QTransform ¶

QTransform class specifies 2D transformations of a coordinate system. 更多 …

概要 ¶

函数 ¶

def __add__ (, n)
def __div__ (, n)
def __eq__ (arg__1)
def __iadd__ (div)
def __idiv__ (div)
def __imul__ (arg__1)
def __imul__ (div)
def __isub__ (div)
def __mul__ (, n)
def __mul__ (o)
def __ne__ (arg__1)
def __reduce__ ()
def __repr__ ()
def __sub__ (, n)
def adjoint ()
def det ()
def determinant ()
def dx ()
def dy ()
def inverted ()
def isAffine ()
def isIdentity ()
def isInvertible ()
def isRotating ()
def isScaling ()
def isTranslating ()
def m11 ()
def m12 ()
def m13 ()
def m21 ()
def m22 ()
def m23 ()
def m31 ()
def m32 ()
def m33 ()
def map (a)
def map (a)
def map (l)
def map (l)
def map (p)
def map (p)
def map (p)
def map (r)
def map (x, y)
def mapRect (arg__1)
def mapRect (arg__1)
def mapToPolygon (r)
def reset ()
def rotate (a[, axis=Qt.ZAxis])
def rotateRadians (a[, axis=Qt.ZAxis])
def scale (sx, sy)
def setMatrix (m11, m12, m13, m21, m22, m23, m31, m32, m33)
def shear (sh, sv)
def toAffine ()
def translate (dx, dy)
def transposed ()
def type ()

静态函数 ¶

def fromScale (dx, dy)
def fromTranslate (dx, dy)
def quadToQuad (arg__1, arg__2)
def quadToQuad (one, two, result)
def quadToSquare (arg__1)
def quadToSquare (quad, result)
def squareToQuad (arg__1)
def squareToQuad (square, result)

详细描述 ¶

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

QTransform differs from QMatrix in that it is a true 3x3 matrix, allowing perspective transformations. QTransform ‘s toAffine() method allows casting QTransform to QMatrix . If a perspective transformation has been specified on the matrix, then the conversion will cause loss of data.

QTransform is the recommended transformation class in Qt.

A QTransform object can be built using the setMatrix() , scale() , rotate() , translate() and shear() functions. Alternatively, it can be built by applying 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() 函数。

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() 函数。

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.

渲染图形 ¶

When rendering graphics, the matrix defines the transformations but the actual transformation is performed by the drawing routines in QPainter .

默认情况下， QPainter operates on the associated device’s own coordinate system. The standard coordinate system of a QPaintDevice has its origin located at the top-left position. The x values increase to the right; y values increase downward. For a complete description, see the coordinate system 文档编制。

QPainter has functions to translate, scale, shear and rotate the coordinate system without using a QTransform 。例如：
def paintEvent(self, event)
    painter = QPainter(self)
    painter.setPen(QPen(Qt.blue, 1, Qt.DashLine))
    painter.drawRect(0, 0, 100, 100)
    painter.rotate(45)
    painter.setFont(QFont("Helvetica", 24))
    painter.setPen(QPen(Qt.black, 1))
    painter.drawText(20, 10, "QTransform")
																
Although these functions are very convenient, it can be more efficient to build a QTransform 和调用 setTransform() if you want to perform more than a single transform operation. For example:
def paintEvent(self, event)
    painter = QPainter(self)
    painter.setPen(QPen(Qt.blue, 1, Qt.DashLine))
    painter.drawRect(0, 0, 100, 100)
    transform = QTransform()
    transform.translate(50, 50)
    transform.rotate(45)
    transform.scale(0.5, 1.0)
    painter.setTransform(transform)
    painter.setFont(QFont("Helvetica", 24))
    painter.setPen(QPen(Qt.black, 1))
    painter.drawText(20, 10, "QTransform")
																

基本矩阵运算 ¶

A QTransform object contains a 3 x 3 matrix. The m31 ( dx ) and m32 ( dy ) elements specify horizontal and vertical translation. The m11 and m22 elements specify horizontal and vertical scaling. The m21 and m12 elements specify horizontal and vertical shearing . And finally, the m13 and m23 elements specify horizontal and vertical projection, with m33 as an additional projection factor.

QTransform transforms a point in the plane to another point using the following formulas:
x' = m11*x + m21*y + dx
y' = m22*y + m12*x + dy
if is not affine:
    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. (x’, y’) can be transformed back to (x, y) by performing the same operation on the inverted() matrix.

