Re: gEDA: picture png support

[Ales Hvezda <ahvezda-at-NOSPAMseul_dot_org>]

Hi Carlos,

[snip]
>Well, hard work is done. I got PNG images without using libgdgeda at
>all. I have not compiled gschem with libgdgeda support, so maybe there
>are some differences between the two ways, but this should be minor
>tweaking now.

	I tried out your code changes.	Very nice!  I did compare
the output between libgdgeda and getting the pixbuf and there are some
visual differences (the libgdgeda is a little crisper), but I'm much
happier with the new mechanism.

	I did fix a couple bugs dealing with:

	* non-default images were not being rendered correctly (the was 
	  some uninitialized data around the image edges).  The fix was
	  to set some more variables in your toplevel copy.

	* I also added some code to convert the color pixbuf to greyscale
	  to support the image-color rc keyword. 

	Unrelated change:

	* I added code to gschem configure.ac to detect if gtk+ 2.6.x or
	  greater is installed.  Could somebody who has gtk+ 2.8.x on their
	  machine please update from cvs and do the following:

		cat config.h | grep HAS_GTK26

	  and send me the output.  This test is in prep for some future work
	  I am planning which requires gtk+ 2.6.x.  Don't worry, gEDA/gaf 
	  will still work build and run for gtk+ 2.2.x for a much longer 
	  time.	

[snip]
>probably not, but I have not tested it. I made a copy of the toplevel
>structure and I used a gdk pixmap when drawing the schematic to a
>drawable, just before getting the pixbuf from it (I couldn't use a
>gdk_drawing_area because it was not visible). Using this trick, I think
>the window flashing when exporting to PNG is also removed.

	Yeah, but I think there is still a coupling between gdk and the
png output code (not sure where yet), but I'm sure we can find a way to
fix this. :)

	Thanks for these significant improvements, Carlos.

								-Ales