double SkDLine::nearPoint(const SkDPoint& xy) const {
if (!AlmostBetweenUlps(fPts[0].fX, xy.fX, fPts[1].fX)
|| !AlmostBetweenUlps(fPts[0].fY, xy.fY, fPts[1].fY)) {
return -1;
}
// project a perpendicular ray from the point to the line; find the T on the line
SkDVector len = fPts[1] - fPts[0]; // the x/y magnitudes of the line
double denom = len.fX * len.fX + len.fY * len.fY; // see DLine intersectRay
SkDVector ab0 = xy - fPts[0];
double numer = len.fX * ab0.fX + ab0.fY * len.fY;
if (!between(0, numer, denom)) {
return -1;
}
double t = numer / denom;
SkDPoint realPt = ptAtT(t);
double dist = realPt.distance(xy); // OPTIMIZATION: can we compare against distSq instead ?
// find the ordinal in the original line with the largest unsigned exponent
double tiniest = SkTMin(SkTMin(SkTMin(fPts[0].fX, fPts[0].fY), fPts[1].fX), fPts[1].fY);
double largest = SkTMax(SkTMax(SkTMax(fPts[0].fX, fPts[0].fY), fPts[1].fX), fPts[1].fY);
largest = SkTMax(largest, -tiniest);
if (!AlmostEqualUlps(largest, largest + dist)) { // is the dist within ULPS tolerance?
return -1;
}
t = SkPinT(t);
SkASSERT(between(0, t, 1));
return t;
}
double SkDLine::NearPointV(const SkDPoint& xy, double top, double bottom, double x) {
if (!AlmostEqualUlps(xy.fX, x)) {
return -1;
}
if (!AlmostBetweenUlps(top, xy.fY, bottom)) {
return -1;
}
double t = (xy.fY - top) / (bottom - top);
t = SkPinT(t);
SkASSERT(between(0, t, 1));
return t;
}
double SkDLine::NearPointH(const SkDPoint& xy, double left, double right, double y) {
if (!AlmostEqualUlps(xy.fY, y)) {
return -1;
}
if (!AlmostBetweenUlps(left, xy.fX, right)) {
return -1;
}
double t = (xy.fX - left) / (right - left);
t = SkPinT(t);
SkASSERT(between(0, t, 1));
return t;
}
double SkDLine::NearPointV(const SkDPoint& xy, double top, double bottom, double x) {
if (!AlmostBequalUlps(xy.fX, x)) {
return -1;
}
if (!AlmostBetweenUlps(top, xy.fY, bottom)) {
return -1;
}
double t = (xy.fY - top) / (bottom - top);
t = SkPinT(t);
SkASSERT(between(0, t, 1));
double realPtY = (1 - t) * top + t * bottom;
SkDVector distU = {xy.fX - x, xy.fY - realPtY};
double distSq = distU.fX * distU.fX + distU.fY * distU.fY;
double dist = sqrt(distSq); // OPTIMIZATION: can we compare against distSq instead ?
double tiniest = SkTMin(SkTMin(x, top), bottom);
double largest = SkTMax(SkTMax(x, top), bottom);
largest = SkTMax(largest, -tiniest);
if (!AlmostEqualUlps(largest, largest + dist)) { // is the dist within ULPS tolerance?
return -1;
}
return t;
}
double SkDLine::NearPointH(const SkDPoint& xy, double left, double right, double y) {
if (!AlmostBequalUlps(xy.fY, y)) {
return -1;
}
if (!AlmostBetweenUlps(left, xy.fX, right)) {
return -1;
}
double t = (xy.fX - left) / (right - left);
t = SkPinT(t);
SkASSERT(between(0, t, 1));
double realPtX = (1 - t) * left + t * right;
SkDVector distU = {xy.fY - y, xy.fX - realPtX};
double distSq = distU.fX * distU.fX + distU.fY * distU.fY;
double dist = sqrt(distSq); // OPTIMIZATION: can we compare against distSq instead ?
double tiniest = SkTMin(SkTMin(y, left), right);
double largest = SkTMax(SkTMax(y, left), right);
largest = SkTMax(largest, -tiniest);
if (!AlmostEqualUlps(largest, largest + dist)) { // is the dist within ULPS tolerance?
return -1;
}
return t;
}
