Make `.quantize(palette=...)` use exact colors when possible, and improve dithering quality - #9829

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akx wants to merge 11 commits into

python-pillow:mainfrom

akx:palettize-fixes

Commits on Sep 8, 2026

Improve docs for Image.quantize()
akx
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a398d3c
Add documentation for ImagingError_MemoryError
akx
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0029372
Document palette constraints better; use constants
akx
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7de084b
Refactor: move topalette to separate file
akx
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7e6646b
Split topalette converter functions for less nesting
akx
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09aef9f
Fix possible null pointer derefs in topalette()
akx
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b1fbca4
Make to-palette conversion use exact colors if available
akx
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bf33faf
Apply hoist and restrict optimizations to palettization
akx
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bf33f56
Move palette cache functions to ConvertToPalette.c
akx
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42bb0c6
Use palette cache to figure out if we might have an exact match
akx
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22bf98b
Fix RGB dithering error cache value at end of row + improve readability

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22dfe86