int SkIntersections::vertical(const SkDLine& line, double top, double bottom,
double x, bool flipped) {
fMax = 3; // cleanup parallel lines will bring this back line
// see if end points intersect the opposite line
double t;
SkDPoint topPt = { x, top };
if ((t = line.exactPoint(topPt)) >= 0) {
insert(t, (double) flipped, topPt);
}
if (top != bottom) {
SkDPoint bottomPt = { x, bottom };
if ((t = line.exactPoint(bottomPt)) >= 0) {
insert(t, (double) !flipped, bottomPt);
}
for (int index = 0; index < 2; ++index) {
if ((t = SkDLine::ExactPointV(line[index], top, bottom, x)) >= 0) {
insert((double) index, flipped ? 1 - t : t, line[index]);
}
}
}
int result = vertical_coincident(line, x);
if (result == 1 && fUsed == 0) {
fT[0][0] = VerticalIntercept(line, x);
double yIntercept = line[0].fY + fT[0][0] * (line[1].fY - line[0].fY);
if (between(top, yIntercept, bottom)) {
fT[1][0] = (yIntercept - top) / (bottom - top);
if (flipped) {
// OPTIMIZATION: instead of swapping, pass original line, use [1].fY - [0].fY
for (int index = 0; index < result; ++index) {
fT[1][index] = 1 - fT[1][index];
}
}
fPt[0].fX = x;
fPt[0].fY = yIntercept;
fUsed = 1;
}
}
if (fAllowNear || result == 2) {
if ((t = line.nearPoint(topPt, nullptr)) >= 0) {
insert(t, (double) flipped, topPt);
}
if (top != bottom) {
SkDPoint bottomPt = { x, bottom };
if ((t = line.nearPoint(bottomPt, nullptr)) >= 0) {
insert(t, (double) !flipped, bottomPt);
}
for (int index = 0; index < 2; ++index) {
if ((t = SkDLine::NearPointV(line[index], top, bottom, x)) >= 0) {
insert((double) index, flipped ? 1 - t : t, line[index]);
}
}
}
}
cleanUpParallelLines(result == 2);
SkASSERT(fUsed <= 2);
return fUsed;
}
int SkIntersections::vertical(const SkDLine& line, double x) {
fMax = 2;
int verticalType = vertical_coincident(line, x);
if (verticalType == 1) {
fT[0][0] = vertical_intercept(line, x);
} else if (verticalType == 2) {
fT[0][0] = 0;
fT[0][1] = 1;
}
return fUsed = verticalType;
}
