The transcript viewport draws every frame. Ratatui's Line::render_ref
does grapheme segmentation and span layout, so repeated redraws can burn
CPU during streaming even when the visible transcript hasn't changed.
Introduce TranscriptViewCache to reduce per-frame work:
- WrappedTranscriptCache memoizes flattened+wrapped transcript lines per
width, appends incrementally as new cells arrive, and rebuilds on width
change, truncation (backtrack), or transcript replacement.
- TranscriptRasterCache caches rasterized rows (Vec<Cell>) per line
index and user-row styling; redraws copy cells instead of rerendering
spans.
The caches are width-scoped and store base transcript content only;
selection highlighting and copy affordances are applied after drawing.
User rows include the row-wide base style in the cached raster.
Refactor transcript_render to expose append_wrapped_transcript_cell for
incremental building and add a test that incremental append matches the
full build.
Add docs/tui2/performance-testing.md as a playbook for macOS sample
profiles and hotspot greps.
Expand transcript_view_cache tests to cover rebuild conditions, raster
equivalence vs direct rendering, user-row caching, and eviction.
Test: cargo test -p codex-tui2
Support multi-click transcript selection using transcript/viewport
coordinates
(wrapped visual line index + content column), not terminal buffer
positions.
Gestures:
- double click: select word-ish token under cursor
- triple click: select entire wrapped line
- quad click: select paragraph (contiguous non-empty wrapped lines)
- quint+ click: select the entire history cell (all wrapped lines
belonging to a
single `HistoryCell`, including blank lines inside the cell)
Selection expansion rebuilds the wrapped transcript view from
`HistoryCell::display_lines(width)` so boundaries match on-screen
wrapping during
scroll/resize/streaming reflow. Click grouping is resilient to minor
drag jitter
(some terminals emit tiny Drag events during clicks) and becomes more
tolerant as
the sequence progresses so quad/quint clicks are practical.
Tests cover expansion (word/line/paragraph/cell), sequence resets
(timing, motion,
line changes, real drags), drag jitter, and behavior on spacer lines
between
history cells (paragraph/cell selection prefers the cell above).
Josh McKinney ·