//------------------------------------------------------------------------------
public bool AddPolygon(PolygonClp pg, PolyType polyType)
{
int len = pg.Count;
if (len < 3) return false;
Int64 maxVal;
if (m_UseFullRange) maxVal = hiRange; else maxVal = loRange;
RangeTest(pg[0], ref maxVal);
PolygonClp p = new PolygonClp(len);
p.Add(new IntPoint(pg[0].X, pg[0].Y));
int j = 0;
for (int i = 1; i < len; ++i)
{
RangeTest(pg[i], ref maxVal);
if (PointsEqual(p[j], pg[i])) continue;
else if (j > 0 && SlopesEqual(p[j - 1], p[j], pg[i], maxVal == hiRange))
{
if (PointsEqual(p[j - 1], pg[i])) j--;
}
else j++;
if (j < p.Count)
p[j] = pg[i];
else
p.Add(new IntPoint(pg[i].X, pg[i].Y));
}
if (j < 2) return false;
m_UseFullRange = maxVal == hiRange;
len = j + 1;
while (len > 2)
{
//nb: test for point equality before testing slopes ...
if (PointsEqual(p[j], p[0])) j--;
else if (PointsEqual(p[0], p[1]) || SlopesEqual(p[j], p[0], p[1], m_UseFullRange))
p[0] = p[j--];
else if (SlopesEqual(p[j - 1], p[j], p[0], m_UseFullRange)) j--;
else if (SlopesEqual(p[0], p[1], p[2], m_UseFullRange))
{
for (int i = 2; i <= j; ++i) p[i - 1] = p[i];
j--;
}
else break;
len--;
}
if (len < 3) return false;
//create a new edge array ...
List<TEdge> edges = new List<TEdge>(len);
for (int i = 0; i < len; i++) edges.Add(new TEdge());
m_edges.Add(edges);
//convert vertices to a double-linked-list of edges and initialize ...
edges[0].xcurr = p[0].X;
edges[0].ycurr = p[0].Y;
InitEdge(edges[len - 1], edges[0], edges[len - 2], p[len - 1], polyType);
for (int i = len - 2; i > 0; --i)
InitEdge(edges[i], edges[i + 1], edges[i - 1], p[i], polyType);
InitEdge(edges[0], edges[1], edges[len - 1], p[0], polyType);
//reset xcurr & ycurr and find 'eHighest' (given the Y axis coordinates
//increase downward so the 'highest' edge will have the smallest ytop) ...
TEdge e = edges[0];
TEdge eHighest = e;
do
{
e.xcurr = e.xbot;
e.ycurr = e.ybot;
if (e.ytop < eHighest.ytop) eHighest = e;
e = e.next;
}
while (e != edges[0]);
//make sure eHighest is positioned so the following loop works safely ...
if (eHighest.windDelta > 0) eHighest = eHighest.next;
if (eHighest.dx == horizontal) eHighest = eHighest.next;
//finally insert each local minima ...
e = eHighest;
do
{
e = AddBoundsToLML(e);
}
while (e != eHighest);
return true;
}
//------------------------------------------------------------------------------
//------------------------------------------------------------------------------
// SimplifyPolygon functions ...
// Convert self-intersecting polygons into simple polygons
//------------------------------------------------------------------------------
public static PolygonsClp SimplifyPolygon(PolygonClp poly,
PolyFillType fillType = PolyFillType.pftEvenOdd)
{
PolygonsClp result = new PolygonsClp();
Clipper c = new Clipper();
c.ForceSimple = true;
c.AddPolygon(poly, PolyType.ptSubject);
c.Execute(ClipType.ctUnion, result, fillType, fillType);
return result;
}
//------------------------------------------------------------------------------
public static PolygonClp CleanPolygon(PolygonClp poly,
double distance = 1.415)
{
//distance = proximity in units/pixels below which vertices
//will be stripped. Default ~= sqrt(2) so when adjacent
//vertices have both x & y coords within 1 unit, then
//the second vertex will be stripped.
