bug#2843: 23.0.92; Emacs.app cannot display X bitmaps

[Alp Aker]

Pyter Dyballa wrote:

> The NS variant of GNU Emacs 24.0.50 shows the GNU Emacs logo slightly
> different than splash.png

What difference do you see?

For png images NS gives the file to the system graphics API and uses the 
image it returns.  It might be that the Cocoa library itself renders png 
images incorrectly, but I don't see a visible difference when I open 
/etc/images/splash.png in Emacs at its original size and when I open in it 
in a graphics editor with native png support.

> It also has a problem with splash.pbm: it's displayed as one deep black
> square.

pbm images on NS work when the data is read from Lisp, but not when read 
from a file.  I'm working on a patch for this (and will file a separate 
bug report, as it's a generic problem with pbm images).

> And it cannot display splash.svg

This image format isn't supported on NS, because the Cocoa image library 
doesn't support svg images. But that's not a bug since the NS port will 
tell you that it's not supported:

  (image-type-available-p 'svg)
  ==> nil

In principle the NS port could use librsvg or ImageMagick, but that would 
require a substantial revision of the image support code, so I doubt it's 
going to happen any time soon.