The QTransform class specifies 2D transformations of a coordinate system. More...

#include <qtransform.h>

Collaboration diagram for QTransform:

Public Types
enum	TransformationType { TxNone = 0x00 , TxTranslate = 0x01 , TxScale = 0x02 , TxRotate = 0x04 , TxShear = 0x08 , TxProject = 0x10 }
	\value TxNone \value TxTranslate \value TxScale \value TxRotate \value TxShear \value TxProject More...

Public Member Functions
	QTransform (Qt::Initialization)

	QTransform ()
	Constructs an identity matrix.

	QTransform (qreal h11, qreal h12, qreal h13, qreal h21, qreal h22, qreal h23, qreal h31, qreal h32, qreal h33)
	Constructs a matrix with the elements, m11, m12, m13, m21, m22, m23, m31, m32, m33.

	QTransform (qreal h11, qreal h12, qreal h21, qreal h22, qreal dx, qreal dy)
	Constructs a matrix with the elements, m11, m12, m21, m22, dx and dy.

QTransform &	operator= (QTransform &&other) noexcept=default

QTransform &	operator= (const QTransform &) noexcept=default
	Assigns the given matrix's values to this matrix.

	QTransform (QTransform &&other) noexcept=default

	QTransform (const QTransform &other) noexcept=default

bool	isAffine () const
	Returns `true` if the matrix represent an affine transformation, otherwise returns `false`.

bool	isIdentity () const
	Returns `true` if the matrix is the identity matrix, otherwise returns `false`.

bool	isInvertible () const
	Returns `true` if the matrix is invertible, otherwise returns `false`.

bool	isScaling () const
	Returns `true` if the matrix represents a scaling transformation, otherwise returns `false`.

bool	isRotating () const
	Returns `true` if the matrix represents some kind of a rotating transformation, otherwise returns `false`.

bool	isTranslating () const
	Returns `true` if the matrix represents a translating transformation, otherwise returns `false`.

TransformationType	type () const
	Returns the transformation type of this matrix.

qreal	determinant () const
	Returns the matrix's determinant.

qreal	m11 () const
	Returns the horizontal scaling factor.

qreal	m12 () const
	Returns the vertical shearing factor.

qreal	m13 () const
	Returns the horizontal projection factor.

qreal	m21 () const
	Returns the horizontal shearing factor.

qreal	m22 () const
	Returns the vertical scaling factor.

qreal	m23 () const
	Returns the vertical projection factor.

qreal	m31 () const
	Returns the horizontal translation factor.

qreal	m32 () const
	Returns the vertical translation factor.

qreal	m33 () const
	Returns the division factor.

qreal	dx () const
	Returns the horizontal translation factor.

qreal	dy () const
	Returns the vertical translation factor.

void	setMatrix (qreal m11, qreal m12, qreal m13, qreal m21, qreal m22, qreal m23, qreal m31, qreal m32, qreal m33)
	Sets the matrix elements to the specified values, m11, m12, m13 m21, m22, m23 m31, m32 and m33.

QTransform	inverted (bool *invertible=nullptr) const
	Returns an inverted copy of this matrix.

QTransform	adjoint () const
	Returns the adjoint of this matrix.

QTransform	transposed () const
	Returns the transpose of this matrix.

QTransform &	translate (qreal dx, qreal dy)
	Moves the coordinate system dx along the x axis and dy along the y axis, and returns a reference to the matrix.

QTransform &	scale (qreal sx, qreal sy)
	Scales the coordinate system by sx horizontally and sy vertically, and returns a reference to the matrix.

QTransform &	shear (qreal sh, qreal sv)
	Shears the coordinate system by sh horizontally and sv vertically, and returns a reference to the matrix.

QTransform &	rotate (qreal a, Qt::Axis axis=Qt::ZAxis, qreal distanceToPlane=1024.0f)

QTransform &	rotateRadians (qreal a, Qt::Axis axis=Qt::ZAxis, qreal distanceToPlane=1024.0f)

bool	operator== (const QTransform &) const
	Returns `true` if this matrix is equal to the given matrix, otherwise returns `false`.

bool	operator!= (const QTransform &) const
	Returns `true` if this matrix is not equal to the given matrix, otherwise returns `false`.

QTransform &	operator*= (const QTransform &)
	This is an overloaded member function, provided for convenience. It differs from the above function only in what argument(s) it accepts.Returns the result of multiplying this matrix by the given matrix.

QTransform	operator* (const QTransform &o) const
	Returns the result of multiplying this matrix by the given matrix.

	operator QVariant () const
	Returns the transform as a QVariant.

void	reset ()
	Resets the matrix to an identity matrix, i.e.

QPoint	map (const QPoint &p) const
	This is an overloaded member function, provided for convenience. It differs from the above function only in what argument(s) it accepts.Creates and returns a QPoint object that is a copy of the given point, mapped into the coordinate system defined by this matrix.

