[FEATURE][composer] New action for toggling visibility of panels

This change adds a new action to the composer which hides or shows
all panels from the window. It's useful for maximising the space
available to interact with a composition. A shortcut (F10) and menu
item can be used to toggle this option, or via pressing 'tab' while
the main composer view is focused.

src/app/composer/qgscomposer.cpp

@@ -343,6 +343,7 @@ QgsComposer::QgsComposer( QgisApp *qgis, const QString& title )
   mToolbarMenu->setObjectName( "mToolbarMenu" );
   viewMenu->addSeparator();
   viewMenu->addAction( mActionToggleFullScreen );
+  viewMenu->addAction( mActionHidePanels );
   viewMenu->addMenu( mPanelMenu );
   viewMenu->addMenu( mToolbarMenu );
   // toolBar already exists, add other widgets as they are created
@@ -1246,6 +1247,16 @@ void QgsComposer::on_mActionToggleFullScreen_triggered()
   }
 }
 
+void QgsComposer::on_mActionHidePanels_triggered()
+{
+  bool showPanels = !mActionHidePanels->isChecked();
+  mItemDock->setVisible( showPanels );
+  mGeneralDock->setVisible( showPanels );
+  mUndoDock->setVisible( showPanels );
+  mAtlasDock->setVisible( showPanels );
+  mItemsDock->setVisible( showPanels );
+}
+
 void QgsComposer::disablePreviewMode()
 {
   if ( !mView )
@@ -3568,6 +3579,14 @@ void QgsComposer::createComposerView()
   mView->setHorizontalRuler( mHorizontalRuler );
   mView->setVerticalRuler( mVerticalRuler );
   mViewLayout->addWidget( mView, 1, 1 );
+
+  //view does not accept focus via tab
+  mView->setFocusPolicy( Qt::ClickFocus );
+  //instead, if view is focused and tab is pressed than mActionHidePanels is triggered,
+  //to toggle display of panels
+  QShortcut* tab = new QShortcut( Qt::Key_Tab, mView );
+  tab->setContext( Qt::WidgetWithChildrenShortcut );
+  connect( tab, SIGNAL( activated() ), mActionHidePanels, SLOT( trigger() ) );
 }
 
 void QgsComposer::writeWorldFile( QString worldFileName, double a, double b, double c, double d, double e, double f ) const

src/app/composer/qgscomposer.h

@@ -362,6 +362,9 @@ class QgsComposer: public QMainWindow, private Ui::QgsComposerBase
     //! Toggle full screen mode
     void on_mActionToggleFullScreen_triggered();
 
+    //! Toggle panels
+    void on_mActionHidePanels_triggered();
+
     //! Save window state
     void saveWindowState();
 

src/ui/qgscomposerbase.ui

@@ -1037,6 +1037,20 @@
     <string>F11</string>
    </property>
   </action>
+  <action name="mActionHidePanels">
+   <property name="checkable">
+    <bool>true</bool>
+   </property>
+   <property name="text">
+    <string>&amp;Hide Panels</string>
+   </property>
+   <property name="toolTip">
+    <string>Hide panels</string>
+   </property>
+   <property name="shortcut">
+    <string>F10</string>
+   </property>
+  </action>
  </widget>
  <resources>
   <include location="../../python/plugins/fTools/resources.qrc"/>