bug#69602: 29.1; Image :map should adjust with :scale and :rotation

[Eli Zaretskii <eliz@gnu.org>]

> From: Joseph Turner <joseph@breatheoutbreathe.in>
> Cc: 69602@debbugs.gnu.org, stephen.berman@gmx.net, juri@linkov.net
> Date: Wed, 20 Mar 2024 23:45:34 -0700
> 
> > I had in mind a special variable (we'd need to mention it in NEWS and
> > in the doc string of the relevant functions).  Adding an argument is a
> > heavier change, and I think it is not justified in this case, because
> > I do agree with you that most, if not all, applications would want the
> > coordinates to scale together with the image.
> 
> Thanks for your feedback and your patience!
> 
> Please see attached patch.

Thanks.  The tests you added have some problems:

 . you use thread-first, but don't require subr-x when compiling
 . the tests fail when run in batch mode
 . when invoked interactively in a GUI session, one test fails:

    F image--compute-map-and-original-map
	Test ‘image--compute-map’ and ‘image--compute-original-map’.
	(ert-test-failed
	 ((should (equal (image--compute-map image) flipped-map)) :form
	  (equal
	   (((circle ... . 24) "a" (help-echo "A"))
	    ((rect ... 162 . 149) "b" (help-echo "B"))
	    ((poly . [6 29 7 22 13 15 21 10 31 7 ...]) "c" (help-echo "C")))
	   (((circle ... . 24) "a" (help-echo "A"))
	    ((rect ... 161 . 149) "b" (help-echo "B"))
	    ((poly . [5 29 6 22 12 15 20 10 30 7 ...]) "c" (help-echo "C"))))
	  :value nil :explanation (list-elt 0 (list-elt 0 (cdr (car ...))))))

It looks like some pixels do not match exactly?  Perhaps some
tolerances need to be allowed?