Every colour layer took a mask, component labels, a fill stack and an edge map the size of the whole image,
and as many layers were traced at once as the machine has cores.
- A layer is traced within the box its pixels lie in.
- The stack that fills components holds `u32` indices (a mask has at most 64 million pixels).
- Layers are traced as many at a time as fit in half a gigabyte (about ten bytes a pixel of the largest
layer's box each), on however many cores.
Peak memory above the image itself, photo-like image (docs/image-trace-quality.md), before -> after:
- 16 megapixels: High Fidelity Photo 3,856 -> 880 MB (2.85 -> 3.65 s), Low Fidelity Photo 1,972 -> 754 MB
(1.49 -> 1.80 s), 16 Colors 1,625 -> 298 MB, Shades of Gray 852 -> 407 MB, Default 256 -> 199 MB
- 4 megapixels: High Fidelity Photo 981 -> 643 MB, 16 Colors 408 -> 122 MB, times unchanged
The traces are the same, path for path.
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