QPinchGesture Class
The QPinchGesture class describes a pinch gesture made by the user. 更多...
| 头文件: | #include <QPinchGesture> |
| qmake: | QT += widgets |
| 开始支持版本: | Qt 4.6 |
| 基类: | QGesture |
公有类型
| enum | ChangeFlag { ScaleFactorChanged, RotationAngleChanged, CenterPointChanged } |
| flags | ChangeFlags |
属性
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公有函数
| ~QPinchGesture() | |
| QPointF | centerPoint() const |
| ChangeFlags | changeFlags() const |
| QPointF | lastCenterPoint() const |
| qreal | lastRotationAngle() const |
| qreal | lastScaleFactor() const |
| qreal | rotationAngle() const |
| qreal | scaleFactor() const |
| void | setCenterPoint(const QPointF &value) |
| void | setChangeFlags(ChangeFlags value) |
| void | setLastCenterPoint(const QPointF &value) |
| void | setLastRotationAngle(qreal value) |
| void | setLastScaleFactor(qreal value) |
| void | setRotationAngle(qreal value) |
| void | setScaleFactor(qreal value) |
| void | setStartCenterPoint(const QPointF &value) |
| void | setTotalChangeFlags(ChangeFlags value) |
| void | setTotalRotationAngle(qreal value) |
| void | setTotalScaleFactor(qreal value) |
| QPointF | startCenterPoint() const |
| ChangeFlags | totalChangeFlags() const |
| qreal | totalRotationAngle() const |
| qreal | totalScaleFactor() const |
其他继承的成员
- 1 个公有槽函数继承自 QObject
- 2 个信号继承自 QObject
- 1 个公有变量继承自 QObject
- 10 个静态公有成员继承自 QObject
- 9 个受保护的函数继承自 QObject
- 2 个受保护的变量继承自 QObject
详细描述
The QPinchGesture class describes a pinch gesture made by the user.
A pinch gesture is a form of touch user input in which the user typically touches two points on the input device with a thumb and finger, before moving them closer together or further apart to change the scale factor, zoom, or level of detail of the user interface.
For an overview of gesture handling in Qt and information on using gestures in your applications, see the Gestures in Widgets and Graphics View document.
Instead of repeatedly applying the same pinching gesture, the user may continue to touch the input device in one place, and apply a second touch to a new point, continuing the gesture. When this occurs, gesture events will continue to be delivered to the target object, containing an instance of QPinchGesture in the Qt::GestureUpdated state.
参见 QPanGesture and QSwipeGesture.
成员类型
enum QPinchGesture::ChangeFlag
flags QPinchGesture::ChangeFlags
This enum describes the changes that can occur to the properties of the gesture object.
| Constant | Value | Description |
|---|---|---|
QPinchGesture::ScaleFactorChanged | 0x1 | The scale factor held by scaleFactor changed. |
QPinchGesture::RotationAngleChanged | 0x2 | The rotation angle held by rotationAngle changed. |
QPinchGesture::CenterPointChanged | 0x4 | The center point held by centerPoint changed. |
The ChangeFlags type is a typedef for QFlags<ChangeFlag>. It stores an OR combination of ChangeFlag values.
参见 changeFlags and totalChangeFlags.
属性
centerPoint : QPointF
This property holds the current center point
The center point is the midpoint between the two input points in the gesture.
访问函数:
| QPointF | centerPoint() const |
| void | setCenterPoint(const QPointF &value) |
参见 startCenterPoint and lastCenterPoint.
changeFlags : ChangeFlags
This property holds the property of the gesture that has changed in the current step
This property indicates which of the other properties has changed since the previous gesture event included information about this gesture. You can use this information to determine which aspect of your user interface needs to be updated.
访问函数:
| ChangeFlags | changeFlags() const |
| void | setChangeFlags(ChangeFlags value) |
参见 totalChangeFlags, scaleFactor, rotationAngle, and centerPoint.
lastCenterPoint : QPointF
This property holds the last position of the center point recorded for this gesture
访问函数:
| QPointF | lastCenterPoint() const |
| void | setLastCenterPoint(const QPointF &value) |
参见 centerPoint and startCenterPoint.
lastRotationAngle : qreal
This property holds the last reported angle covered by the gesture motion
The last rotation angle is the angle as reported in the rotationAngle property when a previous gesture event was delivered for this gesture.
访问函数:
| qreal | lastRotationAngle() const |
| void | setLastRotationAngle(qreal value) |
参见 rotationAngle and totalRotationAngle.
lastScaleFactor : qreal
This property holds the last scale factor recorded for this gesture
The last scale factor contains the scale factor reported in the scaleFactor property when a previous gesture event included information about this gesture.
If no previous event was delivered with information about this gesture (i.e., this gesture object contains information about the first movement in the gesture) then this property contains zero.
访问函数:
| qreal | lastScaleFactor() const |
| void | setLastScaleFactor(qreal value) |
参见 scaleFactor and totalScaleFactor.
rotationAngle : qreal
This property holds the angle covered by the gesture motion
访问函数:
| qreal | rotationAngle() const |
| void | setRotationAngle(qreal value) |
参见 totalRotationAngle and lastRotationAngle.
scaleFactor : qreal
This property holds the current scale factor
The scale factor measures the scale factor associated with the distance between two of the user's inputs on a touch device.
访问函数:
| qreal | scaleFactor() const |
| void | setScaleFactor(qreal value) |
参见 totalScaleFactor and lastScaleFactor.
startCenterPoint : QPointF
This property holds the starting position of the center point
访问函数:
| QPointF | startCenterPoint() const |
| void | setStartCenterPoint(const QPointF &value) |
参见 centerPoint and lastCenterPoint.
totalChangeFlags : ChangeFlags
This property holds the property of the gesture that has change
This property indicates which of the other properties has changed since the gesture has started. You can use this information to determine which aspect of your user interface needs to be updated.
访问函数:
| ChangeFlags | totalChangeFlags() const |
| void | setTotalChangeFlags(ChangeFlags value) |
参见 changeFlags, scaleFactor, rotationAngle, and centerPoint.
totalRotationAngle : qreal
This property holds the total angle covered by the gesture
This total angle measures the complete angle covered by the gesture. Usually, this is equal to the value held by the rotationAngle property, except in the case where the user performs multiple rotations by removing and repositioning one of the touch points, as described above. In this case, the total angle will be the sum of the rotation angles for the multiple stages of the gesture.
访问函数:
| qreal | totalRotationAngle() const |
| void | setTotalRotationAngle(qreal value) |
参见 rotationAngle and lastRotationAngle.
totalScaleFactor : qreal
This property holds the total scale factor
The total scale factor measures the total change in scale factor from the original value to the current scale factor.
访问函数:
| qreal | totalScaleFactor() const |
| void | setTotalScaleFactor(qreal value) |
参见 scaleFactor and lastScaleFactor.