PinchArea: handle smart zoom gesture

This is the double-finger double-tap trackpad gesture on OS X.

Change-Id: Ie79dc533adf382170867318bc9b61b367f819e9b
Reviewed-by: Morten Johan Sørvig <morten.sorvig@theqtcompany.com>

4 files changed, 60 insertions, 1 deletions

diff --git a/examples/quick/demos/photosurface/photosurface.qml b/examples/quick/demos/photosurface/photosurface.qml
index c7d59ffa9b..fc3b505bcf 100644
--- a/examples/quick/demos/photosurface/photosurface.qml
+++ b/examples/quick/demos/photosurface/photosurface.qml
@@ -37,7 +37,7 @@
 ** $QT_END_LICENSE$
 **
 ****************************************************************************/
-import QtQuick 2.4
+import QtQuick 2.5
 import QtQuick.Dialogs 1.0
 import QtQuick.Window 2.1
 import Qt.labs.folderlistmodel 1.0
@@ -104,6 +104,25 @@ Window {
                     pinch.maximumScale: 10
                     pinch.dragAxis: Pinch.XAndYAxis
                     onPinchStarted: setFrameColor();
+                    property real zRestore: 0
+                    onSmartZoom: {
+                        if (pinch.scale > 0) {
+                            photoFrame.rotation = 0;
+                            photoFrame.scale = Math.min(root.width, root.height) / Math.max(image.sourceSize.width, image.sourceSize.height) * 0.85
+                            photoFrame.x = flick.contentX + (flick.width - photoFrame.width) / 2
+                            photoFrame.y = flick.contentY + (flick.height - photoFrame.height) / 2
+                            zRestore = photoFrame.z
+                            photoFrame.z = ++root.highestZ;
+                        } else {
+                            photoFrame.rotation = pinch.previousAngle
+                            photoFrame.scale = pinch.previousScale
+                            photoFrame.x = pinch.previousCenter.x - photoFrame.width / 2
+                            photoFrame.y = pinch.previousCenter.y - photoFrame.height / 2
+                            photoFrame.z = zRestore
+                            --root.highestZ
+                        }
+                    }
+
                     MouseArea {
                         id: dragArea
                         hoverEnabled: true
diff --git a/src/quick/items/qquickitemsmodule.cpp b/src/quick/items/qquickitemsmodule.cpp
index 48e9290cbe..b1116bdb64 100644
--- a/src/quick/items/qquickitemsmodule.cpp
+++ b/src/quick/items/qquickitemsmodule.cpp
@@ -265,6 +265,8 @@ static void qt_quickitems_defineModule(const char *uri, int major, int minor)
     qmlRegisterType<QQuickMouseArea, 1>(uri, 2, 4, "MouseArea");
     qmlRegisterType<QQuickShaderEffect, 1>(uri, 2, 4, "ShaderEffect");
     qmlRegisterUncreatableType<QQuickOpenGLInfo>(uri, 2, 4,"OpenGLInfo", QQuickOpenGLInfo::tr("OpenGLInfo is only available via attached properties"));
+
+    qmlRegisterType<QQuickPinchArea, 1>(uri, 2, 5,"PinchArea");
 }
 
 static void initResources()
diff --git a/src/quick/items/qquickpincharea.cpp b/src/quick/items/qquickpincharea.cpp
index 667a988cba..5c3916cfc4 100644
--- a/src/quick/items/qquickpincharea.cpp
+++ b/src/quick/items/qquickpincharea.cpp
@@ -234,6 +234,22 @@ QQuickPinchAreaPrivate::~QQuickPinchAreaPrivate()
     The corresponding handler is \c onPinchFinished.
 */
 
+/*!
+    \qmlsignal QtQuick::PinchArea::smartZoom()
+    \since 5.5
+
+    This signal is emitted when the pinch area detects the smart zoom gesture.
+    This gesture occurs only on certain operating systems such as OS X.
+
+    The \l {PinchEvent}{pinch} parameter provides information about the pinch
+    gesture, including the location where the gesture occurred.  \c pinch.scale
+    will be greater than zero when the gesture indicates that the user wishes to
+    enter smart zoom, and zero when exiting (even though typically the same gesture
+    is used to toggle between the two states).
+
+    The corresponding handler is \c onSmartZoom.
+*/
+
 
 /*!
     \qmlpropertygroup QtQuick::PinchArea::pinch
@@ -663,6 +679,27 @@ bool QQuickPinchArea::event(QEvent *event)
             d->inPinch = true;
             updatePinchTarget();
         } break;
+        case Qt::SmartZoomNativeGesture: {
+            if (gesture->value() > 0.0 && d->pinch && d->pinch->target()) {
+                d->pinchStartPos = pinch()->target()->position();
+                d->pinchStartCenter = mapToItem(pinch()->target()->parentItem(), pinch()->target()->boundingRect().center());
+                d->pinchStartScale = d->pinch->target()->scale();
+                d->pinchStartRotation = d->pinch->target()->rotation();
+                d->pinchLastScale = d->pinchStartScale = d->pinch->target()->scale();
+                d->pinchLastAngle = d->pinchStartRotation = d->pinch->target()->rotation();
+            }
+            QQuickPinchEvent pe(gesture->localPos(), gesture->value(), d->pinchLastAngle, 0.0);
+            pe.setStartCenter(gesture->localPos());
+            pe.setPreviousCenter(d->pinchStartCenter);
+            pe.setPreviousAngle(d->pinchLastAngle);
+            pe.setPreviousScale(d->pinchLastScale);
+            pe.setStartPoint1(gesture->localPos());
+            pe.setStartPoint2(gesture->localPos());
+            pe.setPoint1(mapFromScene(gesture->windowPos()));
+            pe.setPoint2(mapFromScene(gesture->windowPos()));
+            pe.setPointCount(2);
+            emit smartZoom(&pe);
+        } break;
         case Qt::RotateNativeGesture: {
             qreal angle = d->pinchLastAngle + gesture->value();
             QQuickPinchEvent pe(d->pinchStartCenter, d->pinchLastScale, angle, 0.0);
diff --git a/src/quick/items/qquickpincharea_p.h b/src/quick/items/qquickpincharea_p.h
index ebb5f44379..57f9a87e07 100644
--- a/src/quick/items/qquickpincharea_p.h
+++ b/src/quick/items/qquickpincharea_p.h
@@ -266,6 +266,7 @@ Q_SIGNALS:
     void pinchStarted(QQuickPinchEvent *pinch);
     void pinchUpdated(QQuickPinchEvent *pinch);
     void pinchFinished(QQuickPinchEvent *pinch);
+    Q_REVISION(1) void smartZoom(QQuickPinchEvent *pinch);
 
 protected:
     bool childMouseEventFilter(QQuickItem *i, QEvent *e) Q_DECL_OVERRIDE;