Files
ghostty-rs/scripts/visual-parity/compare.py
T
ddidderr ce9373aa7a feat: visual parity with the original Ghostty (pixel-diff pipeline)
Adds scripts/visual-parity.sh (`just visual-parity`): launches the
installed Ghostty 1.3.1 and the Rust build in an isolated headless
nested weston (GL renderer, Mesa forced, weston-screenshooter via
--debug), with identical isolated config, a deterministic test page
(ASCII, ligatures, all SGR styles and underline kinds, 16/256/truecolor,
box/block/braille/powerline/nerd icons, CJK, emoji, wide chars,
cursor) and a tabs+splits scenario driven through Xwayland, then diffs
the captures (terminal area and chrome separately, heatmaps).

Fixes found by comparing against the original:
- A pane stayed blank after a nested split: the GTK render path called
  draw_frame(false) where Ghostty uses drawFrame(true) (a re-realized
  GLArea has a new swap chain that nothing else redraws).
- Sprite glyph antialiasing now ports z2d's default 4x4 multisample
  rasterizer instead of tiny-skia's analytic coverage (pixels differing
  from Ghostty's reference sprite sheets: 5.76% -> 1.20%, none off by
  more than 96 levels); the sheet test tolerance is tightened to 0.1%.

Result vs Ghostty 1.3.1: test page 0.020% of pixels differ (196 px at
curly-underline ends and diagonal box strokes, max delta 86 levels);
tabs+splits and headerbar/tab bar are bit-identical. Details in
docs/rewrite/notes/visual-parity-VP.md.

Test Plan:
- just visual-parity (needs weston, weston-screenshooter, xdotool)
- cargo test -p ghostty-font (sprite sheet comparison)
2026-10-12 13:52:22 +02:00

55 lines
1.7 KiB
Python
Executable File

#!/usr/bin/env python3
"""Pixel compare two PNG captures: stats + diff heatmap.
usage: compare.py REF.png RUST.png DIFF.png [--crop x,y,w,h] [--name NAME]
Prints one line: name, size, differing pixels (%), >8 / >32 levels, max delta, mean delta.
"""
import sys
import numpy as np
from PIL import Image
def main():
a = sys.argv[1:]
crop = None
name = "all"
pos = []
i = 0
while i < len(a):
if a[i] == "--crop":
crop = tuple(int(v) for v in a[i + 1].split(","))
i += 2
elif a[i] == "--name":
name = a[i + 1]
i += 2
else:
pos.append(a[i])
i += 1
ref = Image.open(pos[0]).convert("RGB")
rs = Image.open(pos[1]).convert("RGB")
if crop:
x, y, w, h = crop
ref, rs = ref.crop((x, y, x + w, y + h)), rs.crop((x, y, x + w, y + h))
if ref.size != rs.size:
print(f"{name}: SIZE MISMATCH {ref.size} vs {rs.size}")
w, h = min(ref.size[0], rs.size[0]), min(ref.size[1], rs.size[1])
ref, rs = ref.crop((0, 0, w, h)), rs.crop((0, 0, w, h))
r = np.asarray(ref).astype(int)
s = np.asarray(rs).astype(int)
d = np.abs(r - s).max(axis=2)
n = d.size
diff = int((d > 0).sum())
print(
f"{name}: {ref.size[0]}x{ref.size[1]} differing={diff} ({100*diff/n:.3f}%) "
f">8={100*(d>8).sum()/n:.3f}% >32={100*(d>32).sum()/n:.3f}% max={d.max()} mean={d.mean():.4f}"
)
# heatmap: dimmed reference with differences in red (intensity ~ delta)
heat = (r * 0.25).astype(np.uint8)
m = np.clip(d * 4, 0, 255).astype(np.uint8)
heat[..., 0] = np.maximum(heat[..., 0], m)
heat[..., 1] = np.where(m > 0, heat[..., 1] // 2, heat[..., 1])
Image.fromarray(heat).save(pos[2])
main()