game-maker / suite (push) Successful in 6m21s
TextureFrame carries optional `border` (left/right/top/bottom) and `fill` (stretch | repeat); absent keys mean "not sliced", so no format bump and undo restores the plain frame instead of four zeroes. The sliced sprite builds its own geometry instead of the shared UNIT_QUAD: a 4x4 grid, and for `repeat` one quad per tile carrying the frame cell's real UVs -- tiling in the geometry, not in the sampler, so a frame out of a sheet cannot pull its neighbour in. Above 64 tiles per axis it stretches, to bound the buffer. A sprite narrower than left+right scales both borders down together until the middle is exactly 0, so the corners meet at a seam and never overlap. The texture editor gets four draggable border lines plus the same four numbers in the inspector. Hit order is resize handles, then the lines, then the frame body -- handleAt reports 'move' anywhere inside a frame, so lines placed after it were unreachable. Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>