Split layout item registry into two separate registries

Instead of relying on forward declared c++ classes from
gui in QgsLayoutItemRegistry, instead create a
QgsLayoutItemGuiRegistry which handles registration
of all the GUI specific behavior relating to layout items.

Remove all GUI related code from QgsLayoutItemRegistry.

This creates a cleaner split between core/gui code, and
given that there'll be a lot of gui specific behavior
which needs to be handled by a registry it makes sense
to keep this isolated in gui.

It also plays nicer with the sip bindings, which can't
handle forward declared gui classes in core.

Author: nyalldawson

python/core/layout/qgslayoutitemregistry.sip

@@ -13,9 +13,13 @@ class QgsLayoutItemAbstractMetadata
 {
 %Docstring
  Stores metadata about one layout item class.
+
+ A companion class, QgsLayoutItemAbstractGuiMetadata, handles the
+ GUI behavior of QgsLayoutItems.
+
 .. note::
 
-   In C++ you can use QgsSymbolLayerMetadata convenience class.
+   In C++ you can use QgsLayoutItemMetadata convenience class.
 .. versionadded:: 3.0
 %End
 
@@ -56,13 +60,6 @@ class QgsLayoutItemAbstractMetadata
  :rtype: QgsLayoutItem
 %End
 
-    virtual QWidget *createItemWidget() /Factory/;
-%Docstring
- Creates a configuration widget for layout items of this type. Can return None if no configuration GUI is required.
- :rtype: QWidget
-%End
-
-
     virtual void resolvePaths( QVariantMap &properties, const QgsPathResolver &pathResolver, bool saving );
 %Docstring
  Resolve paths in the item's ``properties`` (if there are any paths).
@@ -79,8 +76,6 @@ class QgsLayoutItemAbstractMetadata
 
 
 
-
-
 class QgsLayoutItemRegistry : QObject
 {
 %Docstring
@@ -89,6 +84,9 @@ class QgsLayoutItemRegistry : QObject
  QgsLayoutItemRegistry is not usually directly created, but rather accessed through
  QgsApplication.layoutItemRegistry().
 
+ A companion class, QgsLayoutItemGuiRegistry, handles the GUI behavior
+ of layout items.
+
 .. versionadded:: 3.0
 %End
 
@@ -147,13 +145,6 @@ class QgsLayoutItemRegistry : QObject
  :rtype: QgsLayoutItem
 %End
 
-    QWidget *createItemWidget( int type ) const /Factory/;
-%Docstring
- Creates a new instance of a layout item configuration widget for the specified item ``type``.
- :rtype: QWidget
-%End
-
-
     void resolvePaths( int type, QVariantMap &properties, const QgsPathResolver &pathResolver, bool saving ) const;
 %Docstring
  Resolve paths in properties of a particular symbol layer.

python/gui/gui_auto.sip

@@ -42,7 +42,6 @@
 %Include editorwidgets/core/qgseditorwidgetautoconf.sip
 %Include layertree/qgslayertreeembeddedconfigwidget.sip
 %Include layertree/qgslayertreeembeddedwidgetregistry.sip
-%Include layout/qgslayoutitemregistryguiutils.sip
 %Include layout/qgslayoutviewmouseevent.sip
 %Include layout/qgslayoutviewrubberband.sip
 %Include locator/qgslocatorcontext.sip
@@ -278,6 +277,7 @@
 %Include layertree/qgslayertreeview.sip
 %Include layertree/qgslayertreeviewdefaultactions.sip
 %Include layout/qgslayoutdesignerinterface.sip
+%Include layout/qgslayoutitemguiregistry.sip
 %Include layout/qgslayoutview.sip
 %Include layout/qgslayoutviewtool.sip
 %Include layout/qgslayoutviewtooladditem.sip

