image-size

[Lars Magne Ingebrigtsen]

If I remember correctly from previous discussions, if you call
`image-size', Emacs will go through all the normal stuff it does before
displaying it, including pushing it to the X server, and then ask it how
big it was.  (I'm having a bit of a problem following the logic of
lookup_image, but it looks complicated.  :-)

If that's what's happening, it tallies with my experience when using shr
on big images.  shr (by default) scales down images that are too big, so
that they'll fit on the page.  But since it first "semi-displays" the
huge picture, then rescales, then displays the small picture, this is
uncomfortably slow.  At least under X.  And under ssh, it's unbearable.

So:

1) Is this what's going on?

and

2) If so, would someone mind very much if I alter `image-size' to do a
"fast path" iff a) we're asking for the pixel size, and b) we have
imagemagick compiled it?  If those two things are true, I could add some
code to just ask imagemagick how big the image is without involving the
display engine at all, and things would be a lot faster, I imagine.

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