Qt: make ground for proper main interface size management

- Simplify switching between widgets in central stack: showTab() allows
switching only between two states - video state and playlist state - and
does everything needed according to circumstances

- Do not setMinimumWidth/Height/Size() on main interface, because it
inhibits children sizeHint() evaluation, thus preventing interface
self-adjustment when controls are added/removed or shown/hidden.

- Subclass QStackedWidget so it's minimumSizeHint() matches exactly
the one of the currentWidget(), and not the sum of all children.

- Suggest compact mode implementation (commented out for now):
setSizeConstraint( QLayout::SetFixedSize ) on main interface layout.
This automatically keeps and adjusts fixed size in respect to
sizeHint() of children.

modules/gui/qt4/main_interface.cpp

@@ -75,6 +75,7 @@ MainInterface::MainInterface( intf_thread_t *_p_intf ) : QVLCMW( _p_intf )
     bgWidget             = NULL;
     videoWidget          = NULL;
     playlistWidget       = NULL;
+    videoRoleWidget      = NULL;
 #ifndef HAVE_MAEMO
     sysTray              = NULL;
 #endif
@@ -150,6 +151,11 @@ MainInterface::MainInterface( intf_thread_t *_p_intf ) : QVLCMW( _p_intf )
     CONNECT( THEMIM->getIM(), voutListChanged( vout_thread_t **, int ),
              this, destroyPopupMenu() );
 
+    minWidthHolder = new QWidget;
+    minWidthHolder->setMinimumWidth(
+        __MAX( menuBar()->sizeHint().width() + 30, 400 ) );
+    mainLayout->addWidget( minWidthHolder );
+
     /*********************************
      * Create the Systray Management *
      *********************************/
@@ -244,13 +250,13 @@ MainInterface::MainInterface( intf_thread_t *_p_intf ) : QVLCMW( _p_intf )
 
     /* resize to previously saved main window size if appicable */
     //FIXME remove.
-    if( b_keep_size )
+    /*if( b_keep_size )
     {
        if( i_visualmode )
            resize( mainVideoSize );
        else
            resize( mainBasedSize );
-    }
+    }*/
 
     /* Playlist */
     int i_plVis = settings->value( "playlist-visible", 0 ).toInt();
@@ -262,19 +268,17 @@ MainInterface::MainInterface( intf_thread_t *_p_intf ) : QVLCMW( _p_intf )
     /* Final sizing and showing */
     setVisible( !b_hideAfterCreation );
 
-    setMinimumWidth( __MAX( controls->sizeHint().width(),
-                            menuBar()->sizeHint().width() ) + 30 );
-
     /* Switch to minimal view if needed, must be called after the show() */
     if( i_visualmode )
         toggleMinimalView( true );
+    else
+        showTab();
 }
 
 MainInterface::~MainInterface()
 {
     /* Unsure we hide the videoWidget before destroying it */
-    if( stackCentralOldWidget == playlistWidget )
-        showBg();
+    //showTab( PLAYLIST_TAB );
 
     /* Save playlist state */
     if( playlistWidget )
@@ -361,11 +365,12 @@ void MainInterface::createMainWidget( QSettings *settings )
     mainLayout->setSpacing( 0 ); mainLayout->setMargin( 0 );
 
     /* */
-    stackCentralW = new QStackedWidget( main );
+    stackCentralW = new QVLCStackedWidget( main );
 
     /* Bg Cone */
     bgWidget = new BackgroundWidget( p_intf );
     stackCentralW->addWidget( bgWidget );
+    videoRoleWidget = bgWidget;
 
     /* And video Outputs */
     if( b_videoEmbedded )
@@ -378,6 +383,7 @@ void MainInterface::createMainWidget( QSettings *settings )
     /* Create the CONTROLS Widget */
     controls = new ControlsWidget( p_intf,
                    settings->value( "adv-controls", false ).toBool(), this );
+
     CONNECT( controls, advancedControlsToggled( bool ),
              this, adaptGeometry() );
     CONNECT( controls, sizeChanged(),
@@ -481,7 +487,7 @@ inline void MainInterface::createStatusBar()
  */
 void MainInterface::adaptGeometry()
 {
-  resize( sizeHint() );
+  //resize( sizeHint() );
 
 #ifdef DEBUG_INTF
     debug();
@@ -501,36 +507,40 @@ void MainInterface::debug()
 #endif
 }
 
