[richiemcilroy]

What

The cursor recorder ticks every 16 ms for the whole recording. On every tick it asked AppKit for the current cursor and built TIFFRepresentation() of its image, then copied it and compared it byte for byte with the previous tick's.

That image is only used to label the move and click events recorded on that tick. On a tick where the pointer didn't move and no button changed (most of a typical recording: talking, typing, reading), the result was thrown away.

The recorder now reads the cursor image only when the tick records a move or click, or when it has no cursor id yet. Keyboard sampling, the 16 ms cadence, flushes and every recorded event are unchanged. Each event still carries the cursor image from its own tick, exactly as before.

The only output difference: a cursor shape that appears and disappears while the pointer is perfectly still and no button changes is no longer saved as an unused cursor_N.png. Nothing referenced those files.

Cost removed (M4 Max, macOS 27, same AppKit calls as get_cursor_data, 300-call average)

Per tick	Before	After (no event)
NSCursor.currentSystemCursor + TIFFRepresentation	546 µs, 583 KB TIFF built, copied and compared	skipped
At 62 ticks/s with the pointer still	~34 ms/s of CPU (~3.4% of a core), ~36 MB/s copied and compared	~0

A Studio recording was measured at ~5.7% CPU in-process on a static screen, so this was a large share of the recorder's idle cost. Ticks with movement are unchanged.

Tests

cargo test -p cap-recording --lib cursor::: 14 pass. The new button_changes_match_the_pairs_clicks_are_built_from test pins the helper to exactly the button pairs the click loop compares.

Confidence Score: 5/5

The PR appears safe to merge; recorded move and click ticks still request a fresh cursor image.

Summary

The recorder skips cursor-image reads on ticks without movement or button changes once it has a cursor ID.

• Quiet cursor ticks reuse the last cursor id.

_{Reviews (1) · Last reviewed commit: "perf(recording): read the cursor image o..." · Reviewed by Greptile}

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Project	Deployment	Actions	Updated
cap-status	Ready	Preview	Oct 20, 2026 4:04am UTC

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