Re: Redisplay slower in Emacs 28 than Emacs 27

[Lars Ingebrigtsen <larsi@gnus.org>]

And this is the culprit -- i.e., this is what's busting the cache, as
far as I can tell:

(defun tool-bar--image-expression (icon)
  "Return an expression that evaluates to an image spec for ICON."
  (let* ((fg (face-attribute 'tool-bar :foreground))
	 (bg (face-attribute 'tool-bar :background))
	 (colors (nconc (if (eq fg 'unspecified) nil (list :foreground fg))
			(if (eq bg 'unspecified) nil (list :background bg))))
	 (xpm-spec (list :type 'xpm :file (concat icon ".xpm")))
	 (xpm-lo-spec (list :type 'xpm :file
			    (concat "low-color/" icon ".xpm")))
	 (pbm-spec (append (list :type 'pbm :file
                                 (concat icon ".pbm")) colors))
	 (xbm-spec (append (list :type 'xbm :file
                                 (concat icon ".xbm")) colors)))
    `(find-image (cond ((not (display-color-p))
			',(list pbm-spec xbm-spec xpm-lo-spec xpm-spec))
		       ((< (display-color-cells) 256)
			',(list xpm-lo-spec xpm-spec pbm-spec xbm-spec))
		       (t
			',(list xpm-spec pbm-spec xbm-spec))))))

Whenever Emacs is asked to redisplay the toolbar, Emacs will run this
function?  That's what my instrumentation seems to say...

I don't use toolbars normally, so I'm not sure how they're supposed to
work -- but shouldn't this toolbar data be computed only once, instead
of repeatedly?

-- 
(domestic pets only, the antidote for overdose, milk.)
   bloggy blog: http://lars.ingebrigtsen.no