private void setOutput() {
if (points == null) return;
// if init points have no labels, all the points and segments
// of the polygon don't get labels either: in this case we only
// have the polygon itself as output object
if (!labelPointsAndSegments) {
output = new GeoElement[1];
output[0] = poly;
}
// otherwise: points and segments are also output objects
else {
// size = poly + points + segments
GeoSegmentND[] segments = poly.getSegments();
GeoPoint[] points = poly.getPoints();
int size = 1 + segments.length + points.length;
output = new GeoElement[size];
int k = 0;
output[k] = poly;
for (int i = 0; i < segments.length; i++) {
output[++k] = (GeoElement) segments[i];
}
for (int i = 0; i < points.length; i++) {
output[++k] = points[i];
}
}
}
protected final void compute() {
ArrayList<Double> xcoord = new ArrayList<Double>();
ArrayList<Double> ycoord = new ArrayList<Double>();
double[] coords = new double[6];
double[] oldCoords = new double[6];
// Convert input polygons to Area objects
Area a1 = getArea(inPoly0.getPoints());
Area a2 = getArea(inPoly1.getPoints());
// test for empty intersection
Area testArea = getArea(inPoly0.getPoints());
testArea.intersect(a2);
if (testArea.isEmpty()) {
poly.setUndefined();
}
// if intersection is non-empty perform operation
else {
switch (operationType) {
case TYPE_INTERSECTION:
a1.intersect(a2);
break;
case TYPE_UNION:
a1.add(a2);
break;
case TYPE_DIFFERENCE:
a1.subtract(a2);
break;
}
// Iterate through the path of the result
// and recover the polygon vertices.
PathIterator it = a1.getPathIterator(null);
int type = it.currentSegment(coords);
it.next();
oldCoords = coords.clone();
double epsilon = 1E-10;
while (!it.isDone()) {
type = it.currentSegment(coords);
if (type == PathIterator.SEG_CLOSE) {
break;
}
// Sometimes the Path iterator gives two almost identical points and
// we only want one of them.
// TODO: Why does this happen???
if ((double) Math.abs(oldCoords[0] - coords[0]) > epsilon
|| (double) Math.abs(oldCoords[1] - coords[1]) > epsilon) {
xcoord.add(coords[0]);
ycoord.add(coords[1]);
}
oldCoords = coords.clone();
it.next();
}
}
// Update the points array to the correct size
int n = xcoord.size();
// System.out.println("number of points: " + n);
int oldPointNumber = points.length;
if (n != oldPointNumber) {
updatePointsArray(n);
poly.setPoints(points);
setOutput();
}
// Set the points to the new polygon vertices
for (int k = 0; k < n; k++) {
points[k].setCoords(xcoord.get(k), ycoord.get(k), 1);
// System.out.println("vertices: " + xcoord.get(k) + " , " + ycoord.get(k));
}
// Compute area of poly (this will also set our poly geo to be defined)
poly.calcArea();
// update new points and segments
if (n != oldPointNumber) {
updateSegmentsAndPointsLabels(oldPointNumber);
}
}