CSS zoom on document.documentElement causes a coordinate space mismatch
between mouse event clientX/Y (viewport space) and Range.getClientRects()
(CSS space), breaking CodeMirror's click-to-position mapping. The previous
requestMeasure() fix only recalibrated cached geometry, not this mismatch.
New approach: zoomCursorFix extension patches posAtCoords/posAndSideAtCoords
on the EditorView instance to use document.caretRangeFromPoint() — the
browser's native, zoom-aware API — with coord-adjustment fallback.
Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>
Root cause: CSS zoom on document.documentElement caused stale CodeMirror
measurements. Two issues:
1. Race condition: zoom was applied in useEffect (parent), but CodeMirror
was created in useEffect (child) — child effects run first, so CM
measured at zoom=1 before zoom was actually applied.
2. No re-measure on zoom change: CSS zoom changes don't trigger
ResizeObserver on descendant elements, so CodeMirror never updated
its cached scaleX/scaleY, line heights, or character widths.
Fix:
- Apply zoom synchronously during useState init (before child effects)
- Dispatch 'laputa-zoom-change' event when zoom changes
- Listen for this event in useCodeMirror and call view.requestMeasure()
Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>
