Add open auto-hide dock on hover from drag and drop (#663)

doc/user-guide.md

@@ -49,6 +49,7 @@
   - [`AutoHideCloseButtonCollapsesDock`](#autohideclosebuttoncollapsesdock)
   - [`AutoHideHasCloseButton`](#autohidehasclosebutton)
   - [`AutoHideHasMinimizeButton`](#autohidehasminimizebutton)
+  - [`AutoHideOpenOnDragHover`](#autohideopenondraghover)
 - [DockWidget Feature Flags](#dockwidget-feature-flags)
   - [`DockWidgetClosable`](#dockwidgetclosable)
   - [`DockWidgetMovable`](#dockwidgetmovable)
@@ -150,7 +151,7 @@ This ie enabled by default to minimize the size of the saved data.
 
 ### `TabCloseButtonIsToolButton`
 
-If enabled the tab close buttons will be `QToolButtons` instead of `QPushButtons` - 
+If enabled the tab close buttons will be `QToolButtons` instead of `QPushButtons` -
 disabled by default. Normally the default configuration should be ok but if your
 application requires `QToolButtons` instead of `QPushButtons` for styling reasons
 or for any other reasons, then you can enable this flag.
@@ -181,7 +182,7 @@ constant, that means, if enabled, the tabs need more space.
 
 ### `DragPreviewIsDynamic`
 
-If non-opaque undocking is enabled, this flag defines the behavior of the drag 
+If non-opaque undocking is enabled, this flag defines the behavior of the drag
 preview window. If this flag is enabled, then it will give the user the
 impression, that the floating drag preview is dynamically adjusted to the drop
 area. In order to give the perfect impression, you should disable the flags
@@ -197,7 +198,7 @@ CDockManager::setConfigFlag(CDockManager::DragPreviewHasWindowFrame, false);
 
 ### `DragPreviewShowsContentPixmap`
 
-If non-opaque undocking is enabled, the created drag preview window shows a 
+If non-opaque undocking is enabled, the created drag preview window shows a
 copy of the content of the dock widget / dock are that is dragged, if this
 flag is enabled (default).
 
@@ -210,7 +211,7 @@ like window without any content.
 
 ### `DragPreviewHasWindowFrame`
 
-If non-opaque undocking is enabled, then this flag configures if the drag 
+If non-opaque undocking is enabled, then this flag configures if the drag
 preview is frameless (default) or looks like a real window. If it is enabled,
 then the drag preview is a transparent window with a system window frame.
 
@@ -378,7 +379,7 @@ ads--CDockAreaWidget[focused="true"] ads--CDockAreaTitleBar
 
 If you have a content widget that does not support focussing for some reason
 (like `QVTKOpenGLStereoWidget` from the [VTK library](https://github.com/Kitware/VTK)),
-then you can manually switch the focus by reacting on mouse events. The 
+then you can manually switch the focus by reacting on mouse events. The
 following code shows, how to install en event filter on the `QVTKOpenGLStereoWidget`
 to properly switch the focus on `QEvent::MouseButtonPress`:
 
@@ -422,7 +423,7 @@ bool CMainWindow::eventFilter(QObject *watched, QEvent *event)
 ### `EqualSplitOnInsertion`
 
