Qt: Force redraw the display when restoring after minimized

src/duckstation-qt/mainwindow.cpp

@@ -14,6 +14,7 @@
 #include <QtCore/QFileInfo>
 #include <QtCore/QUrl>
 #include <QtGui/QDesktopServices>
+#include <QtGui/QWindowStateChangeEvent>
 #include <QtWidgets/QFileDialog>
 #include <QtWidgets/QMessageBox>
 #include <cmath>
@@ -568,3 +569,15 @@ void MainWindow::closeEvent(QCloseEvent* event)
   m_host_interface->synchronousPowerOffSystem();
   QMainWindow::closeEvent(event);
 }
+
+void MainWindow::changeEvent(QEvent* event)
+{
+  if (static_cast<QWindowStateChangeEvent*>(event)->oldState()& Qt::WindowMinimized)
+  {
+    // TODO: This should check the render-to-main option.
+    if (m_display_widget)
+      m_host_interface->redrawDisplayWindow();
+  }
+
+  QMainWindow::changeEvent(event);
+}

src/duckstation-qt/mainwindow.h

@@ -55,6 +55,7 @@ private Q_SLOTS:
 
 protected:
   void closeEvent(QCloseEvent* event) override;
+  void changeEvent(QEvent* event) override;
 
 private:
   void setupAdditionalUi();

src/duckstation-qt/qtdisplaywidget.cpp

@@ -7,6 +7,7 @@
 #include <QtGui/QKeyEvent>
 #include <QtGui/QScreen>
 #include <QtGui/QWindow>
+#include <QtGui/QWindowStateChangeEvent>
 #include <cmath>
 
 QtDisplayWidget::QtDisplayWidget(QtHostInterface* host_interface, QWidget* parent)
@@ -144,6 +145,16 @@ bool QtDisplayWidget::event(QEvent* event)
       return true;
     }
 
+    case QEvent::WindowStateChange:
+    {
+      QWidget::event(event);
+
+      if (static_cast<QWindowStateChangeEvent*>(event)->oldState() & Qt::WindowMinimized)
+        emit windowRestoredEvent();
+
+      return true;
+    }
+
     default:
       return QWidget::event(event);
   }

src/duckstation-qt/qtdisplaywidget.h

@@ -31,6 +31,7 @@ public:
 
 Q_SIGNALS:
   void windowResizedEvent(int width, int height);
+  void windowRestoredEvent();
 
 protected:
   qreal getDevicePixelRatioFromScreen() const;

src/duckstation-qt/qthostinterface.cpp

@@ -189,6 +189,7 @@ QtDisplayWidget* QtHostInterface::createDisplayWidget()
   m_display_widget = new OpenGLDisplayWidget(this, nullptr);
 #endif
   connect(m_display_widget, &QtDisplayWidget::windowResizedEvent, this, &QtHostInterface::onDisplayWidgetResized);
+  connect(m_display_widget, &QtDisplayWidget::windowRestoredEvent, this, &QtHostInterface::redrawDisplayWindow);
   return m_display_widget;
 }
 
@@ -242,6 +243,20 @@ void QtHostInterface::onDisplayWidgetResized(int width, int height)
     renderDisplay();
 }
 
+void QtHostInterface::redrawDisplayWindow()
+{
+  if (!isOnWorkerThread())
+  {
+    QMetaObject::invokeMethod(this, "redrawDisplayWindow", Qt::QueuedConnection);
+    return;
+  }
+
+  if (!m_display_widget || !m_system)
+    return;
+
+  renderDisplay();
+}
+
 bool QtHostInterface::AcquireHostDisplay()
 {
   DebugAssert(!m_display_widget);

src/duckstation-qt/qthostinterface.h

@@ -102,6 +102,7 @@ public Q_SLOTS:
   void startDumpingAudio();
   void stopDumpingAudio();
   void saveScreenshot();
+  void redrawDisplayWindow();
 
   /// Enables controller polling even without a system active. Must be matched by a call to
   /// disableBackgroundControllerPolling.