Merge remote-tracking branch 'upstream/2.2' into 2.3

6 files changed, 63 insertions, 34 deletions

diff --git a/CHANGELOG.md b/CHANGELOG.md
index 946fd50af8..5be0032ffa 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -82,6 +82,7 @@
 * Use 6 instead of only 4 compatible musical keys (major/minor) [#3205](https://github.com/mixxxdj/mixxx/pull/3205)
 * Fix possible memory corruption using JACK on Linux [#3160](https://github.com/mixxxdj/mixxx/pull/3160)
 * Fix possible crash when trying to refocus the tracks table while another Mixxx window has focus [#3201](https://github.com/mixxxdj/mixxx/pull/3201)
+* Fix touch control [lp:1895431](https://bugs.launchpad.net/mixxx/+bug/1895431)
 
 ## [2.2.4](https://launchpad.net/mixxx/+milestone/2.2.4) (2020-06-27)
 
diff --git a/src/mixxx.cpp b/src/mixxx.cpp
index d81ba5edd3..be6c6dedb7 100644
--- a/src/mixxx.cpp
+++ b/src/mixxx.cpp
@@ -233,7 +233,6 @@ void MixxxMainWindow::initialize(QApplication* pApp, const CmdlineArgs& args) {
         pConfig->getValue(ConfigKey("[Controls]", "Tooltips"),
                 static_cast<int>(mixxx::TooltipsPreference::TOOLTIPS_ON)));
 
-    setAttribute(Qt::WA_AcceptTouchEvents);
     m_pTouchShift = new ControlPushButton(ConfigKey("[Controls]", "touch_shift"));
 
     m_pDbConnectionPool = MixxxDb(pConfig).connectionPool();
@@ -1536,26 +1535,6 @@ bool MixxxMainWindow::eventFilter(QObject* obj, QEvent* event) {
     return QObject::eventFilter(obj, event);
 }
 
-bool MixxxMainWindow::event(QEvent* e) {
-    switch(e->type()) {
-    case QEvent::TouchBegin:
-    case QEvent::TouchUpdate:
-    case QEvent::TouchEnd:
-    {
-        // If the touch event falls through to the main widget, no touch widget
-        // was touched, so we resend it as a mouse event.
-        // We have to accept it here, so QApplication will continue to deliver
-        // the following events of this touch point as well.
-        QTouchEvent* touchEvent = static_cast<QTouchEvent*>(e);
-        touchEvent->accept();
-        return true;
-    }
-    default:
-        break;
-    }
-    return QWidget::event(e);
-}
-
 void MixxxMainWindow::closeEvent(QCloseEvent *event) {
     // WARNING: We can receive a CloseEvent while only partially
     // initialized. This is because we call QApplication::processEvents to
diff --git a/src/mixxx.h b/src/mixxx.h
index dea2bc6bfa..ecfce6e135 100644
--- a/src/mixxx.h
+++ b/src/mixxx.h
@@ -99,7 +99,6 @@ class MixxxMainWindow : public QMainWindow {
     // Event filter to block certain events (eg. tooltips if tooltips are disabled)
     bool eventFilter(QObject *obj, QEvent *event) override;
     void closeEvent(QCloseEvent *event) override;
-    bool event(QEvent* e) override;
 
   private:
     void initialize(QApplication *app, const CmdlineArgs& args);
diff --git a/src/mixxxapplication.cpp b/src/mixxxapplication.cpp
index b75a1b0250..f7ab822f24 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();
 }
diff --git a/src/mixxxapplication.h b/src/mixxxapplication.h
index 1348de29e2..a9a5a67524 100644
--- a/src/mixxxapplication.h
+++ b/src/mixxxapplication.h
@@ -11,13 +11,13 @@ class MixxxApplication : public QApplication {
     MixxxApplication(int& argc, char** argv);
     ~MixxxApplication() override = default;
 
+    bool notify(QObject*, QEvent*) override;
+
   private:
     bool touchIsRightButton();
     void registerMetaTypes();
 
-    int m_fakeMouseSourcePointId;
-    QWidget* m_fakeMouseWidget;
-    enum Qt::MouseButton m_activeTouchButton;
+    int m_rightPressedButtons;
     ControlProxy* m_pTouchShift;
 
 };
diff --git a/src/widget/wwidget.cpp b/src/widget/wwidget.cpp
index 4f05531072..40b006e1ac 100644
--- a/src/widget/wwidget.cpp
+++ b/src/widget/wwidget.cpp
@@ -38,7 +38,7 @@ WWidget::~WWidget() {
 }
 
 bool WWidget::touchIsRightButton() {
-    return (m_pTouchShift->get() != 0.0);
+    return m_pTouchShift->toBool();
 }
 
 bool WWidget::event(QEvent* e) {
@@ -92,11 +92,13 @@ bool WWidget::event(QEvent* e) {
             const QTouchEvent::TouchPoint &touchPoint =
                     touchEvent->touchPoints().first();
             QMouseEvent mouseEvent(eventType,
-                    touchPoint.pos().toPoint(),
-                    touchPoint.screenPos().toPoint(),
+                    touchPoint.pos(),
+                    touchPoint.pos(),
+                    touchPoint.screenPos(),
                     m_activeTouchButton, // Button that causes the event
                     Qt::NoButton, // Not used, so no need to fake a proper value.
-                    touchEvent->modifiers());
+                    touchEvent->modifiers(), 
+                    Qt::MouseEventSynthesizedByApplication);
 
             return QWidget::event(&mouseEvent);
         }