The QPolygon class provides a list of points using integer precision. More...

#include <qpolygon.h>

Inheritance diagram for QPolygon:

Collaboration diagram for QPolygon:

Public Member Functions
	QPolygon ()=default
	Constructs a polygon with no points.

Q_IMPLICIT	QPolygon (const QList< QPoint > &v)
	Constructs a polygon containing the specified points.

Q_IMPLICIT	QPolygon (QList< QPoint > &&v) noexcept

Q_IMPLICIT Q_GUI_EXPORT	QPolygon (const QRect &r, bool closed=false)
	Constructs a polygon from the given rectangle.

Q_GUI_EXPORT	QPolygon (int nPoints, const int *points)

void	swap (QPolygon &other) noexcept

Q_GUI_EXPORT	operator QVariant () const
	Returns the polygon as a QVariant.

Q_GUI_EXPORT void	translate (int dx, int dy)
	Translates all points in the polygon by ({dx}, {dy}).

void	translate (const QPoint &offset)
	This is an overloaded member function, provided for convenience. It differs from the above function only in what argument(s) it accepts.Translates all points in the polygon by the given offset.

Q_GUI_EXPORT QPolygon	translated (int dx, int dy) const
	Returns a copy of the polygon that is translated by ({dx}, {dy}).

QPolygon	translated (const QPoint &offset) const
	This is an overloaded member function, provided for convenience. It differs from the above function only in what argument(s) it accepts.

Q_GUI_EXPORT QRect	boundingRect () const
	Returns the bounding rectangle of the polygon, or QRect(0, 0, 0, 0) if the polygon is empty.

Q_GUI_EXPORT void	point (int i, int x, int y) const
	Extracts the coordinates of the point at the given index to {x} and *{y} (if they are valid pointers).

QPoint	point (int i) const
	This is an overloaded member function, provided for convenience. It differs from the above function only in what argument(s) it accepts.Returns the point at the given index.

Q_GUI_EXPORT void	setPoint (int index, int x, int y)
	Sets the point at the given index to the point specified by ({x}, {y}).

void	setPoint (int index, const QPoint &p)
	This is an overloaded member function, provided for convenience. It differs from the above function only in what argument(s) it accepts.Sets the point at the given index to the given point.

Q_GUI_EXPORT void	setPoints (int nPoints, const int *points)
	Resizes the polygon to nPoints and populates it with the given points.

Q_GUI_EXPORT void	setPoints (int nPoints, int firstx, int firsty,...)
	This is an overloaded member function, provided for convenience. It differs from the above function only in what argument(s) it accepts.Resizes the polygon to nPoints and populates it with the points specified by the variable argument list.

Q_GUI_EXPORT void	putPoints (int index, int nPoints, const int *points)
	This is an overloaded member function, provided for convenience. It differs from the above function only in what argument(s) it accepts.

Q_GUI_EXPORT void	putPoints (int index, int nPoints, int firstx, int firsty,...)
	Copies nPoints points from the variable argument list into this polygon from the given index.

Q_GUI_EXPORT void	putPoints (int index, int nPoints, const QPolygon &from, int fromIndex=0)
	This is an overloaded member function, provided for convenience. It differs from the above function only in what argument(s) it accepts.Copies nPoints points from the given fromIndex ( 0 by default) in fromPolygon into this polygon, starting at the specified index.

Q_GUI_EXPORT bool	containsPoint (const QPoint &pt, Qt::FillRule fillRule) const

Q_GUI_EXPORT QPolygon	united (const QPolygon &r) const

Q_GUI_EXPORT QPolygon	intersected (const QPolygon &r) const

Q_GUI_EXPORT QPolygon	subtracted (const QPolygon &r) const

Q_GUI_EXPORT bool	intersects (const QPolygon &r) const

QPolygonF	toPolygonF () const

Public Member Functions inherited from QList< QPoint >
DataPointer &	data_ptr () &

const DataPointer &	data_ptr () const &

DataPointer &&	data_ptr () &&

	QList (DataPointer dd) noexcept

constexpr	QList () noexcept=default

	QList (qsizetype size)

	QList (qsizetype size, parameter_type t)

