add pinchDragFlingMPTA example

This is a prototype of what 3-finger pinch is intended for:
manipulating a container exclusively with a 3-finger gesture while
not interfering at all with other gestures that occur inside the
container.  And it's normal that existing Items (like MPTA) do
implicit grabs of touchpoints just by accepting, so this is also
a test of cooperation between PointerHandlers and legacy Areas.
It also adds the ability to drag the MPTA only while the Meta
key is held down.  And there is momentum on release whether you
are doing a 3-finger pinch or via the DragHandler.

Change-Id: Icd0e84809ec32dc8f347dd9c8f875d10f52eba19
Reviewed-by: Jan Arve Sæther <jan-arve.saether@qt.io>

1 files changed, 97 insertions, 0 deletions

diff --git a/tests/manual/pointer/pinchDragFlingMPTA.qml b/tests/manual/pointer/pinchDragFlingMPTA.qml
new file mode 100644
index 0000000000..25be48bb42
--- /dev/null
+++ b/tests/manual/pointer/pinchDragFlingMPTA.qml
@@ -0,0 +1,97 @@
+/****************************************************************************
+**
+** Copyright (C) 2017 The Qt Company Ltd.
+** Contact: https://www.qt.io/licensing/
+**
+** This file is part of the manual tests of the Qt Toolkit.
+**
+** $QT_BEGIN_LICENSE:BSD$
+** You may use this file under the terms of the BSD license as follows:
+**
+** "Redistribution and use in source and binary forms, with or without
+** modification, are permitted provided that the following conditions are
+** met:
+**   * Redistributions of source code must retain the above copyright
+**     notice, this list of conditions and the following disclaimer.
+**   * Redistributions in binary form must reproduce the above copyright
+**     notice, this list of conditions and the following disclaimer in
+**     the documentation and/or other materials provided with the
+**     distribution.
+**   * Neither the name of The Qt Company Ltd nor the names of its
+**     contributors may be used to endorse or promote products derived
+**     from this software without specific prior written permission.
+**
+**
+** THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+** "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+** LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+** A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+** OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+** SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+** LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+** DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+** THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+** (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+** OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE."
+**
+** $QT_END_LICENSE$
+**
+****************************************************************************/
+
+import QtQuick 2.8
+import Qt.labs.handlers 1.0
+import "content"
+
+Rectangle {
+    width: 1024; height: 600
+    color: "beige"
+    objectName: "beige root"
+
+    function getTransformationDetails(item, pinchhandler) {
+        return "scale:" + pinchhandler.scale.toFixed(2)
+                + " rotation:" + pinchhandler.rotation.toFixed(2)
+                + " translation:" + "(" + pinchhandler.translation.x.toFixed(2) + "," + pinchhandler.translation.y.toFixed(2) + ")"
+    }
+
+    Rectangle {
+        id: container
+        objectName: "container rect"
+        width: 600
+        height: 500
+        color: pinch3.active ? "red" : "black"
+        antialiasing: true
+        Loader {
+            source: "../touch/mpta-crosshairs.qml"
+            anchors.fill: parent
+            anchors.margins: 2
+        }
+        Item {
+            anchors.fill: parent
+            // In order for PinchHandler to get a chance to take a passive grab, it has to get the touchpoints first.
+            // In order to get the touchpoints first, it has to be on top of the Z order: i.e. come last in paintOrderChildItems().
+            // This is the opposite situation as with filtersChildMouseEvents: e.g. PinchArea would have wanted to be the parent,
+            // if it even knew that trick (which it doesn't).
+            PinchHandler {
+                id: pinch3
+                objectName: "3-finger pinch"
+                target: container
+                requiredPointCount: 3
+                minimumScale: 0.1
+                maximumScale: 10
+                onActiveChanged: if (!active) fling.restart(centroidVelocity)
+            }
+            DragHandler {
+                id: dragHandler
+                objectName: "DragHandler"
+                target: container
+                acceptedModifiers: Qt.MetaModifier
+                onActiveChanged: if (!active) fling.restart(velocity)
+            }
+        }
+        MomentumAnimation { id: fling; target: container }
+    }
+    Text {
+        anchors.bottom: parent.bottom
+        text: pinch3.active ? getTransformationDetails(container, pinch3) : "Pinch with 3 fingers to scale, rotate and translate"
+    }
+}