implement panning using touch events

since we don't get mouse events to send to QGraphicsView's
ScrollHandDrag handlers, we need to do it ourselves

2 files changed, 8 insertions, 6 deletions

diff --git a/examples/multitouch/pinchzoom/graphicsview.cpp b/examples/multitouch/pinchzoom/graphicsview.cpp
index b77c926..f763e6f 100644
--- a/examples/multitouch/pinchzoom/graphicsview.cpp
+++ b/examples/multitouch/pinchzoom/graphicsview.cpp
@@ -41,9 +41,9 @@
 
 #include "graphicsview.h"
 
+#include <QScrollBar>
 #include <QTouchEvent>
 
-
 GraphicsView::GraphicsView(QGraphicsScene *scene, QWidget *parent)
     : QGraphicsView(scene, parent)
 {
@@ -57,10 +57,13 @@ bool GraphicsView::event(QEvent *event)
     case QEvent::TouchUpdate:
     case QEvent::TouchEnd:
     {
-        qDebug("touch events");
-
-            QList<QTouchEvent::TouchPoint *> touchPoints = static_cast<QTouchEvent *>(event)->touchPoints();
-        if (touchPoints.count() == 2) {
+        QList<QTouchEvent::TouchPoint *> touchPoints = static_cast<QTouchEvent *>(event)->touchPoints();
+        if (touchPoints.count() == 1) {
+            const QTouchEvent::TouchPoint *touchPoint = touchPoints.first();
+            QPointF delta = touchPoint->pos() - touchPoint->lastPos();
+            horizontalScrollBar()->setValue(horizontalScrollBar()->value() - delta.x());
+            verticalScrollBar()->setValue(verticalScrollBar()->value() - delta.y());
+        } else if (touchPoints.count() == 2) {
             // determine scale factor
             const QTouchEvent::TouchPoint *touchPoint0 = touchPoints.first();
             const QTouchEvent::TouchPoint *touchPoint1 = touchPoints.last();
diff --git a/examples/multitouch/pinchzoom/main.cpp b/examples/multitouch/pinchzoom/main.cpp
index 6b25060..bb86870 100644
--- a/examples/multitouch/pinchzoom/main.cpp
+++ b/examples/multitouch/pinchzoom/main.cpp
@@ -78,7 +78,6 @@ int main(int argc, char **argv)
 //! [4] //! [5]
     view.setCacheMode(QGraphicsView::CacheBackground);
     view.setViewportUpdateMode(QGraphicsView::BoundingRectViewportUpdate);
-    view.setDragMode(QGraphicsView::ScrollHandDrag);
 //! [5] //! [6]
     view.setWindowTitle(QT_TRANSLATE_NOOP(QGraphicsView, "Colliding Mice"));
     view.showMaximized();