 This flag configures how the space is distributed if a new dock widget is
-inserted into an existing dock area. The flag is disabled by default. If 3 
+inserted into an existing dock area. The flag is disabled by default. If 3
 dock widgets are inserted with the following code
 
 ```c++
@@ -433,7 +434,7 @@ then this is the result, if the flag is disabled:
 
 ![EqualSplitOnInsertion false](cfg_flag_EqualSplitOnInsertion_false.png)
 
-If the flag is enabled, then the space is equally distributed to all widgets 
+If the flag is enabled, then the space is equally distributed to all widgets
 in a  splitter:
 
 ![EqualSplitOnInsertion true](cfg_flag_EqualSplitOnInsertion_true.png)
@@ -501,7 +502,7 @@ for active tabs. Inactive tabs only show their icon:
 
 The Advanced Docking System supports "Auto-Hide" functionality for **all**
 dock containers. The "Auto Hide" feature allows to display more information
-using less screen space by hiding or showing windows pinned to one of the 
+using less screen space by hiding or showing windows pinned to one of the
 four dock container borders.
 
 Enabling this feature adds a button with a pin icon to each dock area.
@@ -563,7 +564,7 @@ That means, you can drag them to a different border or sidebar:
 
 ### Auto-Hide Tab Sorting
 
-You can drag Auto-Hide tabs to a new position in the current sidebar 
+You can drag Auto-Hide tabs to a new position in the current sidebar
 to sort them:
 
 ![Auo-Hide sort tabs](AutoHide_Sort_Tabs.gif)
@@ -632,7 +633,7 @@ the other Auto-Hide flags will be evaluated.
 
 ### `DockAreaHasAutoHideButton`
 
-If this flag is set (default), then each dock area has a pin button in the title 
+If this flag is set (default), then each dock area has a pin button in the title
 bar to toggle Auto-Hide state.
 
 ![DockAreaHasAutoHideButton true](cfg_flag_DockAreaHasAutoHideButton.png)
@@ -676,7 +677,7 @@ works if this feature is enabled.
 Some users don't understand the distinction between closing an auto hide dock and
 collapsing an auto hide dock. This may lead to situations where they press the
 close button (losing the side tab widget) instead of simply clicking outside
-the auto hide dock (collapsing the dock). 
+the auto hide dock (collapsing the dock).
 
 ![AutoHideCloseButtonCollapsesDock false](cfg_flag_AutoHideCloseButtonCollapsesDock_false.gif)
 
@@ -704,6 +705,15 @@ If this flag is set (disabled by default), then each auto hide widget has a mini
 
 ![AutoHideHasMinimizeButton](cfg_flag_AutoHideHasMinimizeButton.png)
 
+
+### `AutoHideOpenOnDragHover`
+
+If this flag is set (disabled by default), then holding a dragging cursor hover an auto-hide collapsed dock's tab will open said dock:
+
+![AutoHideOpenOnDragHover](cfg_flag_AutoHideOpenOnDragHover.gif)
+
+Said dock must be set to accept drops to hide when cursor leaves its scope.
+
 ## DockWidget Feature Flags
 
 ### `DockWidgetClosable`

src/AutoHideDockContainer.h

@@ -18,7 +18,6 @@
 ** License along with this library; If not, see <http://www.gnu.org/licenses/>.
 ******************************************************************************/
 
-
 //============================================================================
 /// \file   AutoHideDockContainer.h
 /// \author Syarif Fakhri
@@ -29,10 +28,10 @@
 //============================================================================
 //                                   INCLUDES
 //============================================================================
-#include "ads_globals.h"
-
 #include <QSplitter>
+
 #include "AutoHideTab.h"
+#include "ads_globals.h"
 
 QT_FORWARD_DECLARE_CLASS(QXmlStreamWriter)
 
@@ -52,151 +51,153 @@ struct SideTabBarPrivate;
  */
 class ADS_EXPORT CAutoHideDockContainer : public QFrame
 {
-	Q_OBJECT
+    Q_OBJECT
     Q_PROPERTY(int sideBarLocation READ sideBarLocation)
 private:
-	AutoHideDockContainerPrivate* d; ///< private data (pimpl)
