> What we want to do is compute coverate and turn it into alpha. Well, > let's think about this for a moment. Any pixel that aligns exactly with > the center of the line should have alpha of 1.0. Any pixel completely > off the line should have alpha of 0, and any pixel which lies on the > edge of the line should have alpha of 0.5. Why not draw a polygon which > varies alpha from 1.0 at the center to 0.0 at the line width away from > the center?
That clearly won't give anything resembling the coverage. If you want to use a polygon for (wide) lines, then you should just use a smooth polygon, given that that is implemented. This won't even work correctly for width 1.0 lines as a horizontal/vertical line at integer coordinate won't show. You should be able to find an algorithm for smooth width 1.0 lines in books/articles; the Gupta-Sproull algorithm seems to be suitable. --ms _______________________________________________ Open-graphics mailing list [email protected] http://lists.duskglow.com/mailman/listinfo/open-graphics List service provided by Duskglow Consulting, LLC (www.duskglow.com)