-inline void MainInterface::showVideo() { showTab( videoWidget ); }
-inline void MainInterface::showBg() { showTab( bgWidget ); }
-
-inline void MainInterface::showTab( QWidget *widget )
+inline void MainInterface::showTab( StackTab tab )
 {
-#ifdef DEBUG_INTF
-    msg_Warn( p_intf, "Old stackCentralOldWidget %i", stackCentralW->indexOf( stackCentralOldWidget ) );
-#endif
-    stackCentralOldWidget = stackCentralW->currentWidget();
-    stackCentralW->setCurrentWidget( widget );
+    if( tab == PLAYLIST_TAB && !b_plDocked ) return;
 
-#ifdef DEBUG_INTF
-    msg_Warn( p_intf, "State change %i",  stackCentralW->currentIndex() );
-    msg_Warn( p_intf, "New stackCentralOldWidget %i", stackCentralW->indexOf( stackCentralOldWidget ) );
-#endif
-}
+    QWidget *widget;
+    switch ( tab )
+    {
+        case PLAYLIST_TAB: widget = playlistWidget; break;
+        case VIDEO_TAB: widget = videoRoleWidget; break;
+        case CURRENT_TAB: widget = stackCentralW->currentWidget(); break;
+    }
 
-inline void MainInterface::restoreStackOldWidget()
-{
-#ifdef DEBUG_INTF
-    msg_Warn( p_intf, "New stackCentralOldWidget %i", stackCentralW->indexOf( stackCentralOldWidget ) );
-#endif
-    QWidget *wTemp = stackCentralW->currentWidget();
+    stackCentralW->setCurrentWidget( widget );
 
-    stackCentralW->setCurrentWidget( stackCentralOldWidget );
+    // Go into compact mode if needed (stackCentralW hidden)
+    if( widget == bgWidget && !b_keep_size && controls->isVisible() && !isFullScreen() )
+    {
+        resize( 0, 0 );
+    }
 
-    stackCentralOldWidget = wTemp;
-#ifdef DEBUG_INTF
-    msg_Warn( p_intf, "Debug %i %i",stackCentralW->indexOf( wTemp ), stackCentralW->indexOf( stackCentralW->currentWidget() ) );
-#endif
+    /* TODO Alternatively, for compact mode the best thing would be to setSizeConstraint
+       on layout, but sadly, we can only constrain the whole size, while we should
+       constrain height only */
+    /*if( widget == bgWidget && !b_keep_size && controls->isVisible() && !isFullScreen() )
+    {
+        stackCentralW->hide();
+        layout()->setSizeConstraint( QLayout::SetFixedSize );
+    }
+    else
+    {
+        layout()->setSizeConstraint( QLayout::SetDefaultConstraint );
+        setMaximumSize( QWIDGETSIZE_MAX, QWIDGETSIZE_MAX );
+        stackCentralW->show();
+    }*/
 }
 
 void MainInterface::destroyPopupMenu()
@@ -602,8 +612,9 @@ void MainInterface::getVideoSlot( WId *p_id, int *pi_x, int *pi_y,
         /* ask videoWidget to show */
         videoWidget->SetSizing( *pi_width, *pi_height );
 
+        videoRoleWidget = videoWidget;
         /* Consider the video active now */
-        showVideo();
+        showTab( VIDEO_TAB );
     }
 }
 
@@ -616,12 +627,11 @@ void MainInterface::releaseVideo( void )
 /* Function that is CONNECTED to the previous emit */
 void MainInterface::releaseVideoSlot( void )
 {
-    videoWidget->release();
+    videoRoleWidget = bgWidget;
 
-    restoreStackOldWidget();
+    showTab( b_plDocked && playlistVisible ? PLAYLIST_TAB : VIDEO_TAB );
 
-    /* We don't want to have a blank video to popup */
-    stackCentralOldWidget = bgWidget;
+    videoWidget->release();
 }
 