+    AutoHideDockContainerPrivate* d;  ///< private data (pimpl)
-	friend struct AutoHideDockContainerPrivate;
+    friend struct AutoHideDockContainerPrivate;
-	friend CAutoHideSideBar;
+    friend CAutoHideSideBar;
-	friend SideTabBarPrivate;
+    friend SideTabBarPrivate;
 
 protected:
-	virtual bool eventFilter(QObject* watched, QEvent* event) override;
+    virtual bool eventFilter(QObject* watched, QEvent* event) override;
-	virtual void resizeEvent(QResizeEvent* event) override;
+    virtual void resizeEvent(QResizeEvent* event) override;
-	virtual void leaveEvent(QEvent *event) override;
+    virtual void leaveEvent(QEvent* event) override;
-	virtual bool event(QEvent* event) override;
+    virtual bool event(QEvent* event) override;
+    virtual void dragLeaveEvent(QDragLeaveEvent* ev) override;
 
-	/**
+    /**
-	 * Updates the size considering the size limits and the resize margins
+     * Updates the size considering the size limits and the resize margins
-	 */
+     */
-	void updateSize();
+    void updateSize();
 
-	/*
+    /*
-	 * Saves the state and size
+     * Saves the state and size
-	 */
+     */
-	void saveState(QXmlStreamWriter& Stream);
+    void saveState(QXmlStreamWriter& Stream);
 
 public:
-	using Super = QFrame;
+    using Super = QFrame;
 
     /**
-	 * Create Auto Hide widget with the given dock widget
+     * Create Auto Hide widget with the given dock widget
-	 */
+     */
-	CAutoHideDockContainer(CDockWidget* DockWidget, SideBarLocation area,
+    CAutoHideDockContainer(CDockWidget* DockWidget, SideBarLocation area,
-		CDockContainerWidget* parent);
+                           CDockContainerWidget* parent);
-
-	/**
-	 * Virtual Destructor
-	 */
-	virtual ~CAutoHideDockContainer();
-
-	/**
-	 * Gets the side tab bar
-	 */
-	CAutoHideSideBar* autoHideSideBar() const;
-
-	/**
-	 * Returns the side tab
-	 */
-	CAutoHideTab* autoHideTab() const;
-
-	/**
-	 * Gets the dock widget in this dock container
-	 */
-	CDockWidget* dockWidget() const;
-
-	/**
-	 * Returns the index of this container in the sidebar
-	 */
-	int tabIndex() const;
-
-	/**
-	 * Adds a dock widget and removes the previous dock widget
-	 */
-	void addDockWidget(CDockWidget* DockWidget);
 
     /**
-	 * Returns the side tab bar area of this Auto Hide dock container
+     * Virtual Destructor
-	 */
+     */
-	SideBarLocation sideBarLocation() const;
+    virtual ~CAutoHideDockContainer();
 
-	/**
+    /**
-	 * Sets a new SideBarLocation.
+     * Gets the side tab bar
-	 * If a new side bar location is set, the auto hide dock container needs
+     */
-	 * to update its resize handle position
+    CAutoHideSideBar* autoHideSideBar() const;
-	 */
-	void setSideBarLocation(SideBarLocation SideBarLocation);
 
-	/**
+    /**
-	 * Returns the dock area widget of this Auto Hide dock container
+     * Returns the side tab
-	 */
+     */
-	CDockAreaWidget* dockAreaWidget() const;
+    CAutoHideTab* autoHideTab() const;
 
-	/**
+    /**
-	 * Returns the parent container that hosts this auto hide container
+     * Gets the dock widget in this dock container
-	 */
+     */
-	CDockContainerWidget* dockContainer() const;
+    CDockWidget* dockWidget() const;
 
-	/**
+    /**
-	 * Moves the contents to the parent container widget
+     * Returns the index of this container in the sidebar
-	 * Used before removing this Auto Hide dock container 
+     */
-	 */
+    int tabIndex() const;
+
+    /**
+     * Adds a dock widget and removes the previous dock widget
+     */
+    void addDockWidget(CDockWidget* DockWidget);
+
+    /**
+     * Returns the side tab bar area of this Auto Hide dock container
+     */
+    SideBarLocation sideBarLocation() const;
+
+    /**
+     * Sets a new SideBarLocation.
+     * If a new side bar location is set, the auto hide dock container needs
+     * to update its resize handle position
+     */
+    void setSideBarLocation(SideBarLocation SideBarLocation);
