for some custom UI.
+
+        // If the pressure stage is the same as what we already have do
+        // nothing
+        let left_pressed = {
+            let mut m = self.mouse.borrow_mut();
+            if m.pressure_stage == stage {
+                return;
+            }
+
+            // Update our pressure stage.
+            m.pressure_stage = stage;
+            m.click_state[MouseButton::Left as usize] == MouseButtonState::Press
+        };
+
+        // If our left mouse button is pressed and we're entering a deep
+        // click then we want to start a selection. We treat this as a word
+        // selection since that is typical macOS behavior.
+        if left_pressed && stage == MousePressureStage::Deep {
+            let handle = self.mouse.borrow().left_click_pin;
+            let word_chars = self.cfg().selection_word_chars.clone();
+            let mut t = self.lock_terminal();
+
+            // This should always be set in this state but we don't want to
+            // handle state inconsistency here.
+            let Some(h) = handle else { return };
+            let Some(pin) = t.screen().pages.tracked_pin(h) else {
+                return;
+            };
+            let Some(sel) = t.screen().select_word(pin, &word_chars) else {
+                return;
+            };
+            if t.screen_mut().select(Some(sel)).is_ok() {
+                self.queue_render();
+            }
+        }
+    }
+
+    // ------------------------------------------------------------------
+    // Cursor position
+
+    /// Cursor position callback.
+    ///
+    /// Send negative x or y values to indicate the cursor is outside the
+    /// viewport. The magnitude of the negative values are meaningless; they
+    /// are only used to indicate the cursor is outside the viewport. It's
+    /// important to do this to ensure hover states are cleared.
+    ///
+    /// The mods parameter is optional because some apprts do not provide
+    /// modifier information on cursor position events. If mods is `None`
+    /// then we'll use the last known mods.
+    pub fn cursor_pos_callback(&self, pos: CursorPos, mods: Option<Mods>) -> Result<(), CoreError> {
+        let mut deferred = Deferred::default();
+
+        // If the position is negative, it is outside our viewport and we
+        // need to clear any hover states.
+        if pos.x < 0.0 || pos.y < 0.0 {
+            // Reset our hyperlink state
+            let was_over_link = {
+                let mut m = self.mouse.borrow_mut();
+                m.link_point = None;
+                let was = m.over_link;
+                m.over_link = false;
+                was
+            };
+            if was_over_link {
+                let shape = self.lock_terminal().mouse_shape;
+                self.perform(RtAction::MouseShape(shape));
+                self.perform(RtAction::MouseOverLink(MouseOverLink {
+                    url: String::new(),
+                }));
+                self.queue_render();
+            }
+
+            let mut st = self.lock_state();
+
+            // No mouse point so we don't highlight links
+            st.mouse.point = None;
+
+            // Mark the link's row as dirty, but continue with updating the
+            // mouse state below so we can scroll when our position is
+            // negative.
+            st.terminal.screen_mut().dirty.hyperlink_hover = true;
+        }
+
+        // Always show the mouse again if it is hidden
+        let hidden = self.mouse.borrow().hidden;
+        if hidden {
+            self.show_mouse();
+        }
+
+        // Update our modifiers if they changed
+        if let Some(v) = mods {
+            self.mods_changed(v);
+        }
+
+        // The mouse position in the viewport
+        let pos_vp = self.pos_to_viewport(f64::from(pos.x), f64::from(pos.y));
+
+        // We always reset the over link status because it will be
+        // reprocessed below. But we need the old value to know if we need to
+        // undo mouse shape changes.
+        let over_link = {
+            let mut m = self.mouse.borrow_mut();
+            let o = m.over_link;
+            m.over_link = false;
+            o
+        };
+
+        let selection_scroll_active = self.selection_scroll_active.get();
+        let size = self.size.get();
+
+        {
+            // We are reading/writing state for the remainder
+            let mut st = self.lock_state();
+
+            // Stop selection scrolling when inside the viewport within a 1px
+            // buffer for fullscreen windows, but only when selection
+            // scrolling is active.