The various matrix elements can be set when constructing the matrix, or by using the setMatrix() function later on. They can also be manipulated using the translate() , rotate() , scale() and shear() convenience functions. The currently set values can be retrieved using the m11() , m12() , m13() , m21() , m22() , m23() , m31() , m32() , m33() , dx() and dy() 函数。

Translation is the simplest transformation. Setting dx and dy will move the coordinate system dx units along the X axis and dy units along the Y axis. Scaling can be done by setting m11 and m22 . For example, setting m11 to 2 and m22 to 1.5 will double the height and increase the width by 50%. The identity matrix has m11 , m22 ，和 m33 set to 1 (all others are set to 0) mapping a point to itself. Shearing is controlled by m12 and m21 . Setting these elements to values different from zero will twist the coordinate system. Rotation is achieved by setting both the shearing factors and the scaling factors. Perspective transformation is achieved by setting both the projection factors and the scaling factors.

Here’s the combined transformations example using basic matrix operations:
def paintEvent(self, event)
    pi = 3.14
    a    = pi/180 * 45.0
    sina = sin(a)
    cosa = cos(a)
    translationTransform = QTransform(1, 0, 0, 1, 50.0, 50.0)
    rotationTransform = QTransform(cosa, sina, -sina, cosa, 0, 0)
    scalingTransform = QTransform(0.5, 0, 0, 1.0, 0, 0)
    transform = QTransform()
    transform = scalingTransform * rotationTransform * translationTransform
    painter = QPainter(self)
    painter.setPen(QPen(Qt.blue, 1, Qt.DashLine))
    painter.drawRect(0, 0, 100, 100)
    painter.setTransform(transform)
    painter.setFont(QFont("Helvetica", 24))
    painter.setPen(QPen(Qt.black, 1))
    painter.drawText(20, 10, "QTransform")
																
另请参阅

QPainter 坐标系统仿射变换范例变换范例

class QTransform ¶

QTransform(mtx)

QTransform(other)

QTransform(h11, h12, h13, h21, h22, h23, h31, h32[, h33=1.0])

QTransform(h11, h12, h21, h22, dx, dy)

param h32

qreal

param h33

qreal

param h21

qreal

param h22

qreal

param h23

qreal

param mtx

QMatrix

param h11

qreal

param h12

qreal

param h13

qreal

param dx

qreal

param dy

qreal

param other

QTransform

param h31

qreal

构造恒等矩阵。

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

另请参阅

reset()

构造矩阵采用元素 m11 , m12 , m13 , m21 , m22 , m23 , m31 , m32 , m33 .

另请参阅

setMatrix()

构造矩阵采用元素 m11 , m12 , m21 , m22 , dx and dy .

另请参阅

setMatrix()

PySide2.QtGui.QTransform. TransformationType ¶

常量	描述
QTransform.TxNone
QTransform.TxTranslate
QTransform.TxScale
QTransform.TxRotate
QTransform.TxShear
QTransform.TxProject

PySide2.QtGui.QTransform. __reduce__ ( ) ¶

返回类型: PyObject

PySide2.QtGui.QTransform. __repr__ ( ) ¶

返回类型: PyObject

PySide2.QtGui.QTransform. adjoint ( ) ¶

返回类型: QTransform

Returns the adjoint of this matrix.

PySide2.QtGui.QTransform. det ( ) ¶

返回类型: qreal

注意

此函数被弃用。

Returns the matrix’s determinant. Use determinant() 代替。

PySide2.QtGui.QTransform. determinant ( ) ¶

返回类型: qreal

Returns the matrix’s determinant.

PySide2.QtGui.QTransform. dx ( ) ¶

返回类型: qreal

Returns the horizontal translation factor.

另请参阅

m31() translate() 基本 Matrix Operations

PySide2.QtGui.QTransform. dy ( ) ¶

返回类型: qreal

Returns the vertical translation factor.

另请参阅

translate() 基本 Matrix Operations

static PySide2.QtGui.QTransform. fromScale ( dx , dy ) ¶

参数

dx – qreal
dy – qreal

返回类型

QTransform

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.

static PySide2.QtGui.QTransform. fromTranslate ( dx , dy ) ¶

参数

dx – qreal
dy – qreal

返回类型

QTransform

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.

PySide2.QtGui.QTransform. inverted ( ) ¶

返回类型: PyTuple

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.