QPointF	map (const QPointF &p) const
	This is an overloaded member function, provided for convenience. It differs from the above function only in what argument(s) it accepts.Creates and returns a QPointF object that is a copy of the given point, p, mapped into the coordinate system defined by this matrix.

QLine	map (const QLine &l) const
	This is an overloaded member function, provided for convenience. It differs from the above function only in what argument(s) it accepts.Creates and returns a QLineF object that is a copy of the given line, l, mapped into the coordinate system defined by this matrix.

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

QPolygonF	map (const QPolygonF &a) const
	This is an overloaded member function, provided for convenience. It differs from the above function only in what argument(s) it accepts.Creates and returns a QPolygonF object that is a copy of the given polygon, mapped into the coordinate system defined by this matrix.

QPolygon	map (const QPolygon &a) const
	This is an overloaded member function, provided for convenience. It differs from the above function only in what argument(s) it accepts.Creates and returns a QPolygon object that is a copy of the given polygon, mapped into the coordinate system defined by this matrix.

QRegion	map (const QRegion &r) const
	This is an overloaded member function, provided for convenience. It differs from the above function only in what argument(s) it accepts.Creates and returns a QRegion object that is a copy of the given region, mapped into the coordinate system defined by this matrix.

QPainterPath	map (const QPainterPath &p) const
	This is an overloaded member function, provided for convenience. It differs from the above function only in what argument(s) it accepts.Creates and returns a QPainterPath object that is a copy of the given path, mapped into the coordinate system defined by this matrix.

QPolygon	mapToPolygon (const QRect &r) const
	Creates and returns a QPolygon representation of the given rectangle, mapped into the coordinate system defined by this matrix.

QRect	mapRect (const QRect &) const
	This is an overloaded member function, provided for convenience. It differs from the above function only in what argument(s) it accepts.Creates and returns a QRect object that is a copy of the given rectangle, mapped into the coordinate system defined by this matrix.

QRectF	mapRect (const QRectF &) const
	Creates and returns a QRectF object that is a copy of the given rectangle, mapped into the coordinate system defined by this matrix.

void	map (int x, int y, int tx, int ty) const
	This is an overloaded member function, provided for convenience. It differs from the above function only in what argument(s) it accepts.Maps the given coordinates x and y into the coordinate system defined by this matrix.

void	map (qreal x, qreal y, qreal tx, qreal ty) const
	Maps the given coordinates x and y into the coordinate system defined by this matrix.

QTransform &	operator*= (qreal div)
	This is an overloaded member function, provided for convenience. It differs from the above function only in what argument(s) it accepts.Returns the result of performing an element-wise multiplication of this matrix with the given scalar.

QTransform &	operator/= (qreal div)
	This is an overloaded member function, provided for convenience. It differs from the above function only in what argument(s) it accepts.Returns the result of performing an element-wise division of this matrix by the given scalar.

QTransform &	operator+= (qreal div)
	This is an overloaded member function, provided for convenience. It differs from the above function only in what argument(s) it accepts.Returns the matrix obtained by adding the given scalar to each element of this matrix.

QTransform &	operator-= (qreal div)
	This is an overloaded member function, provided for convenience. It differs from the above function only in what argument(s) it accepts.Returns the matrix obtained by subtracting the given scalar from each element of this matrix.

auto	asAffineMatrix ()

Static Public Member Functions
static bool	squareToQuad (const QPolygonF &square, QTransform &result)
	Creates a transformation matrix, trans, that maps a unit square to a four-sided polygon, quad.

static bool	quadToSquare (const QPolygonF &quad, QTransform &result)
	Creates a transformation matrix, trans, that maps a four-sided polygon, quad, to a unit square.

static bool	quadToQuad (const QPolygonF &one, const QPolygonF &two, QTransform &result)
	Creates a transformation matrix, trans, that maps a four-sided polygon, one, to another four-sided polygon, two.

static QTransform	fromTranslate (qreal dx, qreal dy)
	Creates a matrix which corresponds to a translation of dx along the x axis and dy along the y axis.

static QTransform	fromScale (qreal dx, qreal dy)
	Creates a matrix which corresponds to a scaling of sx horizontally and sy vertically.

Friends
Q_GUI_EXPORT QDataStream &	operator>> (QDataStream &s, QTransform::Affine &m)

Q_GUI_EXPORT QDataStream &	operator<< (QDataStream &s, const Affine &m)

Related Symbols
(Note that these are not member symbols.)
size_t	qHash (const QTransform &key, size_t seed) noexcept

QDataStream &	operator<< (QDataStream &stream, const QTransform &matrix)

QDataStream &	operator>> (QDataStream &stream, QTransform &matrix)

QPoint	operator* (const QPoint &point, const QTransform &matrix)
	This is the same as {matrix}.map({point}).

