ResolveIconGlyph() guarded its cache with a mutex, but the work under that
lock reached SharedFactory(), whose lazy DWriteCreateFactory() call was
unsynchronized -- and UiFontFamily()/ApplyUiFontFallback() call the same
helper without that mutex from render paths. Two window threads could both
see a null factory, both create one into the same ComPtr, leak one and race
on the raw pointer. Give SharedFactory() a lock of its own.
IconFonts() memoized its result in a function-local static initialized
exactly once. If SharedFactory() returned null or GetSystemFontCollection()
failed on that first call, the empty list was cached for the process
lifetime and every icon degraded to its text label permanently, with no
retry -- while SharedFactory() itself retried on each call, making the
failure mode asymmetric and hard to diagnose. Keep the list only once the
probe finds a font, and skip the ResolveIconGlyph cache while it is empty
so the retry is actually reachable.
The floating toolbar and the emoji panel hardcoded "Segoe Fluent Icons",
which ships with Windows 11 only. DirectWrite substitutes a font silently
instead of failing, so on Windows 10 every private-use codepoint the toolbar
draws (U+E982, U+F110, U+F138, ...) rendered as a blank box: the buttons
still worked but no longer showed any state.
Resolve the font per codepoint rather than per family, because "Segoe MDL2
Assets" is a subset of Segoe Fluent Icons and swapping the family alone would
still draw tofu wherever a glyph is missing:
- add msimeui::ResolveIconGlyph(), which probes the installed icon fonts with
IDWriteFont::HasCharacter() and returns the first family that really carries
the glyph, or no family at all;
- give every toolbar and tab icon a text label to fall back on (中/英, 半/全,
简/繁, ...) when neither font has the glyph;
- drop the unused ToolbarIconButton::SetGlyph/SetLabel, which would bypass the
resolved family.
Add unit tests for the resolver, covering the missing-glyph path that cannot
be reached on a host that has Segoe Fluent Icons installed.
Custom font fallback no longer covers the whole BMP/SIP, so Segoe UI Emoji
can paint color glyphs again; CJK still prefers Noto Sans SC then YaHei.
Drop GaussianBlur compatible targets during BeginDraw (they retained GPU
memory as the candidate window grew), grow the composition swapchain in
64px steps without shrinking, and reuse Card chrome plus cached text
formats instead of reallocating them every layout.
MenuFlyoutItem gains leading SVG icons (ID2D1SvgDocument), an optional
trailing toggle switch, and content-based width measurement so tray-style
menu items match the HTML menu layout. Default UI font is now Noto Sans SC
with Microsoft YaHei fallback via IDWriteFontFallback; CreateTextFormat
gracefully falls back when the primary family is missing.
fanlusky