Re: create-image and find-image consistency

[Lars Ingebrigtsen]

David Ponce <address@hidden> writes:

> I am using Emacs latest master, and noticed some inconsistency between the
> results of function `create-image' and `find-image'.
>
> Here is an example:
>
> (create-image "[EMACS-DIR]/etc/images/icons/hicolor/scalable/apps/emacs.svg")
> ==> (image :type svg :file 
> "[EMACS-DIR]/etc/images/icons/hicolor/scalable/apps/emacs.svg" :scale 1.2)
>
> (find-image '((:type svg :file 
> "[EMACS-DIR]/etc/images/icons/hicolor/scalable/apps/emacs.svg")))
> ==> (image :type svg :file 
> "[EMACS-DIR]/etc/images/icons/hicolor/scalable/apps/emacs.svg")
>
> Contrary to images returned by `create-image', which are automatically scaled
> when no :scale property is provided, those returned by `find-image' are not.
>
> I propose the below patch to have `find-image' use `create-image' in
> order to get consistent results from both functions.

I think it conceptually makes sense to have find-image use create-image,
but looking at the code, and where find-image is used, it looks like the
use case it for creating toolbars and the like, where you want to pick
out one of the (built-in) image formats that Emacs supports...

Looking at your patch, you remove the (image-type-available-p type), and
instead rely on create-image not bugging out instead?  That feels like a
less obvious way to do the test (and more breakable; there may be other
reasons create-image fails).

And I'm not 100% sure that we want to auto-scale toolbars and the like.
I'm pretty sure we do, but perhaps somebody else has an opinion here?

Anyway, I think you should file this as a bug report so that the patch
doesn't get lost, because I think you're basically correct that the
find-image behaviour should be changed.

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