/**
* Add an edge along this line. Overlapping edges are merged.
*
* @param e1 The first edge end
* @param e2 The second edge end
*/
public void add(int e1, int e2) {
// sort the ends
int min = (e1 < e2) ? e1 : e2;
e2 = (e1 > e2) ? e1 : e2;
e1 = min;
// state of the current segment end : first end or last end of the
// current segment
boolean first = true;
boolean inMerge = false;
for (int i = 0; i < edges.size(); ++i) {
int end = edges.get(i).intValue();
// wait till newsegment match this interval in edges list order
if (e1 > end) {
first = !first;
continue;
}
// now e1<=end. Handle case where end is the first segment end
if (first) {
// If not already merging, see if merging is necessary
if (!inMerge) {
// segments overlap => extend existing segment to match
// the new one
if (end <= e2) {
edges.set(i, new Integer(e1));
inMerge = true; // now merging the new segment
} else {
// Segments do not overlap => add a new segment,
// finished
edges.add(i, new Integer(e2)); // insert e2 before
// the current end
edges.add(i, new Integer(e1)); // insert e1 before
// e2
return;
}
// In merge already => it normal that e1<=end. Let's
// check e2
} else {
// new segment terminates before current segment
// => add the new point, finished
if (e2 < end) {
edges.add(i, new Integer(e2));
return;
// new segment terminates after or inside current
// segment => merge this end
} else if (e2 >= end) {
// remove this end, as the segments merge to make
// one bigger segment
edges.remove(i--); // remove corresponding index too
}
}
}
// Handle second case : end is the last end of the segment.
// Note: e1<=end, see above
else {
// new segment terminates inside current one
// => end of the merge, keep this segment's end
if (e2 <= end) return;
// New segment terminates strictly after current segment
// remove this end, as the segments merge to make one bigger
// segment
edges.remove(i--); // remove corresponding index too
// If not already merging, this is necessary
inMerge = true; // now merging the new segment
}
first = !first;
}
// Still here? => new segment terminates after any existing segment
// If not merging, must add the first end of the new segment since
// it was larger than all existing segment ends
if (!inMerge) edges.add(new Integer(e1));
// Close the new segment
edges.add(new Integer(e2));
}
