bug#18333: 24.3.93; ImageMagick: ICO image in multiple sizes is not shown correctly

[Lars Ingebrigtsen]

Lars Ingebrigtsen <larsi@gnus.org> writes:

> YAMAMOTO Mitsuharu <mituharu@math.s.chiba-u.ac.jp> writes:
>
>> 4. Invoke Emacs and evaluate the following expression in *scratch*:
>>
>>     (let (sizes)
>>       (dotimes (i 3)
>>      (push (image-size
>>             (create-image "~/wikipedia.ico" 'imagemagick nil :index i) t)
>>            sizes))
>>       sizes)
>>
>>    The expected result is ((16 . 16) (32 . 32) (48 . 48)) or its
>>    permutation, but the actual one is ((16 . 16) (16 . 16) (16 . 16)).
>
> This bug is still present in Emacs 27.
>
> imagemagick_compute_animated_image (which gets the data out of
> multi-image files) assumes that all the images have the same size,
> because it was written to handle animated GIFs (where this is the
> case).  But for ico files, the logic is wrong.

I've now fixed this on the Emacs trunk.  The ImageMagick code now
distinguishes between animated files (where all sub-images are the same
size) and non-animated files (where this may be different).

Results included below.

-- 
(domestic pets only, the antidote for overdose, milk.)
   bloggy blog: http://lars.ingebrigtsen.no

multi.jpg
Description: JPEG image