double distSqrd = (distance * distance);
int highI = poly.Count - 1;
PolygonClp result = new PolygonClp(highI + 1);
while (highI > 0 && PointsAreClose(poly[highI], poly[0], distSqrd)) highI--;
if (highI < 2) return result;
IntPoint pt = poly[highI];
int i = 0;
for (; ; )
{
while (i < highI && PointsAreClose(pt, poly[i], distSqrd)) i += 2;
int i2 = i;
while (i < highI && (PointsAreClose(poly[i], poly[i + 1], distSqrd) ||
SlopesNearColinear(pt, poly[i], poly[i + 1], distSqrd))) i++;
if (i >= highI) break;
else if (i != i2) continue;
pt = poly[i++];
result.Add(pt);
}
if (i <= highI) result.Add(poly[i]);
i = result.Count;
if (i > 2 && SlopesNearColinear(result[i - 2], result[i - 1], result[0], distSqrd))
result.RemoveAt(i - 1);
if (result.Count < 3) result.Clear();
return result;
}
//------------------------------------------------------------------------------
public PolyOffsetBuilder(PolygonsClp pts, PolygonsClp solution, bool isPolygon, double delta,
JoinType jointype, EndType endtype, double limit = 0)
{
//precondition: solution != pts
if (delta == 0) { solution = pts; return; }
m_p = pts;
m_delta = delta;
m_rmin = 0.5;
if (jointype == JoinType.jtMiter)
{
if (limit > 2) m_rmin = 2.0 / (limit * limit);
limit = 0.25; //just in case endtype == etRound
}
else
{
if (limit <= 0) limit = 0.25;
else if (limit > Math.Abs(delta)) limit = Math.Abs(delta);
}
double deltaSq = delta * delta;
solution.Clear();
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;
else if (len == 1)
{
currentPoly = new PolygonClp();
currentPoly = BuildArc(pts[m_i][0], 0, 2 * Math.PI, delta, limit);
solution.Add(currentPoly);
continue;
}
bool forceClose = PointsEqual(pts[m_i][0], pts[m_i][len - 1]);
if (forceClose) len--;
//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 (isPolygon || forceClose)
normals.Add(GetUnitNormal(pts[m_i][len - 1], pts[m_i][0]));
else
normals.Add(new DoublePoint(normals[len - 2]));
currentPoly = new PolygonClp();
if (isPolygon || forceClose)
{
m_k = len - 1;
for (m_j = 0; m_j < len; ++m_j)
OffsetPoint(jointype, limit);
solution.Add(currentPoly);
if (!isPolygon)
{
currentPoly = new PolygonClp();
m_delta = -m_delta;
m_k = len - 1;
for (m_j = 0; m_j < len; ++m_j)
OffsetPoint(jointype, limit);
m_delta = -m_delta;
currentPoly.Reverse();
solution.Add(currentPoly);
}
}
else
{
m_k = 0;
for (m_j = 1; m_j < len - 1; ++m_j)
OffsetPoint(jointype, limit);
IntPoint pt1;
if (endtype == EndType.etButt)
{
m_j = len - 1;
pt1 = new IntPoint((Int64)Round(pts[m_i][m_j].X + normals[m_j].X *
delta), (Int64)Round(pts[m_i][m_j].Y + normals[m_j].Y * delta));
AddPoint(pt1);
pt1 = new IntPoint((Int64)Round(pts[m_i][m_j].X - normals[m_j].X *
delta), (Int64)Round(pts[m_i][m_j].Y - normals[m_j].Y * delta));
AddPoint(pt1);
}
else
{
m_j = len - 1;
m_k = len - 2;
normals[m_j].X = -normals[m_j].X;
normals[m_j].Y = -normals[m_j].Y;
if (endtype == EndType.etSquare) DoSquare();
else DoRound(limit);
}
//re-build Normals ...
for (int j = len - 1; j > 0; j--)
{
normals[j].X = -normals[j - 1].X;
normals[j].Y = -normals[j - 1].Y;
}
normals[0].X = -normals[1].X;
normals[0].Y = -normals[1].Y;
m_k = len - 1;
for (m_j = m_k - 1; m_j > 0; --m_j)
OffsetPoint(jointype, limit);
if (endtype == EndType.etButt)
{
pt1 = new IntPoint((Int64)Round(pts[m_i][0].X - normals[0].X * delta),
(Int64)Round(pts[m_i][0].Y - normals[0].Y * delta));
AddPoint(pt1);
pt1 = new IntPoint((Int64)Round(pts[m_i][0].X + normals[0].X * delta),
(Int64)Round(pts[m_i][0].Y + normals[0].Y * delta));
AddPoint(pt1);
}
else
{
m_k = 1;
if (endtype == EndType.etSquare) DoSquare();
else DoRound(limit);
}
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();
PolygonClp outer = new PolygonClp(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.ReverseSolution = true;
clpr.Execute(ClipType.ctUnion, solution, PolyFillType.pftNegative, PolyFillType.pftNegative);
if (solution.Count > 0) solution.RemoveAt(0);
}
}
//------------------------------------------------------------------------------
public static PolygonsClp OffsetPolyLines(PolygonsClp lines,
double delta, JoinType jointype, EndType endtype,
double limit)
{
PolygonsClp result = new PolygonsClp();
//automatically strip duplicate points because it gets complicated with
//open and closed lines and when to strip duplicates across begin-end ...