python/gui/layout/qgslayoutitemguiregistry.sip

@@ -0,0 +1,154 @@
+/************************************************************************
+ * This file has been generated automatically from                      *
+ *                                                                      *
+ * src/gui/layout/qgslayoutitemguiregistry.h                            *
+ *                                                                      *
+ * Do not edit manually ! Edit header and run scripts/sipify.pl again   *
+ ************************************************************************/
+
+
+
+
+class QgsLayoutItemAbstractGuiMetadata
+{
+%Docstring
+ Stores GUI metadata about one layout item class.
+
+ This is a companion to QgsLayoutItemAbstractMetadata, storing only
+ the components related to the GUI behavior of a layout item.
+
+.. note::
+
+   In C++ you can use QgsLayoutItemGuiMetadata convenience class.
+.. versionadded:: 3.0
+%End
+
+%TypeHeaderCode
+#include "qgslayoutitemguiregistry.h"
+%End
+  public:
+
+    QgsLayoutItemAbstractGuiMetadata( int type );
+%Docstring
+ Constructor for QgsLayoutItemAbstractGuiMetadata with the specified class ``type``.
+%End
+
+    virtual ~QgsLayoutItemAbstractGuiMetadata();
+
+    int type() const;
+%Docstring
+ Returns the unique item type code for the layout item class.
+ :rtype: int
+%End
+
+    virtual QIcon creationIcon() const;
+%Docstring
+ Returns an icon representing creation of the layout item type.
+ :rtype: QIcon
+%End
+
+    virtual QWidget *createItemWidget() /Factory/;
+%Docstring
+ Creates a configuration widget for layout items of this type. Can return None if no configuration GUI is required.
+ :rtype: QWidget
+%End
+
+    virtual QgsLayoutViewRubberBand *createRubberBand( QgsLayoutView *view ) /Factory/;
+%Docstring
+ Creates a rubber band for use when creating layout items of this type. Can return None if no rubber band
+ should be created. The default behavior is to create a rectangular rubber band.
+ :rtype: QgsLayoutViewRubberBand
+%End
+
+};
+
+
+
+
+class QgsLayoutItemGuiRegistry : QObject
+{
+%Docstring
+ Registry of available layout item GUI behavior.
+
+ QgsLayoutItemGuiRegistry is not usually directly created, but rather accessed through
+ QgsGui.layoutItemGuiRegistry().
+
+ This acts as a companion to QgsLayoutItemRegistry, handling only
+ the components related to the GUI behavior of layout items.
+
+.. versionadded:: 3.0
+%End
+
+%TypeHeaderCode
+#include "qgslayoutitemguiregistry.h"
+%End
+  public:
+
+    QgsLayoutItemGuiRegistry( QObject *parent = 0 );
+%Docstring
+ Creates a new empty item GUI registry.
+
+ QgsLayoutItemGuiRegistry is not usually directly created, but rather accessed through
+ QgsGui.layoutItemGuiRegistry().
+
+.. seealso:: populate()
+%End
+
+    ~QgsLayoutItemGuiRegistry();
+
+    bool populate();
+%Docstring
+ Populates the registry with standard item types. If called on a non-empty registry
+ then this will have no effect and will return false.
+ :rtype: bool
+%End
+
+
+    QgsLayoutItemAbstractGuiMetadata *itemMetadata( int type ) const;
+%Docstring
+ Returns the metadata for the specified item ``type``. Returns None if
+ a corresponding type was not found in the registry.
+ :rtype: QgsLayoutItemAbstractGuiMetadata
+%End
+
+    bool addLayoutItemGuiMetadata( QgsLayoutItemAbstractGuiMetadata *metadata /Transfer/ );
+%Docstring
+ Registers the gui metadata for a new layout item type. Takes ownership of the metadata instance.
+ :rtype: bool
+%End
+
+    QWidget *createItemWidget( int type ) const /Factory/;
+%Docstring
+ Creates a new instance of a layout item configuration widget for the specified item ``type``.
+ :rtype: QWidget
+%End
+
+
+    QList< int > itemTypes() const;
+%Docstring
+ Returns a list of available item types handled by the registry.
+ :rtype: list of int
+%End
+
+  signals:
+
+    void typeAdded( int type );
+%Docstring
+ Emitted whenever a new item type is added to the registry, with the specified
+ ``type``.
+%End
+
+  private:
+    QgsLayoutItemGuiRegistry( const QgsLayoutItemGuiRegistry &rh );
+};
+
+
+
+
+/************************************************************************
+ * This file has been generated automatically from                      *
+ *                                                                      *
+ * src/gui/layout/qgslayoutitemguiregistry.h                            *
+ *                                                                      *
+ * Do not edit manually ! Edit header and run scripts/sipify.pl again   *
+ ************************************************************************/

python/gui/qgsgui.sip

@@ -56,6 +56,12 @@ class QgsGui
  :rtype: QgsMapLayerActionRegistry
 %End
 
+    static QgsLayoutItemGuiRegistry *layoutItemGuiRegistry();
+%Docstring
+ Returns the global layout item GUI registry, used for registering the GUI behavior of layout items.
+ :rtype: QgsLayoutItemGuiRegistry
+%End
+
     ~QgsGui();
 
   private:

src/app/layout/qgslayoutdesignerdialog.cpp

@@ -26,6 +26,8 @@
 #include "qgslayoutviewtoolpan.h"
 #include "qgslayoutviewtoolzoom.h"
 #include "qgslayoutviewtoolselect.h"
+#include "qgsgui.h"
+#include "qgslayoutitemguiregistry.h"
 
