[Image-SIG] Fwd: PIL 1.1.6 and convert cmyk jpegs to rgb and writing png files

[Kevin Cazabon]

>
> A couple years ago, a few of us worked on adding multi-threading  
> support to key routines in PIL - focusing on the ones that would  
> most likely be CPU intensive or long duration operations.  It's a  
> simple fix to release the GIL before starting the op, and re-acquire  
> before returning - look at the C code for resize, for example.   We  
> didn't get it implemented everywhere, but many of the "expensive"  
> operations are now covered.  I'm sure Fred would gladly accept  
> patches to add support elsewhere.
>
> Kevin.
>
>
> On 12 Dec 2008, at 11:34, Michael van Tellingen wrote:
>
>> Hello,
>>
>> I'm currently writing a webapplication which processes images  
>> uploaded
>> by users and i'm running into two problems:
>> - Converting a CMYK jpeg image to RGB results in the wrong colors
>> used, i've solved this by patching PIL with the
>>  file attached to
>> http://mail.python.org/pipermail/image-sig/2006-April/003871.html
>>
>> - It seems that writing a PNG image requires the GIL. I convert all
>> uploaded images in a separate thread to PNG
>>  images and while doing so my complete python application becomes
>> really slow, I don't have this problem when
>>  I convert it to JPEG or TIFF. Is this correct? And if so, how hard
>> would it be to solve this problem?
>>
>> Thanks,
>> Michael van Tellingen
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>