bug#74725: 31.0.50; image-scaling-factor is ignored by create-image

[Eli Zaretskii]

> Date: Fri, 27 Dec 2024 12:11:33 +0000
> From: Alan Third <alan@idiocy.org>
> Cc: Po Lu <luangruo@yahoo.com>, 74725@debbugs.gnu.org, da_vid@orange.fr
> 
> > Alan, could you please prepare a patch (for the master branch) that
> > records the scaling factor in the image cache and rejects a cache hit
> > with a different scaling factor?
> 
> Hi Eli, patch attached.

Thanks, LGTM.

> I named a new function image_compute_scale because most of the other
> functions in that file start image_, however I wasn't sure if I should
> name it compute_image_scale to mirror compute_image_size. Let me know
> if you think I should change it.

Static functions can have any names we see fit, so feel free to rename
if you think compute_image_scale would be better.

Feel free to install on master, when you are satisfied with the code.