Color Quantization

[olivervogel]

Is it possible in any way to reduce the distinct colors in an image with the result being visually similar as possible to the original?

I have found out that I can achieve this by setting the palette and bitdepth parameters when encoding to PNG format.

The question I am asking myself is whether this is also possible outside or before the encoding process and without committing to a certain image format. And if this is the case, is it also possible to reduce to any number of colors instead of fixed bit depths?

Thanks in advance.

[jcupitt]

The GIF saver has this functionality too, though it's also limited to a choice of 2, 4, 8, 16, 32, 64, 128, 256 colours.

There's a PR with some code to expose this as a general operation, but it hasn't been merged because of some upstream issues.

[olivervogel]

Ok thanks, looking forward to it being possible in the future.