[Image-SIG] Transparent paste - another problem

[Florian Höch]

Ok, I think I got it. The alpha channel needs to be updated during and 
inserted after the paste operations.

from PIL import Image, ImageChops

foo = Image.open("bar.png")
alpha = foo.split()[-1]

for p in w:
     baz = Image.open(p.element.binary.path)
     foo.paste(baz, (p.x, p.y), baz)
     alpha = ImageChops.add(alpha, baz.split()[-1])

foo.putalpha(alpha)

Regards,

Florian

Szymon Kosok schrieb:
> Hi,
> 
> Ok. So here is some baz:
> 
> http://i.wonderlife.pl/cache/ubranie-83-620.png
> http://i.wonderlife.pl/cache/ubranie-84-620.png
> 
> And this is foo:
> 
> http://i.wonderlife.pl/img/ciala/mc.png
> 
> Regards,
> Szymon
> 
> 2008/10/8 Florian Höch <lists+Image_SIG at hoech.org>:
>> Hi,
>>
>> without seeing the original foo and at least some of the baz images, it's
>> hard to tell how to achieve what you're looking for. I'd assume you want
>> some sort of "adaptive multiplication", where only transparent parts are
>> "multiplied over" the existing image and fully opaque parts "knock out"
>> everything under it.
>>
>> Regards,
>>
>> Florian
>>
>> Szymon Kosok schrieb:
>>> Hi,
>>>
>>> I have another problem with PIL and transparent images. I have such code:
>>>
>>>        foo = Image.open("bar.png")
>>>
>>>        for p in w:
>>>
>>>            baz = Image.open(p.element.binary.path)
>>>
>>>            foo.paste(baz, (p.x, p.y), baz)
>>>
>>> And the problem is... every baz (some of them are semi-transparent) is
>>> transparent over every previous element.
>>>
>>> Maybe I'll show what I want, and what I got:
>>>
>>> http://i36.tinypic.com/2efjlaw.png - this is what I want,
>>> http://i38.tinypic.com/11glf6t.png - and this what I get.
>>>
>>> Any hints?
>>>
>>> Best regards,
>>> Szymon
>>> _______________________________________________
>>> Image-SIG maillist  -  Image-SIG at python.org
>>> http://mail.python.org/mailman/listinfo/image-sig
>> _______________________________________________
>> Image-SIG maillist  -  Image-SIG at python.org
>> http://mail.python.org/mailman/listinfo/image-sig
>>