Hard SDROP avalanches froze lastRaw while zoom still crawled; soft-clamp
and re-anchor instead. Ballpoint is near-solid, pencil uses soft √p without
multiply stacking; PDF ink falls back to nearest page during zoom settle.
Co-authored-by: Cursor <cursoragent@cursor.com>
Honor each brush's opacity/blend so the brushes feel distinct
(closes TODO(brush-opacity)).
- Shared paint resolver: a stroke's color alpha is multiplied by its
brush opacity; ballpoint/pencil opacity is tied to pressure
(per-stroke average this increment) so a ballpoint reads lighter
than a solid fountain pen.
- Highlighter paints with BlendMode.multiply and draws once, so
cross-stroke overlap darkens like a real marker while self-overlap
doesn't.
- Applied across BOTH render paths (PenCanvas static/live painters and
the PDF _PageOverlayPainter).
Pencil paper-grain texture still deferred (TODO brush-texture); brush
kind is not yet serialized (TODO brush-persist — next). analyze clean,
tests green.
