Bill Baxter wrote:
On 4/25/07, bulia byak <buliabyak@...155...> wrote:
On 4/24/07, Terry Brown <terry_n_brown@...12...> wrote:
I don't think inkscape has that. Looks like the POV-ray pattern 'Crackle':
http://www.povray.org/documentation/view/3.6.1/372/
--clip-- Mathematically, the set crackle(p)=0 is a 3D Voronoi diagram of a field of semi random points and crackle(p) < 0 is the distance from the set along the shortest path (a Voronoi diagram is the locus of points equidistant from their two nearest neighbors from a set of disjoint points, like the membranes in suds are to the centers of the bubbles).
By the way, this might make a useful Python effect for Inkscape: Fill the inside of a path with random points and build a Voronoi diagram (as a set of polygon paths) of these points, or of the path's nodes, or both. Any takers?
Doing Voronoi diagrams (and delaunay triangulations) robustly is tricky. Simpler algorithms tend to barf on input that has too many collinear points, or has points placed exactly on a grid. And the textbook implementations usually avoid constraints altogether. But the Triangle lib by Jonathan Shewchuk handles all that and more quite beautifully and can create both Voronoi diagrams and Delaunay triangulations of the interiors of arbitrary polygons. (Arbitrary in the sense of being concave and having holes. Probably not self-intersecting ones, though I haven't tried that).
Livarot used to do Voronoi diagrams.
http://livarot.sourceforge.net/
:-)
Aaron Spike