QPointF	operator* (const QPointF &point, const QTransform &matrix)
	Same as {matrix}.map({point}).

QLineF	operator* (const QLineF &line, const QTransform &matrix)
	This is the same as {matrix}.map({line}).

QLine	operator* (const QLine &line, const QTransform &matrix)
	This is the same as {matrix}.map({line}).

QPolygonF	operator* (const QPolygonF &polygon, const QTransform &matrix)

QPolygon	operator* (const QPolygon &polygon, const QTransform &matrix)
	This is the same as {matrix}.map({polygon}).

QRegion	operator* (const QRegion &region, const QTransform &matrix)
	This is the same as {matrix}.map({region}).

QPainterPath	operator* (const QPainterPath &path, const QTransform &matrix)

bool	qFuzzyCompare (const QTransform &t1, const QTransform &t2)

Detailed Description

The QTransform class specifies 2D transformations of a coordinate system.

Since: 4.3

\inmodule QtGui

A transformation specifies how to translate, scale, shear, rotate or project the coordinate system, and is typically used when rendering graphics.

A QTransform object can be built using the setMatrix(), scale(), rotate(), translate() and shear() functions. Alternatively, it can be built by applying \l {QTransform::Basic Matrix Operations}{basic matrix operations}. The matrix can also be defined when constructed, and it can be reset to the identity matrix (the default) using the reset() function.

The QTransform class supports mapping of graphic primitives: A given point, line, polygon, region, or painter path can be mapped to the coordinate system defined by this matrix using the map() function. In case of a rectangle, its coordinates can be transformed using the mapRect() function. A rectangle can also be transformed into a polygon (mapped to the coordinate system defined by this matrix), using the mapToPolygon() function.

QTransform provides the isIdentity() function which returns true if the matrix is the identity matrix, and the isInvertible() function which returns true if the matrix is non-singular (i.e. AB = BA = I). The inverted() function returns an inverted copy of this matrix if it is invertible (otherwise it returns the identity matrix), and adjoint() returns the matrix's classical adjoint. In addition, QTransform provides the determinant() function which returns the matrix's determinant.

Finally, the QTransform class supports matrix multiplication, addition and subtraction, and objects of the class can be streamed as well as compared.

Definition at line 19 of file qtransform.h.

Member Enumeration Documentation

◆ TransformationType

enum QTransform::TransformationType

\value TxNone \value TxTranslate \value TxScale \value TxRotate \value TxShear \value TxProject

Enumerator
TxNone
TxTranslate
TxScale
TxRotate
TxShear
TxProject

Definition at line 22 of file qtransform.h.

Constructor & Destructor Documentation

◆ QTransform() [1/6]

QTransform::QTransform ( Qt::Initialization )

inlineexplicit

Definition at line 31 of file qtransform.h.

◆ QTransform() [2/6]

QTransform::QTransform ( )

inline

Constructs an identity matrix.

All elements are set to zero except m11 and m22 (specifying the scale) and m33 which are set to 1.

See also: reset()

Definition at line 32 of file qtransform.h.

◆ QTransform() [3/6]

QTransform::QTransform	(	qreal	m11,
		qreal	m12,
		qreal	m13,
		qreal	m21,
		qreal	m22,
		qreal	m23,
		qreal	m31,
		qreal	m32,
		qreal	m33 )

inline

Constructs a matrix with the elements, m11, m12, m13, m21, m22, m23, m31, m32, m33.

See also: setMatrix()

Definition at line 36 of file qtransform.h.

◆ QTransform() [4/6]

QTransform::QTransform	(	qreal	m11,
		qreal	m12,
		qreal	m21,
		qreal	m22,
		qreal	dx,
		qreal	dy )

inline

Constructs a matrix with the elements, m11, m12, m21, m22, dx and dy.

See also: setMatrix()

Definition at line 42 of file qtransform.h.

◆ QTransform() [5/6]

QTransform::QTransform ( QTransform && other )

defaultnoexcept

◆ QTransform() [6/6]

QTransform::QTransform ( const QTransform & other )

defaultnoexcept

Member Function Documentation

◆ adjoint()

QTransform QTransform::adjoint ( ) const

nodiscard

Returns the adjoint of this matrix.

Definition at line 258 of file qtransform.cpp.

◆ asAffineMatrix()

auto QTransform::asAffineMatrix ( )

inline

Definition at line 142 of file qtransform.h.

◆ determinant()

qreal QTransform::determinant ( ) const

inline

Returns the matrix's determinant.

Definition at line 194 of file qtransform.h.

◆ dx()

qreal QTransform::dx ( ) const

inline

Returns the horizontal translation factor.

See also: m31(), translate(), {QTransform::Basic Matrix Operations}{Basic Matrix Operations}

Definition at line 236 of file qtransform.h.

