Material Symbol icons were allocating a fresh Font wrapper on every
composition (Font(resource = ...) returns a new instance each call),
which invalidated the remember(font) cache in rememberMaterialSymbolsFontFamily
and forced a fresh TextMeasurer per call site. Tint was also baked into
the TextStyle passed to measure(), so any tint change (selected /
unselected reaction icons, hover states) produced a cache miss.
Hoist the FontFamily + TextMeasurer to CompositionLocals provided once
at the root (AmethystTheme on Android, MaterialTheme wrapper on desktop)
via ProvideMaterialSymbols. Every icon in the subtree now reuses:
- One FontFamily (Skia typeface cache hit for every subsequent glyph)
- One TextMeasurer with a 64-entry LRU, shared across all call sites
so its measurement cache is hit across 300+ MaterialSymbols usages
- Tint applied via drawText(layout, color = tint) instead of TextStyle,
so the measured TextLayoutResult is reused across tint variations
Icon(symbol = ...) now delegates to Material3's Icon(painter = ...),
restoring proper sizing/semantics without the custom Box+drawBehind
workaround. autoMirror handled inside the painter's onDraw. The
previously-unused MaterialSymbolPainter is now the single render path.
The weight parameter is dropped from the Icon/Painter APIs since the
app uses a single weight globally (MaterialSymbolsDefaults.WEIGHT).
A local fallback path keeps @Preview composables that don't wrap in
the theme renderable (per-composition allocation, same cost as before).
https://claude.ai/code/session_01V9esGUFH72ujCQNWCAnjKN
Claude
72bef059f2