Ellipse geometry type. More...

#include <qgsellipse.h>

Inheritance diagram for QgsEllipse:

Public Member Functions
	QgsEllipse ()=default
	Constructor for QgsEllipse.
	QgsEllipse (const QgsPoint &center, double semiMajorAxis, double semiMinorAxis, double azimuth=90)
	Constructs an ellipse by defining all the members.
virtual	~QgsEllipse ()=default
virtual double	area () const
	The area of the ellipse.
double	azimuth () const
	Returns the azimuth.
virtual QgsRectangle	boundingBox () const
	Returns the minimal bounding box for the ellipse.
QgsPoint	center () const
	Returns the center point.
virtual double	eccentricity () const
	The eccentricity of the ellipse.
virtual QVector< QgsPoint >	foci () const
	Two foci of the ellipse.
virtual double	focusDistance () const
	The distance between the center and each foci.
virtual bool	isEmpty () const
	An ellipse is empty if axes are equal to 0.
virtual bool	operator!= (const QgsEllipse &elp) const
virtual bool	operator== (const QgsEllipse &elp) const
virtual QgsPolygon *	orientedBoundingBox () const
	Returns the oriented minimal bounding box for the ellipse.
virtual double	perimeter () const
	The circumference of the ellipse using first approximation of Ramanujan.
virtual QgsPointSequence	points (unsigned int segments=36) const
	Returns a list of points with segmentation from segments.
virtual QVector< QgsPoint >	quadrant () const
	The four quadrants of the ellipse.
QgsPoint &	rcenter ()
	Returns a reference to the center point of this ellipse.
double	semiMajorAxis () const
	Returns the semi-major axis.
double	semiMinorAxis () const
	Returns the semi-minor axis.
void	setAzimuth (double azimuth)
	Sets the azimuth (orientation).
void	setCenter (const QgsPoint &center)
	Sets the center point.
virtual void	setSemiMajorAxis (double semiMajorAxis)
	Sets the semi-major axis.
virtual void	setSemiMinorAxis (double semiMinorAxis)
	Sets the semi-minor axis.
virtual QgsLineString *	toLineString (unsigned int segments=36) const
	Returns a segmented linestring.
virtual QgsPolygon *	toPolygon (unsigned int segments=36) const
	Returns a segmented polygon.
virtual QString	toString (int pointPrecision=17, int axisPrecision=17, int azimuthPrecision=2) const
	returns a string representation of the ellipse.

Static Public Member Functions
static QgsEllipse	fromCenter2Points (const QgsPoint &ptc, const QgsPoint &pt1, const QgsPoint &pt2)
	Constructs an ellipse by a central point and two other points.
static QgsEllipse	fromCenterPoint (const QgsPoint &ptc, const QgsPoint &pt1)
	Constructs an ellipse by a center point and a another point.
static QgsEllipse	fromExtent (const QgsPoint &pt1, const QgsPoint &pt2)
	Constructs an ellipse by an extent (aka bounding box / QgsRectangle).
static QgsEllipse	fromFoci (const QgsPoint &pt1, const QgsPoint &pt2, const QgsPoint &pt3)
	Constructs an ellipse by foci (pt1 and pt2) and a point pt3.

Protected Attributes
double	mAzimuth = 90.0
QgsPoint	mCenter
double	mSemiMajorAxis = 0.0
double	mSemiMinorAxis = 0.0

Detailed Description

Ellipse geometry type.

An ellipse is defined by a center point with a semi-major axis, a semi-minor axis and an azimuth. The azimuth is the north angle to the first quadrant (always oriented on the semi-major axis), in degrees. By default, the semi-major axis is oriented to the east (90 degrees). The semi-minor axis is always smaller than the semi-major axis. If it is set larger, it will be swapped and the azimuth will increase by 90 degrees.

Definition at line 38 of file qgsellipse.h.

Constructor & Destructor Documentation

◆ QgsEllipse() [1/2]

QgsEllipse::QgsEllipse ( )

default

Constructor for QgsEllipse.

◆ ~QgsEllipse()

virtual QgsEllipse::~QgsEllipse ( )

virtualdefault

◆ QgsEllipse() [2/2]

QgsEllipse::QgsEllipse	(	const QgsPoint &	center,
		double	semiMajorAxis,
		double	semiMinorAxis,
		double	azimuth = 90 )

Constructs an ellipse by defining all the members.

Parameters

center	The center of the ellipse.
semiMajorAxis	Semi-major axis of the ellipse.
semiMinorAxis	Semi-minor axis of the ellipse.
azimuth	Angle in degrees started from the North to the first quadrant.

Definition at line 39 of file qgsellipse.cpp.

Member Function Documentation

◆ area()

double QgsEllipse::area ( ) const

virtual

The area of the ellipse.

Reimplemented in QgsCircle.

Definition at line 166 of file qgsellipse.cpp.

◆ azimuth()

double QgsEllipse::azimuth ( ) const

inline

Returns the azimuth.

