Qt 4.6: QPinchGesture Class Reference

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# QPinchGesture Class Reference
[QtGui module]

The QPinchGesture class represents a Pinch gesture, providing additional information related to zooming and/or rotation. More...

     #include <QPinchGesture>

Inherits QGesture.

This class was introduced in Qt 4.6.

- List of all members, including inherited members

## Public Types

enum | WhatChange { ScaleFactorChanged, RotationAngleChanged, CenterPointChanged }
flags | WhatChanged

## Properties

- centerPoint : const QPointF
- lastCenterPoint : const QPointF
- lastRotationAngle : const qreal
- lastScaleFactor : const qreal
- rotationAngle : const qreal

- scaleFactor : const qreal
- startCenterPoint : const QPointF
- totalRotationAngle : const qreal
- totalScaleFactor : const qreal
- whatChanged : const WhatChanged

- 2 properties inherited from QGesture
- 1 property inherited from QObject

## Public Functions

| QPinchGesture ( QWidget * gestureTarget, QObject * parent = 0 )
QPointF | centerPoint () const
QPointF | lastCenterPoint () const
qreal | lastRotationAngle () const
qreal | lastScaleFactor () const
qreal | rotationAngle () const
qreal | scaleFactor () const
QPointF | startCenterPoint () const
qreal | totalRotationAngle () const
qreal | totalScaleFactor () const
WhatChanged | whatChanged () const

- 6 public functions inherited from QGesture
- 29 public functions inherited from QObject

### Additional Inherited Members

- 1 public slot inherited from QObject
- 4 signals inherited from QGesture
- 1 signal inherited from QObject
- 5 static public members inherited from QObject
- 2 protected functions inherited from QGesture
- 7 protected functions inherited from QObject

## Detailed Description

The QPinchGesture class represents a Pinch gesture, providing additional information related to zooming and/or rotation.

## Member Type Documentation

### enum QPinchGesture::WhatChange
flags QPinchGesture::WhatChanged

The WhatChanged type is a typedef for QFlags<WhatChange>. It stores an OR combination of WhatChange values.

## Property Documentation

### centerPoint : const QPointF

Specifies a center point of the gesture. The point can be used as a center point that the object is rotated around.

Access functions:

QPointF | centerPoint () const

### lastCenterPoint : const QPointF

Specifies a previous center point of the gesture.

Access functions:

QPointF | lastCenterPoint () const

### lastRotationAngle : const qreal

Specifies a previous rotation angle of the gesture.

The angle is specified in degrees.

Access functions:

qreal | lastRotationAngle () const

### lastScaleFactor : const qreal

Specifies a previous scale factor of the pinch gesture.

Access functions:

qreal | lastScaleFactor () const

### rotationAngle : const qreal

Specifies a rotation angle of the gesture.

If the gesture consists of several pinch sequences (i.e. zoom and rotate sequences), then this property specifies the rotation angle in the current sequence. When pinching changes the scale factor only, the value of this property is 0.

The angle is specified in degrees.

Access functions:

qreal | rotationAngle () const

### scaleFactor : const qreal

Specifies a scale factor of the pinch gesture.

If the gesture consists of several pinch sequences (i.e. zoom and rotate sequences), then this property specifies the scale factor in the current sequence. When pinching changes the rotation angle only, the value of this property is 1.

Access functions:

qreal | scaleFactor () const

### startCenterPoint : const QPointF

Specifies an initial center point of the gesture. Difference between the startCenterPoint and the centerPoint is the distance at which pinching fingers has shifted.

Access functions:

QPointF | startCenterPoint () const

### totalRotationAngle : const qreal

Specifies a total rotation angle of the gesture since the gesture started.

The angle is specified in degrees.

Access functions:

qreal | totalRotationAngle () const

### totalScaleFactor : const qreal

Specifies a total scale factor of the pinch gesture since the gesture started.

Access functions:

qreal | totalScaleFactor () const

### whatChanged : const WhatChanged

Specifies which values were changed in the gesture.

Access functions:

WhatChanged | whatChanged () const

## Member Function Documentation

### QPinchGesture::QPinchGesture ( QWidget * gestureTarget, QObject * parent = 0 )

Creates a new Pinch gesture handler object and marks it as a child of parent. The pan gesture handler watches gestureTarget for its events.

On some platform like Windows it's necessary to provide a non-null widget as parent to get native gesture support.