diff options
Diffstat (limited to 'src/2geom/ellipse.cpp')
| -rw-r--r-- | src/2geom/ellipse.cpp | 37 |
1 files changed, 35 insertions, 2 deletions
diff --git a/src/2geom/ellipse.cpp b/src/2geom/ellipse.cpp index 46c60d85d..0264ab4ae 100644 --- a/src/2geom/ellipse.cpp +++ b/src/2geom/ellipse.cpp @@ -97,6 +97,14 @@ void Ellipse::setCoefficients(double A, double B, double C, double D, double E, makeCanonical(); } +Point Ellipse::initialPoint() const +{ + Coord sinrot, cosrot; + sincos(_angle, sinrot, cosrot); + Point p(ray(X) * cosrot + center(X), ray(X) * sinrot + center(Y)); + return p; +} + Affine Ellipse::unitCircleTransform() const { @@ -299,8 +307,19 @@ Point Ellipse::pointAt(Coord t) const Coord Ellipse::valueAt(Coord t, Dim2 d) const { - // TODO: more efficient version. - return pointAt(t)[d]; + Coord sinrot, cosrot, cost, sint; + sincos(rotationAngle(), sinrot, cosrot); + sincos(t, sint, cost); + + if ( d == X ) { + return ray(X) * cosrot * cost + - ray(Y) * sinrot * sint + + center(X); + } else { + return ray(X) * sinrot * cost + + ray(Y) * cosrot * sint + + center(Y); + } } Coord Ellipse::timeAt(Point const &p) const @@ -319,6 +338,20 @@ Coord Ellipse::timeAt(Point const &p) const return Angle(atan2(p * iuct)).radians0(); // return a value in [0, 2pi) } +Point Ellipse::unitTangentAt(Coord t) const +{ + Point p = Point::polar(t + M_PI/2); + p *= unitCircleTransform().withoutTranslation(); + p.normalize(); + return p; +} + +bool Ellipse::contains(Point const &p) const +{ + Point tp = p * inverseUnitCircleTransform(); + return tp.length() <= 1; +} + std::vector<ShapeIntersection> Ellipse::intersect(Line const &line) const { |