Handle panning touch gestures (#5524)

src/widgets/helper/ChannelView.hpp

@@ -10,6 +10,7 @@
 #include "widgets/TooltipWidget.hpp"
 
 #include <pajlada/signals/signal.hpp>
+#include <QGestureEvent>
 #include <QMenu>
 #include <QPaintEvent>
 #include <QPointer>
@@ -216,6 +217,9 @@ protected:
 #endif
     void leaveEvent(QEvent * /*event*/) override;
 
+    bool event(QEvent *event) override;
+    bool gestureEvent(const QGestureEvent *event);
+
     void mouseMoveEvent(QMouseEvent *event) override;
     void mousePressEvent(QMouseEvent *event) override;
     void mouseReleaseEvent(QMouseEvent *event) override;
@@ -374,6 +378,7 @@ private:
     QTimer clickTimer_;
 
     bool isScrolling_ = false;
+    bool isPanning_ = false;
     QPointF lastMiddlePressPosition_;
     QPointF currentMousePosition_;
     QTimer scrollTimer_;