311246 2026-04-01 00:20:28 -0700 Ligatures affect layout for 0 font-size 2026-04-01 16:53:24 -0700 1 1 1 Unclassified WebKit New Bugs Safari 26 Unspecified Unspecified RESOLVED FIXED https://github.com/web-platform-tests/wpt/pull/58928 BrowserCompat, InRadar P2 Normal --- 1 alexander ahmad.saleem792 ahmad.saleem792 karlcow webkit-bug-importer oldest_to_newest 2195804 0 alexander 2026-04-01 00:20:28 -0700 Here's an example of the issue: 1. I have an icon-only button. 2. I have text inside that button for accessibility tools. 3. I hide text visually using font-size: 0. 4. I use Google Manrope font that has ligatures, for this example, for double t – "tt" 5. The ligatures affect layout even though font size is 0, see the Codepen below: https://codepen.io/waterplea/pen/OPRZyex A button with "User" inside is displayed correctly, a button with "Settings" inside is off-center in Safari due to double t. 2195812 1 ahmad.saleem792 2026-04-01 00:54:36 -0700 I am able to reproduce this bug on Safari Technology Preview 240, where in second button `gear` icon is not centered like first one and is bit shifted on left side. I am not able to reproduce this bug on Chrome Canary 148.0.7766.0 (Official Build) canary (arm64) . 2195813 2 webkit-bug-importer 2026-04-01 00:54:42 -0700 <rdar://problem/173840866> 2195815 3 ahmad.saleem792 2026-04-01 01:04:37 -0700 First bit in: void ComplexTextController::collectComplexTextRuns() We have the early return where if computedSize of font is `0`, we early return. if (!m_end || !m_fontCascade->size()) return; So it might fallback to Simple Text Run. 2195816 4 ahmad.saleem792 2026-04-01 01:05:56 -0700 We might be missing same guard in SimpleTextRun and need to skip this bit. 2195830 5 ahmad.saleem792 2026-04-01 01:51:33 -0700 This fixes it: Source/WebCore/platform/graphics/coretext/FontCoreText.cpp Font::applyTransforms if (!platformData().size()) return makeGlyphBufferAdvance(); Before auto handler = ^(CFRange range, CGGl 2195831 6 478873 karlcow 2026-04-01 01:59:47 -0700 Created attachment 478873 wpt-testcase Working locally with https://wpt.live/ To be removed before uploading with the patch. 2195833 7 ahmad.saleem792 2026-04-01 02:17:29 -0700 Pull request: https://github.com/WebKit/WebKit/pull/61819 2196033 8 ews-feeder 2026-04-01 15:23:11 -0700 Committed 310394@main (36d29c6355ca): <https://commits.webkit.org/310394@main> Reviewed commits have been landed. Closing PR #61819 and removing active labels. 2196076 9 ahmad.saleem792 2026-04-01 16:53:24 -0700 Submitted web-platform-tests pull request: https://github.com/web-platform-tests/wpt/pull/58928 478873 2026-04-01 01:59:47 -0700 2026-04-01 01:59:47 -0700 wpt-testcase font-size-zero-ligature-001.html text/html 2481 karlcow PCFET0NUWVBFIGh0bWw+CjxtZXRhIGNoYXJzZXQ9InV0Zi04Ij4KPHRpdGxlPmZvbnQtc2l6ZTog MCB3aXRoIGxpZ2F0dXJlcyBzaG91bGQgbm90IGFmZmVjdCBsYXlvdXQ8L3RpdGxlPgo8bGluayBy ZWw9ImhlbHAiIGhyZWY9Imh0dHBzOi8vZHJhZnRzLmNzc3dnLm9yZy9jc3MtZm9udHMtNC8jZm9u dC1zaXplLXByb3AiPgo8bGluayByZWw9ImhlbHAiIGhyZWY9Imh0dHBzOi8vYnVncy53ZWJraXQu