Re: new toolbar icons are problematic

[Jan D.]

> > When libXpm is used, that library builds the mask for the icon by
> > looking at the transparent parts of the icon.
>
> I assume it never gets the chance because Emacs builds the mask itself
> -- see toolbar.el.  I don't know what happens at the lower levels,
> though, and I don't know how this interacts with gtk.

I've looked into the lower levels now, and the mask Emacs builds works 
for
GTK also. However, there are some problems on 8 bit and monochrome 
displays.
I haven't found where the bug is exactly, but if I let GTK do all image
handling (i.e. loading and rendering the file) the bug does not appear.
But that means the heuristic for building the mask never comes in to 
play.
Hmm, thanks for pointing this out, I must find some other workaround 
then.

        Jan D.