bug#38109: Updated Emacs to HEAD, consistently not scaling now

[Adam Sjøgren]

Eli writes:

>> However the png-image is still not scaled, and still shown in the larger
>> canvas.

> What do you mean by "shown in the larger canvas"?

I mean that the original 16x16 pixel image is shown in the corner of a
320x320 pixel white box.

As can be seen in the screenshot here:

 · 
https://debbugs.gnu.org/cgi/bugreport.cgi?att=1;filename=emacs27-image-scaling.png;bug=38109;msg=5

> Can you post a screenshot of how you see those PNG images with and
> without scaling, after applying that patch?

The patch doesn't make any difference on the scaling of the PNG images.

--with-cairo does.

Here is a screenshot of the attached .png with and without scaling,
without the patch and without Cairo (i.e. with Xrender):

Here is a screenshot of the attached .png with and without scaling, with
the patch and without Cairo:

with-patch.png
Description: PNG image

Here is what happens when I also apply Alan's patch for
image_set_transform():

And finally what I see with no patches and --with-cairo (this is the
expected result):

Here is the image I'm using for testing:

  medium-wry.png: PNG image data, 16 x 16, 4-bit colormap, non-interlaced: