Nicer API for adding/removing items

Automatically create the corresponding undo commands, so that
plugins and scripts which add/delete items will be added to
the undo stack without any work required.

python/core/layout/qgslayout.sip

@@ -369,6 +369,7 @@ class QgsLayout : QGraphicsScene, QgsExpressionContextGenerator, QgsLayoutUndoOb
 %Docstring
  Removes an ``item`` from the layout. This should be called instead of the base class removeItem()
  method.
+ The item will also be deleted.
 %End
 
     QDomElement writeXml( QDomDocument &document, const QgsReadWriteContext &context ) const;

src/core/layout/qgslayout.cpp

@@ -21,6 +21,7 @@
 #include "qgslayoutguidecollection.h"
 #include "qgsreadwritecontext.h"
 #include "qgsproject.h"
+#include "qgslayoutitemundocommand.h"
 
 QgsLayout::QgsLayout( QgsProject *project )
   : mProject( project )
@@ -360,19 +361,24 @@ QRectF QgsLayout::layoutBounds( bool ignorePages, double margin ) const
 
 void QgsLayout::addLayoutItem( QgsLayoutItem *item )
 {
-  addItem( item );
-  updateBounds();
-  mItemsModel->rebuildZList();
+  addLayoutItemPrivate( item );
+  QString undoText;
+  if ( QgsLayoutItemAbstractMetadata *metadata = QgsApplication::layoutItemRegistry()->itemMetadata( item->type() ) )
+  {
+    undoText = tr( "Created %1" ).arg( metadata->visibleName() );
+  }
+  else
+  {
+    undoText = tr( "Created item" );
+  }
+  mUndoStack->stack()->push( new QgsLayoutItemAddItemCommand( item, undoText ) );
 }
 
 void QgsLayout::removeLayoutItem( QgsLayoutItem *item )
 {
-  mItemsModel->setItemRemoved( item );
-  removeItem( item );
-#if 0 //TODO
-  emit itemRemoved( item );
-#endif
-  item->deleteLater();
+  QgsLayoutItemDeleteUndoCommand *deleteCommand = new QgsLayoutItemDeleteUndoCommand( item, tr( "Deleted item" ) );
+  removeLayoutItemPrivate( item );
+  mUndoStack->stack()->push( deleteCommand );
 }
 
 QgsLayoutUndoStack *QgsLayout::undoStack()
@@ -457,6 +463,23 @@ bool QgsLayout::readXmlLayoutSettings( const QDomElement &layoutElement, const Q
   return true;
 }
 
+void QgsLayout::addLayoutItemPrivate( QgsLayoutItem *item )
+{
+  addItem( item );
+  updateBounds();
+  mItemsModel->rebuildZList();
+}
+
+void QgsLayout::removeLayoutItemPrivate( QgsLayoutItem *item )
+{
+  mItemsModel->setItemRemoved( item );
+  removeItem( item );
+#if 0 //TODO
+  emit itemRemoved( item );
+#endif
+  item->deleteLater();
+}
+
 void QgsLayout::updateZValues( const bool addUndoCommands )
 {
   int counter = mItemsModel->zOrderListSize();

src/core/layout/qgslayout.h

@@ -417,6 +417,7 @@ class CORE_EXPORT QgsLayout : public QGraphicsScene, public QgsExpressionContext
     /**
      * Removes an \a item from the layout. This should be called instead of the base class removeItem()
      * method.
+     * The item will also be deleted.
      */
     void removeLayoutItem( QgsLayoutItem *item );
 
@@ -489,7 +490,19 @@ class CORE_EXPORT QgsLayout : public QGraphicsScene, public QgsExpressionContext
     //! Reads only the layout settings (not member settings like grid settings, etc) from XML
     bool readXmlLayoutSettings( const QDomElement &layoutElement, const QDomDocument &document, const QgsReadWriteContext &context );
 
+    /**
+     * Adds a layout item to the layout, without adding the corresponding undo commands.
+     */
+    void addLayoutItemPrivate( QgsLayoutItem *item );
 
