[TYPO3-core] RFC #8878: Bug: Fix cropscale behaviour for transparent GIF

[Felix Buenemann]

Am 10.08.10 01:38, schrieb Felix Buenemann:
> Jigal van Hemert<jigal at xs4all.nl>  wrote:
>> On 16-7-2010 17:28, Felix Buenemann wrote:
>>> Problem:
>>> When using cropscale on an image with transparent background, the
>>> parameters for cropping differ between im4 and im6, due to how they
>>> handle the transparent canvas. This leads to incorrect cropping when
>>> using im5 or im6.
>>>
>>> Solution:
>>> Adapt behaviour according to im_version_4 flag and revert to pre
>>> #8025
>>> behaviour when im5/6 are used.
>>
>> The '!' flag for cropping was introduced with ImageMagick version
>> 6.2.4-6 [1]. So for earlier versions of IM6 and IM5 this will not
>> work.
>>
>> Because TYPO3 4.5 will support IM4,5 and 6 I don't think this will be
>> the right solution :-(
>>
>> [1] http://www.imagemagick.org/Usage/crop/#crop_viewport
>
> I'll try to come up with a solution that works across the board...

Argh, this is going to be painful...

I have so far tested IM Versions 
4.2.9/5.1.1/5.4.9/5.5.7/6.0.0/6.1.9/6.2.4/6.4.6 (what a pain getting all 
those to build on x86_64 mac)

Results:
4.2.9-6.0.0 will work correctly without !
5.4.9-6.0.0, 6.2.4-6.x.x will work correctly with !

Alternatively we could use -repage, but it is not implemented in 6.0.0 
and buggy in 6.0.8, but works fine in 6.1.9-6.x.x ...

So it's very hard to find a solution that works with all 6.x versions, 
due to the numerous bugs.

-- 
Regards, Felix