See also: setAzimuth()

Definition at line 138 of file qgsellipse.h.

◆ boundingBox()

QgsRectangle QgsEllipse::boundingBox ( ) const

virtual

Returns the minimal bounding box for the ellipse.

Reimplemented in QgsCircle.

Definition at line 301 of file qgsellipse.cpp.

◆ center()

QgsPoint QgsEllipse::center ( ) const

inline

Returns the center point.

See also: setCenter(); rcenter()

Definition at line 120 of file qgsellipse.h.

◆ eccentricity()

double QgsEllipse::eccentricity ( ) const

virtual

The eccentricity of the ellipse.

nan is returned if the ellipse is empty.

Definition at line 157 of file qgsellipse.cpp.

◆ foci()

QVector< QgsPoint > QgsEllipse::foci ( ) const

virtual

Two foci of the ellipse.

The axes are oriented by the azimuth and are on the semi-major axis.

See also: fromFoci(); focusDistance()

Returns: the two foci.

Definition at line 147 of file qgsellipse.cpp.

◆ focusDistance()

double QgsEllipse::focusDistance ( ) const

virtual

The distance between the center and each foci.

See also: fromFoci(); foci()

Returns: The distance between the center and each foci.

Definition at line 142 of file qgsellipse.cpp.

◆ fromCenter2Points()

QgsEllipse QgsEllipse::fromCenter2Points	(	const QgsPoint &	ptc,
		const QgsPoint &	pt1,
		const QgsPoint &	pt2 )

static

Constructs an ellipse by a central point and two other points.

The center point keeps m value from ptc. Z dimension is also supported and is retrieved from the first 3D point amongst ptc, pt1 and pt2. Axes are calculated from the 2D distance between ptc and pt1 and pt2. The azimuth is the angle between ptc and pt1.

Parameters

ptc	Center point.
pt1	First point.
pt2	Second point.

Definition at line 90 of file qgsellipse.cpp.

◆ fromCenterPoint()

QgsEllipse QgsEllipse::fromCenterPoint	(	const QgsPoint &	ptc,
		const QgsPoint &	pt1 )

static

Constructs an ellipse by a center point and a another point.

The center point keeps m value from ptc. Z dimension is also supported and is retrieved from the first 3D point amongst ptc and pt1. Axes are calculated from the 2D distance between ptc and pt1. The azimuth always takes the default value.

Parameters

ptc	Center point.
pt1	First point.

Definition at line 78 of file qgsellipse.cpp.

◆ fromExtent()

QgsEllipse QgsEllipse::fromExtent	(	const QgsPoint &	pt1,
		const QgsPoint &	pt2 )

static

Constructs an ellipse by an extent (aka bounding box / QgsRectangle).

The center point can have m value which is the result from the midpoint operation between pt1 and pt2. Z dimension is also supported and is retrieved from the first 3D point amongst pt1 and pt2. Axes are calculated from the 2D distance between pt1 and pt2. The azimuth always takes the default value.

Parameters

pt1	First corner.
pt2	Second corner.

Definition at line 66 of file qgsellipse.cpp.

◆ fromFoci()

QgsEllipse QgsEllipse::fromFoci	(	const QgsPoint &	pt1,
		const QgsPoint &	pt2,
		const QgsPoint &	pt3 )

static

Constructs an ellipse by foci (pt1 and pt2) and a point pt3.

The center point can have m value which is the result from the midpoint operation between pt1 and pt2. Z dimension is also supported and is retrieved from the first 3D point amongst pt1 and pt2. Axes are calculated from the 2D distance with the third point pt3. The azimuth is the angle between pt1 and pt2.

Parameters

pt1	First focus.
pt2	Second focus.
pt3	A point to calculate the axes.

Definition at line 48 of file qgsellipse.cpp.

◆ isEmpty()

bool QgsEllipse::isEmpty ( ) const

virtual

An ellipse is empty if axes are equal to 0.

Definition at line 119 of file qgsellipse.cpp.

◆ operator!=()

bool QgsEllipse::operator!= ( const QgsEllipse & elp ) const

virtual

Definition at line 114 of file qgsellipse.cpp.

◆ operator==()

bool QgsEllipse::operator== ( const QgsEllipse & elp ) const

virtual

Definition at line 105 of file qgsellipse.cpp.

◆ orientedBoundingBox()

QgsPolygon * QgsEllipse::orientedBoundingBox ( ) const

virtual

Returns the oriented minimal bounding box for the ellipse.

Definition at line 339 of file qgsellipse.cpp.

◆ perimeter()

double QgsEllipse::perimeter ( ) const

virtual

The circumference of the ellipse using first approximation of Ramanujan.

Reimplemented in QgsCircle.

Definition at line 171 of file qgsellipse.cpp.

◆ points()

QgsPointSequence QgsEllipse::points ( unsigned int segments = 36 ) const

virtual

Returns a list of points with segmentation from segments.