另请参阅

isInvertible()

PySide2.QtGui.QTransform. isAffine ( ) ¶

返回类型: bool

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

PySide2.QtGui.QTransform. isIdentity ( ) ¶

返回类型: bool

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

另请参阅

reset()

PySide2.QtGui.QTransform. isInvertible ( ) ¶

返回类型: bool

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

另请参阅

inverted()

PySide2.QtGui.QTransform. isRotating ( ) ¶

返回类型: bool

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

注意

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

另请参阅

reset()

PySide2.QtGui.QTransform. isScaling ( ) ¶

返回类型: bool

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

另请参阅

reset()

PySide2.QtGui.QTransform. isTranslating ( ) ¶

返回类型: bool

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

另请参阅

reset()

PySide2.QtGui.QTransform. m11 ( ) ¶

返回类型: qreal

Returns the horizontal scaling factor.

另请参阅

scale() 基本 Matrix Operations

PySide2.QtGui.QTransform. m12 ( ) ¶

返回类型: qreal

Returns the vertical shearing factor.

另请参阅

shear() 基本 Matrix Operations

PySide2.QtGui.QTransform. m13 ( ) ¶

返回类型: qreal

Returns the horizontal projection factor.

另请参阅

translate() 基本 Matrix Operations

PySide2.QtGui.QTransform. m21 ( ) ¶

返回类型: qreal

Returns the horizontal shearing factor.

另请参阅

shear() 基本 Matrix Operations

PySide2.QtGui.QTransform. m22 ( ) ¶

返回类型: qreal

Returns the vertical scaling factor.

另请参阅

scale() 基本 Matrix Operations

PySide2.QtGui.QTransform. m23 ( ) ¶

返回类型: qreal

Returns the vertical projection factor.

另请参阅

translate() 基本 Matrix Operations

PySide2.QtGui.QTransform. m31 ( ) ¶

返回类型: qreal

Returns the horizontal translation factor.

另请参阅

dx() translate() 基本 Matrix Operations

PySide2.QtGui.QTransform. m32 ( ) ¶

返回类型: qreal

Returns the vertical translation factor.

另请参阅

dy() translate() 基本 Matrix Operations

PySide2.QtGui.QTransform. m33 ( ) ¶

返回类型: qreal

Returns the division factor.

另请参阅

translate() 基本 Matrix Operations

PySide2.QtGui.QTransform. map ( x , y ) ¶

参数

x – qreal
y – qreal

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 is not affine:
    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.

另请参阅

基本 Matrix Operations

PySide2.QtGui.QTransform. map ( r ) ¶

参数: r – QRegion
返回类型: QRegion

PySide2.QtGui.QTransform. map ( a ) ¶

参数: a – QPolygonF
返回类型: QPolygonF

PySide2.QtGui.QTransform. map ( a ) ¶

参数: a – QPolygon
返回类型: QPolygon

PySide2.QtGui.QTransform. map ( p ) ¶

参数: p – QPoint
返回类型: QPoint

PySide2.QtGui.QTransform. map ( p ) ¶

参数: p – QPointF
返回类型: QPointF

PySide2.QtGui.QTransform. map ( l ) ¶

参数: l – QLine
返回类型: QLine

PySide2.QtGui.QTransform. map ( p ) ¶

参数: p – QPainterPath
返回类型: QPainterPath

PySide2.QtGui.QTransform. map ( l ) ¶

参数: l – QLineF
返回类型: QLineF

PySide2.QtGui.QTransform. mapRect ( arg__1 ) ¶

参数: arg__1 – QRect
返回类型: QRect

PySide2.QtGui.QTransform. mapRect ( arg__1 ) ¶

参数: arg__1 – QRectF
返回类型: QRectF

PySide2.QtGui.QTransform. mapToPolygon ( r ) ¶

参数: r – QRect
返回类型: QPolygon

创建和返回 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 is not affine:
    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) .

另请参阅

mapRect() 基本 Matrix Operations

PySide2.QtGui.QTransform. __ne__ ( arg__1 ) ¶

参数: arg__1 – QTransform
返回类型: bool

返回 true if this matrix is not equal to the given matrix ，否则返回 false .

