Hi image-sig, I am producing some png images for a web application. Some of the images are cached and reused for other requests. I am using matplotlib to produce the images. Unfortunately the images are quite large (up to ~300 kb). I therefore tried using the Linux utilities pngcrush and pngnq for compressing the images. pngnq gave by far the best results (~300 kb -> ~90 kb in 0.4-0.5 seconds on my laptop; combining the two tools did not yield further improvements). It reduces the color depth to 8 bits (from 24) without any apparent image quality problems using color quantization (http://en.wikipedia.org/wiki/Color_quantization).
Is it possible to do this in PIL directly or will I have to code it myself? At present I am considering just calling pngnq from my Python code but I would rather not do that. Another thing is that for performance reasons I might want later to reuse the colormap (since the image colors are pretty much the same). Neither pngnq nor pngquant (which pngnq is based on) supports this yet. Best regards, Jesper (Thanks to Jouni K. Seppänen on the matplotlib mailing list for suggesting looking at PIL for this) _______________________________________________ Image-SIG maillist - Image-SIG@python.org http://mail.python.org/mailman/listinfo/image-sig
