Synopsis - Qt for Python

內容

Warning

This section contains snippets that were automatically translated from C++ to Python and may contain errors.

A point is specified by a x coordinate and an y coordinate which can be accessed using the x() and y() functions. The isNull() function returns true if both x and y are set to 0. The coordinates can be set (or altered) using the setX() and setY() functions, or alternatively the rx() and ry() functions which return references to the coordinates (allowing direct manipulation).

Given a point p, the following statements are all equivalent:

p = QPoint() p.setX(p.x() + 1) p += QPoint(1, 0) p.rx() = p.rx() + 1

A QPoint object can also be used as a vector: Addition and subtraction are defined as for vectors (each component is added separately). A QPoint object can also be divided or multiplied by an int or a qreal.

In addition, the QPoint class provides the manhattanLength() function which gives an inexpensive approximation of the length of the QPoint object interpreted as a vector. Finally, QPoint objects can be streamed as well as compared.

See also

QPointF QPolygon

__init__(xpos, ypos)#

Parameters:

Constructs a point with the given coordinates (xpos, ypos).

__init__()

Constructs a null point, i.e. with coordinates (0, 0)

__reduce__()#

Return type:

object

__repr__()#

Return type:

object

static dotProduct(p1, p2)#

Parameters:

Return type:

int

Warning

This section contains snippets that were automatically translated from C++ to Python and may contain errors.

p = QPoint( 3, 7) q = QPoint(-1, 4) dotProduct = QPoint.dotProduct(p, q) # dotProduct becomes 25()

Returns the dot product of p1 and p2.

isNull()#

Return type:

bool

Returns true if both the x and y coordinates are set to 0, otherwise returns false.

manhattanLength()#

Return type:

int

Warning

This section contains snippets that were automatically translated from C++ to Python and may contain errors.

Returns the sum of the absolute values of x() and y() , traditionally known as the “Manhattan length” of the vector from the origin to the point. For example:

oldPosition = QPoint() MyWidget::mouseMoveEvent(QMouseEvent event) point = event.pos() - oldPosition if point.manhattanLength() > 3: # the mouse has moved more than 3 pixels since the oldPosition

This is a useful, and quick to calculate, approximation to the true length:

TrueLength = std::sqrt(std::pow(x(), 2) + std::pow(y(), 2))

The tradition of “Manhattan length” arises because such distances apply to travelers who can only travel on a rectangular grid, like the streets of Manhattan.

__ne__(p2)#

Parameters:

p2QPoint

Return type:

bool

Returns true if p1 and p2 are not equal; otherwise returns false.

__mul__(m)#

Parameters:

Return type:

__mul__(factor)

Parameters:

factor – int

Return type:

Returns a copy of the given point multiplied by the given factor.

__mul__(factor)

Parameters:

factor – int

Return type:

This is an overloaded function.

Returns a copy of the given point multiplied by the given factor.

__mul__(factor)

Parameters:

factor – float

Return type:

Returns a copy of the given point multiplied by the given factor.

Note that the result is rounded to the nearest integer as points are held as integers. Use QPointF for floating point accuracy.

__mul__(factor)

Parameters:

factor – float

Return type:

This is an overloaded function.

Returns a copy of the given point multiplied by the given factor.

Note that the result is rounded to the nearest integer as points are held as integers. Use QPointF for floating point accuracy.

__mul__(factor)

Parameters:

factor – float

Return type:

Returns a copy of the given point multiplied by the given factor.

Note that the result is rounded to the nearest integer as points are held as integers. Use QPointF for floating point accuracy.

__mul__(factor)

Parameters:

factor – float

Return type:

This is an overloaded function.

Returns a copy of the given point multiplied by the given factor.

Note that the result is rounded to the nearest integer as points are held as integers. Use QPointF for floating point accuracy.

__mul__(matrix)

Parameters:

matrixQMatrix4x4

Return type:

__mul__(matrix)

Parameters:

matrixQMatrix4x4

Return type:

Note

This function is deprecated.

