Titles in math-alphanumeric Unicode (𝙌𝙐𝙀…) show as boxes: Wine's DirectWrite fallback has no entry for U+1D400–1D7FF #12

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opened 2026-10-28 17:12:45 +01:00 by The_Void · 0 comments

The_Void commented

2026-10-28 17:12:45 +01:00

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Song titles written in Unicode's Mathematical Alphanumeric Symbols (U+1D400–1D7FF, e.g. 𝙌𝙐𝙀𝘿𝘼𝙏𝙀, common in titles from the web) draw as boxes in iTunes under Wine. The same track synced through iCloud Music Library shows the right title on the iPhone (operator, 2026-10-28), so the data is fine and only the rendering is affected.

Where it is drawn: a WINEDEBUG=+dwrite run while the Songs list was on screen shows iTunes laying text out with DirectWrite (dwritetextlayout_*, 1230 fontfallback_MapCharacters calls, all with base family L"Tahoma"). Wine's DirectWrite system fallback is the hard-coded system_fallback_config[] in dlls/dwrite/analyzer.c (wine-11.20). It has no range covering 1D400–1D7FF, and fallback_map_characters reads no registry override, so those characters stay on Tahoma, which has no glyphs for them.

Tried, no effect (both reverted):

GDI FontLink (HKLM\...\FontLink\SystemLink, Noto Sans Math behind Segoe UI/Tahoma/Arial/…): GDI-only, and DirectWrite ignores it.
Appending NotoSansMath-Regular to CoreText's CoreText.resources\DefaultFontFallbacks.plist and installing the font into C:\windows\Fonts: iTunes loads CoreText.dll, but the list view doesn't render through it.

Possible fixes, not done:

Upstream Wine: add { "1D400-1D7FF", L"Noto Sans Math" } to system_fallback_config (Fedora: google-noto-sans-math-fonts, which has the glyphs, PostScript name NotoSansMath-Regular). This is the real fix and needs a WineHQ bug or MR.
A merged font that adds the math glyphs to a Tahoma installed in the prefix. Fiddly (unitsPerEm 2048 vs 1000), so not attempted.

Low priority: cosmetic, and only in iTunes' own lists.

Song titles written in Unicode's Mathematical Alphanumeric Symbols (U+1D400–1D7FF, e.g. `𝙌𝙐𝙀𝘿𝘼𝙏𝙀`, common in titles from the web) draw as boxes in iTunes under Wine. The same track synced through iCloud Music Library shows the right title on the iPhone (operator, 2026-10-28), so the data is fine and only the rendering is affected. **Where it is drawn:** a `WINEDEBUG=+dwrite` run while the Songs list was on screen shows iTunes laying text out with DirectWrite (`dwritetextlayout_*`, 1230 `fontfallback_MapCharacters` calls, all with base family `L"Tahoma"`). Wine's DirectWrite system fallback is the hard-coded `system_fallback_config[]` in `dlls/dwrite/analyzer.c` (wine-11.20). It has **no range covering 1D400–1D7FF**, and `fallback_map_characters` reads no registry override, so those characters stay on Tahoma, which has no glyphs for them. **Tried, no effect (both reverted):** - GDI FontLink (`HKLM\...\FontLink\SystemLink`, Noto Sans Math behind Segoe UI/Tahoma/Arial/…): GDI-only, and DirectWrite ignores it. - Appending `NotoSansMath-Regular` to CoreText's `CoreText.resources\DefaultFontFallbacks.plist` and installing the font into `C:\windows\Fonts`: iTunes loads CoreText.dll, but the list view doesn't render through it. **Possible fixes, not done:** 1. Upstream Wine: add `{ "1D400-1D7FF", L"Noto Sans Math" }` to `system_fallback_config` (Fedora: `google-noto-sans-math-fonts`, which has the glyphs, PostScript name `NotoSansMath-Regular`). This is the real fix and needs a WineHQ bug or MR. 2. A merged font that adds the math glyphs to a Tahoma installed in the prefix. Fiddly (unitsPerEm 2048 vs 1000), so not attempted. Low priority: cosmetic, and only in iTunes' own lists.

The_Void added the

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Claude

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2026-10-28 17:12:45 +01:00

The_Void referenced this issue

2026-10-28 17:14:56 +01:00

Real run on the Fedora desktop: install, play own MP3s, pair, sync and back up the iPhone #9

The_Void referenced this issue from a commit

2026-10-28 17:18:56 +01:00

Desktop run: usbmuxd bridge as a user unit, iPhone seen, README