 /* Asynchronous call from WindowControl function */
@@ -687,19 +697,8 @@ void MainInterface::togglePlaylist()
 
     if( b_plDocked )
     {
-        /* Playlist is not visible, show it */
-        if( stackCentralW->currentWidget() != playlistWidget )
-        {
-            playlistWidget->forceShow();
-            showTab( playlistWidget );
-        }
-        else /* Hide it! */
-        {
-            restoreStackOldWidget();
-            stackCentralW->updateGeometry();
-            // HACK: So it doesn't limit the stackWidget minimumSize
-            playlistWidget->forceHide();
-        }
+        showTab( stackCentralW->currentWidget() != playlistWidget ?
+                 PLAYLIST_TAB : VIDEO_TAB );
         playlistVisible = ( stackCentralW->currentWidget() == playlistWidget );
     }
     else
@@ -719,20 +718,21 @@ void MainInterface::dockPlaylist( bool p_docked )
     if( !playlistWidget ) return; /* Playlist wasn't created yet */
     if( !p_docked )
     {
+        showTab( VIDEO_TAB );
         stackCentralW->removeWidget( playlistWidget );
         playlistWidget->setWindowFlags( Qt::Window );
         QVLCTools::restoreWidgetPosition( p_intf, "Playlist",
                 playlistWidget, QSize( 600, 300 ) );
         playlistWidget->show();
-        restoreStackOldWidget();
     }
     else
     {
         playlistWidget->setWindowFlags( Qt::Widget ); // Probably a Qt bug here
         // It would be logical that QStackWidget::addWidget reset the flags...
         stackCentralW->addWidget( playlistWidget );
-        stackCentralW->setCurrentWidget( playlistWidget );
+        showTab( PLAYLIST_TAB );
     }
+    playlistVisible = true;
 }
 
 /*
@@ -740,30 +740,14 @@ void MainInterface::dockPlaylist( bool p_docked )
  */
 void MainInterface::toggleMinimalView( bool b_switch )
 {
-    if( i_visualmode == 0 )
-    { /* NORMAL MODE then */
-        if( !videoWidget || stackCentralW->currentWidget() != videoWidget )
-        {
-            showBg();
-        }
-        else
-        {
-            /* If video is visible, then toggle the status of bgWidget */
-            //FIXME
-            //bgWasVisible = !bgWasVisible;
-            /* if( stackCentralOldState == BACK G_TAB )
-                stackCentralOldState = HID DEN_TAB;
-            else
-                stackCentralOldState = BACK G_TAB;
-
-                */
-        }
-    }
-
     menuBar()->setVisible( !b_switch );
     controls->setVisible( !b_switch );
     statusBar()->setVisible( !b_switch );
     inputC->setVisible( !b_switch );
+    minWidthHolder->setVisible( !b_switch );
+
+    // Go to compact mode and back if needed
+    showTab();
 
     emit minimalViewToggled( b_switch );
 }
@@ -1159,6 +1143,7 @@ void MainInterface::toggleFullScreen()
         showFullScreen();
         emit fullscreenInterfaceToggled( true );
     }
+    showTab();
 }
 
 /*****************************************************************************

modules/gui/qt4/main_interface.hpp

@@ -114,10 +114,13 @@ private:
     void handleSystray();
 
     /* Central StackWidget Management */
-    void showTab( QWidget *);
-    void showVideo();
-    void showBg();
-    void restoreStackOldWidget();
+    enum StackTab
+    {
+        PLAYLIST_TAB,
+        VIDEO_TAB,
+        CURRENT_TAB
+    };
+    void showTab( StackTab = CURRENT_TAB );
 
     /* */
     QSettings           *settings;
@@ -138,15 +141,14 @@ private:
     VideoWidget         *videoWidget;
     BackgroundWidget    *bgWidget;
     PlaylistWidget      *playlistWidget;
+    QWidget             *videoRoleWidget;
     //VisualSelector      *visualSelector;
+    QWidget             *minWidthHolder;
 
     /* Status Bar */
     QLabel              *nameLabel;
     QLabel              *cryptedLabel;
 
-    /* Status and flags */
-    QWidget             *stackCentralOldWidget;
-
     /* Flags */
     bool                 b_notificationEnabled; /// Systray Notifications
     bool                 b_keep_size;         ///< persistent resizeable window
@@ -226,4 +228,14 @@ signals:
 
 };
 
+class QVLCStackedWidget : public QStackedWidget
+{
+  public:
+      QVLCStackedWidget( QWidget *parent ) : QStackedWidget( parent ) { }
+      virtual QSize minimumSizeHint () const
+      {
+          return currentWidget() ? currentWidget()->minimumSizeHint() : QSize();
+      }
+};
+
 #endif