2017-03-18 15:27 GMT+01:00 Andreas Politz <politza@hochschule-trier.de>:

> Fabrice Popineau <fabrice.popineau@gmail.com> writes:
>
> > Maybe a stupid question but if emacs is compiled with ImageMagick
> support,
> > what is the point in asking JPEG, PNG, etc support at the same time from
> independent libraries ?
> > Shouldn't configure made those options to be exclusive ?
>
> Imagemagick is handled like an image type, so png and imagemagick are
> two different types.  One uses libpng as backend and the other
> libmagick.


My point is that only one of imagemagick and libpng will handle png files
at a time.
When ImageMagick is available, it supersedes png, jpeg and anything it
handles (AFAICS).
If you want to let libpng handle png files, you need to change some
defaults
(imagemagick-filter-types, etc.)


> > Also what is (are) the drawback(s) of ImageMagick support vs the other
> libraries ?
>
> In my experience, libpng is faster then imagemagick.


Ok, that is understandable.

Fabrice