public Polygon ToPolygon()
{
// Check for empty result
if ((closedPolygons.Count == 0 ||
(closedPolygons.Count == 1 && closedPolygons[0].pointList.Count == 0)) &&
(openPolygons.Count == 0 ||
(openPolygons.Count == 1 && openPolygons[0].pointList.Count == 0))) {
return null;
}
Polygon polygon = new Polygon ();
foreach (PointChain pointChain in closedPolygons) {
Contour c = new Contour ();
c.AddRange (pointChain.pointList);
polygon.AddContour (c);
}
FixOrientation(polygon);
return polygon;
}
public void AddContour(Contour c)
{
contours.Add (c);
}
Polygon ComputeInternal(PolygonOp operation)
{
Polygon result = null;
sortedEvents = new List <SweepEvent>();
// Init event queue
eventQueue = new EventQueue();
// Test 1 for trivial result case
if (subject.contours.Count * clipping.contours.Count == 0)
{
if (operation == PolygonOp.DIFFERENCE)
{
result = subject;
}
else if (operation == PolygonOp.UNION || operation == PolygonOp.XOR)
{
result = (subject.contours.Count == 0) ? clipping : subject;
}
return(result);
}
// Test 2 for trivial result case
Rectangle subjectBB = subject.boundingBox;
Rectangle clippingBB = clipping.boundingBox;
if (!subjectBB.Intersects(clippingBB))
{
if (operation == PolygonOp.DIFFERENCE)
{
result = subject;
}
if (operation == PolygonOp.UNION || operation == PolygonOp.XOR)
{
result = subject;
foreach (Contour c in clipping.contours)
{
result.AddContour(c);
}
}
return(result);
}
// Add each segment to the eventQueue, sorted from left to right.
for (int k = 0; k < subject.contours.Count; k++)
{
Contour sCont = subject.contours[k];
int sContPointsCount = sCont.points.Count;
for (int pParse1 = 0; pParse1 < sContPointsCount; pParse1++)
{
ProcessSegment(sCont.GetSegment(pParse1), PolygonType.SUBJECT);
}
}
for (int k = 0; k < clipping.contours.Count; k++)
{
Contour cCont = clipping.contours[k];
int cContPointsCount = cCont.points.Count;
for (int pParse2 = 0; pParse2 < cContPointsCount; pParse2++)
{
ProcessSegment(cCont.GetSegment(pParse2), PolygonType.CLIPPING);
}
}
Connector connector = new Connector();
// This is the SweepLine. That is, we go through all the polygon edges
// by sweeping from left to right.
SweepEventSet S = new SweepEventSet();
double MINMAX_X = Math.Min(subjectBB.right, clippingBB.right) + Point.PRECISION;
SweepEvent prev, next;
int panicCounter = 0; // This is a safety check to prevent infinite loops (very rare but could happen due to floating-point issues with a high number of points)
while (!eventQueue.isEmpty)
{
if (panicCounter++ > 10000)
{
Debug.Log("PANIC!");
break;
}
prev = null;
next = null;
SweepEvent e = eventQueue.Dequeue();
if ((operation == PolygonOp.INTERSECTION && e.p.x > MINMAX_X) || (operation == PolygonOp.DIFFERENCE && e.p.x > subjectBB.right + Point.PRECISION))
{
return(connector.ToPolygonFromLargestLineStrip());
}
if (operation == PolygonOp.UNION && e.p.x > MINMAX_X)
{
// add all the non-processed line segments to the result
if (!e.isLeft)
{
connector.Add(e.segment);
}
while (!eventQueue.isEmpty)
{
e = eventQueue.Dequeue();
if (!e.isLeft)
{
connector.Add(e.segment);
}
}
return(connector.ToPolygonFromLargestLineStrip());
}
if (e.isLeft) // the line segment must be inserted into S
{
int pos = S.Insert(e);
prev = (pos > 0) ? S.eventSet[pos - 1] : null;
next = (pos < S.eventSet.Count - 1) ? S.eventSet[pos + 1] : null;
if (prev == null)
{
e.inside = e.inOut = false;
}
else if (prev.edgeType != EdgeType.NORMAL)
{
if (pos - 2 < 0) // e overlaps with prev
// Not sure how to handle the case when pos - 2 < 0, but judging
// from the C++ implementation this looks like how it should be handled.
