+
+ if (event->orientation() == Qt::Vertical) {
+ // Vertical scrolling is interpreted as zooming in/out
+ view_.zoom(event->delta() / 120, event->x());
+ } else if (event->orientation() == Qt::Horizontal) {
+ // Horizontal scrolling is interpreted as moving left/right
+ view_.set_scale_offset(view_.scale(),
+ event->delta() * view_.scale()
+ + view_.offset());
+ }
+}
+
+bool Viewport::touchEvent(QTouchEvent *event)
+{
+ QList<QTouchEvent::TouchPoint> touchPoints = event->touchPoints();
+
+ if (touchPoints.count() != 2) {
+ pinch_zoom_active_ = false;
+ return false;
+ }
+
+ const QTouchEvent::TouchPoint &touchPoint0 = touchPoints.first();
+ const QTouchEvent::TouchPoint &touchPoint1 = touchPoints.last();
+
+ if (!pinch_zoom_active_ ||
+ (event->touchPointStates() & Qt::TouchPointPressed)) {
+ pinch_offset0_ = view_.offset() + view_.scale() * touchPoint0.pos().x();
+ pinch_offset1_ = view_.offset() + view_.scale() * touchPoint1.pos().x();
+ pinch_zoom_active_ = true;
+ }
+
+ double w = touchPoint1.pos().x() - touchPoint0.pos().x();
+ if (abs(w) >= 1.0) {
+ double scale = (pinch_offset1_ - pinch_offset0_) / w;
+ if (scale < 0)
+ scale = -scale;
+ double offset = pinch_offset0_ - touchPoint0.pos().x() * scale;
+ if (scale > 0)
+ view_.set_scale_offset(scale, offset);
+ }
+
+ if (event->touchPointStates() & Qt::TouchPointReleased) {
+ pinch_zoom_active_ = false;
+
+ if (touchPoint0.state() & Qt::TouchPointReleased) {
+ // Primary touch released
+ mouse_down_valid_ = false;
+ } else {
+ // Update the mouse down fields so that continued
+ // dragging with the primary touch will work correctly
+ mouse_down_point_ = touchPoint0.pos().toPoint();
+ mouse_down_offset_ = view_.offset();
+ mouse_down_valid_ = true;
+ }
+ }
+
+ return true;