	QList (std::initializer_list< QPoint > args)

	QList (InputIterator i1, InputIterator i2)

	QList (const String &str)

	QList (qsizetype size, Qt::Initialization)

QList< QPoint > &	operator= (std::initializer_list< QPoint > args)

void	swap (QList &other) noexcept

QTypeTraits::compare_eq_result_container< QList, U >	operator== (const QList &other) const

QTypeTraits::compare_eq_result_container< QList, U >	operator!= (const QList &other) const

QTypeTraits::compare_lt_result_container< QList, U >	operator< (const QList &other) const noexcept(noexcept(std::lexicographical_compare< typename QList< U >::const_iterator, typename QList::const_iterator >(std::declval< QList< U > >().begin(), std::declval< QList< U > >().end(), other.begin(), other.end())))

QTypeTraits::compare_lt_result_container< QList, U >	operator> (const QList &other) const noexcept(noexcept(other< std::declval< QList< U > >()))

QTypeTraits::compare_lt_result_container< QList, U >	operator<= (const QList &other) const noexcept(noexcept(other< std::declval< QList< U > >()))

QTypeTraits::compare_lt_result_container< QList, U >	operator>= (const QList &other) const noexcept(noexcept(std::declval< QList< U > >()< other))

constexpr qsizetype	size () const noexcept

constexpr qsizetype	count () const noexcept

qsizetype	count (const AT &t) const noexcept

constexpr qsizetype	length () const noexcept

constexpr bool	isEmpty () const noexcept

void	resize (qsizetype size)

void	resize (qsizetype size, parameter_type c)

void	resizeForOverwrite (qsizetype size)

qsizetype	capacity () const

void	reserve (qsizetype size)

void	squeeze ()

void	detach ()

bool	isDetached () const noexcept

bool	isSharedWith (const QList< QPoint > &other) const

pointer	data ()

const_pointer	data () const noexcept

const_pointer	constData () const noexcept

void	clear ()

const_reference	at (qsizetype i) const noexcept

reference	operator[] (qsizetype i)

const_reference	operator[] (qsizetype i) const noexcept

void	append (parameter_type t)

void	append (const_iterator i1, const_iterator i2)

void	append (rvalue_ref t)

void	append (const QList< QPoint > &l)

void	append (QList< QPoint > &&l)

void	prepend (rvalue_ref t)

void	prepend (parameter_type t)

reference	emplaceBack (Args &&... args)

reference	emplaceFront (Args &&... args)

iterator	insert (qsizetype i, parameter_type t)

iterator	insert (qsizetype i, qsizetype n, parameter_type t)

iterator	insert (const_iterator before, parameter_type t)

iterator	insert (const_iterator before, qsizetype n, parameter_type t)

iterator	insert (const_iterator before, rvalue_ref t)

iterator	insert (qsizetype i, rvalue_ref t)

QList &	assign (qsizetype n, parameter_type t)

QList &	assign (InputIterator first, InputIterator last)

QList &	assign (std::initializer_list< QPoint > l)

iterator	emplace (const_iterator before, Args &&... args)

iterator	emplace (qsizetype i, Args &&... args)

void	replace (qsizetype i, parameter_type t)

void	replace (qsizetype i, rvalue_ref t)

void	remove (qsizetype i, qsizetype n=1)

void	removeFirst () noexcept

void	removeLast () noexcept

value_type	takeFirst ()

value_type	takeLast ()

QList< QPoint > &	fill (parameter_type t, qsizetype size=-1)

void	removeAt (qsizetype i)

qsizetype	removeAll (const AT &t)

bool	removeOne (const AT &t)

qsizetype	removeIf (Predicate pred)

QPoint	takeAt (qsizetype i)

void	move (qsizetype from, qsizetype to)

iterator	begin ()

const_iterator	begin () const noexcept

iterator	end ()

const_iterator	end () const noexcept

const_iterator	cbegin () const noexcept

const_iterator	cend () const noexcept

const_iterator	constBegin () const noexcept

const_iterator	constEnd () const noexcept

reverse_iterator	rbegin ()

const_reverse_iterator	rbegin () const noexcept

reverse_iterator	rend ()

const_reverse_iterator	rend () const noexcept

const_reverse_iterator	crbegin () const noexcept

const_reverse_iterator	crend () const noexcept

iterator	erase (const_iterator begin, const_iterator end)

iterator	erase (const_iterator pos)

