// Return the X projections of the edges that overlap y1,y2.
void ExclusionPolygon::computeEdgeIntersections(float y1, float y2, Vector<ExclusionInterval>& result) const
{
Vector<ExclusionPolygon::EdgeInterval> overlappingEdges;
m_edgeTree.allOverlaps(ExclusionPolygon::EdgeInterval(y1, y2, 0), overlappingEdges);
EdgeIntersection intersection;
for (unsigned i = 0; i < overlappingEdges.size(); i++) {
const ExclusionPolygonEdge *edge = static_cast<ExclusionPolygonEdge*>(overlappingEdges[i].data());
float x1;
float x2;
if (edge->minY() < y1) {
computeXIntersection(edge, y1, intersection);
x1 = intersection.point.x();
} else
x1 = (edge->vertex1().y() < edge->vertex2().y()) ? edge->vertex1().x() : edge->vertex2().x();
if (edge->maxY() > y2) {
computeXIntersection(edge, y2, intersection);
x2 = intersection.point.x();
} else
x2 = (edge->vertex1().y() > edge->vertex2().y()) ? edge->vertex1().x() : edge->vertex2().x();
if (x1 > x2)
std::swap(x1, x2);
if (x2 > x1)
result.append(ExclusionInterval(x1, x2));
}
sortExclusionIntervals(result);
}
static void computeOverlappingEdgeXProjections(const FloatPolygon& polygon, float y1, float y2, Vector<ExclusionInterval>& result)
{
Vector<const FloatPolygonEdge*> edges;
if (!polygon.overlappingEdges(y1, y2, edges))
return;
EdgeIntersection intersection;
for (unsigned i = 0; i < edges.size(); ++i) {
const FloatPolygonEdge *edge = edges[i];
float x1;
float x2;
if (edge->minY() < y1) {
computeXIntersection(edge, y1, intersection);
x1 = intersection.point.x();
} else
x1 = (edge->vertex1().y() < edge->vertex2().y()) ? edge->vertex1().x() : edge->vertex2().x();
if (edge->maxY() > y2) {
computeXIntersection(edge, y2, intersection);
x2 = intersection.point.x();
} else
x2 = (edge->vertex1().y() > edge->vertex2().y()) ? edge->vertex1().x() : edge->vertex2().x();
if (x1 > x2)
std::swap(x1, x2);
if (x2 > x1)
result.append(ExclusionInterval(x1, x2));
}
sortExclusionIntervals(result);
}
static inline bool appendIntervalX(float x, bool inside, Vector<ExclusionInterval>& result)
{
if (!inside)
result.append(ExclusionInterval(x));
else
result[result.size() - 1].x2 = x;
return !inside;
}
void subtractExclusionIntervals(const Vector<ExclusionInterval>& v1, const Vector<ExclusionInterval>& v2, Vector<ExclusionInterval>& rv)
{
size_t v1Size = v1.size();
size_t v2Size = v2.size();
if (!v1Size)
return;
if (!v2Size)
rv.appendRange(v1.begin(), v1.end());
else {
size_t i1 = 0, i2 = 0;
rv.appendRange(v1.begin(), v1.end());
while (i1 < rv.size() && i2 < v2Size) {
ExclusionInterval& interval1 = rv[i1];
const ExclusionInterval& interval2 = v2[i2];
if (interval2.x1 <= interval1.x1 && interval2.x2 >= interval1.x2)
rv.remove(i1);
else if (interval2.x2 < interval1.x1)
i2 += 1;
else if (interval2.x1 > interval1.x2)
i1 += 1;
else if (interval2.x1 > interval1.x1 && interval2.x2 < interval1.x2) {
rv.insert(i1, ExclusionInterval(interval1.x1, interval2.x1));
interval1.x1 = interval2.x2;
i2 += 1;
} else if (interval2.x1 <= interval1.x1) {
interval1.x1 = interval2.x2;
i2 += 1;
} else { // (interval2.x2 >= interval1.x2)
interval1.x2 = interval2.x1;
i1 += 1;
}
}
}
}
