Refactored gesture api

Rewritten the api almost from scratch, making it simplier and more
flexible at the same time.

The current implementation will not have complex gseturemanager class
inside Qt, but the QGesture base class, which represents both a
gesture recognizer and a gesture itself with a set of properties. A
set of common gestures that can use used in third-party applications
(and in Qt itself internally) is supposed to be found in
qstandardgestures.h, and a base class for user-defined gestures is in
qgesture.h

Gesture implementation for Pan on Windows7 has also been added as a
reference implementation for platform gestures.

2 files changed, 58 insertions, 35 deletions

diff --git a/examples/gestures/imageviewer/imagewidget.cpp b/examples/gestures/imageviewer/imagewidget.cpp
index a4f3c9a..717bb09 100644
--- a/examples/gestures/imageviewer/imagewidget.cpp
+++ b/examples/gestures/imageviewer/imagewidget.cpp
@@ -46,6 +46,7 @@
 ImageWidget::ImageWidget(QWidget *parent)
     : QWidget(parent)
 {
+    setAttribute(Qt::WA_AcceptTouchEvents);
     setAttribute(Qt::WA_PaintOnScreen);
     setAttribute(Qt::WA_OpaquePaintEvent);
     setAttribute(Qt::WA_NoSystemBackground);
@@ -61,9 +62,11 @@ ImageWidget::ImageWidget(QWidget *parent)
     horizontalOffset = 0;
     verticalOffset = 0;
 
-    grabGesture(Qt::DoubleTapGesture);
-    grabGesture(Qt::PanGesture);
-    grabGesture(Qt::TapAndHoldGesture);
+    panGesture = new QPanGesture(this);
+    connect(panGesture, SIGNAL(triggered()), this, SLOT(gestureTriggered()));
+
+    tapAndHoldGesture = new QTapAndHoldGesture(this);
+    connect(tapAndHoldGesture, SIGNAL(triggered()), this, SLOT(gestureTriggered()));
 }
 
 void ImageWidget::paintEvent(QPaintEvent*)
@@ -131,30 +134,33 @@ void ImageWidget::paintEvent(QPaintEvent*)
     p.restore();
 }
 
-bool ImageWidget::event(QEvent *event)
+void ImageWidget::mousePressEvent(QMouseEvent *event)
 {
-    if (event->type() == QEvent::Gesture) {
-        gestureEvent(static_cast<QGestureEvent*>(event));
-        return true;
-    }
-    return QWidget::event(event);
+    touchFeedback.tapped = true;
+    touchFeedback.position = event->pos();
+}
+
+void ImageWidget::mouseDoubleClickEvent(QMouseEvent *event)
+{
+    touchFeedback.doubleTapped = true;
+    const QPoint p = event->pos();
+    touchFeedback.position = p;
+    horizontalOffset = p.x() - currentImage.width()*1.0*p.x()/width();
+    verticalOffset = p.y() - currentImage.height()*1.0*p.y()/height();
+    setZoomedIn(!zoomedIn);
+    zoomed = rotated = false;
+    updateImage();
+
+    feedbackFadeOutTimer.start(500, this);
 }
 
-void ImageWidget::gestureEvent(QGestureEvent *event)
+void ImageWidget::gestureTriggered()
 {
+    touchFeedback.tapped = false;
     touchFeedback.doubleTapped = false;
 