PySide2.QtGui.QTransform. __mul__ ( n ) ¶

参数: n – qreal
返回类型: QTransform

PySide2.QtGui.QTransform. __mul__ ( o ) ¶

参数: o – QTransform
返回类型: QTransform

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

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

PySide2.QtGui.QTransform. __imul__ ( arg__1 ) ¶

参数: arg__1 – QTransform
返回类型: QTransform

PySide2.QtGui.QTransform. __imul__ ( div ) ¶

参数: div – qreal
返回类型: QTransform

这是重载函数。

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

PySide2.QtGui.QTransform. __add__ ( n ) ¶

参数: n – qreal
返回类型: QTransform

PySide2.QtGui.QTransform. __iadd__ ( div ) ¶

参数: div – qreal
返回类型: QTransform

这是重载函数。

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

PySide2.QtGui.QTransform. __sub__ ( n ) ¶

参数: n – qreal
返回类型: QTransform

PySide2.QtGui.QTransform. __isub__ ( div ) ¶

参数: div – qreal
返回类型: QTransform

这是重载函数。

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

PySide2.QtGui.QTransform. __div__ ( n ) ¶

参数: n – qreal
返回类型: QTransform

PySide2.QtGui.QTransform. __idiv__ ( div ) ¶

参数: div – qreal
返回类型: QTransform

这是重载函数。

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

PySide2.QtGui.QTransform. __eq__ ( arg__1 ) ¶

参数: arg__1 – QTransform
返回类型: bool

返回 true if this matrix is equal to the given matrix ，否则返回 false .

static PySide2.QtGui.QTransform. quadToQuad ( arg__1 , arg__2 ) ¶

参数

arg__1 – QPolygonF
arg__2 – QPolygonF

返回类型

PyObject

static PySide2.QtGui.QTransform. quadToQuad ( one , two , result ) ¶

参数

one – QPolygonF
two – QPolygonF
result – QTransform

返回类型

bool

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

另请参阅

squareToQuad() quadToSquare()

static PySide2.QtGui.QTransform. quadToSquare ( arg__1 ) ¶

参数: arg__1 – QPolygonF
返回类型: PyObject

static PySide2.QtGui.QTransform. quadToSquare ( quad , result ) ¶

参数

quad – QPolygonF
result – QTransform

返回类型

bool

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.

另请参阅

squareToQuad() quadToQuad()

PySide2.QtGui.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.

另请参阅

QTransform() isIdentity() 基本 Matrix Operations

PySide2.QtGui.QTransform. rotate ( a [ , axis=Qt.ZAxis ] ) ¶

参数

a – qreal
axis – Axis

返回类型

QTransform

Rotates the coordinate system counterclockwise by the given angle about the specified axis and returns a reference to the matrix.

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.

另请参阅

setMatrix()

PySide2.QtGui.QTransform. rotateRadians ( a [ , axis=Qt.ZAxis ] ) ¶

参数

a – qreal
axis – Axis

返回类型

QTransform

Rotates the coordinate system counterclockwise by the given angle about the specified axis and returns a reference to the matrix.

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.

另请参阅

setMatrix()

PySide2.QtGui.QTransform. scale ( sx , sy ) ¶

参数

sx – qreal
sy – qreal

返回类型

QTransform

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

另请参阅

setMatrix()

PySide2.QtGui.QTransform. setMatrix ( m11 , m12 , m13 , m21 , m22 , m23 , m31 , m32 , m33 ) ¶

参数

m11 – qreal
m12 – qreal
m13 – qreal
m21 – qreal
m22 – qreal
m23 – qreal
m31 – qreal
m32 – qreal
m33 – qreal

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.

另请参阅

QTransform()

PySide2.QtGui.QTransform. shear ( sh , sv ) ¶

参数

sh – qreal
sv – qreal

返回类型

QTransform

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

另请参阅

setMatrix()

static PySide2.QtGui.QTransform. squareToQuad ( arg__1 ) ¶

参数: arg__1 – QPolygonF
返回类型: PyObject

static PySide2.QtGui.QTransform. squareToQuad ( square , result ) ¶

参数

square – QPolygonF
result – QTransform

返回类型

bool

Creates a transformation matrix, trans , that maps a unit square to a four-sided polygon, quad 。返回 true if the transformation is constructed or false if such a transformation does not exist.

另请参阅

quadToSquare() quadToQuad()

PySide2.QtGui.QTransform. toAffine ( ) ¶

返回类型: QMatrix

返回 QTransform as an affine matrix.

警告

If a perspective transformation has been specified, then the conversion will cause loss of data.

PySide2.QtGui.QTransform. translate ( dx , dy ) ¶

参数

dx – qreal
dy – qreal

返回类型

QTransform

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

另请参阅

setMatrix()

PySide2.QtGui.QTransform. transposed ( ) ¶

返回类型: QTransform

Returns the transpose of this matrix.

PySide2.QtGui.QTransform. type ( ) ¶

返回类型: TransformationType

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.

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QTransform ¶

概要 ¶

函数 ¶

静态函数 ¶

详细描述 ¶

渲染图形 ¶

基本矩阵运算 ¶