//------------------------------------------------------------------------------
public static Polygons SimplifyPolygons(Polygons polys)
{
Polygons result = new Polygons();
Clipper c = new Clipper();
c.AddPolygons(polys, PolyType.ptSubject);
c.Execute(ClipType.ctUnion, result);
return result;
}
public PolyOffsetBuilder(Polygons pts, Polygons solution, double delta, JoinType jointype, double MiterLimit = 2)
{
//precondtion: solution != pts
if (delta == 0)
{
solution = pts;
return;
}
this.pts = pts;
this.delta = delta;
if (MiterLimit <= 1) MiterLimit = 1;
double RMin = 2/(MiterLimit*MiterLimit);
normals = new List<DoublePoint>();
solution.Clear();
solution.Capacity = pts.Count;
for (m_i = 0; m_i < pts.Count; m_i++)
{
int len = pts[m_i].Count;
if (len > 1 && pts[m_i][0].X == pts[m_i][len - 1].X &&
pts[m_i][0].Y == pts[m_i][len - 1].Y) len--;
if (len == 0 || (len < 3 && delta <= 0))
continue;
else if (len == 1)
{
Polygon arc;
arc = BuildArc(pts[m_i][len - 1], 0, 2 * Math.PI, delta);
solution.Add(arc);
continue;
}
//build normals ...
normals.Clear();
normals.Capacity = len;
for (int j = 0; j < len -1; ++j)
normals.Add(GetUnitNormal(pts[m_i][j], pts[m_i][j+1]));
normals.Add(GetUnitNormal(pts[m_i][len - 1], pts[m_i][0]));
currentPoly = new Polygon();
m_k = len - 1;
for (m_j = 0; m_j < len; ++m_j)
{
switch (jointype)
{
case JoinType.jtMiter:
{
m_R = 1 + (normals[m_j].X*normals[m_k].X +
normals[m_j].Y*normals[m_k].Y);
if (m_R >= RMin) DoMiter(); else DoSquare(MiterLimit);
break;
}
case JoinType.jtRound:
DoRound();
break;
case JoinType.jtSquare:
DoSquare(1);
break;
}
m_k = m_j;
}
solution.Add(currentPoly);
}
//finally, clean up untidy corners ...
Clipper clpr = new Clipper();
clpr.AddPolygons(solution, PolyType.ptSubject);
if (delta > 0)
{
clpr.Execute(ClipType.ctUnion, solution, PolyFillType.pftPositive, PolyFillType.pftPositive);
}
else
{
IntRect r = clpr.GetBounds();
Polygon outer = new Polygon(4);
outer.Add(new IntPoint(r.left - 10, r.bottom + 10));
outer.Add(new IntPoint(r.right + 10, r.bottom + 10));
outer.Add(new IntPoint(r.right + 10, r.top - 10));
outer.Add(new IntPoint(r.left - 10, r.top - 10));
clpr.AddPolygon(outer, PolyType.ptSubject);
clpr.Execute(ClipType.ctUnion, solution, PolyFillType.pftNegative, PolyFillType.pftNegative);
if (solution.Count > 0)
{
solution.RemoveAt(0);
for (int i = 0; i < solution.Count; i++)
solution[i].Reverse();
}
}
}
