On 2010-03-14 10:50-0500 Hezekiah M. Carty wrote: >>>> Hmm. after updating to get your fix and "make cairo" I still get the same >>>> (bad) result (with page 1 still visible underneath) for >>>> >>>> examples/c/x02c -dev xcairo -bg 0000FF_0.1 >>>> >>>> examples/c/x02c -dev qtwidget -bg 0000FF_01 >>>> >>>> was fine. >>>> >> >> I get similar results on a fresh trunk source tree. What should the >> default background color be? The qtwidget device seems to assume >> white as the default background, regardless of the base color palette: >> > > Revision 10866 should fix this. If the background color has an alpha > value < 1.0 then a white surface is drawn before the transparent > background color. This produces good looking results for all of the > Cairo devices on my system (Ubuntu 9.10, Cairo 1.8.8).
This fix obscures the underlying layers as advertised so stops the leaking through of the first page onto the second. However, I don't like this way of dealing with the issue (which from your comments, qtwidget uses as well). We want transparent backgrounds to be transparent because we would like to implement the absolutely cool effect of seeing the plot superimposed on the desktop underneath the GUI. To work toward that goal, we must avoid putting in any obscuring layers. Actually, the previous cairo version did not put in an obscuring layer which was good, but the problem was the plot from the previous page was not removed. Shouldn't you be able to deal with this issue by closing the old page and initiating a completely new one each time there is a new page in the example? I think that is what the cairo file devices do. Furthermore, is there a cairo page setup feature you could use that initiated the GUI with no cairo (as opposed to PLplot) background? If so, then the PLplot background would be the absolutely first layer of the GUI so that if it were transparent, you would see through to the underlying desktop. In sum, that is potentially a very cool effect which I hope we will be able to implement by initiating pango/cairo correctly and by not putting in any obscuring layers. Same comment for qt. Alan __________________________ Alan W. Irwin Astronomical research affiliation with Department of Physics and Astronomy, University of Victoria (astrowww.phys.uvic.ca). Programming affiliations with the FreeEOS equation-of-state implementation for stellar interiors (freeeos.sf.net); PLplot scientific plotting software package (plplot.org); the libLASi project (unifont.org/lasi); the Loads of Linux Links project (loll.sf.net); and the Linux Brochure Project (lbproject.sf.net). __________________________ Linux-powered Science __________________________ ------------------------------------------------------------------------------ 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