+            if pos.y >= 1.0 && selection_scroll_active {
+                deferred.io.push(IoMessage::SelectionScroll(false));
+            }
+
+            // Update our mouse state. We set this to null initially because
+            // we only want to set it when we're not selecting or doing any
+            // other mouse event.
+            st.mouse.point = None;
+
+            // Handle link hovering. We refresh links when
+            // 1. we were previously over a link
+            // OR
+            // 2. the cursor position has changed (either we have no
+            //    previous state, or the state has changed)
+            // AND
+            // 1. mouse reporting is off
+            // OR
+            // 2. mouse reporting is on and we are not reporting shift to the
+            //    terminal
+            let (link_point, mouse_mods) = {
+                let m = self.mouse.borrow();
+                (m.link_point, m.mods)
+            };
+            if (over_link || link_point.is_none_or(|p| p != pos_vp))
+                && (st.terminal.flags.mouse_event == MouseEvents::None
+                    || (mouse_mods.shift && !self.mouse_shift_capture(&st.terminal)))
+            {
+                // If we were previously over a link, we always update. We do
+                // this so that if the text changed underneath us, even if the
+                // mouse didn't move, we update the URL hints and state
+                self.mouse_refresh_links_locked(&mut st, pos, pos_vp, over_link, &mut deferred);
+            }
+
+            // Do a mouse report
+            if self.is_mouse_reporting(&st.terminal) {
+                // Shift overrides mouse "grabbing" in the window, taken from
+                // Kitty. This only applies if there is a mouse button
+                // pressed so that movement reports are not affected.
+                let skip = mouse_mods.shift
+                    && !self.mouse_shift_capture(&st.terminal)
+                    && self
+                        .mouse
+                        .borrow()
+                        .click_state
+                        .iter()
+                        .any(|s| *s != MouseButtonState::Release);
+
+                if !skip {
+                    let mut m = self.mouse.borrow_mut();
+
+                    // We use the first mouse button we find pressed in order
+                    // to report since the spec (afaict) does not say...
+                    let button = m
+                        .click_state
+                        .iter()
+                        .position(|s| *s == MouseButtonState::Press)
+                        .and_then(button_from_index);
+
+                    let mods = m.mods;
+                    if let Some(b) = self.mouse_report(
+                        &st.terminal,
+                        &mut m,
+                        button,
+                        MouseReportAction::Motion,
+                        mods,
+                        pos,
+                    ) {
+                        deferred.io.push(IoMessage::write_req(&b));
+                    }
+
+                    // If we're doing mouse motion tracking, we do not
+                    // support text selection.
+                    drop(m);
+                    drop(st);
+                    deferred.run(self);
+                    return Ok(());
+                }
+            }
+
+            // Handle cursor position for text selection
+            let (left_pressed, count, click_screen, handle, click_xpos, sel_mods) = {
+                let m = self.mouse.borrow();
+                (
+                    m.click_state[MouseButton::Left as usize] == MouseButtonState::Press,
+                    m.left_click_count,
+                    m.left_click_screen,
+                    m.left_click_pin,
+                    m.left_click_xpos,
+                    m.mods,
+                )
+            };
+
+            // Left click pressed but count zero can happen if mouse
+            // reporting is on. In this scenario, we mark the click state
+            // because we need that to properly make some mouse reports, but
+            // we don't keep track of the count because we don't want to
+            // handle selection.
+            //
+            // If our terminal screen changed then we don't process this. We
+            // don't invalidate our pin or mouse state because if the screen
+            // switches back then we can continue our selection.
+            if left_pressed && count != 0 && click_screen == st.terminal.screens.active_key {
+                // All roads lead to requiring a re-render at this point.
