Properly implemented handling of DockWidget flag DockWidgetIsMovable for NonOpaque undocking - creating the drag preview is allowed even if the DockWidget is not floatable

Author: githubuser0xFFFF

demo/MainWindow.cpp

@@ -331,6 +331,8 @@ void MainWindowPrivate::createContent()
 	auto ToolBar = FileSystemWidget->createDefaultToolBar();
 	ToolBar->addAction(ui.actionSaveState);
 	ToolBar->addAction(ui.actionRestoreState);
+	FileSystemWidget->setFeature(ads::CDockWidget::DockWidgetFloatable, false);
+	appendFeaturStringToWindowTitle(FileSystemWidget);
 	DockManager->addDockWidget(ads::BottomDockWidgetArea, FileSystemWidget);
 
 	FileSystemWidget = createFileSystemTreeDockWidget(ViewMenu);
@@ -484,9 +486,9 @@ CMainWindow::CMainWindow(QWidget *parent) :
 	// a QToolButton instead of a QPushButton
 	// CDockManager::setConfigFlags(CDockManager::configFlags() | CDockManager::TabCloseButtonIsToolButton);
 
-    // comment the following line if you want to use opaque undocking and
+    // uncomment the following line if you want to use opaque undocking and
 	// opaque splitter resizing
-    CDockManager::setConfigFlags(CDockManager::DefaultNonOpaqueConfig);
+    // CDockManager::setConfigFlags(CDockManager::DefaultOpaqueConfig);
 
     // uncomment the following line if you want a fixed tab width that does
 	// not change if the visibility of the close button changes

src/DockAreaTitleBar.cpp

@@ -600,7 +600,11 @@ void CDockAreaTitleBar::mouseMoveEvent(QMouseEvent* ev)
 
 	// If one single dock widget in this area is not floatable then the whole
 	// area is not floatable
-	if (!d->DockArea->features().testFlag(CDockWidget::DockWidgetFloatable))
+	// If we do non opaque undocking, then we can create the floating drag
+	// preview if the dock widget is movable
+	auto Features = d->DockArea->features();
+    if (!Features.testFlag(CDockWidget::DockWidgetFloatable)
+    && !(Features.testFlag(CDockWidget::DockWidgetMovable) && !CDockManager::testConfigFlag(CDockManager::OpaqueUndocking)))
 	{
 		return;
 	}

src/DockManager.cpp

@@ -58,7 +58,7 @@
 
 namespace ads
 {
-static CDockManager::ConfigFlags StaticConfigFlags = CDockManager::DefaultOpaqueConfig;
+static CDockManager::ConfigFlags StaticConfigFlags = CDockManager::DefaultNonOpaqueConfig;
 
 /**
  * Private data class of CDockManager class (pimpl)

src/DockWidgetTab.cpp

@@ -368,8 +368,13 @@ void CDockWidgetTab::mouseMoveEvent(QMouseEvent* ev)
 			return;
 		}
 
-    	// Floating is only allowed for widgets that are movable
-        if (d->DockWidget->features().testFlag(CDockWidget::DockWidgetFloatable))
+
+    	// Floating is only allowed for widgets that are floatable
+		// If we do non opaque undocking, then can create the drag preview
+		// if the widget is movable.
+		auto Features = d->DockWidget->features();
+        if (Features.testFlag(CDockWidget::DockWidgetFloatable)
+        || (Features.testFlag(CDockWidget::DockWidgetMovable) && !CDockManager::testConfigFlag(CDockManager::OpaqueUndocking)))
         {
         	// If we undock, we need to restore the initial position of this
         	// tab because it looks strange if it remains on its dragged position

src/FloatingDragPreview.cpp

@@ -291,25 +291,33 @@ void CFloatingDragPreview::finishDragging()
 	else
 	{
 		CDockWidget* DockWidget = qobject_cast<CDockWidget*>(d->Content);
-		CFloatingDockContainer* FloatingWidget;
-		if (DockWidget)
+		CFloatingDockContainer* FloatingWidget = nullptr;
+
+		if (DockWidget && DockWidget->features().testFlag(CDockWidget::DockWidgetFloatable))
 		{
 			FloatingWidget = new CFloatingDockContainer(DockWidget);
 		}
 		else
 		{
 			CDockAreaWidget* DockArea = qobject_cast<CDockAreaWidget*>(d->Content);
-			FloatingWidget = new CFloatingDockContainer(DockArea);
+			if (DockArea->features().testFlag(CDockWidget::DockWidgetFloatable))
+			{
+				FloatingWidget = new CFloatingDockContainer(DockArea);
+			}
 		}
-		FloatingWidget->setGeometry(this->geometry());
-		FloatingWidget->show();
-		if (!CDockManager::configFlags().testFlag(CDockManager::DragPreviewHasWindowFrame))
+
+		if (FloatingWidget)
 		{
-			QApplication::processEvents();
-			int FrameHeight = FloatingWidget->frameGeometry().height() - FloatingWidget->geometry().height();
-			QRect FixedGeometry = this->geometry();
-			FixedGeometry.adjust(0, FrameHeight, 0, 0);
-			FloatingWidget->setGeometry(FixedGeometry);
+			FloatingWidget->setGeometry(this->geometry());
+			FloatingWidget->show();
+			if (!CDockManager::configFlags().testFlag(CDockManager::DragPreviewHasWindowFrame))
+			{
+				QApplication::processEvents();
+				int FrameHeight = FloatingWidget->frameGeometry().height() - FloatingWidget->geometry().height();
+				QRect FixedGeometry = this->geometry();
+				FixedGeometry.adjust(0, FrameHeight, 0, 0);
+				FloatingWidget->setGeometry(FixedGeometry);
+			}
 		}
 	}