[foxnne]

Made by: claude

Part of fizzyedit/plans#65 (step A)

A pencil stroke was stored as a hash map, so its step was a sorted pixel set and a tape lost the order it was drawn in. Now:

• Buffers.Stroke.order records each pixel index when first touched (append, appendAssumeCapacity); cleared in toChange and clearAndFree.
• strokeUndoCommit sets history.showing_order/showing_marks (one pen mark)/showing_ms around the append, as commands.zig does, so motionOf emits Step.motion. A stroke flushed from the deferred snapshot is found by row scan, so it gets no motion.
• motionOf's index-to-position mapping moved to steps.positionsOf so it is testable.

Not in this PR: overdraw and per-sample timing (step B, a format change). Step format 2 is unchanged; steps without motion decode and apply as before.

Ran: zig build test (new tests: out-of-order hand stroke exports in drawn order, repeats rejected by decodeMotion, step without motion still applies) and zig build, both pass locally. Not exercised: drawing by hand in the running app.

Fix (crash on first hand stroke): strokeUndoCommit zipped Stroke.order with a drawn buffer that was empty whenever the stroke was not "live" (the deferred-snapshot flush, or an allocation failure) while order was not, so Debug panicked on non-equal lengths. order is now converted by steps.orderOf (its own length, no zip), and only for a live stroke. Tests added: empty and one-pixel orders, and an order longer than the pixels returns no motion.

Not tested: strokeUndoCommit itself (it needs a File and dvui, outside zig build test) and I have not drawn in the running app, which is why the first version crashed. Please try one stroke before ready. Ran after the fix: zig build test, zig build.

🤖 Generated with Claude Code

[foxnne]

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Review	Status	Commit	Review trigger
📝 Code Review	✅ Completed 2026-10-22T22:38:00.041781Z	1c8e38a	Manual request

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Reviewed commit: 1c8e38a610

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Route live stroke releases through the motion-aware commit

When a stroke uses the live buffer—for example, after its deferred snapshot exceeds the size cap—normal pointer release still calls drawPoint/drawLine with to_change = true, which reaches File.commitStroke. Its non-deferred branch calls toChange and history.append directly, bypassing this new metadata setup and clearing the recorded order. Consequently, these live hand-drawn strokes still export without motion; the new path is only reached when such a stroke is cancelled by cancelActiveDrawing. Route the non-deferred release path through the motion-aware commit as well.

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