Optimise rendering of Pageviewer pages for HiDPI screens #608
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Optimise rendering of Pageviewer pages for HiDPI screens #608
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Multiply the canvas backing store dimensions by window.devicePixelRatio and set explicit CSS width/height to maintain the same logical layout footprint. Apply canvasContext.scale(dpr, dpr) so PDF.js renders at the higher resolution. The logical scale returned in CachedPreview is unchanged, so text overlays (for selection/copy-paste), search highlights, find-in-document highlights, and comment selection geometry are all unaffected.
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Fixes #609
All screens are 'Retina'/HiDPI these days, so optimising for 72px/inch is no longer appropriate.
This multiplies the canvas backing store dimensions by window.devicePixelRatio and sets explicit CSS width/height to maintain the same footprint. Applies canvasContext.scale(dpr, dpr) so PDF.js renders at the higher resolution.
The logical scale returned in CachedPreview is unchanged, so text overlays (for selection and copy-paste), search highlights, find-in-document highlights, and comment selection geometry are all unaffected.
Before:
After:
Tested: