The University of Manchester GPC library (wikipedia: GPC) is a flexible and highly robust polygon set operations library for use with C, C#, Delphi, Java, Perl, Python, Haskell, Lua, VB.Net (and other) applications.

Information

• Author: Alan Murta
• Website: http://www.cs.man.ac.uk/~toby/gpc/

GPC Features

• Difference, intersection, exclusive-or and union clip operations are supported.
• Polygons may be comprised of multiple disjoint contours.
• Contour vertices may be given in any order - clockwise or anticlockwise.
• Contours may be convex, concave or self-intersecting.
• Contours may be nested (i.e. polygons may have holes).
• Output may take the form of either polygon contours or tristrips.
• Hole and external contours are differentiated in the result.
• Coincident edges and degenerate regions are handled correctly.

On-line documentation: http://www.cs.man.ac.uk/~toby/alan/software/gpc.html