◆ dy()

qreal QTransform::dy ( ) const

inline

Returns the vertical translation factor.

See also: translate(), {QTransform::Basic Matrix Operations}{Basic Matrix Operations}

Definition at line 240 of file qtransform.h.

◆ fromScale()

QTransform QTransform::fromScale	(	qreal	sx,
		qreal	sy )

static

Creates a matrix which corresponds to a scaling of sx horizontally and sy vertically.

This is the same as QTransform().scale(sx, sy) but slightly faster.

Since: 4.5

Definition at line 459 of file qtransform.cpp.

◆ fromTranslate()

QTransform QTransform::fromTranslate	(	qreal	dx,
		qreal	dy )

static

Creates a matrix which corresponds to a translation of dx along the x axis and dy along the y axis.

This is the same as QTransform().translate(dx, dy) but slightly faster.

Since: 4.5

Definition at line 393 of file qtransform.cpp.

◆ inverted()

QTransform QTransform::inverted ( bool * invertible = nullptr ) const

nodiscard

Returns an inverted copy of this matrix.

If the matrix is singular (not invertible), the returned matrix is the identity matrix. If invertible is valid (i.e. not 0), its value is set to true if the matrix is invertible, otherwise it is set to false.

See also: isInvertible()

Definition at line 299 of file qtransform.cpp.

◆ isAffine()

bool QTransform::isAffine ( ) const

inline

Returns true if the matrix represent an affine transformation, otherwise returns false.

Definition at line 166 of file qtransform.h.

◆ isIdentity()

bool QTransform::isIdentity ( ) const

inline

Returns true if the matrix is the identity matrix, otherwise returns false.

See also: reset()

Definition at line 170 of file qtransform.h.

◆ isInvertible()

bool QTransform::isInvertible ( ) const

inline

Returns true if the matrix is invertible, otherwise returns false.

See also: inverted()

Definition at line 175 of file qtransform.h.

◆ isRotating()

bool QTransform::isRotating ( ) const

inline

Returns true if the matrix represents some kind of a rotating transformation, otherwise returns false.

Note: A rotation transformation of 180 degrees and/or 360 degrees is treated as a scaling transformation.

See also: reset()

Definition at line 184 of file qtransform.h.

◆ isScaling()

bool QTransform::isScaling ( ) const

inline

Returns true if the matrix represents a scaling transformation, otherwise returns false.

See also: reset()

Definition at line 180 of file qtransform.h.

◆ isTranslating()

bool QTransform::isTranslating ( ) const

inline

Returns true if the matrix represents a translating transformation, otherwise returns false.

See also: reset()

Definition at line 189 of file qtransform.h.

◆ m11()

qreal QTransform::m11 ( ) const

inline

Returns the horizontal scaling factor.

See also: scale(), {QTransform::Basic Matrix Operations}{Basic Matrix Operations}

Definition at line 200 of file qtransform.h.

◆ m12()

qreal QTransform::m12 ( ) const

inline

Returns the vertical shearing factor.

See also: shear(), {QTransform::Basic Matrix Operations}{Basic Matrix Operations}

Definition at line 204 of file qtransform.h.

◆ m13()

qreal QTransform::m13 ( ) const

inline

Returns the horizontal projection factor.

See also: translate(), {QTransform::Basic Matrix Operations}{Basic Matrix Operations}

Definition at line 208 of file qtransform.h.

◆ m21()

qreal QTransform::m21 ( ) const

inline

Returns the horizontal shearing factor.

See also: shear(), {QTransform::Basic Matrix Operations}{Basic Matrix Operations}

Definition at line 212 of file qtransform.h.

◆ m22()

qreal QTransform::m22 ( ) const

inline

Returns the vertical scaling factor.

See also: scale(), {QTransform::Basic Matrix Operations}{Basic Matrix Operations}

Definition at line 216 of file qtransform.h.

◆ m23()

qreal QTransform::m23 ( ) const

inline

Returns the vertical projection factor.

See also: translate(), {QTransform::Basic Matrix Operations}{Basic Matrix Operations}

Definition at line 220 of file qtransform.h.

◆ m31()

qreal QTransform::m31 ( ) const

inline

Returns the horizontal translation factor.

See also: dx(), translate(), {QTransform::Basic Matrix Operations}{Basic Matrix Operations}

Definition at line 224 of file qtransform.h.

◆ m32()

qreal QTransform::m32 ( ) const

inline

Returns the vertical translation factor.

See also: dy(), translate(), {QTransform::Basic Matrix Operations}{Basic Matrix Operations}

Definition at line 228 of file qtransform.h.

◆ m33()

qreal QTransform::m33 ( ) const

inline

Returns the division factor.

