// 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);
}
void ExclusionPolygon::computeXIntersections(float y, bool isMinY, Vector<ExclusionInterval>& result) const
{
Vector<ExclusionPolygon::EdgeInterval> overlappingEdges;
m_edgeTree.allOverlaps(ExclusionPolygon::EdgeInterval(y, y, 0), overlappingEdges);
Vector<EdgeIntersection> intersections;
EdgeIntersection intersection;
for (unsigned i = 0; i < overlappingEdges.size(); i++) {
ExclusionPolygonEdge* edge = static_cast<ExclusionPolygonEdge*>(overlappingEdges[i].data());
if (computeXIntersection(edge, y, intersection) && intersection.type != VertexYBoth)
intersections.append(intersection);
}
if (intersections.size() < 2)
return;
std::sort(intersections.begin(), intersections.end(), WebCore::compareEdgeIntersectionX);
unsigned index = 0;
int windCount = 0;
bool inside = false;
while (index < intersections.size()) {
const EdgeIntersection& thisIntersection = intersections[index];
if (index + 1 < intersections.size()) {
const EdgeIntersection& nextIntersection = intersections[index + 1];
if ((thisIntersection.point.x() == nextIntersection.point.x()) && (thisIntersection.type == VertexMinY || thisIntersection.type == VertexMaxY)) {
if (thisIntersection.type == nextIntersection.type) {
// Skip pairs of intersections whose types are VertexMaxY,VertexMaxY and VertexMinY,VertexMinY.
index += 2;
} else {
// Replace pairs of intersections whose types are VertexMinY,VertexMaxY or VertexMaxY,VertexMinY with one intersection.
index++;
}
continue;
}
}
const ExclusionPolygonEdge& thisEdge = *thisIntersection.edge;
bool evenOddCrossing = !windCount;
if (fillRule() == RULE_EVENODD) {
windCount += (thisEdge.vertex2().y() > thisEdge.vertex1().y()) ? 1 : -1;
evenOddCrossing = evenOddCrossing || !windCount;
}
if (evenOddCrossing) {
bool edgeCrossing = thisIntersection.type == Normal;
if (!edgeCrossing) {
FloatPoint prevVertex;
FloatPoint thisVertex;
FloatPoint nextVertex;
if (getVertexIntersectionVertices(thisIntersection, prevVertex, thisVertex, nextVertex)) {
if (nextVertex.y() == y)
edgeCrossing = (isMinY) ? prevVertex.y() > y : prevVertex.y() < y;
else if (prevVertex.y() == y)
edgeCrossing = (isMinY) ? nextVertex.y() > y : nextVertex.y() < y;
else
edgeCrossing = true;
}
}
if (edgeCrossing)
inside = appendIntervalX(thisIntersection.point.x(), inside, result);
}
index++;
}
}
