Re: Building Emacs with graphics support on a Mac system

[Alp Aker]

Jan Djärv wrote:

> > Is this generally true, that Emacs built on OS X will provide the same
> > functionality as, say, Linux, but without external libraries being
> > installed?
>
> Mostly yes.  Stuff that doesn't make sense (dbus, gconf) have no
> counterpart.  Imagemagic is missing from the OSX port.

In the specific case of image support, the situation is (to be the best of my
understanding) as follows:

(1) xbm, pbm, xpm, jpeg, png, gif, and tiff images are supported without the
need of additional libraries.

(2) One can compile with librsvg if building on GNUstep, but the configure
script does not currently allow one to do that if building on Cocoa.  (But
the script is easily edited to allow building with librsvg on Cocoa, and svg
images will then display fine.)

(3) You *can* build with Imagemagick and Ghostscript support on OSX, but
again this requires manually editing the configure script.  The result seems
to work, but I haven't done any kind of thorough testing, so adding support
for these options on NextStep might not be as straightforward as it is in the
case of librsvg.

And there are two respects in which image support on NextStep is buggy:

(a) Image types that allow :foreground and :background keywords in their
descriptors will not default correctly to the frame foreground and background
colors when those keywords are omitted.  They default instead to black
(except in the case of xbm images; see the next item).  This most commonly
causes problems when viewing mono pbm files.  (I have patch for this that
I'll post after my copyright assignment is processed.)

(b) xbm images are always drawn with foreground in black and background in
the frame background color.  (I'll be posting a patch for this as well.)