PolygonsClp pts = new PolygonsClp(lines);
for (int i = 0; i < pts.Count; ++i)
{
for (int j = pts[i].Count - 1; j > 0; j--)
if (PointsEqual(pts[i][j], pts[i][j - 1]))
pts[i].RemoveAt(j);
}
if (endtype == EndType.etClosed)
{
int sz = pts.Count;
pts.Capacity = sz * 2;
for (int i = 0; i < sz; ++i)
{
PolygonClp line = new PolygonClp(pts[i]);
line.Reverse();
pts.Add(line);
}
new PolyOffsetBuilder(pts, result, true, delta, jointype, endtype, limit);
}
else
new PolyOffsetBuilder(pts, result, false, delta, jointype, endtype, limit);
return result;
}
//------------------------------------------------------------------------------
// OffsetPolygon functions ...
//------------------------------------------------------------------------------
internal static PolygonClp BuildArc(IntPoint pt, double a1, double a2, double r, double limit)
{
//see notes in clipper.pas regarding steps
double arcFrac = Math.Abs(a2 - a1) / (2 * Math.PI);
int steps = (int)(arcFrac * Math.PI / Math.Acos(1 - limit / Math.Abs(r)));
if (steps < 2)
steps = 2;
else if (steps > (int)(222.0 * arcFrac))
steps = (int)(222.0 * arcFrac);
double x = Math.Cos(a1);
double y = Math.Sin(a1);
double c = Math.Cos((a2 - a1) / steps);
double s = Math.Sin((a2 - a1) / steps);
PolygonClp result = new PolygonClp(steps + 1);
for (int i = 0; i <= steps; ++i)
{
result.Add(new IntPoint(pt.X + Round(x * r), pt.Y + Round(y * r)));
double x2 = x;
x = x * c - s * y; //cross product
y = x2 * s + y * c; //dot product
}
return result;
}
//------------------------------------------------------------------------------
public static double Area(PolygonClp poly)
{
int highI = poly.Count - 1;
if (highI < 2) return 0;
if (FullRangeNeeded(poly))
{
Int128 a = new Int128(0);
a = Int128.Int128Mul(poly[highI].X + poly[0].X, poly[0].Y - poly[highI].Y);
for (int i = 1; i <= highI; ++i)
a += Int128.Int128Mul(poly[i - 1].X + poly[i].X, poly[i].Y - poly[i - 1].Y);
return a.ToDouble() / 2;
}
else
{
double area = ((double)poly[highI].X + poly[0].X) * ((double)poly[0].Y - poly[highI].Y);
for (int i = 1; i <= highI; ++i)
area += ((double)poly[i - 1].X + poly[i].X) * ((double)poly[i].Y - poly[i - 1].Y);
return area / 2;
}
}
//------------------------------------------------------------------------------
private static bool FullRangeNeeded(PolygonClp pts)
{
bool result = false;
for (int i = 0; i < pts.Count; i++)
{
if (Math.Abs(pts[i].X) > hiRange || Math.Abs(pts[i].Y) > hiRange)
throw new ClipperException("Coordinate exceeds range bounds.");
else if (Math.Abs(pts[i].X) > loRange || Math.Abs(pts[i].Y) > loRange)
result = true;
}
return result;
}
//------------------------------------------------------------------------------
private void BuildResult(PolygonsClp polyg)
{
polyg.Clear();
polyg.Capacity = m_PolyOuts.Count;
for (int i = 0; i < m_PolyOuts.Count; i++)
{
OutRec outRec = m_PolyOuts[i];
if (outRec.pts == null) continue;
OutPt p = outRec.pts;
int cnt = PointCount(p);
if (cnt < 3) continue;
PolygonClp pg = new PolygonClp(cnt);
for (int j = 0; j < cnt; j++)
{
pg.Add(p.pt);
p = p.prev;
}
polyg.Add(pg);
}
}
//------------------------------------------------------------------------------
public static bool Orientation(PolygonClp poly)
{
return Area(poly) >= 0;
}
