Per docs/pmacs-gpu-perline-reshape-framing.md. Every keystroke ran a
full visible-slice reshape: rebuild all rich chunks, set_rich_text
(resets every BufferLine's shape cache), shape_until_scroll re-shapes
every visible line with Shaping::Advanced. Now a single-line edit —
the keystroke case — rebuilds exactly ONE BufferLine; the other
lines' shape caches survive and shape_until_scroll touches only the
fresh line.
- Q#R1: clipped_chunks_for_range is the single chunk source both the
full reshape and the surgery derive from (full = slice range,
surgery = the line's content range), so the two paths cannot
disagree about a line's content. Parity with cosmic-text's own
line splitting verified against the vendored 0.18.2 source:
BidiParagraphs strips the separator per line in both its ASCII and
BidiInfo paths, creates no trailing empty line, and set_rich_text
assigns LineEnding::Lf uniformly + adds attr spans only when they
differ from the defaults — the surgery mirrors all three.
- Fallbacks to full reshape: slice origin moved, line count changed
(Enter / multi-line deletes), '\n' in the inserted text, edited
line outside the shaped slice (an edit entirely PAST the slice updates
view_range + redraws without any shaping), exotic paragraph
separators, multi-edit batches.
- Q#R2: the pointer hit map goes lazy — surgery marks it dirty and
hit_test_source_byte rebuilds on demand from the same chunk fn
(clicks are rare next to keystrokes; the rebuild is an O(slice)
byte walk, no shaping).
- Pure parity test pins full-walk == concatenated per-line walks
(text + colors), including the newline-anchored inlay-hint
boundary case (predicted finding #1's most likely site).
Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>
