bug#69992: Minor improvement to image map transformation logic

[Eli Zaretskii <eliz@gnu.org>]

> Date: Fri, 29 Mar 2024 11:19:11 +0100
> From: David Ponce <da_vid@orange.fr>
> Cc: Eli Zaretskii <eliz@gnu.org>, Joseph Turner <joseph@breatheoutbreathe.in>
> 
> > The attached new patch fixes the logic to be consistent with Emacs
> > internal implementation, plus some other tweaks to check if a
> > transformation apply before to call the transformation function.
> > I also updated some tests according to functions changes.
> > Here is a possible change log:
> > 
> > 2024-03-28  David Ponce  <da_vid@orange.fr>
> > 
> >      * lisp/image.el (image--compute-scaling)
> >      (image--compute-rotation): New functions.
> >      (image--compute-map, image--compute-original-map): Use them.
> >      Ensure all transformations are applied or undone according to what
> >      Emacs does internally.  Call a transformation function only when
> >      needed.  Fix doc string.
> >      (image--scale-map): Assume effective scale argument.
> >      (image--rotate-map): Assume effective rotation argument.
> >      (image--rotate-coord): Improve doc string.
> >      (image--flip-map): Remove no more used flip argument.
> > 
> >      * test/lisp/image-tests.el (image-create-image-with-map): Use a
> >      valid SVG image otherwise `image-size' will not return a valid
> >      value and calculation of scale could fail.
> >      (image-transform-map): Update according to changed signature of
> >      image--flip-map.
> [...]
> 
> Hello,
> 
> Please find attached a new patch with an additional small fix I forgot to
> include.  Sorry.

Thanks.  Please resend with the updated commit log message, and I will
install it.