内容

• 特性
• 公共函数
• 重实现公共函数
• 信号
• 详细描述

QGraphicsRotation 类

QGraphicsRotation class provides a rotation transformation around a given axis. 更多...

头：	#include <QGraphicsRotation>
qmake:	QT += widgets
Since:	Qt 4.6
继承：	QGraphicsTransform

• 所有成员列表，包括继承成员

特性

• angle : qreal
• axis : QVector3D
• origin : QVector3D

• 1 特性继承自 QObject

公共函数

	QGraphicsRotation (QObject * parent = Q_NULLPTR)
	~QGraphicsRotation ()
qreal	angle () const
QVector3D	axis () const
QVector3D	origin () const
void	setAngle ( qreal )
void	setAxis (const QVector3D & axis )
void	setAxis (Qt::Axis axis )
void	setOrigin (const QVector3D & point )

重实现公共函数

virtual void

applyTo (QMatrix4x4 * matrix ) const

• 1 公共函数继承自 QGraphicsTransform
• 32 公共函数继承自 QObject

信号

void	angleChanged ()
void	axisChanged ()
void	originChanged ()

• 2 信号继承自 QObject

额外继承成员

• 1 公共槽继承自 QObject
• 11 静态公共成员继承自 QObject
• 9 保护函数继承自 QObject
• 1 保护槽继承自 QGraphicsTransform

详细描述

QGraphicsRotation class provides a rotation transformation around a given axis.

You can provide the desired axis by assigning a QVector3D to the axis property or by passing a member if Qt::Axis 到 setAxis convenience function. By default the axis is (0, 0, 1) i.e., rotation around the Z axis.

The angle property, which is provided by QGraphicsRotation , now describes the number of degrees to rotate around this axis.

QGraphicsRotation provides certain parameters to help control how the rotation should be applied.

The origin is the point that the item is rotated around (i.e., it stays fixed relative to the parent as the rest of the item is rotated). By default the origin is QPointF (0, 0).

The angle property provides the number of degrees to rotate the item clockwise around the origin. This value also be negative, indicating a counter-clockwise rotation. For animation purposes it may also be useful to provide rotation angles exceeding (-360, 360) degrees, for instance to animate how an item rotates several times.

Note: the final rotation is the combined effect of a rotation in 3D space followed by a projection back to 2D. If several rotations are performed in succession, they will not behave as expected unless they were all around the Z axis.

另请参阅 QGraphicsTransform , QGraphicsItem::setRotation ()，和 QTransform::rotate ().

特性文档编制

angle : qreal

This property holds the angle for clockwise rotation, in degrees.

The angle can be any real number; the default value is 0.0. A value of 180 will rotate 180 degrees, clockwise. If you provide a negative number, the item will be rotated counter-clockwise. Normally the rotation angle will be in the range (-360, 360), but you can also provide numbers outside of this range (e.g., a angle of 370 degrees gives the same result as 10 degrees). Setting the angle to NaN results in no rotation.

访问函数：

qreal	angle () const
void	setAngle ( qreal )

通知程序信号：

void	angleChanged ()

另请参阅 origin .

axis : QVector3D

This property holds a rotation axis, specified by a vector in 3D space.

This can be any axis in 3D space. By default the axis is (0, 0, 1), which is aligned with the Z axis. If you provide another axis, QGraphicsRotation will provide a transformation that rotates around this axis. For example, if you would like to rotate an item around its X axis, you could pass (1, 0, 0) as the axis.

访问函数：

QVector3D	axis () const
void	setAxis (const QVector3D & axis )
void	setAxis (Qt::Axis axis )

通知程序信号：

void	axisChanged ()

另请参阅 QTransform and QGraphicsRotation::angle .

origin : QVector3D

This property holds the origin of the rotation in 3D space.

All rotations will be done relative to this point (i.e., this point will stay fixed, relative to the parent, when the item is rotated).

访问函数：

QVector3D	origin () const
void	setOrigin (const QVector3D & point )

通知程序信号：

void	originChanged ()

另请参阅 angle .

成员函数文档编制

QGraphicsRotation:: QGraphicsRotation ( QObject * parent = Q_NULLPTR)

构造新的 QGraphicsRotation 采用给定 parent .

QGraphicsRotation:: ~QGraphicsRotation ()

Destroys the graphics rotation.

[signal] void QGraphicsRotation:: angleChanged ()

This signal is emitted whenever the angle has changed.

注意： 通知程序信号对于特性 angle .

另请参阅 QGraphicsRotation::angle .

[virtual] void QGraphicsRotation:: applyTo ( QMatrix4x4 * matrix ) const

重实现自 QGraphicsTransform::applyTo ().

[signal] void QGraphicsRotation:: axisChanged ()

This signal is emitted whenever the axis of the object changes.

注意： 通知程序信号对于特性 axis .

另请参阅 QGraphicsRotation::axis .

[signal] void QGraphicsRotation:: originChanged ()

This signal is emitted whenever the origin has changed.

注意： 通知程序信号对于特性 origin .

另请参阅 QGraphicsRotation::origin .

void QGraphicsRotation:: setAxis ( Qt::Axis axis )

Convenience function to set the axis to axis .

Note: the Qt::YAxis rotation for QTransform is inverted from the correct mathematical rotation in 3D space. The QGraphicsRotation class implements a correct mathematical rotation. The following two sequences of code will perform the same transformation:

QTransform t;
t.rotate(45, Qt::YAxis);
QGraphicsRotation r;
r.setAxis(Qt::YAxis);
r.setAngle(-45);
					

注意： Setter 函数对于特性 axis .