b3JnL3Nob3dfYnVnLmNnaT9pZD0zMTEyNDYiPgo8c2NyaXB0IHNyYz0iaHR0cHM6Ly93cHQubGl2 ZS9yZXNvdXJjZXMvdGVzdGhhcm5lc3MuanMiPjwvc2NyaXB0Pgo8c2NyaXB0IHNyYz0iaHR0cHM6 Ly93cHQubGl2ZS9yZXNvdXJjZXMvdGVzdGhhcm5lc3NyZXBvcnQuanMiPjwvc2NyaXB0Pgo8c3R5 bGU+CkBmb250LWZhY2UgewogIGZvbnQtZmFtaWx5OiAiTGF0b0xpZ2EiOwogIHNyYzogdXJsKCJo dHRwczovL3dwdC5saXZlL2ZvbnRzL0xhdG8tTWVkaXVtLUxpZ2EudHRmIik7Cn0KCi5jb250YWlu ZXIgewogIGRpc3BsYXk6IGlubGluZS1ibG9jazsKICBmb250LWZhbWlseTogIkxhdG9MaWdhIiwg c2VyaWY7Cn0KCi56ZXJvIHsKICBmb250LXNpemU6IDA7Cn0KPC9zdHlsZT4KPGJvZHk+CjxkaXYg aWQ9ImxvZyI+PC9kaXY+Cgo8IS0tIFJlZmVyZW5jZTogZW1wdHkgY29udGFpbmVyIC0tPgo8ZGl2 IGNsYXNzPSJjb250YWluZXIiIGlkPSJlbXB0eSI+PC9kaXY+Cgo8IS0tIFRleHQgd2l0aG91dCBs aWdhdHVyZSwgZm9udC1zaXplOiAwIC0tPgo8ZGl2IGNsYXNzPSJjb250YWluZXIiPjxzcGFuIGNs YXNzPSJ6ZXJvIiBpZD0ibm8tbGlnYSI+YWI8L3NwYW4+PC9kaXY+Cgo8IS0tIFRleHQgd2l0aCBm aSBsaWdhdHVyZSwgZm9udC1zaXplOiAwIC0tPgo8ZGl2IGNsYXNzPSJjb250YWluZXIiPjxzcGFu IGNsYXNzPSJ6ZXJvIiBpZD0id2l0aC1saWdhIj5maTwvc3Bhbj48L2Rpdj4KCjwhLS0gVGV4dCB3 aXRoIG11bHRpcGxlIGxpZ2F0dXJlIHBhaXJzLCBmb250LXNpemU6IDAgLS0+CjxkaXYgY2xhc3M9 ImNvbnRhaW5lciI+PHNwYW4gY2xhc3M9Inplcm8iIGlkPSJtdWx0aS1saWdhIj5mZmkgZmZsPC9z cGFuPjwvZGl2PgoKPHNjcmlwdD4Kc2V0dXAoeyBleHBsaWNpdF9kb25lOiB0cnVlIH0pOwoKZG9j dW1lbnQuZm9udHMucmVhZHkudGhlbigoKSA9PiB7CiAgY29uc3QgZW1wdHkgPSBkb2N1bWVudC5n ZXRFbGVtZW50QnlJZCgiZW1wdHkiKTsKICBjb25zdCBub0xpZ2EgPSBkb2N1bWVudC5nZXRFbGVt ZW50QnlJZCgibm8tbGlnYSIpOwogIGNvbnN0IHdpdGhMaWdhID0gZG9jdW1lbnQuZ2V0RWxlbWVu dEJ5SWQoIndpdGgtbGlnYSIpOwogIGNvbnN0IG11bHRpTGlnYSA9IGRvY3VtZW50LmdldEVsZW1l bnRCeUlkKCJtdWx0aS1saWdhIik7CgogIHRlc3QoKCkgPT4gewogICAgYXNzZXJ0X2VxdWFscyhu b0xpZ2Eub2Zmc2V0V2lkdGgsIDAsCiAgICAgICJUZXh0IHdpdGhvdXQgbGlnYXR1cmUgYXQgZm9u dC1zaXplOiAwIHNob3VsZCBoYXZlIHplcm8gd2lkdGgiKTsKICB9LCAiZm9udC1zaXplOiAwIHdp dGhvdXQgbGlnYXR1cmUgcHJvZHVjZXMgemVybyB3aWR0aCIpOwoKICB0ZXN0KCgpID0+IHsKICAg IGFzc2VydF9lcXVhbHMod2l0aExpZ2Eub2Zmc2V0V2lkdGgsIDAsCiAgICAgICJUZXh0IHdpdGgg ZmkgbGlnYXR1cmUgYXQgZm9udC1zaXplOiAwIHNob3VsZCBoYXZlIHplcm8gd2lkdGgiKTsKICB9 LCAiZm9udC1zaXplOiAwIHdpdGggZmkgbGlnYXR1cmUgcHJvZHVjZXMgemVybyB3aWR0aCIpOwoK ICB0ZXN0KCgpID0+IHsKICAgIGFzc2VydF9lcXVhbHMobXVsdGlMaWdhLm9mZnNldFdpZHRoLCAw LAogICAgICAiVGV4dCB3aXRoIG11bHRpcGxlIGxpZ2F0dXJlcyBhdCBmb250LXNpemU6IDAgc2hv dWxkIGhhdmUgemVybyB3aWR0aCIpOwogIH0sICJmb250LXNpemU6IDAgd2l0aCBtdWx0aXBsZSBs aWdhdHVyZXMgcHJvZHVjZXMgemVybyB3aWR0aCIpOwoKICB0ZXN0KCgpID0+IHsKICAgIGNvbnN0 IGVtcHR5V2lkdGggPSBlbXB0eS5wYXJlbnRFbGVtZW50ID8gZW1wdHkub2Zmc2V0V2lkdGggOiAw OwogICAgY29uc3Qgbm9MaWdhUGFyZW50V2lkdGggPSBub0xpZ2EuY2xvc2VzdCgiLmNvbnRhaW5l ciIpLm9mZnNldFdpZHRoOwogICAgY29uc3Qgd2l0aExpZ2FQYXJlbnRXaWR0aCA9IHdpdGhMaWdh LmNsb3Nlc3QoIi5jb250YWluZXIiKS5vZmZzZXRXaWR0aDsKICAgIGFzc2VydF9lcXVhbHMobm9M aWdhUGFyZW50V2lkdGgsIHdpdGhMaWdhUGFyZW50V2lkdGgsCiAgICAgICJDb250YWluZXJzIHdp dGggZm9udC1zaXplOiAwIHRleHQgc2hvdWxkIGJlIHRoZSBzYW1lIHdpZHRoIHJlZ2FyZGxlc3Mg b2YgbGlnYXR1cmVzIik7CiAgfSwgIkxpZ2F0dXJlIHRleHQgYW5kIG5vbi1saWdhdHVyZSB0ZXh0 IGF0IGZvbnQtc2l6ZTogMCBwcm9kdWNlIGlkZW50aWNhbCBjb250YWluZXIgd2lkdGgiKTsKCiAg ZG9uZSgpOwp9KTsKPC9zY3JpcHQ+CjwvYm9keT4K