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# QVector2D Class Reference
[QtGui module]

The QVector2D class represents a vector or vertex in 2D space. More...

### Methods

- __init__ (self)
- __init__ (self, float xpos, float ypos)
- __init__ (self, QPoint point)
- __init__ (self, QPointF point)
- __init__ (self, QVector3D vector)
- __init__ (self, QVector4D vector)
- __init__ (self, QVector2D)
- bool isNull (self)
- float length (self)
- float lengthSquared (self)
- normalize (self)
- QVector2D normalized (self)
- setX (self, float aX)
- setY (self, float aY)
- QPoint toPoint (self)
- QPointF toPointF (self)
- QVector3D toVector3D (self)
- QVector4D toVector4D (self)
- float x (self)
- float y (self)

### Static Methods

- float dotProduct (QVector2D v1, QVector2D v2)

### Special Methods

- QVector2D __add__ (self, QVector2D v2)
- QVector2D __div__ (self, float divisor)
- bool __eq__ (self, QVector2D v2)
- QVector2D __iadd__ (self, QVector2D vector)
- QVector2D __idiv__ (self, float divisor)
- QVector2D __imul__ (self, float factor)
- QVector2D __imul__ (self, QVector2D vector)
- QVector2D __isub__ (self, QVector2D vector)
- QVector2D __mul__ (self, QVector2D vector)
- QVector2D __mul__ (self, float factor)
- QVector2D __mul__ (self, QVector2D v2)
- bool __ne__ (self, QVector2D v2)
- QVector2D __neg__ (self)
- str __repr__ (self)
- QVector2D __sub__ (self, QVector2D v2)

## Detailed Description

This class can be pickled.

The QVector2D class represents a vector or vertex in 2D space.

The QVector2D class can also be used to represent vertices in 2D space. We therefore do not need to provide a separate vertex class.

Note: By design values in the QVector2D instance are stored as `float`. This means that on platforms where the `qreal` arguments to QVector2D functions are represented by `double` values, it is possible to lose precision.

## Method Documentation

### QVector2D.__init__ (self)

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

### QVector2D.__init__ (self, float xpos, float ypos)

Constructs a vector with coordinates (xpos, ypos).

### QVector2D.__init__ (self, QPoint point)

Constructs a vector with x and y coordinates from a 2D point.

### QVector2D.__init__ (self, QPointF point)

Constructs a vector with x and y coordinates from a 2D point.

### QVector2D.__init__ (self, QVector3D vector)

Constructs a vector with x and y coordinates from a 3D vector. The z coordinate of vector is dropped.

See also toVector3D().

### QVector2D.__init__ (self, QVector4D vector)

Constructs a vector with x and y coordinates from a 3D vector. The z and w coordinates of vector are dropped.

See also toVector4D().

### QVector2D.__init__ (self, QVector2D)

### float QVector2D.dotProduct (QVector2D v1, QVector2D v2)

Returns the dot product of v1 and v2.

### bool QVector2D.isNull (self)

Returns true if the x and y coordinates are set to 0.0, otherwise returns false.

### float QVector2D.length (self)

Returns the length of the vector from the origin.

See also lengthSquared() and normalized().

### float QVector2D.lengthSquared (self)

Returns the squared length of the vector from the origin. This is equivalent to the dot product of the vector with itself.

See also length() and dotProduct().

### QVector2D.normalize (self)

Normalizes the currect vector in place. Nothing happens if this vector is a null vector or the length of the vector is very close to 1.

See also length() and normalized().

### QVector2D QVector2D.normalized (self)

Returns the normalized unit vector form of this vector.

If this vector is null, then a null vector is returned. If the length of the vector is very close to 1, then the vector will be returned as-is. Otherwise the normalized form of the vector of length 1 will be returned.

See also length() and normalize().

### QVector2D.setX (self, float aX)

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

See also x() and setY().

### QVector2D.setY (self, float aY)

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

See also y() and setX().

### QPoint QVector2D.toPoint (self)

Returns the QPoint form of this 2D vector.

See also toPointF() and toVector3D().

### QPointF QVector2D.toPointF (self)

Returns the QPointF form of this 2D vector.

See also toPoint() and toVector3D().

### QVector3D QVector2D.toVector3D (self)

Returns the 3D form of this 2D vector, with the z coordinate set to zero.

See also toVector4D() and toPoint().

### QVector4D QVector2D.toVector4D (self)

Returns the 4D form of this 2D vector, with the z and w coordinates set to zero.

See also toVector3D() and toPoint().

### float QVector2D.x (self)

Returns the x coordinate of this point.

See also setX() and y().

### float QVector2D.y (self)

Returns the y coordinate of this point.

See also setY() and x().

### QVector2D QVector2D.__add__ (self, QVector2D v2)

### QVector2D QVector2D.__div__ (self, float divisor)

### bool QVector2D.__eq__ (self, QVector2D v2)

### QVector2D QVector2D.__iadd__ (self, QVector2D vector)

### QVector2D QVector2D.__idiv__ (self, float divisor)

### QVector2D QVector2D.__imul__ (self, float factor)

### QVector2D QVector2D.__imul__ (self, QVector2D vector)

### QVector2D QVector2D.__isub__ (self, QVector2D vector)

### QVector2D QVector2D.__mul__ (self, QVector2D vector)

### QVector2D QVector2D.__mul__ (self, float factor)

### QVector2D QVector2D.__mul__ (self, QVector2D v2)

### bool QVector2D.__ne__ (self, QVector2D v2)

### QVector2D QVector2D.__neg__ (self)

### str QVector2D.__repr__ (self)

### QVector2D QVector2D.__sub__ (self, QVector2D v2)