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emrg: gen-assets — fall back to next renderer when icon renders transparent #722

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Merged
argszero merged 1 commit into from
Aug 12, 2026
Merged

emrg: gen-assets — fall back to next renderer when icon renders transparent #722

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85 changes: 52 additions & 33 deletions packaging/gen-assets.sh
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Original file line number Diff line number Diff line change
Expand Up @@ -28,12 +28,25 @@ if [ ! -f "$SVG" ]; then
fi

echo "==> rendering icon.svg → 1024x1024 icon.png"
# Renderer priority: rsvg-convert → Chrome/Chromium headless → sips.
# ⚡ v0.2.29 CI lesson (Build Release 31604108964): rsvg-convert (librsvg 2.58 on
# Ubuntu 24.04 / Homebrew / Windows) renders icon.svg 99.2% transparent — even
# the opaque background rect does not paint. The #705 opacity gate correctly
# caught it, but the script exited instead of falling back to the next
# renderer. Fix: each renderer's output is validated by the opacity check
# BEFORE being accepted; a blank render falls through to the next renderer.
# Only when ALL renderers produce blank output do we fail loudly.
render_svg_to_png() {
local renderer_found=0
# 1) rsvg-convert (librsvg) — full SVG + filter support
if command -v rsvg-convert >/dev/null 2>&1; then
renderer_found=1
echo " renderer: rsvg-convert"
rsvg-convert -w 1024 -h 1024 "$SVG" -o "$OUT/icon.png"
return 0
if rsvg-convert -w 1024 -h 1024 "$SVG" -o "$OUT/icon.png" \
&& check_icon_opaque; then
return 0
fi
echo " ⚠️ rsvg-convert produced a blank/transparent icon — falling back to Chrome headless" >&2
fi
# 2) Chrome/Chromium headless --screenshot (full filter support)
# Windows (Git Bash): convert /c/... → file:///C:/... so Chrome resolves the URL.
Expand All @@ -58,6 +71,7 @@ render_svg_to_png() {
"/c/Program Files/Google/Chrome/Application/chrome.exe" \
"/c/Program Files (x86)/Microsoft/Edge/Application/msedge.exe"; do
if [ -n "$chrome" ] && command -v "$chrome" >/dev/null 2>&1 || [ -x "$chrome" ] 2>/dev/null; then
renderer_found=1
echo " renderer: $chrome (headless, HTML wrapper, opaque white bg)"
HTML="$OUT/.icon-render.html"
# cygpath the wrapper page URL too — on Windows Git Bash $HTML is an MSYS
Expand All @@ -74,49 +88,46 @@ render_svg_to_png() {
<style>html,body{margin:0;padding:0;background:#fff}</style></head>
<body><img src="$SVG_URL" width="1024" height="1024"></body></html>
HTMLEOF
"$chrome" --headless --disable-gpu --hide-scrollbars --force-device-scale-factor=1 \
--allow-file-access-from-files \
--screenshot="$OUT/icon.png" --window-size=1024,1024 \
"$PAGE_URL" >/dev/null 2>&1
if "$chrome" --headless --disable-gpu --hide-scrollbars --force-device-scale-factor=1 \
--allow-file-access-from-files \
--screenshot="$OUT/icon.png" --window-size=1024,1024 \
"$PAGE_URL" >/dev/null 2>&1 \
&& check_icon_opaque; then
rm -f "$HTML"
return 0
fi
rm -f "$HTML"
return 0
echo " ⚠️ $chrome produced a blank/transparent icon — trying next renderer" >&2
fi
done
# 3) sips (macOS last resort) — 辉光（feGaussianBlur）可能丢失
if command -v sips >/dev/null 2>&1; then
renderer_found=1
echo " ⚠️ renderer: sips (last resort) — glow may be lost (feGaussianBlur unsupported)" >&2
sips -s format png "$SVG" --out "$OUT/icon.png" >/dev/null 2>&1
return 0
if sips -s format png "$SVG" --out "$OUT/icon.png" >/dev/null 2>&1 \
&& check_icon_opaque; then
return 0
fi
echo " ⚠️ sips produced a blank/transparent icon — all renderers failed" >&2
fi
if [ "$renderer_found" -eq 0 ]; then
echo "ERROR: no SVG renderer found (rsvg-convert / chrome / sips)" >&2
fi
echo "ERROR: no SVG renderer found (rsvg-convert / chrome / sips)" >&2
return 1
}
render_svg_to_png || exit 1
# sanity: non-empty 1024x1024 PNG
python3 - "$OUT/icon.png" <<'PYEOF'
import sys, struct
data = open(sys.argv[1], "rb").read()
assert data[:8] == b"\x89PNG\r\n\x1a\n", "not a PNG"
pos = 8
while pos < len(data):
ln = struct.unpack(">I", data[pos:pos+4])[0]
tag = data[pos+4:pos+8]
if tag == b"IHDR":
w, h = struct.unpack(">II", data[pos+8:pos+16])
assert (w, h) == (1024, 1024), f"expected 1024x1024, got {w}x{h}"
print(f" icon.png OK: {w}x{h}")
break
pos += 12 + ln
PYEOF

# ⚡ transparency check (rant 2026-08-12T17:25:28): Chrome headless can silently
# produce a fully-transparent PNG (SVG not painted). Fail loudly instead of
# shipping a blank icon. Sample the alpha channel; if >90% of pixels are
# transparent, the renderer failed → exit 1.
python3 - "$OUT/icon.png" <<'PYEOF'
# ⚡ transparency check (rant 2026-08-12T17:25:28 + v0.2.29 CI lesson): Chrome
# headless / rsvg-convert can silently produce a fully-transparent PNG (SVG
# not painted). Fail loudly instead of shipping a blank icon. Sample the
# alpha channel; if >90% of pixels are transparent, the renderer failed.
# Returns 0 when the icon is opaque enough (accepted), 1 when blank (caller
# falls back to the next renderer).
check_icon_opaque() {
python3 - "$OUT/icon.png" <<'PYEOF'
import sys, struct, zlib

data = open(sys.argv[1], "rb").read()
assert data[:8] == b"\x89PNG\r\n\x1a\n", "not a PNG"
pos, w, h, idat, colortype = 8, 0, 0, b"", 0
while pos < len(data):
ln = struct.unpack(">I", data[pos:pos+4])[0]
Expand All @@ -129,6 +140,11 @@ while pos < len(data):
idat += chunk
pos += 12 + ln

if (w, h) != (1024, 1024):
sys.stderr.write(f"ERROR: expected 1024x1024 PNG, got {w}x{h} — renderer failed\n")
sys.exit(1)
print(f" icon.png OK: {w}x{h}")

if colortype == 6: # RGBA — only then is transparency meaningful
raw = zlib.decompress(idat)
stride0 = w * 4 + 1
Expand All @@ -145,12 +161,15 @@ if colortype == 6: # RGBA — only then is transparency meaningful
if ratio < 0.10:
sys.stderr.write(
f"ERROR: icon.png is {1-ratio:.1%} transparent — renderer failed to paint "
"the SVG. Fix the rsvg-convert/Chrome headless path (see rant 2026-08-12T17:25:28).\n"
"the SVG. Falling back to next renderer (see rant 2026-08-12T17:25:28).\n"
)
sys.exit(1)
else:
print(f" icon.png alpha: colortype={colortype} (no alpha channel) — assumed opaque")
PYEOF
}

render_svg_to_png || exit 1

echo "==> resizing to 512/256 (stdlib area-average box filter)"
python3 - "$OUT/icon.png" "$OUT" <<'PYEOF'
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