 QgsAppLayoutDesignerInterface::QgsAppLayoutDesignerInterface( QgsLayoutDesignerDialog *dialog )
   : QgsLayoutDesignerInterface( dialog )
@@ -89,14 +91,12 @@ QgsLayoutDesignerDialog::QgsLayoutDesignerDialog( QWidget *parent, Qt::WindowFla
   connect( mActionClose, &QAction::triggered, this, &QWidget::close );
 
   // populate with initial items...
-  QMap< int, QString> types = QgsApplication::layoutItemRegistry()->itemTypes();
-  QMap< int, QString>::const_iterator typeIt = types.constBegin();
-  for ( ; typeIt != types.constEnd(); ++typeIt )
+  Q_FOREACH ( int type,  QgsGui::layoutItemGuiRegistry()->itemTypes() )
   {
-    itemTypeAdded( typeIt.key(), typeIt.value() );
+    itemTypeAdded( type );
   }
   //..and listen out for new item types
-  connect( QgsApplication::layoutItemRegistry(), &QgsLayoutItemRegistry::typeAdded, this, &QgsLayoutDesignerDialog::itemTypeAdded );
+  connect( QgsGui::layoutItemGuiRegistry(), &QgsLayoutItemGuiRegistry::typeAdded, this, &QgsLayoutDesignerDialog::itemTypeAdded );
 
   mAddItemTool = new QgsLayoutViewToolAddItem( mView );
   mPanTool = new QgsLayoutViewToolPan( mView );
@@ -192,14 +192,15 @@ void QgsLayoutDesignerDialog::closeEvent( QCloseEvent * )
   saveWindowState();
 }
 
-void QgsLayoutDesignerDialog::itemTypeAdded( int type, const QString &name )
+void QgsLayoutDesignerDialog::itemTypeAdded( int type )
 {
+  QString name = QgsApplication::layoutItemRegistry()->itemMetadata( type )->visibleName();
   // update UI for new item type
   QAction *action = new QAction( tr( "Add %1" ).arg( name ), this );
   action->setToolTip( tr( "Adds a new %1 to the layout" ).arg( name ) );
   action->setCheckable( true );
   action->setData( type );
-  action->setIcon( QgsApplication::layoutItemRegistry()->itemMetadata( type )->icon() );
+  action->setIcon( QgsGui::layoutItemGuiRegistry()->itemMetadata( type )->creationIcon() );
   mToolsActionGroup->addAction( action );
   mItemMenu->addAction( action );
   mToolsToolbar->addAction( action );

src/app/layout/qgslayoutdesignerdialog.h

@@ -115,7 +115,7 @@ class QgsLayoutDesignerDialog: public QMainWindow, private Ui::QgsLayoutDesigner
 
   private slots:
 
-    void itemTypeAdded( int type, const QString &name );
+    void itemTypeAdded( int type );
 
   private:
 

src/core/layout/qgslayoutitemregistry.cpp

@@ -65,25 +65,6 @@ QgsLayoutItem *QgsLayoutItemRegistry::createItem( int type, QgsLayout *layout, c
   return mMetadata[type]->createItem( layout, properties );
 }
 
-QWidget *QgsLayoutItemRegistry::createItemWidget( int type ) const
-{
-  if ( !mMetadata.contains( type ) )
-    return nullptr;
-
-  return mMetadata[type]->createItemWidget();
-}
-
-QgsLayoutViewRubberBand *QgsLayoutItemRegistry::createItemRubberBand( int type, QgsLayoutView *view ) const
-{
-  if ( mRubberBandFunctions.contains( type ) )
-    return mRubberBandFunctions.value( type )( view );
-
-  if ( !mMetadata.contains( type ) )
-    return nullptr;
-
-  return mMetadata[type]->createRubberBand( view );
-}
-
 void QgsLayoutItemRegistry::resolvePaths( int type, QVariantMap &properties, const QgsPathResolver &pathResolver, bool saving ) const
 {
   if ( !mMetadata.contains( type ) )