Merge 9bb04d7154 into 69951fe248

Handle middle mouse button in `mouseMoveEvent()` (new) and `mousePressEvent()` methods.

(Removed preprocessor conditions; deprecated QMouseEvent::pos() / QMouseEvent::x() were chosen.)

src/GUI/graphview.cpp

@@ -342,10 +342,24 @@ void GraphView::resizeEvent(QResizeEvent *e)
 	QGraphicsView::resizeEvent(e);
 }
 
+void GraphView::mouseMoveEvent(QMouseEvent *e)
+{
+	if (e->buttons() & Qt::MiddleButton) {
+		QScrollBar *sb = horizontalScrollBar();
+		int x = e->x();
+		sb->setSliderPosition(sb->sliderPosition() - (x - _xStartDrag));
+		_xStartDrag = x;
+	}
+
+	QGraphicsView::mouseMoveEvent(e);
+}
+
 void GraphView::mousePressEvent(QMouseEvent *e)
 {
 	if (e->button() == Qt::LeftButton)
 		newSliderPosition(mapToScene(e->pos()));
+	else if (e->button() == Qt::MiddleButton)
+		_xStartDrag = e->x();
 
 	QGraphicsView::mousePressEvent(e);
 }

src/GUI/graphview.h

@@ -57,6 +57,7 @@ protected:
 	void setUnits(Units units);
 
 	void resizeEvent(QResizeEvent *e);
+	void mouseMoveEvent(QMouseEvent *e);
 	void mousePressEvent(QMouseEvent *e);
 	void wheelEvent(QWheelEvent *e);
 	void changeEvent(QEvent *e);
@@ -122,6 +123,7 @@ private:
 	qreal _minYRange;
 
 	qreal _zoom;
+	int _xStartDrag;
 };
 
 #endif // GRAPHVIEW_H