See also: translate(), {QTransform::Basic Matrix Operations}{Basic Matrix Operations}

Definition at line 232 of file qtransform.h.

◆ map() [1/10]

QLine QTransform::map ( const QLine & l ) const

This is an overloaded member function, provided for convenience. It differs from the above function only in what argument(s) it accepts.Creates and returns a QLineF object that is a copy of the given line, l, mapped into the coordinate system defined by this matrix.

Definition at line 1206 of file qtransform.cpp.

◆ map() [2/10]

QLineF QTransform::map ( const QLineF & line ) const

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

Creates and returns a QLine object that is a copy of the given line, mapped into the coordinate system defined by this matrix. Note that the transformed coordinates are rounded to the nearest integer.

Definition at line 1232 of file qtransform.cpp.

◆ map() [3/10]

QPainterPath QTransform::map ( const QPainterPath & p ) const

This is an overloaded member function, provided for convenience. It differs from the above function only in what argument(s) it accepts.Creates and returns a QPainterPath object that is a copy of the given path, mapped into the coordinate system defined by this matrix.

Definition at line 1518 of file qtransform.cpp.

◆ map() [4/10]

QPoint QTransform::map ( const QPoint & point ) const

This is an overloaded member function, provided for convenience. It differs from the above function only in what argument(s) it accepts.Creates and returns a QPoint object that is a copy of the given point, mapped into the coordinate system defined by this matrix.

Note that the transformed coordinates are rounded to the nearest integer.

Definition at line 1132 of file qtransform.cpp.

◆ map() [5/10]

QPointF QTransform::map ( const QPointF & p ) const

This is an overloaded member function, provided for convenience. It differs from the above function only in what argument(s) it accepts.Creates and returns a QPointF object that is a copy of the given point, p, mapped into the coordinate system defined by this matrix.

Definition at line 1160 of file qtransform.cpp.

◆ map() [6/10]

QPolygon QTransform::map ( const QPolygon & polygon ) const

This is an overloaded member function, provided for convenience. It differs from the above function only in what argument(s) it accepts.Creates and returns a QPolygon object that is a copy of the given polygon, mapped into the coordinate system defined by this matrix.

Note that the transformed coordinates are rounded to the nearest integer.

Definition at line 1301 of file qtransform.cpp.

◆ map() [7/10]

QPolygonF QTransform::map ( const QPolygonF & a ) const

This is an overloaded member function, provided for convenience. It differs from the above function only in what argument(s) it accepts.Creates and returns a QPolygonF object that is a copy of the given polygon, mapped into the coordinate system defined by this matrix.

Definition at line 1274 of file qtransform.cpp.

◆ map() [8/10]

QRegion QTransform::map ( const QRegion & region ) const

This is an overloaded member function, provided for convenience. It differs from the above function only in what argument(s) it accepts.Creates and returns a QRegion object that is a copy of the given region, mapped into the coordinate system defined by this matrix.

Calling this method can be rather expensive if rotations or shearing are used.

Definition at line 1343 of file qtransform.cpp.

◆ map() [9/10]

void QTransform::map	(	int	x,
		int	y,
		int *	tx,
		int *	ty ) const

This is an overloaded member function, provided for convenience. It differs from the above function only in what argument(s) it accepts.Maps the given coordinates x and y into the coordinate system defined by this matrix.

The resulting values are put in *tx and *ty, respectively. Note that the transformed coordinates are rounded to the nearest integer.

Definition at line 1885 of file qtransform.cpp.

◆ map() [10/10]

void QTransform::map	(	qreal	x,
		qreal	y,
		qreal *	tx,
		qreal *	ty ) const

Maps the given coordinates x and y into the coordinate system defined by this matrix.

The resulting values are put in *tx and *ty, respectively.

The coordinates are transformed using the following formulas:

x' = m11*x + m21*y + dx
y' = m22*y + m12*x + dy
if (!isAffine()) {
    w' = m13*x + m23*y + m33
    x' /= w'
    y' /= w'
}

The point (x, y) is the original point, and (x', y') is the transformed point.

See also: {QTransform::Basic Matrix Operations}{Basic Matrix Operations}

Definition at line 1872 of file qtransform.cpp.

◆ mapRect() [1/2]

QRect QTransform::mapRect ( const QRect & rectangle ) const

This is an overloaded member function, provided for convenience. It differs from the above function only in what argument(s) it accepts.Creates and returns a QRect object that is a copy of the given rectangle, mapped into the coordinate system defined by this matrix.

Note that the transformed coordinates are rounded to the nearest integer.

Definition at line 1737 of file qtransform.cpp.

◆ mapRect() [2/2]

QRectF QTransform::mapRect ( const QRectF & rectangle ) const

Creates and returns a QRectF object that is a copy of the given rectangle, mapped into the coordinate system defined by this matrix.

