fix(gallery): subpixel scroll stall + scroll resync + resize remeasure - #34
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Faych (neverbiasu) wants to merge 1 commit into
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fix(gallery): subpixel scroll stall + scroll resync + resize remeasure#34Faych (neverbiasu) wants to merge 1 commit into
Faych (neverbiasu) wants to merge 1 commit into
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Chrome rounds subpixel scrollLeft writes to the nearest integer, so writing 0.4/0.45px directly rounds to 0 every frame and the marquee stalls. Keep the fractional position in a floating-point phase accumulator and only write the integer part to scrollLeft. - phase accumulator: s.phase += SPEED * dir; write Math.round(s.phase) - manual-scroll resync: scroll listener compares against the last written value and resyncs the phase on user scrolls (arrows, touch, wheel) - resize remeasurement: setup is idempotent (dataset.looping guard), re-measures the loop period and re-syncs phase to the current position without duplicating content a second time - retain main's updated 32px padding (no CSS changes) - fix stale-state capture: listeners looked up state by closure, which broke hover-pause after resize re-ran setup; now look up by element
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Summary
Fix the marquee stall caused by Chrome subpixel
scrollLeftrounding in the gallery carousels.This patch keeps the auto-scroll phase continuous while still allowing user-driven manual scrolls to resync cleanly after pointer/touch/wheel interaction. It also re-measures loop periods on resize without duplicating content again.
Root cause
Chrome rounds subpixel
scrollLeftvalues to integers during DOM writes. When the marquee loop keeps updating from a stale phase, the next frame can effectively write0.4pxor0.45px, which Chrome rounds to0, causing the carousel to appear stuck.What changed
docs/idea-page/gallery.js_lastWrittenvalue for the last DOM writesingleWidthon resize without duplicating content againdocs/reel-page/gallery.jsscrollLeftvalueFiles changed
docs/idea-page/gallery.jsdocs/reel-page/gallery.jsVerification
upstream/mainNotes
This is a follow-up to the earlier marquee ping-pong fix that was already merged upstream. This PR specifically addresses the remaining subpixel/rounding stall issue.