QPoint &	first ()

const QPoint &	first () const noexcept

QList< QPoint >	first (qsizetype n) const

const QPoint &	constFirst () const noexcept

QPoint &	last ()

const QPoint &	last () const noexcept

QList< QPoint >	last (qsizetype n) const

const QPoint &	constLast () const noexcept

bool	startsWith (parameter_type t) const

bool	endsWith (parameter_type t) const

QList< QPoint >	mid (qsizetype pos, qsizetype len=-1) const

QList< QPoint >	sliced (qsizetype pos) const

QList< QPoint >	sliced (qsizetype pos, qsizetype n) const

QPoint	value (qsizetype i) const

QPoint	value (qsizetype i, parameter_type defaultValue) const

void	swapItemsAt (qsizetype i, qsizetype j)

void	push_back (parameter_type t)

void	push_back (rvalue_ref t)

void	push_front (rvalue_ref t)

void	push_front (parameter_type t)

void	pop_back () noexcept

void	pop_front () noexcept

reference	emplace_back (Args &&... args)

bool	empty () const noexcept

reference	front ()

const_reference	front () const noexcept

reference	back ()

const_reference	back () const noexcept

void	shrink_to_fit ()

constexpr qsizetype	max_size () const noexcept

QList< QPoint > &	operator+= (const QList< QPoint > &l)

QList< QPoint > &	operator+= (QList< QPoint > &&l)

QList< QPoint > &	operator+= (parameter_type t)

QList< QPoint > &	operator+= (rvalue_ref t)

QList< QPoint >	operator+ (const QList< QPoint > &l) const &

QList< QPoint >	operator+ (const QList< QPoint > &l) &&

QList< QPoint >	operator+ (QList< QPoint > &&l) const &

QList< QPoint >	operator+ (QList< QPoint > &&l) &&

QList< QPoint > &	operator<< (parameter_type t)

QList< QPoint > &	operator<< (const QList< QPoint > &l)

QList< QPoint > &	operator<< (QList< QPoint > &&l)

QList< QPoint > &	operator<< (rvalue_ref t)

QList< QPoint >	toList () const noexcept

QList< QPoint >	toVector () const noexcept

Public Member Functions inherited from QListSpecialMethodsBase< QPoint >
qsizetype	indexOf (const AT &t, qsizetype from=0) const noexcept

qsizetype	lastIndexOf (const AT &t, qsizetype from=-1) const noexcept

bool	contains (const AT &t) const noexcept

Related Symbols
(Note that these are not member symbols.)
QDataStream &	operator<< (QDataStream &stream, const QPolygon &polygon)

QDataStream &	operator>> (QDataStream &stream, QPolygon &polygon)

Additional Inherited Members
Public Types inherited from QList< QPoint >
using	Type

using	value_type

using	pointer

using	const_pointer

using	reference

using	const_reference

using	size_type

using	difference_type

using	parameter_type

using	rvalue_ref

using	Iterator

using	ConstIterator

using	reverse_iterator

using	const_reverse_iterator

Static Public Member Functions inherited from QList< QPoint >
static constexpr qsizetype	maxSize ()

static QList< QPoint >	fromList (const QList< QPoint > &list) noexcept

static QList< QPoint >	fromVector (const QList< QPoint > &vector) noexcept

static QList< QPoint >	fromReadOnlyData (const QPoint(&t)[N]) noexcept

Protected Types inherited from QListSpecialMethodsBase< QPoint >
using	Self

Protected Member Functions inherited from QListSpecialMethods< QPoint >
	QListSpecialMethods ()=default

Protected Member Functions inherited from QListSpecialMethodsBase< QPoint >
	QListSpecialMethodsBase ()=default

Self *	self ()

const Self *	self () const

Detailed Description

The QPolygon class provides a list of points using integer precision.

