perf(region): skip full repaint on idle/no-op redisplays - #119
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The active-region WFFULL escalation ran before the 'nothing to redisplay' early-out, so every update() cycle re-rendered the whole window while a region was active -- even no-op keys that moved nothing. Move it after the w_rflag==0 continue: only escalate a redraw that's already needed. Correctness is unchanged (a real move sets w_rflag, so the region still repaints and tracks point), and selecting-case bytes are identical (uline already diffs cells and emits only the changed boundary rows -- the region repaint was never sending the whole window). macOS 331/331, TSan clean, c-legacy clean. Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com> Claude-Session: https://claude.ai/code/session_01Pj1ZHaD7aNhVWJ69SFKJcp
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While investigating region-highlight latency, confirmed mg's
ulinealready diffs at the cell level — so the active-region repaint was never sending the whole window; the extra bytes on a move are the inherent cost of the highlight shifting across ~2 boundary rows.The one real waste: the
WFFULLescalation ran before thew_rflag == 0early-out, so everyupdate()re-rendered all rows while a region was active, even for no-op keys. Moved it after the early-out — only escalate a redraw that is already needed. Correctness unchanged (a genuine move setsw_rflag, region still tracks point); selecting-case bytes identical (15 B plain / 153 B region, before and after).macOS 331/331 · TSan zero races · Alpine/musl 331/331 · legacy plain-C clean.
🤖 Generated with Claude Code
https://claude.ai/code/session_01Pj1ZHaD7aNhVWJ69SFKJcp