public static List <GeneralPolygon2d> PolygonBoolean(
ICollection <GeneralPolygon2d> poly1, ICollection <GeneralPolygon2d> poly2,
BooleanOp opType, double minArea = -1)
{
// handle cases where one list is empty
if (poly1.Count == 0)
{
if (opType == BooleanOp.Difference || opType == BooleanOp.Intersection)
{
return(new List <GeneralPolygon2d>());
}
else
{
return(DeepCopy.List(poly2));
}
}
else if (poly2.Count == 0)
{
if (opType == BooleanOp.Intersection)
{
return(new List <GeneralPolygon2d>());
}
else
{
return(DeepCopy.List(poly1));
}
}
double nIntScale = Math.Max(GetIntScale(poly1), GetIntScale(poly2));
if (minArea < 0)
{
minArea = DiscardMinArea;
}
try {
Clipper clipper = new Clipper(Clipper.ioStrictlySimple);
foreach (GeneralPolygon2d sub in poly1)
{
CPolygonList cpoly = ConvertToClipper(sub, nIntScale);
clipper.AddPaths(cpoly, PolyType.ptSubject, true);
}
foreach (GeneralPolygon2d clip in poly2)
{
CPolygonList cpoly = ConvertToClipper(clip, nIntScale);
clipper.AddPaths(cpoly, PolyType.ptClip, true);
}
ClipType cType = ClipType.ctUnion;
if (opType == BooleanOp.Difference)
{
cType = ClipType.ctDifference;
}
else if (opType == BooleanOp.Intersection)
{
cType = ClipType.ctIntersection;
}
else if (opType == BooleanOp.Xor)
{
cType = ClipType.ctXor;
}
PolyTree tree = new PolyTree();
bool bOK = clipper.Execute(cType, tree);
if (bOK == false)
{
//System.Diagnostics.Debug.WriteLine("ClipperUtil.PolygonBoolean: Clipper failed");
return(new List <GeneralPolygon2d>());
}
List <GeneralPolygon2d> result = new List <GeneralPolygon2d>();
for (int ci = 0; ci < tree.ChildCount; ++ci)
{
Convert(tree.Childs[ci], result, nIntScale, minArea);
}
return(result);
} catch /*(Exception e)*/ {
//System.Diagnostics.Debug.WriteLine("ClipperUtil.PolygonBoolean: Clipper threw exception: " + e.Message);
return(new List <GeneralPolygon2d>());
}
}