The rectangle's coordinates are transformed using the following formulas:

x' = m11*x + m21*y + dx
y' = m22*y + m12*x + dy
if (!isAffine()) {
    w' = m13*x + m23*y + m33
    x' /= w'
    y' /= w'
}

If rotation or shearing has been specified, this function returns the bounding rectangle. To retrieve the exact region the given rectangle maps to, use the mapToPolygon() function instead.

See also: mapToPolygon(), {QTransform::Basic Matrix Operations}{Basic Matrix Operations}

Definition at line 1802 of file qtransform.cpp.

◆ mapToPolygon()

QPolygon QTransform::mapToPolygon ( const QRect & rectangle ) const

Creates and returns a QPolygon representation of the given rectangle, mapped into the coordinate system defined by this matrix.

The rectangle's coordinates are transformed using the following formulas:

x' = m11*x + m21*y + dx
y' = m22*y + m12*x + dy
if (!isAffine()) {
    w' = m13*x + m23*y + m33
    x' /= w'
    y' /= w'
}

Polygons and rectangles behave slightly differently when transformed (due to integer rounding), so {matrix.map(QPolygon(rectangle))} is not always the same as {matrix.mapToPolygon(rectangle)}.

See also: mapRect(), {QTransform::Basic Matrix Operations}{Basic Matrix Operations}

Definition at line 1563 of file qtransform.cpp.

◆ operator QVariant()

QTransform::operator QVariant ( ) const

Returns the transform as a QVariant.

Definition at line 1953 of file qtransform.cpp.

◆ operator!=()

bool QTransform::operator!= ( const QTransform & matrix ) const

Returns true if this matrix is not equal to the given matrix, otherwise returns false.

Definition at line 809 of file qtransform.cpp.

◆ operator*()

QTransform QTransform::operator* ( const QTransform & matrix ) const

Returns the result of multiplying this matrix by the given matrix.

Note that matrix multiplication is not commutative, i.e. a*b != b*a.

Definition at line 906 of file qtransform.cpp.

◆ operator*=() [1/2]

QTransform & QTransform::operator*= ( const QTransform & matrix )

This is an overloaded member function, provided for convenience. It differs from the above function only in what argument(s) it accepts.Returns the result of multiplying this matrix by the given matrix.

Definition at line 821 of file qtransform.cpp.

◆ operator*=() [2/2]

QT_WARNING_PUSH QT_WARNING_DISABLE_FLOAT_COMPARE QTransform & QTransform::operator*= ( qreal div )

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 result of performing an element-wise multiplication of this matrix with the given scalar.

Definition at line 248 of file qtransform.h.

◆ operator+=()

QTransform & QTransform::operator+= ( qreal div )

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 matrix obtained by adding the given scalar to each element of this matrix.

Definition at line 272 of file qtransform.h.

◆ operator-=()

QTransform & QTransform::operator-= ( qreal div )

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 matrix obtained by subtracting the given scalar from each element of this matrix.

Definition at line 288 of file qtransform.h.

◆ operator/=()

QTransform & QTransform::operator/= ( qreal div )

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 result of performing an element-wise division of this matrix by the given scalar.

Definition at line 265 of file qtransform.h.

◆ operator=() [1/2]

QTransform & QTransform::operator= ( const QTransform & matrix )

defaultnoexcept

Assigns the given matrix's values to this matrix.

◆ operator=() [2/2]

QTransform & QTransform::operator= ( QTransform && other )

defaultnoexcept

◆ operator==()

bool QTransform::operator== ( const QTransform & matrix ) const

Returns true if this matrix is equal to the given matrix, otherwise returns false.

Definition at line 768 of file qtransform.cpp.

◆ quadToQuad()

bool QTransform::quadToQuad	(	const QPolygonF &	one,
		const QPolygonF &	two,
		QTransform &	trans )

static

Creates a transformation matrix, trans, that maps a four-sided polygon, one, to another four-sided polygon, two.

Returns true if the transformation is possible; otherwise returns false.

This is a convenience method combining quadToSquare() and squareToQuad() methods. It allows the input quad to be transformed into any other quad.

See also: squareToQuad(), quadToSquare()

Definition at line 1701 of file qtransform.cpp.

◆ quadToSquare()

bool QTransform::quadToSquare	(	const QPolygonF &	quad,
		QTransform &	trans )

static

Creates a transformation matrix, trans, that maps a four-sided polygon, quad, to a unit square.

Returns true if the transformation is constructed or false if such a transformation does not exist.

See also: squareToQuad(), quadToQuad()

Definition at line 1678 of file qtransform.cpp.

◆ reset()

void QTransform::reset ( )

Resets the matrix to an identity matrix, i.e.

all elements are set to zero, except m11 and m22 (specifying the scale) and m33 which are set to 1.

