smarter color reducer? (considering visual similarity)

[chrisyelf]

Hello,

Would it be possible to have a smarter color reducer?
Converting the attached png

pngquant -o serbia_quantized.png 6 serbia.png

results in ~5 colors visually (I'm sure pixels are slightly different):
white, yellow, brown, red, black

The blue in crown was converted to brown. Instead, black outlines could be converted to brown (closer visually) and leave blue alone.
If the colors are close visually, I'd prefer to have just one instead of two separate black and dark brown (the one with most pixels).

What do you think?

[kornelski]

pngquant uses median cut algorithm, which is not optimal for very low numbers of colors. The library is designed for minimum 16, and typically 256 colors. I do not plan to support fewer number of colors, because at that point you can select them by hand.

[chrisyelf]

Thanks