Re: Testing native image scaling

[Andy Moreton <andrewjmoreton@gmail.com>]

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On Wed 27 Mar 2019, Eli Zaretskii wrote:

>> Date: Wed, 27 Mar 2019 11:35:26 +0900
>> From: YAMAMOTO Mitsuharu <mituharu@math.s.chiba-u.ac.jp>
>> Cc: Alan Third <alan@idiocy.org>,
>> 	emacs-devel@gnu.org
>> 
>>   (insert-sliced-image (create-image "splash.png" nil nil :scale 0.5) nil nil 3 5)
>> 
>> Actually, I suspect this does not work on W32 because the comparison
>> with the original image size is made for s->slice.width (or height)
>> rather than s->img->width (or height) as I just did for cairo code.
>> Could you check it on W32?
>
> It seems to work, but maybe I don't know what and how to check.  Can
> you show what I should expect to see with and without the :scale
> attribute, in "emacs -Q"?
>
> Thanks.

I would expect a sliced image to be composed of a grid of tiled images
instead of a single image, but to have the same visual appearance as the
original image. The w32 code does not get this right.


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Adding the ":scale 0.5" argument scales down the tiled array of images
correctly, but they still contain the same display artifacts as the
sliced image without scaling.

    AndyM