+
+    /**
+     * Returns the dock area widget of this Auto Hide dock container
+     */
+    CDockAreaWidget* dockAreaWidget() const;
+
+    /**
+     * Returns the parent container that hosts this auto hide container
+     */
+    CDockContainerWidget* dockContainer() const;
+
+    /**
+     * Moves the contents to the parent container widget
+     * Used before removing this Auto Hide dock container
+     */
     void moveContentsToParent();
 
-	/**
+    /**
-	 * Cleanups up the side tab widget and then deletes itself
+     * Cleanups up the side tab widget and then deletes itself
-	 */
+     */
-	void cleanupAndDelete();
+    void cleanupAndDelete();
 
-	/*
+    /*
-	 * Toggles the auto Hide dock container widget
+     * Toggles the auto Hide dock container widget
-	 * This will also hide the side tab widget
+     * This will also hide the side tab widget
-	 */
+     */
-	void toggleView(bool Enable);
+    void toggleView(bool Enable);
 
-	/*
+    /*
-	 * Collapses the auto hide dock container widget
+     * Collapses the auto hide dock container widget
-	 * Does not hide the side tab widget
+     * Does not hide the side tab widget
-	 */
+     */
-	void collapseView(bool Enable);
+    void collapseView(bool Enable);
 
-	/**
+    /**
-	 * Toggles the current collapse state
+     * Toggles the current collapse state
-	 */
+     */
-	void toggleCollapseState();
+    void toggleCollapseState();
 
-	/**
+    /**
-	 * Use this instead of resize.
+     * Use this instead of resize.
-	 * Depending on the sidebar location this will set the width or height
+     * Depending on the sidebar location this will set the width or height
-	 * of this auto hide container.
+     * of this auto hide container.
-	 */
+     */
-	void setSize(int Size);
+    void setSize(int Size);
 
-	/**
+    /**
-	 * Resets the width or height to the initial dock widget size dependinng on
+     * Resets the width or height to the initial dock widget size dependinng on
-	 * the orientation.
+     * the orientation.
-	 * If the orientation is Qt::Horizontal, then the height is reset to
+     * If the orientation is Qt::Horizontal, then the height is reset to
-	 * the initial size and if orientation is Qt::Vertical, then the width is
+     * the initial size and if orientation is Qt::Vertical, then the width is
-	 * reset to the initial size
+     * reset to the initial size
-	 */
+     */
-	void resetToInitialDockWidgetSize();
+    void resetToInitialDockWidgetSize();
 
-	/**
+    /**
-	 * Returns orientation of this container.
+     * Returns orientation of this container.
-	 * Left and right containers have a Qt::Vertical orientation and top / bottom
+     * Left and right containers have a Qt::Vertical orientation and top / bottom
-	 * containers have a Qt::Horizontal orientation.
+     * containers have a Qt::Horizontal orientation.
-	 * The function returns the orientation of the corresponding auto hide
+     * The function returns the orientation of the corresponding auto hide
-	 * side bar.
+     * side bar.
-	 */
+     */
-	Qt::Orientation orientation() const;
+    Qt::Orientation orientation() const;
 
-	/**
+    /**
-	 * Removes the AutoHide container from the current side bar and adds
+     * Removes the AutoHide container from the current side bar and adds
-	 * it to the new side bar given in SideBarLocation
+     * it to the new side bar given in SideBarLocation
-	 */
+     */
-	void moveToNewSideBarLocation(SideBarLocation SideBarLocation, int TabIndex = -1);
+    void moveToNewSideBarLocation(SideBarLocation SideBarLocation,
+                                  int TabIndex = -1);
 };
-} // namespace ads
+}  // namespace ads
 
 //-----------------------------------------------------------------------------
 #endif

src/AutoHideTab.cpp

@@ -33,6 +33,8 @@
 #include <QApplication>
 #include <QElapsedTimer>
 #include <QMenu>