+    /**
+     * Removes an item from the layout, without adding the corresponding undo commands.
+     */
+    void removeLayoutItemPrivate( QgsLayoutItem *item );
+
+    friend class QgsLayoutItemAddItemCommand;
+    friend class QgsLayoutItemDeleteUndoCommand;
+    friend class QgsLayoutItemUndoCommand;
     friend class QgsLayoutUndoCommand;
     friend class QgsLayoutModel;
 };

src/core/layout/qgslayoutitemundocommand.cpp

@@ -75,7 +75,7 @@ void QgsLayoutItemUndoCommand::restoreState( QDomDocument &stateDoc )
 QgsLayoutItem *QgsLayoutItemUndoCommand::recreateItem( int itemType, QgsLayout *layout )
 {
   QgsLayoutItem *item = QgsApplication::layoutItemRegistry()->createItem( itemType, layout );
-  mLayout->addLayoutItem( item );
+  mLayout->addLayoutItemPrivate( item );
   return item;
 }
 
@@ -116,7 +116,7 @@ void QgsLayoutItemDeleteUndoCommand::redo()
   QgsLayoutItem *item = layout()->itemByUuid( itemUuid() );
   Q_ASSERT_X( item, "QgsLayoutItemDeleteUndoCommand::redo", "could not find item to re-delete!" );
 
-  layout()->removeLayoutItem( item );
+  layout()->removeLayoutItemPrivate( item );
 }
 
 QgsLayoutItemAddItemCommand::QgsLayoutItemAddItemCommand( QgsLayoutItem *item, const QString &text, int id, QUndoCommand *parent )
@@ -146,7 +146,7 @@ void QgsLayoutItemAddItemCommand::undo()
   QgsLayoutItem *item = layout()->itemByUuid( itemUuid() );
   if ( item )
   {
-    layout()->removeLayoutItem( item );
+    layout()->removeLayoutItemPrivate( item );
   }
 }
 

src/gui/layout/qgslayoutview.cpp

@@ -585,9 +585,7 @@ void QgsLayoutView::deleteSelectedItems()
     //delete selected items
     for ( QgsLayoutItem *item : selectedItems )
     {
-      QgsLayoutItemDeleteUndoCommand *deleteCommand = new QgsLayoutItemDeleteUndoCommand( item, QString() );
       currentLayout()->removeLayoutItem( item );
-      currentLayout()->undoStack()->stack()->push( deleteCommand );
     }
     currentLayout()->undoStack()->endMacro();
     currentLayout()->project()->setDirty( true );

src/gui/layout/qgslayoutviewtooladditem.cpp

@@ -26,7 +26,6 @@
 #include "qgslayoutitemguiregistry.h"
 #include "qgslayoutnewitempropertiesdialog.h"
 #include "qgssettings.h"
-#include "qgslayoutitemundocommand.h"
 #include <QGraphicsRectItem>
 #include <QPen>
 #include <QBrush>
@@ -119,7 +118,6 @@ void QgsLayoutViewToolAddItem::layoutReleaseEvent( QgsLayoutViewMouseEvent *even
   settings.setValue( QStringLiteral( "LayoutDesigner/lastSizeUnit" ), static_cast< int >( item->sizeWithUnits().units() ) );
 
   layout()->addLayoutItem( item );
-  layout()->undoStack()->stack()->push( new QgsLayoutItemAddItemCommand( item, tr( "Created %1" ).arg( QgsApplication::layoutItemRegistry()->itemMetadata( mItemType )->visibleName() ) ) );
   layout()->setSelectedItem( item );
 }
 

tests/src/core/testqgslayoutitem.cpp

@@ -1372,7 +1372,6 @@ void TestQgsLayoutItem::undoRedo()
   item->setFrameStrokeColor( QColor( 255, 100, 200 ) );
   l.addLayoutItem( item );
 
-  l.undoStack()->stack()->push( new QgsLayoutItemAddItemCommand( item, QString() ) );
   QVERIFY( pItem );
   QVERIFY( l.items().contains( item ) );
   QCOMPARE( l.itemByUuid( uuid ), item );
@@ -1412,9 +1411,7 @@ void TestQgsLayoutItem::undoRedo()
   QCOMPARE( item->frameStrokeColor().name(), QColor( 255, 100, 200 ).name() );
 
   // delete item
-  QgsLayoutItemDeleteUndoCommand *deleteCommand = new QgsLayoutItemDeleteUndoCommand( item, QString() );
   l.removeLayoutItem( item );
-  l.undoStack()->stack()->push( deleteCommand );
 
   QgsApplication::sendPostedEvents( nullptr, QEvent::DeferredDelete );
   QVERIFY( !pItem );