See also: QTransform(), isIdentity(), {QTransform::Basic Matrix Operations}{Basic Matrix Operations}

Definition at line 1028 of file qtransform.cpp.

◆ rotate()

QTransform & QTransform::rotate	(	qreal	a,
		Qt::Axis	axis = Qt::ZAxis,
		qreal	distanceToPlane = 1024.0f )

\since 6.5

Rotates the coordinate system counterclockwise by the given angle \a a
about the specified \a axis at distance \a distanceToPlane from the
screen and returns a reference to the matrix.

! [transform-rotate-note] Note that if you apply a QTransform to a point defined in widget coordinates, the direction of the rotation will be clockwise because the y-axis points downwards.

The angle is specified in degrees. ! [transform-rotate-note]

If \a distanceToPlane is zero, it will be ignored. This is suitable
for implementing orthographic projections where the z coordinate should
be dropped rather than projected.

\sa setMatrix()

Definition at line 549 of file qtransform.cpp.

◆ rotateRadians()

QTransform & QTransform::rotateRadians	(	qreal	a,
		Qt::Axis	axis = Qt::ZAxis,
		qreal	distanceToPlane = 1024.0f )

\since 6.5

Rotates the coordinate system counterclockwise by the given angle \a a
about the specified \a axis at distance \a distanceToPlane from the
screen and returns a reference to the matrix.

! [transform-rotate-radians-note] Note that if you apply a QTransform to a point defined in widget coordinates, the direction of the rotation will be clockwise because the y-axis points downwards.

The angle is specified in radians. ! [transform-rotate-radians-note]

If \a distanceToPlane is zero, it will be ignored. This is suitable
for implementing orthographic projections where the z coordinate should
be dropped rather than projected.

\sa setMatrix()

Definition at line 674 of file qtransform.cpp.

◆ scale()

QTransform & QTransform::scale	(	qreal	sx,
		qreal	sy )

Scales the coordinate system by sx horizontally and sy vertically, and returns a reference to the matrix.

See also: setMatrix()

Definition at line 416 of file qtransform.cpp.

◆ setMatrix()

void QTransform::setMatrix	(	qreal	m11,
		qreal	m12,
		qreal	m13,
		qreal	m21,
		qreal	m22,
		qreal	m23,
		qreal	m31,
		qreal	m32,
		qreal	m33 )

Sets the matrix elements to the specified values, m11, m12, m13 m21, m22, m23 m31, m32 and m33.

Note that this function replaces the previous values. QTransform provides the translate(), rotate(), scale() and shear() convenience functions to manipulate the various matrix elements based on the currently defined coordinate system.

See also: QTransform()

Definition at line 1726 of file qtransform.cpp.

◆ shear()

QTransform & QTransform::shear	(	qreal	sh,
		qreal	sv )

Shears the coordinate system by sh horizontally and sv vertically, and returns a reference to the matrix.

See also: setMatrix()

Definition at line 482 of file qtransform.cpp.

◆ squareToQuad()

bool QTransform::squareToQuad	(	const QPolygonF &	quad,
		QTransform &	trans )

static

Creates a transformation matrix, trans, that maps a unit square to a four-sided polygon, quad.

Returns true if the transformation is constructed or false if such a transformation does not exist.

See also: quadToSquare(), quadToQuad()

Definition at line 1613 of file qtransform.cpp.

◆ translate()

QTransform & QTransform::translate	(	qreal	dx,
		qreal	dy )

Moves the coordinate system dx along the x axis and dy along the y axis, and returns a reference to the matrix.

See also: setMatrix()

Definition at line 348 of file qtransform.cpp.

◆ transposed()

QTransform QTransform::transposed ( ) const

nodiscard

Returns the transpose of this matrix.

Definition at line 281 of file qtransform.cpp.

◆ type()

QTransform::TransformationType QTransform::type ( ) const

Returns the transformation type of this matrix.

The transformation type is the highest enumeration value capturing all of the matrix's transformations. For example, if the matrix both scales and shears, the type would be TxShear, because TxShear has a higher enumeration value than TxScale.

Knowing the transformation type of a matrix is useful for optimization: you can often handle specific types more optimally than handling the generic case.

Definition at line 1905 of file qtransform.cpp.

Friends And Related Symbol Documentation

◆ operator*() [1/8]

QLine operator*	(	const QLine &	line,
		const QTransform &	matrix )

See also: QTransform::map()

Definition at line 339 of file qtransform.h.

◆ operator*() [2/8]

QLineF operator*	(	const QLineF &	line,
		const QTransform &	matrix )

See also: QTransform::map()

Definition at line 337 of file qtransform.h.

◆ operator*() [3/8]

QPainterPath operator*	(	const QPainterPath &	path,
		const QTransform &	matrix )

Since: 4.3

This is the same as {matrix}.map({path}).

See also: QTransform::map()

Definition at line 300 of file qpainterpath.h.