\inmodule QtGui

\reentrant

A QPolygon object is a QList<QPoint>. The easiest way to add points to a QPolygon is to use QList's streaming operator, as illustrated below:

In addition to the functions provided by QList, QPolygon provides some point-specific functions.

Each point in a polygon can be retrieved by passing its index to the point() function. To populate the polygon, QPolygon provides the setPoint() function to set the point at a given index, the setPoints() function to set all the points in the polygon (resizing it to the given number of points), and the putPoints() function which copies a number of given points into the polygon from a specified index (resizing the polygon if necessary).

QPolygon provides the boundingRect() and translate() functions for geometry functions. Use the QTransform::map() function for more general transformations of QPolygons.

The QPolygon class is \l {Implicit Data Sharing}{implicitly shared}.

See also: QList, QPolygonF, QLine

Definition at line 22 of file qpolygon.h.

Constructor & Destructor Documentation

◆ QPolygon() [1/5]

QPolygon::QPolygon ( )

default

Constructs a polygon with no points.

See also: QList::isEmpty()

◆ QPolygon() [2/5]

Q_IMPLICIT QPolygon::QPolygon ( const QList< QPoint > & points )

inline

Constructs a polygon containing the specified points.

See also: setPoints()

Definition at line 27 of file qpolygon.h.

◆ QPolygon() [3/5]

Q_IMPLICIT QPolygon::QPolygon ( QList< QPoint > && v )

inlinenoexcept

Definition at line 28 of file qpolygon.h.

◆ QPolygon() [4/5]

QPolygon::QPolygon	(	const QRect &	rectangle,
		bool	closed = false )

Constructs a polygon from the given rectangle.

If closed is false, the polygon just contains the four points of the rectangle ordered clockwise, otherwise the polygon's fifth point is set to {rectangle}.topLeft().

Note that the bottom-right corner of the rectangle is located at (rectangle.x() + rectangle.width(), rectangle.y() + rectangle.height()).

See also: setPoints()

Definition at line 123 of file qpolygon.cpp.

◆ QPolygon() [5/5]

QPolygon::QPolygon	(	int	nPoints,
		const int *	points )

Constructs a point array with nPoints points, taken from the points array.

Equivalent to setPoints(nPoints, points).

Definition at line 142 of file qpolygon.cpp.

Member Function Documentation

◆ boundingRect()

QRect QPolygon::boundingRect ( ) const

Returns the bounding rectangle of the polygon, or QRect(0, 0, 0, 0) if the polygon is empty.

See also: QList::isEmpty()

Definition at line 386 of file qpolygon.cpp.

◆ containsPoint()

bool QPolygon::containsPoint	(	const QPoint &	point,
		Qt::FillRule	fillRule ) const

Since: 4.3

Returns true if the given point is inside the polygon according to the specified fillRule; otherwise returns false.

Definition at line 762 of file qpolygon.cpp.

◆ intersected()

QPolygon QPolygon::intersected ( const QPolygon & r ) const

nodiscard

Since: 4.3

Returns a polygon which is the intersection of this polygon and r.

Set operations on polygons will treat the polygons as areas. Non-closed polygons will be treated as implicitly closed.

See also: intersects()

Definition at line 816 of file qpolygon.cpp.

◆ intersects()

bool QPolygon::intersects ( const QPolygon & p ) const

Since: 5.10

Returns true if the current polygon intersects at any point the given polygon p. Also returns true if the current polygon contains or is contained by any part of p.

Set operations on polygons will treat the polygons as areas. Non-closed polygons will be treated as implicitly closed.

See also: intersected()

Definition at line 854 of file qpolygon.cpp.

◆ operator QVariant()

QPolygon::operator QVariant ( ) const

Returns the polygon as a QVariant.

Definition at line 638 of file qpolygon.cpp.

◆ point() [1/2]

QPoint QPolygon::point ( int i ) const

inline

This is an overloaded member function, provided for convenience. It differs from the above function only in what argument(s) it accepts.Returns the point at the given index.

Definition at line 84 of file qpolygon.h.

◆ point() [2/2]

void QPolygon::point	(	int	index,
		int *	x,
		int *	y ) const

Extracts the coordinates of the point at the given index to {x} and *{y} (if they are valid pointers).