+                deferred.render = true;
+
+                // If our y is negative, we're above the window. In this
+                // case, we scroll up. The amount we scroll up is dependent
+                // on how negative we are. We allow for a 1 pixel buffer at
+                // the top and bottom to detect scroll even in full screen
+                // windows.
+                let max_y = size.screen.height as f32;
+
+                // If the mouse is outside the viewport and we have the left
+                // mouse button pressed then we need to start the scroll
+                // timer.
+                if (pos.y <= 1.0 || pos.y > max_y - 1.0) && !selection_scroll_active {
+                    deferred.io.push(IoMessage::SelectionScroll(true));
+                }
+
+                // Convert to points
+                let t = &mut st.terminal;
+                let Some(pin) = t.screen().pages.pin(Point::Viewport(pos_vp)) else {
+                    debug_assert!(false, "viewport pin not found");
+                    drop(st);
+                    deferred.run(self);
+                    return Ok(());
+                };
+
+                // Handle dragging depending on click count
+                if let Some(click_pin) = handle.and_then(|h| t.screen().pages.tracked_pin(h)) {
+                    let word_chars = self.cfg().selection_word_chars.clone();
+                    match count {
+                        1 => Self::drag_left_click_single(
+                            t,
+                            click_pin,
+                            pin,
+                            click_xpos,
+                            f64::from(pos.x),
+                            sel_mods,
+                            size,
+                        ),
+                        2 => {
+                            let sel = drag_left_click_double_selection(
+                                t.screen(),
+                                click_pin,
+                                pin,
+                                &word_chars,
+                            );
+                            match sel {
+                                Some(sel) => {
+                                    let _ = t.screen_mut().select(Some(sel));
+                                }
+                                None => {
+                                    let _ = self.set_selection(t, None);
+                                }
+                            }
+                        }
+                        3 => {
+                            if let Some(sel) =
+                                drag_left_click_triple_selection(t.screen(), click_pin, pin)
+                            {
+                                let _ = t.screen_mut().select(Some(sel));
+                            }
+                        }
+                        _ => unreachable!(),
+                    }
+                }
+            }
+        }
+
+        deferred.run(self);
+        Ok(())
+    }
+
+    fn drag_left_click_single(
+        t: &mut Terminal,
+        click_pin: Pin,
+        drag_pin: Pin,
+        click_xpos: f64,
+        drag_x: f64,
+        mods: Mods,
+        size: Size,
+    ) {
+        // This logic is in a separate function so that it can be unit
+        // tested.
+        let sel = mouse_selection(
+            &t.screen().pages,
+            click_pin,
+            drag_pin,
+            click_xpos.max(0.0) as u32,
+            drag_x.max(0.0) as u32,
+            mods,
+            size,
+        );
+        let _ = t.screen_mut().select(sel);
+    }
+
+    /// Selection scrolling tick (Zig `selectionScrollTick`).
+    pub(crate) fn selection_scroll_tick(&self) -> Result<(), CoreError> {
+        // If we're no longer active then we don't do anything.
+        if !self.selection_scroll_active.get() {
+            return Ok(());
+        }
+
+        // If we don't have a left mouse button down then we don't do
+        // anything.
+        let (count, screen_key, handle, xpos, mods) = {
+            let m = self.mouse.borrow();
+            (
+                m.left_click_count,
+                m.left_click_screen,
+                m.left_click_pin,
+                m.left_click_xpos,
+                m.mods,
+            )
+        };
+        if count == 0 {
+            return Ok(());
+        }
+
+        let pos = self.rt_surface.get_cursor_pos();
+        let pos_vp = self.pos_to_viewport(f64::from(pos.x), f64::from(pos.y));
+        let delta: isize = if pos.y < 0.0 { -1 } else { 1 };
+        let size = self.size.get();
+
+        let mut t = self.lock_terminal();
+
+        // If our screen changed while this is happening, we stop our
+        // selection scroll.
