Any other comments? Alex,
Pillow says: Please report any non-packaging related issues here first: - https://bitbucket.org/effbot/pil-2009-raclette/issues Should i report the issue there? Lars On Mon, Oct 29, 2012 at 4:33 PM, Alex Clark <acl...@aclark.net> wrote: > On 2012-10-29 15:05:28 +0000, Lars Ruoff said: > > Hi, >> >> I'm new to this list, so excuse me if this is a known issue. >> I didn't find anything on it on the net so far but didn't have time to >> search much. >> >> I have observed what i consider a flaw in the Image.paste algorithm when >> used with transparent images. >> >> transparent-columns.png is an image with 3 vertical black columns with >> alpha=0.5, 0.2 and transparent respectively. >> transparent-bars.png is an image with 2 horizontal black bars with >> transparent and alpha=0.5 respectively. >> (images attached) >> >> When these two images are transparently pasted one over the other, using >> the following code: >> >> from PIL import Image >> source = Image.open('transparent-**columns.png') >> result = Image.open('transparent-bars.**png') >> result.paste(source, (0, 0), source) >> result.save('transparent-**columns-on-bars-pil.png') >> >> The result is unexpectet to say the least. >> PIL seems to modify the transparency even in regions where only one of >> the images has non-transparent values. >> Very wrong in my opinion. >> >> Doing the same manipulation in GIMP 2.6 gives what i consider the >> expected result. >> (attached for reference) >> >> I guess the per-pixel transparency of the result should be result_alpha = >> 1 - (1-alpha1)*(1-alpha2), >> where alpha1,alpha2 are the alpha channel values from the original images. >> > > > You are welcome to submit a patch to Pillow (the "friendly" PIL fork) here: > > - > https://github.com/python-**imaging/Pillow<https://github.com/python-imaging/Pillow> > > > Speaking of that, can anyone review: > > - > https://github.com/python-**imaging/Pillow<https://github.com/python-imaging/Pillow> > > > Also, I'm looking for a few folks willing to "stand up" and regularly > review image code fixes. I know nothing about that code, and plan to stick > with being the release manager only. I'll be doing a 1.7.8 release soon (by > the end of this month) then maybe Pillow 1.8 will contain support for > Python 3.3 (and cut everything before 2.7). > > > >> Regards, >> Lars Ruoff >> >> <image> >> <image> >> <image> >> <image> >> <image> >> <image> >> ______________________________**_________________ >> Image-SIG maillist - Image-SIG@python.org >> http://mail.python.org/**mailman/listinfo/image-sig<http://mail.python.org/mailman/listinfo/image-sig> >> > > > -- > Alex Clark ยท > https://www.gittip.com/**aclark4life/<https://www.gittip.com/aclark4life/> > > > ______________________________**_________________ > Image-SIG maillist - Image-SIG@python.org > http://mail.python.org/**mailman/listinfo/image-sig<http://mail.python.org/mailman/listinfo/image-sig> >
_______________________________________________ Image-SIG maillist - Image-SIG@python.org http://mail.python.org/mailman/listinfo/image-sig
