perf(image): remove per-pixel allocs + redundant merged-image copy (MAPCO-11321) - #256
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perf(image): remove per-pixel allocs + redundant merged-image copy (MAPCO-11321)#256shimoncohen wants to merge 1 commit into
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…MAPCO-11321) Image hot path allocated on every pixel and copied the whole merged image. - TileScaler.Upscale: read the source pixel buffer once via GetValues() and index it by offset instead of calling GetValue(i,j) — which allocates a byte[] per source pixel — inside the nested scaling loop. - TileMerger.MergeTiles: Flatten() already returns an image independent of the collection, so keep it directly instead of cloning it into a new MagickImage just to survive the using scope. Output is byte-identical: the TileScaler/TileMerger golden-image tests pass unchanged. Note: the deeper encode->decode->encode round-trip is coupled to GetTileFormat's opaque->jpeg behavior (MAPCO-4731) and is intentionally left untouched here to keep format-selection semantics out of this change. Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
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LOGIC-2 of MAPCO-11317. Native image-path allocation cleanup — no read-API changes.
Changes
srcPixels.GetValue(i,j), which allocates abyte[]per source pixel. Now reads the whole source buffer once withGetValues()and copies by offset — one allocation instead of one-per-pixel.Flatten()returns an image independent of the collection, so the merged image no longer gets cloned into anew MagickImage(...)just to outlive theusingscope.Output is byte-identical
The
TileScaler/TileMergergolden-image tests (reference upscaled/merged jpegs & pngs) pass unchanged. Full suite: 1141 passed, 0 failed.Scope note
The deeper encode→decode→encode round-trip in the merge path is coupled to
GetTileFormat's opaque→jpeg behavior, which is MAPCO-4731's concern. Left untouched here to keep format-selection semantics out of this PR. #175 (MAPCO-8749, format-threading) also overlaps this area and is intentionally not folded in.🤖 Generated with Claude Code