QVector2D Class

成员函数

QVector2D::QVector2D()

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

QVector2D::QVector2D(float xpos, float ypos)

Constructs a vector with coordinates (xpos, ypos).

QVector2D::QVector2D(const QPoint &point)

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

QVector2D::QVector2D(const QPointF &point)

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

QVector2D::QVector2D(const QVector3D &vector)

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

参见 toVector3D().

QVector2D::QVector2D(const QVector4D &vector)

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

参见 toVector4D().

float QVector2D::distanceToLine(const QVector2D &point, const QVector2D &direction) const

Returns the distance that this vertex is from a line defined by point and the unit vector direction.

If direction is a null vector, then it does not define a line. In that case, the distance from point to this vertex is returned.

This function was introduced in Qt 5.1.

参见 distanceToPoint().

float QVector2D::distanceToPoint(const QVector2D &point) const

Returns the distance from this vertex to a point defined by the vertex point.

This function was introduced in Qt 5.1.

参见 distanceToLine().

[static] float QVector2D::dotProduct(const QVector2D &v1, const QVector2D &v2)

Returns the dot product of v1 and v2.

bool QVector2D::isNull() const

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

float QVector2D::length() const

Returns the length of the vector from the origin.

参见 lengthSquared() and normalized().

float QVector2D::lengthSquared() const

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

参见 length() and dotProduct().

void QVector2D::normalize()

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.

参见 length() and normalized().

QVector2D QVector2D::normalized() const

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.

参见 length() and normalize().

void QVector2D::setX(float x)

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

参见 x() and setY().

void QVector2D::setY(float y)

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

参见 y() and setX().

QPoint QVector2D::toPoint() const

Returns the QPoint form of this 2D vector.

参见 toPointF() and toVector3D().

QPointF QVector2D::toPointF() const

Returns the QPointF form of this 2D vector.

参见 toPoint() and toVector3D().

QVector3D QVector2D::toVector3D() const

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

参见 toVector4D() and toPoint().

QVector4D QVector2D::toVector4D() const

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

参见 toVector3D() and toPoint().

float QVector2D::x() const

Returns the x coordinate of this point.

参见 setX() and y().

float QVector2D::y() const

Returns the y coordinate of this point.

参见 setY() and x().

QVector2D::operator QVariant() const

Returns the 2D vector as a QVariant.

QVector2D &QVector2D::operator*=(float factor)

Multiplies this vector's coordinates by the given factor, and returns a reference to this vector.

参见 operator/=().

QVector2D &QVector2D::operator*=(const QVector2D &vector)

Multiplies the components of this vector by the corresponding components in vector.

QVector2D &QVector2D::operator+=(const QVector2D &vector)

Adds the given vector to this vector and returns a reference to this vector.

参见 operator-=().

QVector2D &QVector2D::operator-=(const QVector2D &vector)

Subtracts the given vector from this vector and returns a reference to this vector.

参见 operator+=().

QVector2D &QVector2D::operator/=(float divisor)

Divides this vector's coordinates by the given divisor, and returns a reference to this vector.

参见 operator*=().

QVector2D &QVector2D::operator/=(const QVector2D &vector)

Divides the components of this vector by the corresponding components in vector.

This function was introduced in Qt 5.5.

参见 operator*=().

float &QVector2D::operator[](int i)

Returns the component of the vector at index position i as a modifiable reference.

i must be a valid index position in the vector (i.e., 0 <= i < 2).

This function was introduced in Qt 5.2.

float QVector2D::operator[](int i) const

Returns the component of the vector at index position i.

i must be a valid index position in the vector (i.e., 0 <= i < 2).

This function was introduced in Qt 5.2.