Comment # 26 on bug 1206322 from Petr Gajdos

(In reply to Dirk Weber from comment #24)
> The images created by montage seem to depend on the HW they are created on.
> Therefore tolerate deviating values in the output of gm compare which
> compares the image created during the test with a given image possibly
> created on an other HW type.

This is interesting and I will look at it during hackweek (tbh I have no other
idea so far).

(In reply to Dirk Weber from comment #22)
> Sorry, the "compare" used in the test is not the compare binary from
> ImageMagick but the compare function of the script test.sh which correctly
> uses 
> gm compare ...
> 
> I was on the wrong track but Dominique corrected me, thanks for that.
> 
> Therefore no mixing of ImageMagick and GraphicsMagick in these test cases.

Ah, now I understand, thanks. I was misled by

(In reply to Dirk Weber from comment #19)
> ImageMagick-7.1.0.55-1.1.i586
> GraphicsMagick-1.3.38-1.6.i586

Thank you Dirk for the evaluation again.

By the way: do you know why we are testing GraphicsMagick and not ImageMagick?
Or is there similar test for ImageMagick?

TL;DR:
GraphicsMagick is just an old fork of ImageMagick. ImageMagick is more
developed, but less stable. They broke API in IM7, GM keeps the API same as
IM6, that's perhaps one of reasons why some projects prefer GraphicsMagick
(octave is one of examples, used to build also with IM6). But ImageMagick feels
little bit like a mainstream.