fix(vterm): track SGR per cell so re-attach replays colors#24
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The emulator stored bare runes and discarded SGR by design, so the
replay a re-attaching client receives (Redraw) repainted the screen
black and white; the follow-up resize nudge only rescues full-screen
TUIs that fully repaint on SIGWINCH - inline agents (claude, omp) never
repaint their history, so everything stayed monochrome until new output
arrived.
Track attributes per cell and replay them:
- cell = rune + attr (16/256/truecolor fg+bg, bold/dim/italic/
underline/blink/reverse/strike), stamped from the terminal's current
SGR state
- a real SGR parser, including colon sub-parameter forms (38:5:196,
38:2::r:g:b, 4:0) and a 58 underline-color skip
- back-color-erase: erases, scroll-revealed rows, and inserted blanks
fill with the current background so colored bars replay intact;
resize keeps bg-colored blank rows the same way Redraw paints them
- Redraw repaints each cell with its original attributes (reset
prefix, per-run transitions, reset before the cursor park)
Capture/peek stays plain text by contract, and history stays plain
rowText - scrollback replays uncolored; only the visible screen carries
attributes.
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Problem
Re-attaching to a session rendered it black and white: vterm stored bare runes and discarded SGR by design, so
Redraw(the replay a new attach client receives) repainted the screen colorless. The SIGWINCH nudge only rescues full-screen TUIs; inline agents (claude, omp) never repaint their history.Fix
Per-cell SGR tracking + attribute-aware replay:
cell = rune + attr(16/256/truecolor fg+bg, bold/dim/italic/underline/blink/reverse/strike).38:5:196,38:2::r:g:b,4:0) and58underline-color skip.Redrawrepaints each cell with its original attributes; reset-prefixed transitions; reset before the cursor park.Capture/peek stays plain text by contract; history stays plain (scrollback replays uncolored — only the visible screen carries attributes).Test plan
-racegreen; adversarially reviewed (one finding — resize/Redraw blank-row inconsistency — fixed in-branch).