- pipeline::transform::manual: Vertical/Horizontal keystone as a virtual camera rotation K·R·K⁻¹ (re-centred,
local scale preserved), Rotate, Aspect, Scale, Offset X/Y composed into one homography
- the homography lives in the Warp: output → crop affine → inverse perspective → lens model → source, still a
single resample; masks/crop/spots stay in transformed normalized coordinates
- Constrain Crop: the effective crop shrinks about its centre until no blank (outside-source) area remains;
aspect unchanged
- UI: Constrain Crop checkbox in the crop panel's Geometry section
- tests: slider signs, known keystones straightened (3 slider combos), constrain removes blank corners,
preview vs export match
Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