See also: setPoint()

Definition at line 206 of file qpolygon.cpp.

◆ putPoints() [1/3]

void QPolygon::putPoints	(	int	index,
		int	nPoints,
		const int *	points )

This is an overloaded member function, provided for convenience. It differs from the above function only in what argument(s) it accepts.

Copies nPoints points from the points coord array into this point array, and resizes the point array if {index+nPoints} exceeds the size of the array.

See also: setPoint()

Definition at line 303 of file qpolygon.cpp.

◆ putPoints() [2/3]

void QPolygon::putPoints	(	int	index,
		int	nPoints,
		const QPolygon &	fromPolygon,
		int	fromIndex = 0 )

This is an overloaded member function, provided for convenience. It differs from the above function only in what argument(s) it accepts.Copies nPoints points from the given fromIndex ( 0 by default) in fromPolygon into this polygon, starting at the specified index.

For example:

QPolygon polygon1;
polygon1.putPoints(0, 3, 1,2, 0,0, 5,6);
// polygon1 is now the three-point polygon(1,2, 0,0, 5,6);
 
QPolygon polygon2;
polygon2.putPoints(0, 3, 4,4, 5,5, 6,6);
// polygon2 is now (4,4, 5,5, 6,6);
 
polygon1.putPoints(2, 3, polygon2);
// polygon1 is now the five-point polygon(1,2, 0,0, 4,4, 5,5, 6,6);

Definition at line 365 of file qpolygon.cpp.

◆ putPoints() [3/3]

void QPolygon::putPoints	(	int	index,
		int	nPoints,
		int	firstx,
		int	firsty,
			... )

Copies nPoints points from the variable argument list into this polygon from the given index.

The points are given as a sequence of integers, starting with firstx then firsty, and so on. The polygon is resized if {index+nPoints} exceeds its current size.

The example code creates a polygon with three points (4,5), (6,7) and (8,9), by expanding the polygon from 1 to 3 points:

QPolygon polygon(1);
polygon[0] = QPoint(4, 5);
polygon.putPoints(1, 2, 6,7, 8,9);

The following code has the same result, but here the putPoints() function overwrites rather than extends:

QPolygon polygon(3);
polygon.putPoints(0, 3, 4,5, 0,0, 8,9);
polygon.putPoints(1, 1, 6,7);

See also: setPoints()

Definition at line 335 of file qpolygon.cpp.

◆ setPoint() [1/2]

void QPolygon::setPoint	(	int	index,
		const QPoint &	p )

inline

This is an overloaded member function, provided for convenience. It differs from the above function only in what argument(s) it accepts.Sets the point at the given index to the given point.

Definition at line 81 of file qpolygon.h.

References setPoint().

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◆ setPoint() [2/2]

void QPolygon::setPoint	(	int	index,
		int	x,
		int	y )

Sets the point at the given index to the point specified by ({x}, {y}).

See also: point(), putPoints(), setPoints(),

Definition at line 235 of file qpolygon.cpp.

Referenced by setPoint().

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◆ setPoints() [1/2]

void QPolygon::setPoints	(	int	nPoints,
		const int *	points )

Resizes the polygon to nPoints and populates it with the given points.

The example code creates a polygon with two points (10, 20) and (30, 40):

static const int points[] = { 10, 20, 30, 40 };
QPolygon polygon;
polygon.setPoints(2, points);

See also: setPoint(), putPoints()

Definition at line 253 of file qpolygon.cpp.

◆ setPoints() [2/2]

void QPolygon::setPoints	(	int	nPoints,
		int	firstx,
		int	firsty,
			... )

This is an overloaded member function, provided for convenience. It differs from the above function only in what argument(s) it accepts.Resizes the polygon to nPoints and populates it with the points specified by the variable argument list.

The points are given as a sequence of integers, starting with firstx then firsty, and so on.

The example code creates a polygon with two points (10, 20) and (30, 40):

QPolygon polygon;

polygon.setPoints(2, 10, 20, 30, 40);

Definition at line 277 of file qpolygon.cpp.