+        if screen_key != t.screens.active_key {
+            drop(t);
+            self.queue_io(IoMessage::SelectionScroll(false));
+            return Ok(());
+        }
+
+        // Scroll the viewport as required
+        t.scroll_viewport(ScrollViewport::Delta(delta));
+
+        // Next, trigger our drag behavior
+        let Some(pin) = t.screen().pages.pin(Point::Viewport(pos_vp)) else {
+            debug_assert!(false, "viewport pin not found");
+            return Ok(());
+        };
+        if let Some(click_pin) = handle.and_then(|h| t.screen().pages.tracked_pin(h)) {
+            Self::drag_left_click_single(
+                &mut t,
+                click_pin,
+                pin,
+                xpos,
+                f64::from(pos.x),
+                mods,
+                size,
+            );
+        }
+
+        // We modified our viewport and selection so we need to queue a
+        // render.
+        drop(t);
+        self.queue_render();
+        Ok(())
+    }
+}
+
+/// `@enumFromInt(i)` for the click state index.
+fn button_from_index(i: usize) -> Option<MouseButton> {
+    Some(match i {
+        0 => MouseButton::Unknown,
+        1 => MouseButton::Left,
+        2 => MouseButton::Right,
+        3 => MouseButton::Middle,
+        4 => MouseButton::Four,
+        5 => MouseButton::Five,
+        6 => MouseButton::Six,
+        7 => MouseButton::Seven,
+        8 => MouseButton::Eight,
+        9 => MouseButton::Nine,
+        10 => MouseButton::Ten,
+        11 => MouseButton::Eleven,
+        _ => return None,
+    })
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+    use ghostty_renderer::size::{CellSize, Padding, ScreenSize};
+    use ghostty_terminal::screen::Options as ScreenOptions;
+
+    /// Our screen size is 10x5 cells that are 10x20 px, with 5px padding on
+    /// all sides.
+    fn test_size() -> Size {
+        Size {
+            cell: CellSize {
+                width: 10,
+                height: 20,
+            },
+            padding: Padding {
+                left: 5,
+                top: 5,
+                right: 5,
+                bottom: 5,
+            },
+            screen: ScreenSize {
+                width: 110,
+                height: 110,
+            },
+        }
+    }
+
+    struct Setup {
+        screen: Screen,
+        mods: Mods,
+        click_pin: Pin,
+        drag_pin: Pin,
+        click_x_pos: u32,
+        drag_x_pos: u32,
+    }
+
+    fn setup(click_x: f64, click_y: u32, drag_x: f64, drag_y: u32, rect: bool) -> Setup {
+        let size = test_size();
+        let screen = Screen::new(ScreenOptions::new(10, 5, 0)).unwrap();
+
+        // We hold both ctrl and alt for rectangular select so that this
+        // test is platform agnostic.
+        let mods = Mods {
+            ctrl: rect,
+            alt: rect,
+            ..Mods::default()
+        };
+        assert_eq!(rect, surface_mouse::is_rectangle_select_state(mods));
+
+        let vp = |x: f64, y: u32| {
+            Point::Viewport(PointCoordinate {
+                x: x.floor() as u16,
+                y,
+            })
+        };
+        let click_pin = screen.pages.pin(vp(click_x, click_y)).unwrap();
+        let drag_pin = screen.pages.pin(vp(drag_x, drag_y)).unwrap();
+
+        let cell_width = f64::from(size.cell.width);
+        let click_x_pos = (click_x * cell_width).floor() as u32 + size.padding.left;
+        let drag_x_pos = (drag_x * cell_width).floor() as u32 + size.padding.left;
+
+        Setup {
+            screen,
+            mods,
+            click_pin,
+            drag_pin,
+            click_x_pos,
+            drag_x_pos,
+        }
+    }
+
+    #[allow(clippy::too_many_arguments)]
+    fn test_mouse_selection(
+        click_x: f64,
+        click_y: u32,
+        drag_x: f64,
+        drag_y: u32,
+        start_x: u16,
+        start_y: u32,
+        end_x: u16,
+        end_y: u32,
+        rect: bool,
+    ) {
+        let s = setup(click_x, click_y, drag_x, drag_y, rect);
+        let start_pin = s
+            .screen
+            .pages
+            .pin(Point::Viewport(PointCoordinate {
+                x: start_x,
+                y: start_y,
+            }))
+            .unwrap();
+        let end_pin = s
+            .screen
+            .pages
+            .pin(Point::Viewport(PointCoordinate { x: end_x, y: end_y }))
+            .unwrap();
+
+        assert_eq!(
+            Some(Selection::new(start_pin, end_pin, rect)),
+            mouse_selection(
+                &s.screen.pages,
+                s.click_pin,
+                s.drag_pin,
+                s.click_x_pos,
+                s.drag_x_pos,
+                s.mods,
+                test_size(),
+            )
+        );
+    }
+
+    /// Like `test_mouse_selection` but checks that the resulting selection
+    /// is null.
