Trackpad gesture support for graph views (#2453)

Zooming using pinch gesture.

src/widgets/CutterGraphView.cpp

@@ -80,6 +80,8 @@ CutterGraphView::CutterGraphView(QWidget *parent)
 
     }
     layoutMenu->addActions(layoutGroup->actions());
+
+    grabGesture(Qt::PinchGesture);
 }
 
 QPoint CutterGraphView::getTextOffset(int line) const
@@ -236,6 +238,30 @@ void CutterGraphView::refreshView()
     setLayoutConfig(getLayoutConfig());
 }
 
+bool CutterGraphView::gestureEvent(QGestureEvent *event)
+{
+    if (!event) {
+        return false;
+    }
+
+    if (auto gesture =
+                static_cast<QPinchGesture *>(event->gesture(Qt::PinchGesture))) {
+        auto changeFlags = gesture->changeFlags();
+
+        if (changeFlags & QPinchGesture::ScaleFactorChanged) {
+            auto cursorPos = gesture->centerPoint();
+            cursorPos.rx() /= size().width();
+            cursorPos.ry() /= size().height();
+
+            setZoom(cursorPos, getViewScale() * gesture->scaleFactor());
+        }
+
+        event->accept(gesture);
+        return true;
+    }
+
+    return false;
+}
 
 void CutterGraphView::wheelEvent(QWheelEvent *event)
 {

src/widgets/CutterGraphView.h

@@ -7,6 +7,8 @@
 #include <QShortcut>
 #include <QLabel>
 
+#include <QGestureEvent>
+
 #include "widgets/GraphView.h"
 #include "common/CachedFontMetrics.h"
 
@@ -32,7 +34,8 @@ public:
      * @param graphCommand r2 graph printing command without type, not required for direct image export
      * @param address object address for commands like agf
      */
-    void exportGraph(QString filePath, GraphExportType type, QString graphCommand = "", RVA address = RVA_INVALID);
+    void exportGraph(QString filePath, GraphExportType type, QString graphCommand = "",
+                     RVA address = RVA_INVALID);
     /**
      * @brief Export image using r2 ag*w command and graphviz.
      * Requires graphviz dot executable in the path.
@@ -86,6 +89,7 @@ protected:
     void mouseMoveEvent(QMouseEvent *event) override;
     void wheelEvent(QWheelEvent *event) override;
     void resizeEvent(QResizeEvent *event) override;
+    bool gestureEvent(QGestureEvent *event) override;
 
     /**
      * @brief Save the the currently viewed or displayed block.

src/widgets/GraphView.cpp

@@ -104,11 +104,21 @@ bool GraphView::event(QEvent *event)
         if (helpEvent(static_cast<QHelpEvent *>(event))) {
             return true;
         }
+    } else if (event->type() == QEvent::Gesture) {
+        if (gestureEvent(static_cast<QGestureEvent *>(event))) {
+            return true;
+        }
     }
 
     return QAbstractScrollArea::event(event);
 }
 
+bool GraphView::gestureEvent(QGestureEvent *event)
+{
+    Q_UNUSED(event)
+    return false;
+}
+
 void GraphView::contextMenuEvent(QContextMenuEvent *event)
 {
     event->ignore();

src/widgets/GraphView.h

@@ -8,6 +8,7 @@
 #include <QScrollBar>
 #include <QElapsedTimer>
 #include <QHelpEvent>
+#include <QGestureEvent>
 
 #include <unordered_map>
 #include <unordered_set>
@@ -134,6 +135,7 @@ protected:
     virtual void wheelEvent(QWheelEvent *event) override;
     virtual EdgeConfiguration edgeConfiguration(GraphView::GraphBlock &from, GraphView::GraphBlock *to,
                                                 bool interactive = true);
+    virtual bool gestureEvent(QGestureEvent *event);
     /**
      * @brief Called when user requested context menu for a block. Should open a block specific contextmenu.
      * Typically triggered by right click.