This thread has morphed into something that should be on plplot-devel so I have moved it there under a new subject.
On 2008-11-19 00:02+0100 Werner Smekal wrote: > Hi Jerry and David, > > actually such "hairlines" showed up when I worked on the AGG backend of > the wxWidgets drivers (which produces antialiased plots as well) when I > only filled a "filled polygon" and didn't add a stroke around it, i.e. > draw a line around it. > > Actually I believe that our cairo device shows this behaviour no matter > which driver you use (pdf, xcairo, ...) because it uses only cairo_fill > and not cairo_stroke in addition to draw filled polygons. I can't check > that at the moment but will do that tomorrow (need sleep). > > Also the pdf driver which is based on haru pdf library, doesn't show > this hairlines (if I'm not wrong) and this driver also fills and strokes > filled polygons. Those are most interesting comments, Werner. One of our users once sent a patch to solve the same problem for the ps device by essentially repeating the filled areas with slight x,y shifts to suppress the background leak-through you get with antialiasing. That patch worked, but we didn't accept it because it made the plots too large/too slow to render. Your idea of adding a boundary stroke for the filled area to keep the background from leaking through when antialiasing does essentially the same thing but without the too large/too slow baggage. Of course, you should save and restore the user stroke width and find the optimal stroke width for your boundary stroke, and I am positive this idea will work if you do that. I am looking forward to seeing what your cairo results look like. This antialiasing issue is the number one issue for the cairo devices (and the reason the svg results look so much better than cairo results at the moment). Once we are happy with the cairo antialiased results, then we should propagate the boundary stroke idea to the other devices (e.g., ps and psttf) as well that show this same issue. Personally, I think it is worth (slightly) delaying the release to get this long-standing important issue fixed. Hazen, if you agree, then does the weekend of December 6th seem like a good time to release? 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 __________________________ ------------------------------------------------------------------------- This SF.Net email is sponsored by the Moblin Your Move Developer's challenge Build the coolest Linux based applications with Moblin SDK & win great prizes Grand prize is a trip for two to an Open Source event anywhere in the world http://moblin-contest.org/redirect.php?banner_id=100&url=/ _______________________________________________ Plplot-devel mailing list Plplot-devel@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/plplot-devel
