geos::geom::CircularArc Class Reference

#include <CircularArc.h>

Public Types
using	CoordinateXY = geom::CoordinateXY

Public Member Functions
	CircularArc (const CoordinateXY &q0, const CoordinateXY &q1, const CoordinateXY &q2)
int	orientation () const
const CoordinateXY &	getCenter () const
	Return the center point of the circle associated with this arc.
double	getRadius () const
	Return the radius of the circle associated with this arc.
bool	isCircle () const
	Return whether this arc forms a complete circle.
bool	isLinear () const
	Returns whether this arc forms a straight line (p0, p1, and p2 are collinear)
double	getAngle () const
	Return the inner angle of the sector associated with this arc. More...
double	getLength () const
	Return the length of the arc.
double	getArea () const
	Return the area enclosed by the arc p0-p1-p2 and the line segment p2-p0.
double	theta0 () const
	Return the angle of p0.
double	theta2 () const
	Return the angle of p2.
bool	containsPointOnCircle (const CoordinateXY &q) const
bool	containsPoint (const CoordinateXY &q)
bool	containsAngle (double theta) const
	Check to see if a given angle lies on this arc.
bool	isUpwardAtPoint (const CoordinateXY &q) const
Iterator	begin () const
Iterator	end () const

Public Attributes
const CoordinateXY &	p0
const CoordinateXY &	p1
const CoordinateXY &	p2

Detailed Description

A CircularArc is a reference to three points that define a circular arc. It provides for the lazy calculation of various arc properties such as the center, radius, and orientation

Member Function Documentation

containsPoint()

bool geos::geom::CircularArc::containsPoint ( const CoordinateXY &  q )

inline

Check to see if a coordinate lies on the arc, after testing whether it lies on the circle.

References geos::geom::BOUNDARY, and geos::triangulate::quadedge::TrianglePredicate::isInCircleNormalized().

containsPointOnCircle()

bool geos::geom::CircularArc::containsPointOnCircle ( const CoordinateXY &  q ) const

inline

Check to see if a coordinate lies on the arc Only the angle is checked, so it is assumed that the point lies on the circle of which this arc is a part.

getAngle()

double geos::geom::CircularArc::getAngle ( ) const

inline

Return the inner angle of the sector associated with this arc.

Even Rouault: potential optimization?: using crossproduct(p0 - center, p2 - center) = radius * radius * sin(angle) could yield the result by just doing a single asin(), instead of 2 atan2() actually one should also likely compute dotproduct(p0 - center, p2 - center) = radius * radius * cos(angle), and thus angle = atan2(crossproduct(p0 - center, p2 - center) , dotproduct(p0 - center, p2 - center) )

isUpwardAtPoint()

bool geos::geom::CircularArc::isUpwardAtPoint ( const CoordinateXY &  q ) const

inline

Return true if the arc is pointing positive in the y direction at the location of a specified point. The point is assumed to be on the arc.

References geos::geom::Quadrant::quadrant().

orientation()

int geos::geom::CircularArc::orientation ( ) const

inline

Return the orientation of the arc as one of:

• algorithm::Orientation::CLOCKWISE,
• algorithm::Orientation::COUNTERCLOCKWISE
• algorithm::Orientation::COLLINEAR

References geos::algorithm::Orientation::index().

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

• CircularArc.h