Ports main_wasm.zig as crates/ghostty-wasm (cdylib exporting the Zig
names: atlas_*, face_*, deferred_face_*, shaper_*, config_*), the
web_canvas font face and shaper (backend selected on wasm32), os/wasm
(logging, target, JS interop) and config/Wasm.zig.
C-library dependencies (freetype, harfbuzz, fontconfig, onig, gettext,
D-Bus, rustix) are target-gated. Like Zig's wasm build, link regex
search (StringMap::search_iterator) is unavailable without Oniguruma;
Collection/SharedGrid/harfbuzz are compiled out on wasm32. ghostty-os
switches from forbid to deny unsafe_code for the JS import blocks.
The JS import ABI is currently a documented handle-based interface with
a reference host (js/ghostty_host.js); aligning it with zig-js's exact
import names follows separately.
Test Plan:
- cargo build --target wasm32-unknown-unknown -p ghostty-font \
-p ghostty-config -p ghostty-terminal -p ghostty-vt -p ghostty-wasm
- cargo test -p ghostty-wasm (node runs the module against a fake canvas)
rustfmt.toml sets group_imports, imports_granularity and imports_layout,
which are nightly-only; agents formatted with stable rustfmt, which
ignored them. This is a formatting-only pass with `cargo +nightly fmt`.
Test Plan:
- cargo clippy --workspace --all-targets -- -D warnings
- cargo test --workspace
Completes the font engine port:
- shaper/run.rs ports run.zig: the RunIterator over terminal rows that
splits text runs at style/face boundaries, selection and cursor,
handles graphemes and ligatures; Shaper::shape_run shapes a run.
- shared_grid_set.rs ports SharedGridSet.zig: grids keyed by a config
derived key, handed out as Arc<SharedGrid>.
- Font-related types now have one canonical definition in ghostty-config
(Variation, Descriptor, CodepointMap, metric modifiers, freetype load
flags, synthetic style, shaping break) which the font crate re-exports.
MetricModifier::apply_i32 now saturates to -i32::MAX like Zig.
- The 23 terminal-driven harfbuzz shaper tests are ported, printing via
Screen until Terminal lands.
Test Plan:
- cargo test -p ghostty-font (157 passed, 3 ignored - also skipped in
Zig); Devanagari/Chakma/Bengali tests return early without system fonts
- cargo test -p ghostty-config (255 passed)
Ports ZIG/src/font/{Metrics,Atlas,Glyph}.zig and the whole sprite font
(font/sprite/**): box drawing, block elements, braille, branch/git
graph symbols, geometric shapes, powerline, and the symbols for legacy
computing (+ supplement, incl. the octants table).
Ghostty draws sprites with z2d; we use tiny-skia for path coverage,
composited onto an alpha8 canvas, while following the Zig geometry
(positions, thickness, rounding). Comptime discovery of draw functions
is replaced by explicit, overlap-checked codepoint range tables.
Upstream reference sheets are vendored in testdata/ and compared with a
tolerance: braille and U+1CD00 are pixel-identical; other sheets differ
only in antialiasing on thin diagonals/curves. Review renders are written
to target/sprite_sheets/.
The crate temporarily drops its config/unicode/terminal deps until the
rest of the font engine is ported (Phase 3).
Test Plan:
- cargo test -p ghostty-font (49 tests incl. reference sheet comparison)
- inspect target/sprite_sheets/review-all-18x36.png
ddidderr