-    Q_ASSERT(event);
-    if (event->contains(Qt::TapGesture)) {
-        //
-    } else if (const QGesture *g = event->gesture(Qt::DoubleTapGesture)) {
-        touchFeedback.doubleTapped = true;
-        horizontalOffset = g->hotSpot().x() - currentImage.width()*1.0*g->hotSpot().x()/width();
-        verticalOffset = g->hotSpot().y() - currentImage.height()*1.0*g->hotSpot().y()/height();
-        setZoomedIn(!zoomedIn);
-        zoomed = rotated = false;
-        updateImage();
-    } else if (const QGesture *g = event->gesture(Qt::PanGesture)) {
+    QGesture *g = qobject_cast<QGesture*>(sender());
+    if (sender() == panGesture) {
         if (zoomedIn) {
             // usual panning
 #ifndef QT_NO_CURSOR
@@ -170,24 +176,22 @@ void ImageWidget::gestureEvent(QGestureEvent *event)
             update();
         } else {
             // only slide gesture should be accepted
-            const QPanningGesture *pg = static_cast<const QPanningGesture*>(g);
-            if (pg->direction() != pg->lastDirection()) {
-                // ###: event->cancel();
-            }
+            const QPanGesture *pg = static_cast<const QPanGesture*>(g);
             if (g->state() == Qt::GestureFinished) {
                 touchFeedback.sliding = false;
                 zoomed = rotated = false;
-                if (pg->direction() == Qt::RightDirection) {
+                if (pg->totalOffset().width() > 0) {
                     qDebug() << "slide right";
                     goNextImage();
-                } else if (pg->direction() == Qt::LeftDirection) {
+                } else {
                     qDebug() << "slide left";
                     goPrevImage();
                 }
                 updateImage();
             }
         }
-    } else if (const QGesture *g = event->gesture(Qt::TapAndHoldGesture)) {
+        feedbackFadeOutTimer.start(500, this);
+    } else if (sender() == tapAndHoldGesture) {
         if (g->state() == Qt::GestureFinished) {
             qDebug() << "tap and hold detected";
             touchFeedback.reset();
@@ -197,13 +201,20 @@ void ImageWidget::gestureEvent(QGestureEvent *event)
             menu.addAction("Action 1");
             menu.addAction("Action 2");
             menu.addAction("Action 3");
-            menu.exec(mapToGlobal(g->hotSpot()));
+            menu.exec(mapToGlobal(g->pos()));
         }
-    } else {
-        qDebug() << "unknown gesture";
+        feedbackFadeOutTimer.start(500, this);
     }
-    feedbackFadeOutTimer.start(500, this);
-    event->accept();
+}
+
+void ImageWidget::gestureFinished()
+{
+    qDebug() << "gesture finished" << sender();
+}
+
+void ImageWidget::gestureCancelled()
+{
+    qDebug() << "gesture cancelled" << sender();
 }
 
 void ImageWidget::resizeEvent(QResizeEvent*)
@@ -345,3 +356,5 @@ void ImageWidget::timerEvent(QTimerEvent *event)
     }
     update();
 }
+
+#include "moc_imagewidget.cpp"
diff --git a/examples/gestures/imageviewer/imagewidget.h b/examples/gestures/imageviewer/imagewidget.h
index 7ec73a7..e12634d 100644
--- a/examples/gestures/imageviewer/imagewidget.h
+++ b/examples/gestures/imageviewer/imagewidget.h
@@ -50,17 +50,24 @@
 
 class ImageWidget : public QWidget
 {
+    Q_OBJECT
+
 public:
     ImageWidget(QWidget *parent = 0);
 
     void openDirectory(const QString &path);
 
 protected:
-    bool event(QEvent *event);
     void paintEvent(QPaintEvent*);
-    void gestureEvent(QGestureEvent *event);
     void resizeEvent(QResizeEvent*);
     void timerEvent(QTimerEvent*);
+    void mousePressEvent(QMouseEvent*);
+    void mouseDoubleClickEvent(QMouseEvent*);
+
+private slots:
+    void gestureTriggered();
+    void gestureFinished();
+    void gestureCancelled();
 
 private:
     void updateImage();
@@ -71,6 +78,9 @@ private:
     void goPrevImage();
     void goToImage(int index);
 
+    QPanGesture *panGesture;
+    QTapAndHoldGesture *tapAndHoldGesture;
+
     QString path;
     QStringList files;
     int position;