/**
* Trims a grid of lines for points outside a polygon
*
* @param waypoints2 Polygon vertices
* @param grid Array with Grid lines
* @return array with the trimmed grid lines
*/
private List<LineLatLng> trimGridLines(List<LatLng> waypoints2, List<LineLatLng> grid) {
List<LineLatLng> hatchLines = new ArrayList<LineLatLng>();
// find intersections
for (LineLatLng gridLine : grid) {
double closestDistance = Double.MAX_VALUE;
double farestDistance = Double.MIN_VALUE;
LatLng closestPoint = null;
LatLng farestPoint = null;
int crosses = 0;
for (int b = 0; b < waypoints2.size(); b++) {
LatLng newlatlong;
if (b != waypoints2.size() - 1) {
newlatlong =
GeoTools.FindLineIntersection(
waypoints2.get(b), waypoints2.get(b + 1), gridLine.p1, gridLine.p2);
} else { // Don't forget the last polygon line
newlatlong =
GeoTools.FindLineIntersection(
waypoints2.get(b), waypoints2.get(0), gridLine.p1, gridLine.p2);
}
if (newlatlong != null) {
crosses++;
if (closestDistance > GeoTools.getDistance(gridLine.p1, newlatlong)) {
closestPoint = new LatLng(newlatlong.latitude, newlatlong.longitude);
closestDistance = GeoTools.getDistance(gridLine.p1, newlatlong);
}
if (farestDistance < GeoTools.getDistance(gridLine.p1, newlatlong)) {
farestPoint = new LatLng(newlatlong.latitude, newlatlong.longitude);
farestDistance = GeoTools.getDistance(gridLine.p1, newlatlong);
}
}
}
switch (crosses) {
case 0:
case 1:
break;
default: // TODO handle multiple crossings in a better way
case 2:
hatchLines.add(new LineLatLng(closestPoint, farestPoint));
break;
}
}
return hatchLines;
}