__imul__(factor)#

Parameters:

factor – int

Return type:

Multiplies this point’s coordinates by the given factor, and returns a reference to this point.

__imul__(factor)

Parameters:

factor – float

Return type:

Multiplies this point’s coordinates by the given factor, and returns a reference to this point.

Note that the result is rounded to the nearest integer as points are held as integers. Use QPointF for floating point accuracy.

__imul__(factor)

Parameters:

factor – float

Return type:

Warning

This section contains snippets that were automatically translated from C++ to Python and may contain errors.

Multiplies this point’s coordinates by the given factor, and returns a reference to this point. For example:

p = QPoint(-1, 4) = 2.5 # p becomes (-3, 10)

Note that the result is rounded to the nearest integer as points are held as integers. Use QPointF for floating point accuracy.

__add__()#

Return type:

Returns point unmodified.

__add__(p2)

Parameters:

p2QPoint

Return type:

Returns a QPoint object that is the sum of the given points, p1 and p2; each component is added separately.

__iadd__(p)#

Parameters:

pQPoint

Return type:

Warning

This section contains snippets that were automatically translated from C++ to Python and may contain errors.

Adds the given point to this point and returns a reference to this point. For example:

p = QPoint( 3, 7) q = QPoint(-1, 4) p += q # p becomes (2, 11)

__sub__()#

Return type:

This is an overloaded function.

Returns a QPoint object that is formed by changing the sign of both components of the given point.

Equivalent to QPoint(0,0) - point.

__sub__(p2)

Parameters:

p2QPoint

Return type:

Returns a QPoint object that is formed by subtracting p2 from p1; each component is subtracted separately.

__isub__(p)#

Parameters:

pQPoint

Return type:

Warning

This section contains snippets that were automatically translated from C++ to Python and may contain errors.

Subtracts the given point from this point and returns a reference to this point. For example:

p = QPoint( 3, 7) q = QPoint(-1, 4) p -= q # p becomes (4, 3)

__div__(c)#

Parameters:

c – float

Return type:

Returns the QPoint formed by dividing both components of the given point by the given divisor.

Note that the result is rounded to the nearest integer as points are held as integers. Use QPointF for floating point accuracy.

operator/=(divisor)

Parameters:

divisor – float

Return type:

Warning

This section contains snippets that were automatically translated from C++ to Python and may contain errors.

This is an overloaded function.

Divides both x and y by the given divisor, and returns a reference to this point. For example:

p = QPoint(-3, 10) p /= 2.5 # p becomes (-1, 4)

Note that the result is rounded to the nearest integer as points are held as integers. Use QPointF for floating point accuracy.

__eq__(p2)#

Parameters:

p2QPoint

Return type:

bool

Returns true if p1 and p2 are equal; otherwise returns false.

setX(x)#

Parameters:

x – int

Sets the x coordinate of this point to the given x coordinate.

setY(y)#

Parameters:

y – int

Sets the y coordinate of this point to the given y coordinate.

toPointF()#

Return type:

Returns this point as a point with floating point accuracy.

toTuple()#

Return type:

object

transposed()#

Return type:

Returns a point with x and y coordinates exchanged:

QPoint{1, 2}.transposed() // {2, 1}

See also

x() y() setX() setY()

x()#

Return type:

int

Returns the x coordinate of this point.

y()#

Return type:

int

Returns the y coordinate of this point.

總結
The article discusses the QPoint class in Python, which represents a point with x and y coordinates. It explains functions like x(), y(), isNull(), setX(), setY(), rx(), ry(), manhattanLength(), dotProduct(), __ne__(), __mul__(), __imul__(), __add__(), and __iadd__(). The QPoint class can be used as a vector, supporting addition, subtraction, multiplication by int or qreal, and dot product calculations. The manhattanLength() function provides an approximation of the vector length. The article also mentions the use of QPointF and QPolygon classes. It includes examples of using QPoint objects and explains the significance of 'Manhattan length' in distance calculations on a grid. Deprecated functions like __mul__() with QMatrix4x4 and __imul__() with float factors are noted. Overall, the article serves as a guide to working with QPoint objects in Python.