+    fn test_mouse_selection_is_null(
+        click_x: f64,
+        click_y: u32,
+        drag_x: f64,
+        drag_y: u32,
+        rect: bool,
+    ) {
+        let s = setup(click_x, click_y, drag_x, drag_y, rect);
+        assert_eq!(
+            None,
+            mouse_selection(
+                &s.screen.pages,
+                s.click_pin,
+                s.drag_pin,
+                s.click_x_pos,
+                s.drag_x_pos,
+                s.mods,
+                test_size(),
+            )
+        );
+    }
+
+    #[test]
+    fn surface_selection_logic() {
+        // -- LTR
+        // single cell selection
+        test_mouse_selection(3.0, 3, 3.9, 3, 3, 3, 3, 3, false);
+        // including click and drag pin cells
+        test_mouse_selection(3.0, 3, 5.9, 3, 3, 3, 5, 3, false);
+        // including click pin cell but not drag pin cell
+        test_mouse_selection(3.0, 3, 5.0, 3, 3, 3, 4, 3, false);
+        // including drag pin cell but not click pin cell
+        test_mouse_selection(3.9, 3, 5.9, 3, 4, 3, 5, 3, false);
+        // including neither click nor drag pin cells
+        test_mouse_selection(3.9, 3, 5.0, 3, 4, 3, 4, 3, false);
+        // empty selection (single cell on only left half)
+        test_mouse_selection_is_null(3.0, 3, 3.1, 3, false);
+        // empty selection (single cell on only right half)
+        test_mouse_selection_is_null(3.8, 3, 3.9, 3, false);
+        // empty selection (between two cells, not crossing threshold)
+        test_mouse_selection_is_null(3.9, 3, 4.0, 3, false);
+
+        // -- RTL
+        // single cell selection
+        test_mouse_selection(3.9, 3, 3.0, 3, 3, 3, 3, 3, false);
+        // including click and drag pin cells
+        test_mouse_selection(5.9, 3, 3.0, 3, 5, 3, 3, 3, false);
+        // including click pin cell but not drag pin cell
+        test_mouse_selection(5.9, 3, 3.9, 3, 5, 3, 4, 3, false);
+        // including drag pin cell but not click pin cell
+        test_mouse_selection(5.0, 3, 3.0, 3, 4, 3, 3, 3, false);
+        // including neither click nor drag pin cells
+        test_mouse_selection(5.0, 3, 3.9, 3, 4, 3, 4, 3, false);
+        // empty selection (single cell on only left half)
+        test_mouse_selection_is_null(3.1, 3, 3.0, 3, false);
+        // empty selection (single cell on only right half)
+        test_mouse_selection_is_null(3.9, 3, 3.8, 3, false);
+        // empty selection (between two cells, not crossing threshold)
+        test_mouse_selection_is_null(4.0, 3, 3.9, 3, false);
+
+        // -- Wrapping
+        // LTR, wrap excluded cells
+        test_mouse_selection(9.9, 2, 0.0, 4, 0, 3, 9, 3, false);
+        // RTL, wrap excluded cells
+        test_mouse_selection(0.0, 4, 9.9, 2, 9, 3, 0, 3, false);
+    }
+
+    #[test]
+    fn surface_rectangle_selection_logic() {
+        // -- LTR
+        // single column selection
+        test_mouse_selection(3.0, 2, 3.9, 4, 3, 2, 3, 4, true);
