Re: [Image-SIG] Help with PIL, Imagemagick Composite function in PIL?
On 4/10/07, César Pérez [EMAIL PROTECTED] wrote: Hi, I am new to this list but and i have a small problem with PIL. I am looking for a function that works like composite does in imagemagick. [..snip..] from PIL import Image dtop = Image.open(dtop.png) frame = Image.open(frame.png) dtop.paste(frame,(0,0),frame) dtop.save(test.png) I tried every form of paste but I always get this result or worst. The problem you have happens because alpha channel of images *also* gets composited using the mask you specified. To do it right you actually need to split image, save target image alpha channel and after compositing merge it back using original alpha channel: from PIL import Image dtop = Image.open(dtop.png) frame = Image.open(frame.png) assert dtop.mode == RGBA r,g,b,a = dtop.split() dtop = Image.merge(RGB, (r,g,b)) dtop.paste(frame,(0,0),frame) r,g,b = dtop.split() dtop = Image.merge(RGBA, (r,g,b,a)) dtop.save(test.png) Best regards, Alexey. ___ Image-SIG maillist - Image-SIG@python.org http://mail.python.org/mailman/listinfo/image-sig
Re: [Image-SIG] Help with PIL, Imagemagick Composite function in PIL?
Thanks to both of you and yes I was expecting the paste function to work just like a paste in any Image Editor. César On Wed, 2007-04-11 at 11:48 +1200, Douglas Bagnall wrote: Alexey Borzenkov wrote: The problem you have happens because alpha channel of images *also* gets composited using the mask you specified. To do it right you actually need to split image, save target image alpha channel and after compositing merge it back using original alpha channel: Alexey, I think you are completely right about the problem, but the solution can be quite a bit simpler: dtop = Image.open(dtop.png) frame = Image.open(frame.png) dtop.paste(frame.convert('RGB'), (0,0), frame) dtop.save(test.png) I would say that this alpha-merging quirk comes close to being a bug -- it's probably not what most people expect. douglas ___ Image-SIG maillist - Image-SIG@python.org http://mail.python.org/mailman/listinfo/image-sig