+#include <qevent.h>
+#include <qnamespace.h>
 
 #include "AutoHideDockContainer.h"
 #include "AutoHideSideBar.h"
@@ -41,6 +43,7 @@
 #include "DockWidget.h"
 #include "FloatingDragPreview.h"
 #include "DockOverlay.h"
+#include "ads_globals.h"
 
 namespace ads
 {
@@ -55,6 +58,7 @@ struct AutoHideTabPrivate
     CAutoHideSideBar* SideBar = nullptr;
 	Qt::Orientation Orientation{Qt::Vertical};
 	QElapsedTimer TimeSinceHoverMousePress;
+	QElapsedTimer TimeSinceDragOver;
 	bool MousePressed = false;
 	eDragState DragState = DraggingInactive;
 	QPoint GlobalDragStartMousePosition;
@@ -252,6 +256,9 @@ CAutoHideTab::CAutoHideTab(QWidget* parent) :
 {
 	setAttribute(Qt::WA_NoMousePropagation);
 	setFocusPolicy(Qt::NoFocus);
+    if (CDockManager::testAutoHideConfigFlag(CDockManager::AutoHideOpenOnDragHover)) {
+        setAcceptDrops(true);
+    }
 }
 
 
@@ -355,7 +362,6 @@ bool CAutoHideTab::event(QEvent* event)
 	case QEvent::Leave:
 		 d->forwardEventToDockContainer(event);
 		 break;
-
 	default:
 		break;
 	}
@@ -537,6 +543,37 @@ void CAutoHideTab::mouseMoveEvent(QMouseEvent* ev)
     Super::mouseMoveEvent(ev);
 }
 
+//============================================================================
+void CAutoHideTab::dragEnterEvent(QDragEnterEvent* ev) {
+    if (CDockManager::testAutoHideConfigFlag(CDockManager::AutoHideOpenOnDragHover)) {
+        if (!d->TimeSinceDragOver.isValid()) {
+            d->TimeSinceDragOver.restart();
+            ev->accept();
+        }
+        else if (d->TimeSinceDragOver.hasExpired(500)) {
+            ev->accept();
+        }
+    }
+}
+
+//============================================================================
+void CAutoHideTab::dragLeaveEvent(QDragLeaveEvent* ev) {
+    if (CDockManager::testAutoHideConfigFlag(CDockManager::AutoHideOpenOnDragHover)) {
+        d->TimeSinceDragOver.invalidate();
+        d->forwardEventToDockContainer(ev);
+    }
+}
+
+//============================================================================
+void CAutoHideTab::dragMoveEvent(QDragMoveEvent* ev) {
+    if (CDockManager::testAutoHideConfigFlag(CDockManager::AutoHideOpenOnDragHover)
+        && d->TimeSinceDragOver.isValid()
+        && d->TimeSinceDragOver.hasExpired(500)) {
+        d->TimeSinceDragOver.invalidate();
+        d->DockWidget->autoHideDockContainer()->collapseView(false);
+        ev->accept();
+    }
+}
 
 //============================================================================
 void CAutoHideTab::requestCloseDockWidget()

src/AutoHideTab.h

@@ -55,7 +55,7 @@ class ADS_EXPORT CAutoHideTab : public CPushButton
 	Q_PROPERTY(bool activeTab READ isActiveTab)
 	Q_PROPERTY(bool iconOnly READ iconOnly)
 
-private:    
+private:
 	AutoHideTabPrivate* d; ///< private data (pimpl)
     friend struct AutoHideTabPrivate;
 	friend class CDockWidget;
@@ -76,6 +76,9 @@ protected:
 	virtual void mousePressEvent(QMouseEvent* ev) override;
 	virtual void mouseReleaseEvent(QMouseEvent* ev) override;
 	virtual void mouseMoveEvent(QMouseEvent* ev) override;
+    virtual void dragEnterEvent(QDragEnterEvent* ev) override;
+    virtual void dragLeaveEvent(QDragLeaveEvent* ev) override;
+    virtual void dragMoveEvent(QDragMoveEvent* ev) override;
 
 public:
     using Super = CPushButton;

src/DockManager.h

@@ -254,6 +254,7 @@ public:
 		AutoHideCloseButtonCollapsesDock = 0x40, ///< Close button of an auto hide container collapses the dock instead of hiding it completely
 		AutoHideHasCloseButton = 0x80, //< If the flag is set an auto hide title bar has a close button
 		AutoHideHasMinimizeButton = 0x100, ///< if this flag is set, the auto hide title bar has a minimize button to collapse the dock widget
+        AutoHideOpenOnDragHover = 0x200,  ///< if this flag is set, dragging hover the tab bar will open the dock
 
 		DefaultAutoHideConfig = AutoHideFeatureEnabled
 			                  | DockAreaHasAutoHideButton