Hi, >I modified the Line2D class to correct the linesIntersect() method - a >patch is attached. The fix is based on an algorithm described in >"Computational Geometry in C" (2nd edition) by Joseph O'Rourke.
Great! I've tried it out, and it seems to work just fine. And it appears to be relatively robust too. (But not invincible) For instance, Sun's implementation can't handle lines which are colinear within numerical error, for instance try: (492.4307556152344,315.69091796875) to (213.55988088439742,243.2761970031803) and (201.19495192826076,240.0653816715973) to (195.03655523160162,238.4662237143015) (There are open-source CAD/GIS libraries like JTS http://www.vividsolutions.com/jts/ which provide numerically robust algorithms for those who really need 14 significant digits for every calculation and don't mind speed.) Actually most of my work on Area() at the moment is trying out the robustness. At the moment it gets into some trouble with shapes that have > 1000 or so self-intersections. >Re-reading Sven's earlier post, it sounds as though he has a fix for >the problem also, which I'll try to find out more about (I couldn't >find it posted anywhere). Yes, I've written intersection-point code for Area, so I figured I'd just adapt that to return true or false instead of a point or null. But I think your code seems better (haven't compared them against eachother though). Just one suggestion: I'm (hopefully) going to be done with Area before the end of the month, and the remaining Arc2D stuff (and whatever else is left in geom.*) should be pretty trivial to do. So instead of making a bunch of small commits, I'd like to roll this all into one big geom.* patch, since any updates to this will need to be sent over to the gcj-gui-branch guys, and it'd be less work for them. Does that sound OK? Oh, and keep up the good work on writing tests! It's very useful! (If only someone with Mauve CVS would commit them for you.. doesn't seem to be much action on that mailing-list) /Sven _______________________________________________ Classpath mailing list [EMAIL PROTECTED] http://lists.gnu.org/mailman/listinfo/classpath