Parameters

segments Number of segments used to segment geometry.

Definition at line 189 of file qgsellipse.cpp.

◆ quadrant()

QVector< QgsPoint > QgsEllipse::quadrant ( ) const

virtual

The four quadrants of the ellipse.

They are oriented and started always from semi-major axis.

Returns: quadrants defined by four points.

Definition at line 178 of file qgsellipse.cpp.

◆ rcenter()

QgsPoint & QgsEllipse::rcenter ( )

inline

Returns a reference to the center point of this ellipse.

Using a reference makes it possible to directly manipulate center in place.

See also: center(); setCenter()

Note: not available in Python bindings

Definition at line 147 of file qgsellipse.h.

◆ semiMajorAxis()

double QgsEllipse::semiMajorAxis ( ) const

inline

Returns the semi-major axis.

See also: setSemiMajorAxis()

Definition at line 126 of file qgsellipse.h.

◆ semiMinorAxis()

double QgsEllipse::semiMinorAxis ( ) const

inline

Returns the semi-minor axis.

See also: setSemiMinorAxis()

Definition at line 132 of file qgsellipse.h.

◆ setAzimuth()

void QgsEllipse::setAzimuth ( double azimuth )

Sets the azimuth (orientation).

See also: azimuth()

Definition at line 136 of file qgsellipse.cpp.

◆ setCenter()

void QgsEllipse::setCenter ( const QgsPoint & center )

inline

Sets the center point.

See also: center(); rcenter()

Definition at line 154 of file qgsellipse.h.

◆ setSemiMajorAxis()

void QgsEllipse::setSemiMajorAxis ( double semiMajorAxis )

virtual

Sets the semi-major axis.

See also: semiMajorAxis()

Reimplemented in QgsCircle.

Definition at line 125 of file qgsellipse.cpp.

◆ setSemiMinorAxis()

void QgsEllipse::setSemiMinorAxis ( double semiMinorAxis )

virtual

Sets the semi-minor axis.

See also: semiMinorAxis()

Reimplemented in QgsCircle.

Definition at line 130 of file qgsellipse.cpp.

◆ toLineString()

QgsLineString * QgsEllipse::toLineString ( unsigned int segments = 36 ) const

virtual

Returns a segmented linestring.

Parameters

segments Number of segments used to segment geometry.

Definition at line 274 of file qgsellipse.cpp.

◆ toPolygon()

QgsPolygon * QgsEllipse::toPolygon ( unsigned int segments = 36 ) const

virtual

Returns a segmented polygon.

Parameters

segments Number of segments used to segment geometry.

Definition at line 261 of file qgsellipse.cpp.

◆ toString()

QString QgsEllipse::toString	(	int	pointPrecision = 17,
		int	axisPrecision = 17,
		int	azimuthPrecision = 2 ) const

virtual

returns a string representation of the ellipse.

Members will be truncated to the specified precision.

Reimplemented in QgsCircle.

Definition at line 324 of file qgsellipse.cpp.

Member Data Documentation

◆ mAzimuth

double QgsEllipse::mAzimuth = 90.0

protected

Definition at line 254 of file qgsellipse.h.

◆ mCenter

QgsPoint QgsEllipse::mCenter

protected

Definition at line 251 of file qgsellipse.h.

◆ mSemiMajorAxis

double QgsEllipse::mSemiMajorAxis = 0.0

protected

Definition at line 252 of file qgsellipse.h.

◆ mSemiMinorAxis

double QgsEllipse::mSemiMinorAxis = 0.0

protected

Definition at line 253 of file qgsellipse.h.

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

/build/qgis-3.99.0+git20251207+21b3aa880ba+99sid/src/core/geometry/qgsellipse.h
/build/qgis-3.99.0+git20251207+21b3aa880ba+99sid/src/core/geometry/qgsellipse.cpp

Public Member Functions

Static Public Member Functions

Protected Attributes

Detailed Description

Constructor & Destructor Documentation

◆ QgsEllipse() [1/2]

◆ ~QgsEllipse()

◆ QgsEllipse() [2/2]

Member Function Documentation

◆ area()

◆ azimuth()

◆ boundingBox()

◆ center()

◆ eccentricity()

◆ foci()

◆ focusDistance()

◆ fromCenter2Points()

◆ fromCenterPoint()

◆ fromExtent()

◆ fromFoci()

◆ isEmpty()

◆ operator!=()

◆ operator==()

◆ orientedBoundingBox()

◆ perimeter()

◆ points()

◆ quadrant()

◆ rcenter()

◆ semiMajorAxis()

◆ semiMinorAxis()

◆ setAzimuth()

◆ setCenter()

◆ setSemiMajorAxis()

◆ setSemiMinorAxis()

◆ toLineString()

◆ toPolygon()

◆ toString()

Member Data Documentation

◆ mAzimuth

◆ mCenter

◆ mSemiMajorAxis

◆ mSemiMinorAxis