◆ operator*() [4/8]

QPoint operator*	(	const QPoint &	point,
		const QTransform &	matrix )

See also: QTransform::map()

Definition at line 333 of file qtransform.h.

◆ operator*() [5/8]

QPointF operator*	(	const QPointF &	point,
		const QTransform &	matrix )

See also: QTransform::map()

Definition at line 335 of file qtransform.h.

◆ operator*() [6/8]

QPolygon operator*	(	const QPolygon &	polygon,
		const QTransform &	matrix )

See also: QTransform::map()

Definition at line 341 of file qtransform.h.

◆ operator*() [7/8]

QPolygonF operator*	(	const QPolygonF &	polygon,
		const QTransform &	matrix )

Since: 4.3

This is the same as {matrix}.map({polygon}).

See also: QTransform::map()

Definition at line 343 of file qtransform.h.

◆ operator*() [8/8]

QRegion operator*	(	const QRegion &	region,
		const QTransform &	matrix )

See also: QTransform::map()

Definition at line 345 of file qtransform.h.

◆ operator<< [1/2]

Q_GUI_EXPORT QDataStream & operator<<	(	QDataStream &	s,
		const Affine &	m )

friend

Definition at line 2201 of file qtransform.cpp.

◆ operator<<() [2/2]

QDataStream & operator<<	(	QDataStream &	stream,
		const QTransform &	matrix )

Since: 4.3

Writes the given matrix to the given stream and returns a reference to the stream.

See also: {Serializing Qt Data Types}

◆ operator>> [1/2]

Q_GUI_EXPORT QDataStream & operator>>	(	QDataStream &	s,
		QTransform::Affine &	m )

friend

Definition at line 2175 of file qtransform.cpp.

◆ operator>>() [2/2]

QDataStream & operator>>	(	QDataStream &	stream,
		QTransform &	matrix )

Since: 4.3

Reads the given matrix from the given stream and returns a reference to the stream.

See also: {Serializing Qt Data Types}

◆ qFuzzyCompare()

bool qFuzzyCompare	(	const QTransform &	t1,
		const QTransform &	t2 )

Since: 4.6

Returns true if t1 and t2 are equal, allowing for a small fuzziness factor for floating-point comparisons; false otherwise.

Definition at line 307 of file qtransform.h.

◆ qHash()

size_t qHash	(	const QTransform &	key,
		size_t	seed )

Since: 5.6

Returns the hash value for key, using seed to seed the calculation.

Definition at line 788 of file qtransform.cpp.

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

qtbase/src/gui/painting/qtransform.h (6a3a28236c6a0c34d37a614ca4e68ccd136d90e2)
qtbase/src/gui/painting/qtransform.cpp (cd8244131e2d6fe2c2453ae40213e7f12bff893d)

Public Types

Public Member Functions

Static Public Member Functions

Friends

Related Symbols

Detailed Description

Member Enumeration Documentation

◆ TransformationType

Constructor & Destructor Documentation

◆ QTransform() [1/6]

◆ QTransform() [2/6]

◆ QTransform() [3/6]

◆ QTransform() [4/6]

◆ QTransform() [5/6]

◆ QTransform() [6/6]

Member Function Documentation

◆ adjoint()

◆ asAffineMatrix()

◆ determinant()

◆ dx()

◆ dy()

◆ fromScale()

◆ fromTranslate()

◆ inverted()

◆ isAffine()

◆ isIdentity()

◆ isInvertible()

◆ isRotating()

◆ isScaling()

◆ isTranslating()

◆ m11()

◆ m12()

◆ m13()

◆ m21()

◆ m22()

◆ m23()

◆ m31()

◆ m32()

◆ m33()

◆ map() [1/10]

◆ map() [2/10]

◆ map() [3/10]

◆ map() [4/10]

◆ map() [5/10]

◆ map() [6/10]

◆ map() [7/10]

◆ map() [8/10]

◆ map() [9/10]

◆ map() [10/10]

◆ mapRect() [1/2]

◆ mapRect() [2/2]

◆ mapToPolygon()

◆ operator QVariant()

◆ operator!=()

◆ operator*()

◆ operator*=() [1/2]

◆ operator*=() [2/2]

◆ operator+=()

◆ operator-=()

◆ operator/=()

◆ operator=() [1/2]

◆ operator=() [2/2]

◆ operator==()

◆ quadToQuad()

◆ quadToSquare()

◆ reset()

◆ rotate()

◆ rotateRadians()

◆ scale()

◆ setMatrix()

◆ shear()

◆ squareToQuad()

◆ translate()

◆ transposed()

◆ type()

Friends And Related Symbol Documentation

◆ operator*() [1/8]

◆ operator*() [2/8]

◆ operator*() [3/8]

◆ operator*() [4/8]