Re: [PATCH v2] Add native image scaling (bug#33587)

[Alan Third]

On Fri, Jan 04, 2019 at 10:21:17PM +0200, Eli Zaretskii wrote:
> > Date: Fri, 4 Jan 2019 19:09:14 +0000
> > From: Alan Third <address@hidden>
> > Cc: address@hidden
> > 
> > (Another option would be to automatically fall‐back to ImageMagick if
> > required, but given that we’re doing this because people are concerned
> > about ImageMagick’s security record, I doubt making it’s use automatic
> > would appeal.)
> 
> I guess I've misread the code, because I thought we did fall back
> automatically.  FWIW, I think if the user builds Emacs with
> ImageMagick, they already considered the security issues and decided
> they are okay with them.  We shouldn't second-guess them.

If you load an image then use image-mode’s + and - bindings it
automatically falls back to ImageMagick, but if you just load and
insert an image like this:

    (insert-image (create-image "image.gif" nil nil :width 25))

it doesn’t. To get :width to do anything you need to specify that you
want to use ImageMagick:

    (insert-image (create-image "image.gif" imagemagick nil :width 25))

I suspect the simplest place to do it would be in create-image, but
someone who understands image.el better than me might have a different
opinion. (In other words: I hope someone else fancies implementing the
fallback, as I’m not very confident digging into lisp.)
-- 
Alan Third