[Image-SIG] pil rotate 90 bug ?

[Chris Mitchell]

You could load the image into numpy, rotate the array, then read it back out
to pil.
On Aug 4, 2011 4:39 PM, "Edward Cannon" <cannon.el at gmail.com> wrote:
> A possible workaround is to convert the images to some more standard
format ie im.convert("rgb"). If you need to rotate by multiples of 90 the
transform method works and is faster.
>
>
>
> On Aug 4, 2011, at 1:24 PM, Guilherme Polo <ggpolo at gmail.com> wrote:
>
>> 2011/7/28 Jeremy Craven <c.j.craven at sheffield.ac.uk>:
>>> I have a program that has been working fine rotating images by arbitrary
>>> angles.
>>>
>>> I just found that if I specify 90 degrees exactly then the image goes
crazy:
>>> only appears in left hand half of image and every other line is black
and
>>> image is stretched vertically.
>>>
>>> Any ideas if this is a bug or I am perhaps doing something in a
>>> non-recommended way.
>>>
>>
>> It is a bug, it doesn't rotate the image by 90 degrees.
>>
>> Looking through PIL code, I would think the problem is that you have
>> these "special images" with mode as "I;16B", which PIL marks as
>> IMAGING_TYPE_SPECIAL. The code paths used for such special things
>> probably are under tested.
>>
>>> I attach a cut down version of the code which shows the problem. It
reads
>>> "test_in.tif". It rotates it 90.0 and writes "test.tif". It rotates it
89.99
>>> and writes "test1.tif". The second output file looks fine. The first is
>>> wonky.
>>>
>>> I'm using version 1.1.7
>>>
>>> Thanks for listening
>>>
>>> Jeremy
>>>
>>> --
>>>
*********************************************************************************
>>>
>>> Dr C. Jeremy Craven
>>> Department of Molecular Biology and Biotechnology
>>> University of Sheffield,
>>> Firth Court, Western Bank
>>> S10 2TN Sheffield UK
>>
>>
>>
>> --
>> -- Guilherme H. Polo Goncalves
>> _______________________________________________
>> 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
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