Cause: Auto dropped to Half below 75 % magnification, so text between
50 % and 75 % was rendered with fewer pixels than the screen shows and
looked soft. Below 100 % the frame texture was minified with a plain
bilinear sampler and no mip levels (Full at 46 % skipped most frame
pixels), so edges stair-stepped.
Fix:
- Auto renders the pixels the magnification needs, as in After Effects:
the coarsest whole factor that still gives every screen pixel a
rendered one (Full above 50 %, Half down to 33.3 %, Third down to
25 %, Quarter below).
- GPU frames: the display texture carries a full mip chain, each level
the 2 x 2 mean of the one above (display.wgsl `mip`, same bind group
layout as `display`), sampled trilinearly with Viewer Zoom Quality
More Accurate (Faster keeps the nearest pixel of the full-size frame).
- CPU frames (egui-wgpu textures have no mips): uploaded averaged down
by the whole factor that leaves about one texel per screen pixel, the
same box average as the texture-limit fit (#201), re-uploaded when the
magnification calls for another factor; drawn with texture coordinates
that keep each texel over its pixels when the size isn't a multiple.
Show Channel / exposure textures follow.
Tests: gpu tests::display_frames_are_mipmapped (level count and level 1
= 2 x 2 means of level 0), viewer_tools
auto_resolution_follows_the_magnification (60 % was Half) and
minified_frames_keep_their_texels_in_place.
Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
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