static SkScalar sect_clamp_with_vertical(const SkPoint src[2], SkScalar x) {
SkScalar y = sect_with_vertical(src, x);
// Our caller expects y to be between src[0].fY and src[1].fY (unsorted), but due to the
// numerics of floats/doubles, we might have computed a value slightly outside of that,
// so we have to manually clamp afterwards.
// See skbug.com/7491
return pin_unsorted(y, src[0].fY, src[1].fY);
}
// return X coordinate of intersection with horizontal line at Y
static SkScalar sect_with_horizontal(const SkPoint src[2], SkScalar Y) {
SkScalar dy = src[1].fY - src[0].fY;
if (SkScalarNearlyZero(dy)) {
return SkScalarAve(src[0].fX, src[1].fX);
} else {
// need the extra precision so we don't compute a value that exceeds
// our original limits
double X0 = src[0].fX;
double Y0 = src[0].fY;
double X1 = src[1].fX;
double Y1 = src[1].fY;
double result = X0 + ((double)Y - Y0) * (X1 - X0) / (Y1 - Y0);
// The computed X value might still exceed [X0..X1] due to quantum flux
// when the doubles were added and subtracted, so we have to pin the
// answer :(
return (float)pin_unsorted(result, X0, X1);
}
}
