On Mon, Mar 15, 2010 at 10:15 PM, Alan W. Irwin <ir...@beluga.phys.uvic.ca> wrote: > On 2010-03-15 20:38-0400 Hazen Babcock wrote: > >> The problem is that we currently do not allow any choices. The cairo driver >> is explicitly starting with a non-transparent white background. It is not as >> clear to me exactly what the Qt driver is doing when it starts a new page, >> though I don't believe that the driver itself sets the background to be >> white. > > Hazen, wouldn't it be fairly straightforward to infer from the good svgcairo > results what to do for the other cairo file devices to get proper > transparent backgrounds for those devices? My feeling is it would be easier > to deal with the cairo file devices first since their code is similar to the > svgcairo case and much simpler than in the xcairo case. > > Similarly, I think that whoever tackles the qt case should attempt to expand > the good svgqt transparent background results to the other qt devices before > finally attempting to deal with the complicated qtwidget case. >
The fix for pngcairo is fairly straightforward. The pngcairo device was using an RGB surface rather than an ARGB surface, so the Cairo drawing routines were treating it like it does not support transparency (which it didn't). Changing the pngcairo to use an ARGB surface fixes this issue and gives output with a properly transparent background, like the svgcairo case. I have committed this change as revision 10847. Should I back-out the xcairo device change? From what I have read so far, having nicely window-manager independent transparent backgrounds for the xcairo (and xwin and possiblt qtwidget) devices would require pulling in more X dependencies and would only work with window managers which support such niceties. Hez ------------------------------------------------------------------------------ Download Intel® Parallel Studio Eval Try the new software tools for yourself. Speed compiling, find bugs proactively, and fine-tune applications for parallel performance. See why Intel Parallel Studio got high marks during beta. http://p.sf.net/sfu/intel-sw-dev _______________________________________________ Plplot-devel mailing list Plplot-devel@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/plplot-devel
