The colour histogram used the top 5 bits of each channel, so tones less
than 8 values apart always shared a bin and could never get their own
palette entry, however many colours were asked for. A dark, low-contrast
photo (a book-cover texture with RGB 33..66) traced to 5 colours when 12
were requested, and eight grey stripes 32..39 traced to one:
vectorcraft-cli run --in stripes-32-39.png --cmd select.all \
--cmd imageTrace.makeAndExpand \
--params '{"params":{"mode":"color","colors":8,"noise":0,"method":"overlapping"}}'
-> {"anchors":4,"colors":1,"id":4,"paths":1}
The histogram keeps its 32x32x32 bins, now fitted to each channel's range
among the opaque pixels: a channel spanning at most 32 values keeps every
value apart, a full-range channel keeps the old 5-bit bins.
Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
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