Legacy ImageMagick Discussions Archive

I am using ImageMagick-6.7.9-Q16 on Windows, the Magickcore interface. I am adding one function at a time to my GUI interface for IM, I am now working on Quantize.

No matter what values I put into the QuantizeInfo structure (Colourspace, Treedepth etc.) the results of Quantize always appear lighter than the original image with less colour saturation too.

Is there a problem with my usage, I am starting with a true colour image, or is there a problem with IM?

Alan

It is very hard to say, without a small example. Also what versions of IM you are using. and even the commands you are using. As you talk about structures, I gather you are doing this from a programming interface?

Looks like some problem with RGB versus sRGB colorspace. Are you writing PNG files?

Yes, it was a colourspace problem. I was setting the colourspace value of the Image structure to RGB without checking that it did not have a valid value first, and if it had leaving it alone.

Alan