Packed atlas compose inset Linear samples after blitting the full
drawable into the slot, which dropped edge texels and opened
multi-pixel gaps on text that crossed tile seams (#11696), especially
under HiDPI packing. Write the drawable into the inset content rect
and clamp-pad the 1px frame so Linear compose keeps coverage without
bleeding into the next cell.
Closes#11696
those textures across zoom for progressive previews, and invalidate
by old∪new document coverage so rotate/move edits do not leave
stale fragments on zoom-out.
Present visible tiles via ViewportReady so zoom settle turns sharp
without waiting on the interest ring, and paint at atlas slot size so
DPR 2 does not rasterize 1024 only to downscale into 512 slots.
HQ tiles are 512px and the atlas stays at 4096² (64 full-size
slots). Browser zoom plus a forced ?dpr= can need more visible
tiles than that, and a framebuffer larger than the GPU allows.
Pack interest tiles into smaller atlas cells, blit at 512 then
scale, and inset Linear samples so seams do not bleed. Clamp the
canvas backing store and DPR together, wrap Skia at the real
drawingBuffer size, and wait one frame after DPR changes so CSS
client size and overlays stay aligned.
Partition pending tiles into 4 groups by visibility and cache status.
Visible tiles are processed first to eliminate empty squares during
pan/zoom. Cached tiles within each group are processed before uncached.
