FloatShapeInterval OffsetPolygonEdge::clippedEdgeXRange(float y1,
float y2) const {
if (!overlapsYRange(y1, y2) || (y1 == maxY() && minY() <= y1) ||
(y2 == minY() && maxY() >= y2))
return FloatShapeInterval();
if (isWithinYRange(y1, y2))
return FloatShapeInterval(minX(), maxX());
// Clip the edge line segment to the vertical range y1,y2 and then return
// the clipped line segment's horizontal range.
FloatPoint minYVertex;
FloatPoint maxYVertex;
if (vertex1().y() < vertex2().y()) {
minYVertex = vertex1();
maxYVertex = vertex2();
} else {
minYVertex = vertex2();
maxYVertex = vertex1();
}
float xForY1 = (minYVertex.y() < y1) ? xIntercept(y1) : minYVertex.x();
float xForY2 = (maxYVertex.y() > y2) ? xIntercept(y2) : maxYVertex.x();
return FloatShapeInterval(std::min(xForY1, xForY2), std::max(xForY1, xForY2));
}
static FloatShapeInterval clippedCircleXRange(const FloatPoint& center, float radius, float y1, float y2)
{
if (y1 > center.y() + radius || y2 < center.y() - radius)
return FloatShapeInterval();
if (center.y() >= y1 && center.y() <= y2)
return FloatShapeInterval(center.x() - radius, center.x() + radius);
// Clip the circle to the vertical range y1,y2 and return the extent of the clipped circle's
// projection on the X axis
float xi = circleXIntercept((y2 < center.y() ? y2 : y1) - center.y(), radius);
return FloatShapeInterval(center.x() - xi, center.x() + xi);
}
static void computeOverlappingEdgeXProjections(const FloatPolygon& polygon, float y1, float y2, FloatShapeIntervals& 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(FloatShapeInterval(x1, x2));
}
sortAndMergeShapeIntervals(result);
}
static inline bool appendIntervalX(float x, bool inside, FloatShapeIntervals& result)
{
if (!inside)
result.append(FloatShapeInterval(x, x));
else
result.last().setX2(x);
return !inside;
}
