//------------------------------------------------------------------------------
#endif
//------------------------------------------------------------------------------
// SimplifyPolygon functions ...
// Convert self-intersecting polygons into simple polygons
//------------------------------------------------------------------------------
public static Paths SimplifyPolygon(Path poly,
PolyFillType fillType = PolyFillType.pftEvenOdd)
{
Paths result = new Paths();
Clipper c = new Clipper();
c.StrictlySimple = true;
c.AddPath(poly, PolyType.ptSubject, true);
c.Execute(ClipType.ctUnion, result, fillType, fillType);
return result;
}
//------------------------------------------------------------------------------
public PolyOffsetBuilder(Paths pts, out Paths solution, double delta,
JoinType jointype, EndType endtype, double limit = 0)
{
//precondition: solution != pts
solution = new Paths();
if (ClipperBase.near_zero(delta)) {solution = pts; return; }
m_p = pts;
if (endtype != EndType.etClosed && delta < 0) delta = -delta;
m_delta = delta;
if (jointype == JoinType.jtMiter)
{
//m_miterVal: see offset_triginometry.svg in the documentation folder ...
if (limit > 2) m_miterLim = 2 / (limit * limit);
else m_miterLim = 0.5;
if (endtype == EndType.etRound) limit = 0.25;
}
if (jointype == JoinType.jtRound || endtype == EndType.etRound)
{
if (limit <= 0) limit = 0.25;
else if (limit > Math.Abs(delta)*0.25) limit = Math.Abs(delta)*0.25;
//m_roundVal: see offset_triginometry2.svg in the documentation folder ...
m_Steps360 = Math.PI / Math.Acos(1 - limit / Math.Abs(delta));
m_sin = Math.Sin(2 * Math.PI / m_Steps360);
m_cos = Math.Cos(2 * Math.PI / m_Steps360);
m_Steps360 /= Math.PI * 2;
if (delta < 0) m_sin = -m_sin;
}
solution.Capacity = pts.Count;
for (m_i = 0; m_i < pts.Count; m_i++)
{
int len = pts[m_i].Count;
if (len == 0 || (len < 3 && delta <= 0)) continue;
if (len == 1)
{
if (jointype == JoinType.jtRound)
{
double X = 1.0, Y = 0.0;
for (cInt j = 1; j <= Round(m_Steps360 * 2 * Math.PI); j++)
{
AddPoint(new IntPoint(
Round(m_p[m_i][0].X + X * delta),
Round(m_p[m_i][0].Y + Y * delta)));
double X2 = X;
X = X * m_cos - m_sin * Y;
Y = X2 * m_sin + Y * m_cos;
}
}
else
{
double X = -1.0, Y = -1.0;
for (int j = 0; j < 4; ++j)
{
AddPoint(new IntPoint(Round(m_p[m_i][0].X + X * delta),
Round(m_p[m_i][0].Y + Y * delta)));
if (X < 0) X = 1;
else if (Y < 0) Y = 1;
else X = -1;
}
}
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]));
if (endtype == EndType.etClosed)
normals.Add(GetUnitNormal(pts[m_i][len - 1], pts[m_i][0]));
else
normals.Add(new DoublePoint(normals[len - 2]));
currentPoly = new Path();
if (endtype == EndType.etClosed)
{
m_k = len - 1;
for (m_j = 0; m_j < len; ++m_j)
OffsetPoint(jointype);
solution.Add(currentPoly);
}
else
{
m_k = 0;
for (m_j = 1; m_j < len - 1; ++m_j)
OffsetPoint(jointype);
IntPoint pt1;
if (endtype == EndType.etButt)
{
m_j = len - 1;
pt1 = new IntPoint((cInt)Round(pts[m_i][m_j].X + normals[m_j].X *
delta), (cInt)Round(pts[m_i][m_j].Y + normals[m_j].Y * delta));
AddPoint(pt1);
pt1 = new IntPoint((cInt)Round(pts[m_i][m_j].X - normals[m_j].X *
delta), (cInt)Round(pts[m_i][m_j].Y - normals[m_j].Y * delta));
AddPoint(pt1);
}
else
{
m_j = len - 1;
m_k = len - 2;
m_sinA = 0;
normals[m_j] = new DoublePoint(-normals[m_j].X, -normals[m_j].Y);
if (endtype == EndType.etSquare)
DoSquare();
else
DoRound();
}
//re-build Normals ...
for (int j = len - 1; j > 0; j--)
normals[j] = new DoublePoint(-normals[j - 1].X, -normals[j - 1].Y);
normals[0] = new DoublePoint(-normals[1].X, -normals[1].Y);
m_k = len - 1;
for (m_j = m_k - 1; m_j > 0; --m_j)
OffsetPoint(jointype);
if (endtype == EndType.etButt)
{
pt1 = new IntPoint((cInt)Round(pts[m_i][0].X - normals[0].X * delta),
(cInt)Round(pts[m_i][0].Y - normals[0].Y * delta));
AddPoint(pt1);
pt1 = new IntPoint((cInt)Round(pts[m_i][0].X + normals[0].X * delta),
(cInt)Round(pts[m_i][0].Y + normals[0].Y * delta));
AddPoint(pt1);
}
else
{
m_k = 1;
m_sinA = 0;
if (endtype == EndType.etSquare)
DoSquare();
else
DoRound();
}
solution.Add(currentPoly);
}
}
//finally, clean up untidy corners ...
Clipper clpr = new Clipper();
clpr.AddPaths(solution, PolyType.ptSubject, true);
if (delta > 0)
{
clpr.Execute(ClipType.ctUnion, solution, PolyFillType.pftPositive, PolyFillType.pftPositive);
}
else
{
IntRect r = clpr.GetBounds();
Path outer = new Path(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.AddPath(outer, PolyType.ptSubject, true);
clpr.ReverseSolution = true;
clpr.Execute(ClipType.ctUnion, solution, PolyFillType.pftNegative, PolyFillType.pftNegative);
if (solution.Count > 0) solution.RemoveAt(0);
}
}