Quadrilateral geometry type. More...

#include <qgsquadrilateral.h>

Public Types
enum	ConstructionOption { Distance , Projected }
	A quadrilateral can be constructed from 3 points where the second distance can be determined by the third point. More...

enum	Point { Point1 , Point2 , Point3 , Point4 }
	Simple enumeration to ensure indices in setPoint. More...

Public Member Functions
	QgsQuadrilateral ()
	Constructor for an empty quadrilateral geometry.

	QgsQuadrilateral (const QgsPoint &p1, const QgsPoint &p2, const QgsPoint &p3, const QgsPoint &p4)
	Construct a QgsQuadrilateral from four QgsPoint.

	QgsQuadrilateral (const QgsPointXY &p1, const QgsPointXY &p2, const QgsPointXY &p3, const QgsPointXY &p4)
	Construct a QgsQuadrilateral from four QgsPointXY.

double	area () const
	Returns the area of the quadrilateral, or 0 if the quadrilateral is empty.

bool	equals (const QgsQuadrilateral &other, double epsilon=4 *std::numeric_limits< double >::epsilon()) const
	Compares two QgsQuadrilateral, allowing specification of the maximum allowable difference between points.

bool	isValid () const
	Convenient method to determine if a QgsQuadrilateral is valid.

bool	operator!= (const QgsQuadrilateral &other) const

bool	operator== (const QgsQuadrilateral &other) const

double	perimeter () const
	Returns the perimeter of the quadrilateral, or 0 if the quadrilateral is empty.

QgsPointSequence	points () const
	Returns a list including the vertices of the quadrilateral.

bool	setPoint (const QgsPoint &newPoint, Point index)
	Sets the point newPoint at the index.

bool	setPoints (const QgsPoint &p1, const QgsPoint &p2, const QgsPoint &p3, const QgsPoint &p4)
	Set all points Returns `false` if the QgsQuadrilateral is not valid:

QgsLineString *	toLineString (bool force2D=false) const
	Returns the quadrilateral as a new linestring.

QgsPolygon *	toPolygon (bool force2D=false) const
	Returns the quadrilateral as a new polygon.

QString	toString (int pointPrecision=17) const
	Returns a string representation of the quadrilateral.

Static Public Member Functions
static QgsQuadrilateral	fromRectangle (const QgsRectangle &rectangle)
	Construct a QgsQuadrilateral as a rectangle from a QgsRectangle.

static QgsQuadrilateral	rectangleFrom3Points (const QgsPoint &p1, const QgsPoint &p2, const QgsPoint &p3, ConstructionOption mode)
	Construct a QgsQuadrilateral as a Rectangle from 3 points.

static QgsQuadrilateral	rectangleFromCenterPoint (const QgsPoint &center, const QgsPoint &point)
	Construct a QgsQuadrilateral as a rectangle from center point center and another point point.

static QgsQuadrilateral	rectangleFromExtent (const QgsPoint &p1, const QgsPoint &p2)
	Construct a QgsQuadrilateral as a rectangle from an extent, defined by two opposite corner points.

static QgsQuadrilateral	squareFromDiagonal (const QgsPoint &p1, const QgsPoint &p2)
	Construct a QgsQuadrilateral as a square from a diagonal.

Static Public Attributes
static constexpr auto &	rectangleFromDiagonal = rectangleFromExtent
	Alias for rectangleFromDiagonal.

Detailed Description

Quadrilateral geometry type.

A quadrilateral is a polygon with four edges (or sides) and four vertices or corners. This class allows the creation of simple quadrilateral (which does not self-intersect).

Since: QGIS 3.6

Definition at line 36 of file qgsquadrilateral.h.

Member Enumeration Documentation

◆ ConstructionOption

enum QgsQuadrilateral::ConstructionOption

A quadrilateral can be constructed from 3 points where the second distance can be determined by the third point.

Enumerator
Distance	Second distance is equal to the distance between 2nd and 3rd point.
Projected	Second distance is equal to the distance of the perpendicular projection of the 3rd point on the segment or its extension.

Definition at line 70 of file qgsquadrilateral.h.

◆ Point

enum QgsQuadrilateral::Point

Simple enumeration to ensure indices in setPoint.