◆ subtracted()

QPolygon QPolygon::subtracted ( const QPolygon & r ) const

nodiscard

Since: 4.3

Returns a polygon which is r subtracted from this polygon.

Set operations on polygons will treat the polygons as areas. Non-closed polygons will be treated as implicitly closed.

Definition at line 834 of file qpolygon.cpp.

◆ swap()

void QPolygon::swap ( QPolygon & other )

inlinenoexcept

Since: 4.8 \memberswap{polygon}

Definition at line 31 of file qpolygon.h.

◆ toPolygonF()

QPolygonF QPolygon::toPolygonF ( ) const

inlinenodiscard

Since: 6.4

Returns this polygon as a polygon with floating point accuracy.

See also: QPolygonF::toPolygon()

Definition at line 130 of file qpolygon.h.

◆ translate() [1/2]

void QPolygon::translate ( const QPoint & offset )

inline

This is an overloaded member function, provided for convenience. It differs from the above function only in what argument(s) it accepts.Translates all points in the polygon by the given offset.

See also: translated()

Definition at line 87 of file qpolygon.h.

References translate().

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◆ translate() [2/2]

void QPolygon::translate	(	int	dx,
		int	dy )

Translates all points in the polygon by ({dx}, {dy}).

See also: translated()

Definition at line 153 of file qpolygon.cpp.

Referenced by translate().

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◆ translated() [1/2]

QPolygon QPolygon::translated ( const QPoint & offset ) const

inlinenodiscard

This is an overloaded member function, provided for convenience. It differs from the above function only in what argument(s) it accepts.

Since: 4.6

Returns a copy of the polygon that is translated by the given offset.

See also: translate()

Definition at line 90 of file qpolygon.h.

◆ translated() [2/2]

QPolygon QPolygon::translated	(	int	dx,
		int	dy ) const

nodiscard

Returns a copy of the polygon that is translated by ({dx}, {dy}).

Since: 4.6

See also: translate()

Definition at line 182 of file qpolygon.cpp.

◆ united()

QPolygon QPolygon::united ( const QPolygon & r ) const

nodiscard

Since: 4.3

Returns a polygon which is the union of this polygon and r.

Set operations on polygons, will treat the polygons as areas, and implicitly close the polygon.

See also: intersected(), subtracted()

Definition at line 797 of file qpolygon.cpp.

Friends And Related Symbol Documentation

◆ operator<<()

QDataStream & operator<<	(	QDataStream &	stream,
		const QPolygon &	polygon )

Since: 4.4

Writes the given polygon to the given stream, and returns a reference to the stream.

See also: {Serializing Qt Data Types}

◆ operator>>()

QDataStream & operator>>	(	QDataStream &	stream,
		QPolygon &	polygon )

Since: 4.4

Reads a polygon from the given stream into the given polygon, and returns a reference to the stream.

See also: {Serializing Qt Data Types}

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

qtbase/src/gui/painting/qpolygon.h (05fc3aef53348fb58be6308076e000825b704e58)
qtbase/src/gui/painting/qpolygon.cpp (3ccb4ce781463f1b8e0cb4c9283b3067fe92a32e)

Public Member Functions

Related Symbols

Additional Inherited Members

Detailed Description

Constructor & Destructor Documentation

◆ QPolygon() [1/5]

◆ QPolygon() [2/5]

◆ QPolygon() [3/5]

◆ QPolygon() [4/5]

◆ QPolygon() [5/5]

Member Function Documentation

◆ boundingRect()

◆ containsPoint()

◆ intersected()

◆ intersects()

◆ operator QVariant()

◆ point() [1/2]

◆ point() [2/2]

◆ putPoints() [1/3]

◆ putPoints() [2/3]

◆ putPoints() [3/3]

◆ setPoint() [1/2]

◆ setPoint() [2/2]

◆ setPoints() [1/2]

◆ setPoints() [2/2]

◆ subtracted()

◆ swap()

◆ toPolygonF()

◆ translate() [1/2]

◆ translate() [2/2]

◆ translated() [1/2]

◆ translated() [2/2]

◆ united()

Friends And Related Symbol Documentation

◆ operator<<()

◆ operator>>()