mirror of
https://github.com/LadybirdBrowser/ladybird
synced 2026-04-25 17:25:08 +02:00
0bfe4677ae
When inline layout emits a whitespace chunk, it previously selected the surrounding text's font without checking whether that font actually contains a glyph for the whitespace codepoint. On pages that use `@font-face` rules sharded by `unicode-range` (e.g. a Roboto webfont split across one file for Cyrillic letters and another for basic Latin), the shard covering the letters is picked for an adjacent space even though the space codepoint lives in a different shard. HarfBuzz then shapes the space with a font that has no glyph for it and emits `.notdef`, rendering spaces as tofu boxes. Check `contains_glyph(space_code_point)` on each candidate in `font_for_space()` and fall through to `FontCascadeList::font_for_code_point()` for the whitespace codepoint when no surrounding font has the glyph. Fixes whitespace rendering on web.telegram.org/a.
38 lines
1.3 KiB
HTML
38 lines
1.3 KiB
HTML
<!DOCTYPE html>
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<style>
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@font-face {
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font-family: "HashFontNoSpace";
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src: url("../../Assets/HashSansNoSpace.woff");
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unicode-range: U+0041-005A;
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}
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.subset {
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font-family: "HashFontNoSpace", "SerenitySans";
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font-size: 100px;
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}
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.fallback-only {
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font-family: "SerenitySans";
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font-size: 100px;
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}
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span {
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white-space: pre;
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}
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</style>
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<script src="include.js"></script>
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<div>
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<span class="subset" id="letters-only">AB</span>
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<span class="subset" id="with-space">A B</span>
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<span class="fallback-only" id="ref-space"> </span>
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</div>
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<script>
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test(() => {
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// HashFontNoSpace covers only A–Z; the space in "A B" must come from the
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// SerenitySans fallback, not from HashFontNoSpace's .notdef glyph.
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let lettersOnlyWidth = document.getElementById("letters-only").getBoundingClientRect().width;
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let withSpaceWidth = document.getElementById("with-space").getBoundingClientRect().width;
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let fallbackSpaceWidth = document.getElementById("ref-space").getBoundingClientRect().width;
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let spaceWidth = withSpaceWidth - lettersOnlyWidth;
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println("space matches fallback: " + (Math.abs(spaceWidth - fallbackSpaceWidth) < 2));
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});
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</script>
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