Enumerator
Point1
Point2
Point3
Point4

Definition at line 157 of file qgsquadrilateral.h.

Constructor & Destructor Documentation

◆ QgsQuadrilateral() [1/3]

QgsQuadrilateral::QgsQuadrilateral ( )

default

Constructor for an empty quadrilateral geometry.

◆ QgsQuadrilateral() [2/3]

QgsQuadrilateral::QgsQuadrilateral	(	const QgsPoint &	p1,
		const QgsPoint &	p2,
		const QgsPoint &	p3,
		const QgsPoint &	p4
	)

Construct a QgsQuadrilateral from four QgsPoint.

Parameters

p1	first point
p2	second point
p3	third point
p4	fourth point

See also: setPoints

Definition at line 23 of file qgsquadrilateral.cpp.

◆ QgsQuadrilateral() [3/3]

QgsQuadrilateral::QgsQuadrilateral	(	const QgsPointXY &	p1,
		const QgsPointXY &	p2,
		const QgsPointXY &	p3,
		const QgsPointXY &	p4
	)

explicit

Construct a QgsQuadrilateral from four QgsPointXY.

Parameters

p1	first point
p2	second point
p3	third point
p4	fourth point

See also: setPoints

Definition at line 28 of file qgsquadrilateral.cpp.

Member Function Documentation

◆ area()

double QgsQuadrilateral::area ( ) const

Returns the area of the quadrilateral, or 0 if the quadrilateral is empty.

Definition at line 436 of file qgsquadrilateral.cpp.

◆ equals()

bool QgsQuadrilateral::equals	(	const QgsQuadrilateral &	other,
		double	epsilon = `4 * std::numeric_limits<double>::epsilon()`
	)		const

Compares two QgsQuadrilateral, allowing specification of the maximum allowable difference between points.

Parameters

other	the QgsQuadrilateral to compare
epsilon	the maximum difference allowed / tolerance

Definition at line 246 of file qgsquadrilateral.cpp.

◆ fromRectangle()

QgsQuadrilateral QgsQuadrilateral::fromRectangle ( const QgsRectangle & rectangle )

static

Construct a QgsQuadrilateral as a rectangle from a QgsRectangle.

Parameters

rectangle rectangle

Definition at line 219 of file qgsquadrilateral.cpp.

◆ isValid()

bool QgsQuadrilateral::isValid ( ) const

Convenient method to determine if a QgsQuadrilateral is valid.

A QgsQuadrilateral must be simple (not self-intersecting) and cannot have collinear points.

Definition at line 330 of file qgsquadrilateral.cpp.

◆ operator!=()

bool QgsQuadrilateral::operator!= ( const QgsQuadrilateral & other ) const

Definition at line 267 of file qgsquadrilateral.cpp.

◆ operator==()

bool QgsQuadrilateral::operator== ( const QgsQuadrilateral & other ) const

Definition at line 262 of file qgsquadrilateral.cpp.

◆ perimeter()

double QgsQuadrilateral::perimeter ( ) const

Returns the perimeter of the quadrilateral, or 0 if the quadrilateral is empty.

Definition at line 442 of file qgsquadrilateral.cpp.

◆ points()

QgsPointSequence QgsQuadrilateral::points ( ) const

Returns a list including the vertices of the quadrilateral.

Definition at line 377 of file qgsquadrilateral.cpp.

◆ rectangleFrom3Points()

QgsQuadrilateral QgsQuadrilateral::rectangleFrom3Points	(	const QgsPoint &	p1,
		const QgsPoint &	p2,
		const QgsPoint &	p3,
		ConstructionOption	mode
	)

static

Construct a QgsQuadrilateral as a Rectangle from 3 points.

In the case where one of the points is of type PointZ. The other points will also be of type Z, even if they are of type Point. In addition, the z used will be the one of the first point with a Z. This ensures consistency in point types and the ability to export to a Polygon or LineString. M is taken from point p1.

Parameters

p1	first point
p2	second point
p3	third point
mode	Construction mode to construct the rectangle from 3 points

See also: ConstructionOption

Definition at line 33 of file qgsquadrilateral.cpp.

