Give macOS scrolling momentum

2026-10-01T03:12:14Z

A swipe that was still moving when the fingers lifted stopped dead. The dial next to it has thrown properly since pardes_rotate_end, and this is that same curve on the scroll accumulator: velocity sampled between events off the monotonic clock, weighted toward the newest sample because a flick is decided by how the hand was moving when it left, and a fling that ramps up from zero at the floor rather than switching on at it. A coast stops at the end of a document rather than spinning its remaining velocity against the edge, which is why spendScroll now reports whether the pane moved and why paneAt is public. Only a step that delivered a press can report an edge — the many steps between two rows cross nothing. Nothing suppresses AppKit's own momentum, and nothing needs to: its momentum events are ordinary pardes_scroll calls, every one of which cancels the coast before spending its travel, so on a real trackpad the system takes the gesture over about a frame after the lift and the tail it ends on is below the floor. This is the path for devices AppKit does not fling for — and the only one a script can reach, since NSEvent phases have no public constructor. momentum.snap asserts both halves, which is why it needs the long scrollback: a flick with no document left proves nothing. A slow swipe is byte-identical after the release; a hard one coasts twenty-four rows further on its own, and a finger back on the pad stops it there. Co-Authored-By: Claude Opus 5 (1M context)

pardes.git/test/macos-snapshots/momentum.snap, branch main

Give macOS scrolling momentum