FA-51675 / Raster clipping / Member archive

Blit source destination clip: scissor left origin · case 05

Left trimming only happens for negative destination origins, ignoring a scissor whose left edge is inside the target.

Member previewVariant 5 · 3 implementations · 12 checks per implementation

Case contract

Each command is [sw,sh,sx,sy,w,h,dx,dy,clip]: a source image sw by sh, a requested source rectangle origin and size, a destination origin, and a half-open destination scissor [left,top,right,bottom) first intersected with the size by size target. Negative source origins trim width/height and shift the destination by the same amount; the source rectangle is limited to the image; destination pixels left/top of the scissor trim size and advance the source origin; right/bottom trims use half-open bounds. The result is [sx,sy,dx,dy,w,h] or None when either dimension is empty.

Why this case matters

Raster clipping decides which pixels a primitive may touch; a single wrong clip decision writes outside the target or scissor, or silently drops visible coverage.

One recorded failure

Sample boundary fixture

This sample comes from the broken implementation of a controlled reproducer.

Boundary fixture	Actual	Expected	Outcome
explicit case 8	`[[0, 0, 1, 0, 6, 6]]`	`[[2, 0, 3, 0, 4, 6]]`	Failed

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This record includes three runnable implementations, regression fixtures, execution results, and source hashes.

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