1 files changed, 53 insertions, 5 deletions

diff --git a/src/mixxxapplication.cpp b/src/mixxxapplication.cpp
index f2b5e965ee..7bed455878 100644
--- a/src/mixxxapplication.cpp
+++ b/src/mixxxapplication.cpp
@@ -36,13 +36,24 @@ Q_IMPORT_PLUGIN(QGifPlugin)
 //Q_IMPORT_PLUGIN(AccessibleFactory)
 #endif
 
+namespace {
+
+/// This class allows to change the button of a mouse event on the fly. 
+/// This is required because we want to change the behaviour of Qts mouse
+/// buttony synthesizer without duplicate all the code. 
+class QMouseEventEditable : public QMouseEvent {
+  public:
+    void setButton(Qt::MouseButton button) {
+        b = button;
+    }
+};
+
+} // anonymous namespace
 
 MixxxApplication::MixxxApplication(int& argc, char** argv)
         : QApplication(argc, argv),
-          m_fakeMouseSourcePointId(0),
-          m_fakeMouseWidget(NULL),
-          m_activeTouchButton(Qt::NoButton),
-          m_pTouchShift(NULL) {
+          m_rightPressedButtons(0),
+          m_pTouchShift(nullptr) {
     registerMetaTypes();
 
     // Increase the size of the global thread pool to at least
@@ -86,10 +97,47 @@ void MixxxApplication::registerMetaTypes() {
     qRegisterMetaType<std::optional<mixxx::RgbColor>>("std::optional<mixxx::RgbColor>");
 }
 
+bool MixxxApplication::notify(QObject* target, QEvent* event) {
+    // All touch events are translated into two simultaneous events: one for
+    // the target QWidgetWindow and one for the target QWidget.
+    // A second touch becomes a mouse move without additional press and release
+    // events.
+    switch (event->type()) {
+    case QEvent::MouseButtonPress: {
+        QMouseEventEditable* mouseEvent = static_cast<QMouseEventEditable*>(event);
+        if (mouseEvent->source() == Qt::MouseEventSynthesizedByQt &&
+                mouseEvent->button() == Qt::LeftButton &&
+                touchIsRightButton()) {
+            // Assert the assumption that QT synthesizes only one click at a time
+            // = two events (see above)
+            VERIFY_OR_DEBUG_ASSERT(m_rightPressedButtons < 2) {
+                break;
+            }
+            mouseEvent->setButton(Qt::RightButton);
+            m_rightPressedButtons++;
+        }
+        break;
+    }
+    case QEvent::MouseButtonRelease: {
+        QMouseEventEditable* mouseEvent = static_cast<QMouseEventEditable*>(event);
+        if (mouseEvent->source() == Qt::MouseEventSynthesizedByQt &&
+                mouseEvent->button() == Qt::LeftButton &&
+                m_rightPressedButtons > 0) {
+            mouseEvent->setButton(Qt::RightButton);
+            m_rightPressedButtons--;
+        }
+        break;
+    }
+    default:
+        break;
+    }
+    return QApplication::notify(target, event);
+}
+
 bool MixxxApplication::touchIsRightButton() {
     if (!m_pTouchShift) {
         m_pTouchShift = new ControlProxy(
                 "[Controls]", "touch_shift", this);
     }
-    return (m_pTouchShift->get() != 0.0);
+    return m_pTouchShift->toBool();
 }