-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;
-}
-
-} // namespace view