◆ rectangleFromCenterPoint()

QgsQuadrilateral QgsQuadrilateral::rectangleFromCenterPoint	(	const QgsPoint &	center,
		const QgsPoint &	point
	)

static

Construct a QgsQuadrilateral as a rectangle from center point center and another point point.

Z and M are taken from point p1. QgsQuadrilateral will have the same dimension as center dimension.

Parameters

center	center point
point	corner point

Definition at line 206 of file qgsquadrilateral.cpp.

◆ rectangleFromExtent()

QgsQuadrilateral QgsQuadrilateral::rectangleFromExtent	(	const QgsPoint &	p1,
		const QgsPoint &	p2
	)

static

Construct a QgsQuadrilateral as a rectangle from an extent, defined by two opposite corner points.

Z and M are taken from point p1. QgsQuadrilateral will have the same dimension as p1 dimension.

Parameters

p1	first point
p2	second point

Definition at line 134 of file qgsquadrilateral.cpp.

◆ setPoint()

bool QgsQuadrilateral::setPoint	(	const QgsPoint &	newPoint,
		Point	index
	)

Sets the point newPoint at the index.

Returns false if the QgsQuadrilateral is not valid.

See also: Point

Definition at line 335 of file qgsquadrilateral.cpp.

◆ setPoints()

bool QgsQuadrilateral::setPoints	(	const QgsPoint &	p1,
		const QgsPoint &	p2,
		const QgsPoint &	p3,
		const QgsPoint &	p4
	)

Set all points Returns false if the QgsQuadrilateral is not valid:

The points do not have the same type
The quadrilateral would have auto intersections
The quadrilateral has double points
The quadrilateral has collinear points

Definition at line 364 of file qgsquadrilateral.cpp.

◆ squareFromDiagonal()

QgsQuadrilateral QgsQuadrilateral::squareFromDiagonal	(	const QgsPoint &	p1,
		const QgsPoint &	p2
	)

static

Construct a QgsQuadrilateral as a square from a diagonal.

Z and M are taken from point p1. QgsQuadrilateral will have the same dimension as p1 dimension.

Parameters

p1	first point
p2	second point

Definition at line 177 of file qgsquadrilateral.cpp.

◆ toLineString()

QgsLineString * QgsQuadrilateral::toLineString ( bool force2D = false ) const

Returns the quadrilateral as a new linestring.

Ownership is transferred to the caller.

Definition at line 399 of file qgsquadrilateral.cpp.

◆ toPolygon()

QgsPolygon * QgsQuadrilateral::toPolygon ( bool force2D = false ) const

Returns the quadrilateral as a new polygon.

Ownership is transferred to the caller.

Definition at line 386 of file qgsquadrilateral.cpp.

◆ toString()

QString QgsQuadrilateral::toString ( int pointPrecision = 17 ) const

Returns a string representation of the quadrilateral.

Members will be truncated to the specified precision.

Definition at line 421 of file qgsquadrilateral.cpp.

Member Data Documentation

◆ rectangleFromDiagonal

constexpr auto& QgsQuadrilateral::rectangleFromDiagonal = rectangleFromExtent

staticconstexpr

Alias for rectangleFromDiagonal.

Definition at line 107 of file qgsquadrilateral.h.

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

/build/qgis-3.41.0+git20241214+cea29feecf2+99sid/src/core/geometry/qgsquadrilateral.h
/build/qgis-3.41.0+git20241214+cea29feecf2+99sid/src/core/geometry/qgsquadrilateral.cpp

Public Types

Public Member Functions

Static Public Member Functions

Static Public Attributes

Detailed Description

Member Enumeration Documentation

◆ ConstructionOption

◆ Point

Constructor & Destructor Documentation

◆ QgsQuadrilateral() [1/3]

◆ QgsQuadrilateral() [2/3]

◆ QgsQuadrilateral() [3/3]

Member Function Documentation

◆ area()

◆ equals()

◆ fromRectangle()

◆ isValid()

◆ operator!=()

◆ operator==()

◆ perimeter()

◆ points()

◆ rectangleFrom3Points()

◆ rectangleFromCenterPoint()

◆ rectangleFromExtent()

◆ setPoint()

◆ setPoints()

◆ squareFromDiagonal()

◆ toLineString()

◆ toPolygon()

◆ toString()

Member Data Documentation

◆ rectangleFromDiagonal