+        // including click and drag pin columns
+        test_mouse_selection(3.0, 2, 5.9, 4, 3, 2, 5, 4, true);
+        // including click pin column but not drag pin column
+        test_mouse_selection(3.0, 2, 5.0, 4, 3, 2, 4, 4, true);
+        // including drag pin column but not click pin column
+        test_mouse_selection(3.9, 2, 5.9, 4, 4, 2, 5, 4, true);
+        // including neither click nor drag pin columns
+        test_mouse_selection(3.9, 2, 5.0, 4, 4, 2, 4, 4, true);
+        // empty selection (single column on only left half)
+        test_mouse_selection_is_null(3.0, 2, 3.1, 4, true);
+        // empty selection (single column on only right half)
+        test_mouse_selection_is_null(3.8, 2, 3.9, 4, true);
+        // empty selection (between two columns, not crossing threshold)
+        test_mouse_selection_is_null(3.9, 2, 4.0, 4, true);
+
+        // -- RTL
+        // single column selection
+        test_mouse_selection(3.9, 2, 3.0, 4, 3, 2, 3, 4, true);
+        // including click and drag pin columns
+        test_mouse_selection(5.9, 2, 3.0, 4, 5, 2, 3, 4, true);
+        // including click pin column but not drag pin column
+        test_mouse_selection(5.9, 2, 3.9, 4, 5, 2, 4, 4, true);
+        // including drag pin column but not click pin column
+        test_mouse_selection(5.0, 2, 3.0, 4, 4, 2, 3, 4, true);
+        // including neither click nor drag pin columns
+        test_mouse_selection(5.0, 2, 3.9, 4, 4, 2, 4, 4, true);
+        // empty selection (single column on only left half)
+        test_mouse_selection_is_null(3.1, 2, 3.0, 4, true);
+        // empty selection (single column on only right half)
+        test_mouse_selection_is_null(3.9, 2, 3.8, 4, true);
+        // empty selection (between two columns, not crossing threshold)
+        test_mouse_selection_is_null(4.0, 2, 3.9, 4, true);
+
+        // -- Wrapping
+        // LTR, do not wrap
+        test_mouse_selection(9.9, 2, 0.0, 4, 9, 2, 0, 4, true);
+        // RTL, do not wrap
+        test_mouse_selection(0.0, 4, 9.9, 2, 0, 4, 9, 2, true);
+    }
+
+    #[test]
+    fn resolve_path_for_opening_semantics() {
+        // Absolute paths are used as-is.
+        assert_eq!(resolve_path_for_opening(Some("/tmp"), "/etc/passwd"), None);
+        // No pwd, no resolution.
+        assert_eq!(resolve_path_for_opening(None, "foo"), None);
+        // Non-existent relative paths are not resolved.
+        assert_eq!(
+            resolve_path_for_opening(Some("/tmp"), "does-not-exist-xyz"),
+            None
+        );
+        // Existing relative path resolves, including `..`.
+        assert_eq!(
+            resolve_path_for_opening(Some("/tmp"), "../etc"),
+            Some("/etc".to_owned())
+        );
+    }
+
+    #[test]
+    fn scroll_amount_direction() {
+        let a = ScrollAmount { delta: -3 };
+        assert!(!a.up_right());
+        assert_eq!(a.magnitude(), 3);
+        assert!(ScrollAmount { delta: 2 }.up_right());
+    }
+}