{
e.inside = e.inOut = false;
if (prev.polygonType != e.polygonType)
{
e.inside = true;
}
else
{
e.inOut = true;
}
}
else
{
SweepEvent prevTwo = S.eventSet[pos - 2];
if (prev.polygonType == e.polygonType)
{
e.inOut = !prev.inOut;
e.inside = !prevTwo.inOut;
}
else
{
e.inOut = !prevTwo.inOut;
e.inside = !prev.inOut;
}
}
}
else if (e.polygonType == prev.polygonType)
{
e.inside = prev.inside;
e.inOut = !prev.inOut;
}
else
{
e.inside = !prev.inOut;
e.inOut = prev.inside;
}
// Process a possible intersection between "e" and its next neighbor in S
if (next != null)
{
PossibleIntersection(e, next);
}
// Process a possible intersection between "e" and its previous neighbor in S
if (prev != null)
{
PossibleIntersection(prev, e);
}
}
else // the line segment must be removed from S
// Get the next and previous line segments to "e" in S
{
int otherPos = -1;
for (int evt = 0; evt < S.eventSet.Count; evt++)
{
if (e.otherSE.Equals(S.eventSet[evt]))
{
otherPos = evt;
break;
}
}
if (otherPos != -1)
{
prev = (otherPos > 0) ? S.eventSet[otherPos - 1] : null;
next = (otherPos < S.eventSet.Count - 1) ? S.eventSet[otherPos + 1] : null;
}
switch (e.edgeType)
{
case EdgeType.NORMAL:
switch (operation)
{
case PolygonOp.INTERSECTION:
if (e.otherSE.inside)
{
connector.Add(e.segment);
}
break;
case PolygonOp.UNION:
if (!e.otherSE.inside)
{
connector.Add(e.segment);
}
break;
case PolygonOp.DIFFERENCE:
if ((e.polygonType == PolygonType.SUBJECT && !e.otherSE.inside) || (e.polygonType == PolygonType.CLIPPING && e.otherSE.inside))
{
connector.Add(e.segment);
}
break;
case PolygonOp.XOR:
connector.Add(e.segment);
break;
}
break;
case EdgeType.SAME_TRANSITION:
if (operation == PolygonOp.INTERSECTION || operation == PolygonOp.UNION)
{
connector.Add(e.segment);
}
break;
case EdgeType.DIFFERENT_TRANSITION:
if (operation == PolygonOp.DIFFERENCE)
{
connector.Add(e.segment);
}
break;
}
if (otherPos != -1)
{
S.Remove(S.eventSet[otherPos]);
}
if (next != null && prev != null)
{
PossibleIntersection(prev, next);
}
}
}
return(connector.ToPolygonFromLargestLineStrip());
}
public void AddContour(Contour c)
{
contours.Add(c);
}
public Contour Clone()
{
Contour u = new Contour();
u.points = new List<Point>(this.points);
u.bounds = this.bounds;
return u;
}
/// <summary>
/// Since polygons from countries and cells are not perfectly aligned in all cases, this method will take the largest contour and assume this is the resulting polygon
/// (even if it's not closed...)
/// </summary>
public Polygon ToPolygonFromLargestLineStrip()
{
// Check for empty result
if ((closedPolygons.Count == 0 ||
(closedPolygons.Count == 1 && closedPolygons[0].pointList.Count == 0)) &&
(openPolygons.Count == 0 ||
(openPolygons.Count == 1 && openPolygons[0].pointList.Count == 0))) {
return null;
}
// Get the largest contour (open or closed)
int maxPoints=-1;
PointChain largestPointChain = null;
foreach (PointChain pointChain in closedPolygons) {
if (pointChain.pointList.Count>maxPoints) {
maxPoints = pointChain.pointList.Count;
largestPointChain = pointChain;
}
}
foreach (PointChain pointChain in openPolygons) {
if (pointChain.pointList.Count>maxPoints) {
maxPoints = pointChain.pointList.Count;
largestPointChain = pointChain;
}
}
// ... and create a new polygon of that
if (maxPoints<0) return null;
Polygon polygon = new Polygon ();
Contour c = new Contour ();
c.AddRange (largestPointChain.pointList);
polygon.AddContour (c);
FixOrientation(polygon);
return polygon;
}
bool PolyInPoly(Contour outer, Contour inner)
{
for (int p=0;p<inner.points.Count;p++) {
if (!outer.ContainsPoint(inner.points[p])) {
return false;
}
}
return true;
}