Returns the value of the angle parameter for a point near or on the circumference of the ellipse.
Namespace:
ceometric.VectorGeometryAssembly: ceometric.VectorGeometry (in ceometric.VectorGeometry.dll) Version: 1.8.0.0 (1.8.0.0)
Syntax
C# |
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public double GetParameterAtPoint( Point point ) |
Visual Basic (Declaration) |
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Public Function GetParameterAtPoint ( _ point As Point _ ) As Double |
Visual C++ |
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public: double GetParameterAtPoint( Point^ point ) |
Parameters
- point
- Type: ceometric.VectorGeometry..::.Point
A point.
Return Value
Returns the value of the parameter angle tetha for a point near or on the ellipse.Returns 0.0 if point coincides with the center of the ellipse.
Remarks
A point on the ellipse is defined by
p = c + a*cos(t) + b*sin(t), where
tetha- t is the parameter angle tetha with t: [0, 2*pi]
- c is the center point of the ellipse.
- a is the semimajor axis vector of the ellipse.
- b is the semiminor axis vector of the ellipse.
In these terms, this function returns the ellipse parameter t for a given point p.
Use GetPointAtParameter(Double) to find the point p for a given ellipse parameter t
If p lies on the circumference of an ellipse e, then p = e.GetPointAtParameter(GetParameterAtPoint(p))
If point is coplanar to the ellipse but not on the circumference of the ellipse, this method returns the ellipse parameter t of the intersection point of the ellipse and the line through the center of the ellipse and pointReturns meaningless results if point is not coplanar to the ellipse!