QML手势相关的实验模块：Qt.labs.gestures模块介绍

1、QtQuick 1 vs QtQuick2

二者还是有很大区别的，无论从模块重组还是从底层实现，均需注意。下面是两个官方文档给出的差别说明及列表：

1. 差别说明
2. 差别列表

2、Qt.labs.gestures

• 虽然没有正式的Release模块(Types in the Qt.labs module are not guaranteed to remain compatible in future versions.)，但在qt4.8中，提供了一个gesture特性的试验模块。

• 此外，还有一个开发者写的非官方文档可供了解gesture模块开发的背景及主要接口、属性及函数:Getting in touch with Qt Quick: Gestures and QML。

• 但，我们依然要注意，在qt文档中给出如下说明：
  Warning: GestureArea is an experimental element whose development has been discontinued. PinchArea is available in QtQuick 1.1 and handles two finger gesture input.
Note: This element is only functional on devices with touch input.

• 此外，附上一个git网址，里面全是Qt libs特性的实验项目，你可以找到自己需要的模块。不过有一些项目已经很久没有更新了。例如这里讨论的gestures。
  所以，在实际项目中，需要权衡一下，或者找到替代方案！！！

• 实验特性实现文件在qt5当中的路径为：xxx/qt5.3.1/qtbase/qml/Qt/labs。
  目前只有2个内置特性模块：settings和folderlistmodel。

• 另外：Qt Sensor Gestures也有与手势相关的传感器的内容。

• 在qt5.3中的开发文档中，亦有相关的demo，路径为：xxx/qt5.3.1/qtquick1/examples/declarative/touchinteraction。
  目录下面有3个例子：一个是关于gesture的，一个是鼠标域(MouseArea)的，一个是弹碰域(PinchArea)的。

3、官方demo

<!-- lang: js -->
import QtQuick 1.0
import Qt.labs.gestures 1.0

// Only works on platforms with Touch support.

Rectangle {
id: rect
width: 320
height: 180

Text {
    anchors.centerIn: parent
    text: "Tap / TapAndHold / Pan / Pinch / Swipe\nOnly works on platforms with Touch support."
    horizontalAlignment: Text.Center
}

GestureArea {
    anchors.fill: parent
    focus: true

    // Only some of the many gesture properties are shown. See Gesture documentation.

    onTap:
        console.log("tap pos = (",gesture.position.x,",",gesture.position.y,")")
    onTapAndHold:
        console.log("tap and hold pos = (",gesture.position.x,",",gesture.position.y,")")
    onPan:
        console.log("pan delta = (",gesture.delta.x,",",gesture.delta.y,") acceleration = ",gesture.acceleration)
    onPinch:
        console.log("pinch center = (",gesture.centerPoint.x,",",gesture.centerPoint.y,") rotation =",gesture.rotationAngle," scale =",gesture.scaleFactor)
    onSwipe:
        console.log("swipe angle=",gesture.swipeAngle)
    onGesture:
        console.log("gesture hot spot = (",gesture.hotSpot.x,",",gesture.hotSpot.y,")")
}
}