Detailed Description

Class representing an ellipse in 2D space.

See also: Intersections between geometry primitives can be computed using the sets of free functions Geometry::intersection() and Geometry::intersects().

Public Member Functions
	Ellipse2D (const vec2 &center, const vec2 &semiAxis, double lengthOtherSemiAxis)
	Construct ellipse from center, a semi-axis (the radius equivalent) and the length of the second semi-axis.

const vec2 &	center () const

const vec2 &	majorSemiAxis () const

const vec2 &	minorSemiAxis () const

bool	isApprox (const Ellipse2D &other)
	Comparison using the same epsilon as Eigen::isApprox.

bool	isEquivalent (const Ellipse2D &other)
	Returns if both Ellipse objects desribe the same geometrical objects.

vec2	closestPoint (const vec2 &p) const
	Returns the point on or inside the ellipse closest to p.

vec2	closestPointOnBoundary (const vec2 &p) const
	Returns the point on the ellipse (excluding the enclosed area) closest to p.

double	distanceToPoint (const vec2 &p) const
	Returns the L2 distance between p and closestPoint(p)

bool	includesPoint (const vec2 &p) const
	Returns if p is part of the ellipse or enclosed area.

double	signedArcLength (double angleRadians) const
	Computes the length of the arc between the given angle (in radians, relative to major semi-axis) and zero.

double	signedArcLength (double startAngleRad, double endAngleRad) const
	Like ellipticIntegral, but with specific starting angle instead of zero.

vec2	getPoint (double angleRad) const
	Returns a point on the ellipse boundary identified by an angle (in radians, from major towards minor semi-axis)

bool	operator== (const Ellipse2D &) const
	Exact comparisons of Ellipse instances.

bool	operator!= (const Ellipse2D &) const

Constructor & Destructor Documentation

◆ Ellipse2D()

Ellipse2D	(	const vec2 &	center,
		const vec2 &	semiAxis,
		double	lengthOtherSemiAxis )

Construct ellipse from center, a semi-axis (the radius equivalent) and the length of the second semi-axis.

The passed semi-axis should not be normalized. Whether the major or minor one is used does not matter. If the given axis has length zero the resulting ellipse causes undefined behaviour. The sign of lengthOtherSemiAxis is discarded, passing 0 effectively turns the ellipse into an inefficient line. Passing NAN into any argument also results in an undefined ellipse.

Member Function Documentation

◆ operator==()

bool operator== ( const Ellipse2D & ) const

Exact comparisons of Ellipse instances.

If you instead want to check if the represented geometric structures are the same, use isEquivalent.

◆ isEquivalent()

bool isEquivalent ( const Ellipse2D & other )

Returns if both Ellipse objects desribe the same geometrical objects.

Note that since this allows anti-parallel axes, the result of getPoint may differ between equivalent objects.

◆ signedArcLength()

double signedArcLength ( double angleRadians ) const

Computes the length of the arc between the given angle (in radians, relative to major semi-axis) and zero.

Note that the result is signed, negative angles give negative arc length. Angles of magnitude 2 PI or more will do a full revolution, i.e. the integral from 0 to 2 PI is not zero.

The documentation for this class was generated from the following file:

ImFusion/Core/Geometry/Ellipse.h