Work on layout and layout item serialization and restoration

python/core/layout/qgslayout.sip

@@ -424,6 +424,23 @@ class QgsLayout : QGraphicsScene, QgsExpressionContextGenerator, QgsLayoutUndoOb
  :rtype: bool
 %End
 
+    QVector< QgsLayoutItem * > addItemsFromXml( const QDomElement &parentElement, const QDomDocument &document,
+        const QgsReadWriteContext &context,
+        QPointF *position = 0, bool pasteInPlace = false );
+%Docstring
+ Add items from an XML representation to the layout. Used for project file reading and pasting items from clipboard.
+
+ The ``position`` argument is optional, and if it is not specified the items will be restored to their
+ original position from the XML serialization. If specified, the items will be positioned such that the top-left
+ bounds of all added items is located at this ``position``.
+
+ The ``pasteInPlace`` argument determines whether the serialized position should be respected, but remapped to the
+ origin of the page corresponding to the page at ``position``.
+
+ A list of the newly added items is returned.
+ :rtype: list of QgsLayoutItem
+%End
+
     QgsLayoutUndoStack *undoStack();
 %Docstring
  Returns a pointer to the layout's undo stack, which manages undo/redo states for the layout

python/core/layout/qgslayoutframe.sip

@@ -35,8 +35,6 @@ class QgsLayoutFrame: QgsLayoutItem
 
     virtual int type() const;
 
-    virtual QString stringType() const;
-
     virtual QString uuid() const;
 
 

python/core/layout/qgslayoutitemattributetable.sip

@@ -38,8 +38,6 @@ class QgsLayoutItemAttributeTable: QgsLayoutTable
 
     virtual int type() const;
 
-    virtual QString stringType() const;
-
     virtual QString displayName() const;
 
 

python/core/layout/qgslayoutitemgroup.sip

@@ -28,8 +28,6 @@ class QgsLayoutItemGroup: QgsLayoutItem
 
     virtual int type() const;
 
-    virtual QString stringType() const;
-
     virtual QString displayName() const;
 
 
@@ -70,6 +68,9 @@ class QgsLayoutItemGroup: QgsLayoutItem
     virtual void paint( QPainter *painter, const QStyleOptionGraphicsItem *itemStyle, QWidget *pWidget );
 
 
+    virtual void finalizeRestoreFromXml();
+
+
   protected:
     virtual void draw( QgsRenderContext &context, const QStyleOptionGraphicsItem *itemStyle = 0 );
 

python/core/layout/qgslayoutitemhtml.sip

@@ -38,8 +38,6 @@ class QgsLayoutItemHtml: QgsLayoutMultiFrame
 
     virtual int type() const;
 
-    virtual QString stringType() const;
-
 
     static QgsLayoutItemHtml *create( QgsLayout *layout ) /Factory/;
 %Docstring

python/core/layout/qgslayoutitemlabel.sip

@@ -40,11 +40,8 @@ class QgsLayoutItemLabel: QgsLayoutItem
  :rtype: QgsLayoutItemLabel
 %End
 
-
     virtual int type() const;
 
-    virtual QString stringType() const;
-
     virtual QString displayName() const;
 
     void adjustSizeToText();

python/core/layout/qgslayoutitemlegend.sip

@@ -65,8 +65,6 @@ class QgsLayoutItemLegend : QgsLayoutItem
 
     virtual int type() const;
 
-    virtual QString stringType() const;
-
     virtual QString displayName() const;
 
 
@@ -451,6 +449,9 @@ class QgsLayoutItemLegend : QgsLayoutItem
     virtual void paint( QPainter *painter, const QStyleOptionGraphicsItem *itemStyle, QWidget *pWidget );
 
 
+    virtual void finalizeRestoreFromXml();
+
+
 
   public slots:
 

python/core/layout/qgslayoutitemmap.sip

@@ -38,8 +38,6 @@ class QgsLayoutItemMap : QgsLayoutItem
 
     virtual int type() const;
 
-    virtual QString stringType() const;
-
 
     void assignFreeId();
 %Docstring
@@ -423,6 +421,9 @@ Returns true if the map contains layers with blend modes or flattened layers for
  :rtype: QgsMapSettings
 %End
 
+    virtual void finalizeRestoreFromXml();
+
+
   protected:
 
     virtual void draw( QgsRenderContext &context, const QStyleOptionGraphicsItem *itemStyle = 0 );

python/core/layout/qgslayoutitempage.sip

@@ -46,9 +46,8 @@ class QgsLayoutItemPage : QgsLayoutItem
  :rtype: QgsLayoutItemPage
 %End
 
-
     virtual int type() const;
-    virtual QString stringType() const;
+
 
     void setPageSize( const QgsLayoutSize &size );
 %Docstring

python/core/layout/qgslayoutitempicture.sip

@@ -50,8 +50,6 @@ class QgsLayoutItemPicture: QgsLayoutItem
 
     virtual int type() const;
 
-    virtual QString stringType() const;
-
 
     static QgsLayoutItemPicture *create( QgsLayout *layout ) /Factory/;
 %Docstring
@@ -234,6 +232,9 @@ class QgsLayoutItemPicture: QgsLayoutItem
  :rtype: Format
 %End
 
+    virtual void finalizeRestoreFromXml();
+
+
   public slots:
 
     void setPictureRotation( double rotation );

python/core/layout/qgslayoutitempolygon.sip

@@ -43,8 +43,6 @@ class QgsLayoutItemPolygon: QgsLayoutNodesItem
 
     virtual int type() const;
 
-    virtual QString stringType() const;
-
     virtual QString displayName() const;
 
 

python/core/layout/qgslayoutitempolyline.sip

@@ -49,8 +49,6 @@ class QgsLayoutItemPolyline: QgsLayoutNodesItem
 
     virtual int type() const;
 
-    virtual QString stringType() const;
-
     virtual QString displayName() const;
 
 

python/core/layout/qgslayoutitemscalebar.sip

@@ -27,8 +27,6 @@ class QgsLayoutItemScaleBar: QgsLayoutItem
 
     virtual int type() const;
 
-    virtual QString stringType() const;
-
 
     static QgsLayoutItemScaleBar *create( QgsLayout *layout ) /Factory/;
 %Docstring
@@ -436,6 +434,7 @@ class QgsLayoutItemScaleBar: QgsLayoutItem
 
     virtual void refreshDataDefinedProperty( const QgsLayoutObject::DataDefinedProperty property = QgsLayoutObject::AllProperties );
 
+    virtual void finalizeRestoreFromXml();
 
   protected:
 

python/core/layout/qgslayoutitemshape.sip

@@ -34,7 +34,7 @@ class QgsLayoutItemShape : QgsLayoutItem
 %End
 
     virtual int type() const;
-    virtual QString stringType() const;
+
 
     virtual QString displayName() const;
 

python/core/layout/qgslayoutitemtexttable.sip

@@ -30,8 +30,6 @@ class QgsLayoutItemTextTable : QgsLayoutTable
 
     virtual int type() const;
 
-    virtual QString stringType() const;
-
     virtual QString displayName() const;
 
 

src/core/layout/qgslayout.cpp

@@ -584,6 +584,26 @@ QDomElement QgsLayout::writeXml( QDomDocument &document, const QgsReadWriteConte
   save( &mGridSettings );
   save( mPageCollection.get() );
 
+  //save items except paper items and frame items (they are saved with the corresponding multiframe)
+  const QList<QGraphicsItem *> itemList = items();
+  for ( const QGraphicsItem *graphicsItem : itemList )
+  {
+    if ( const QgsLayoutItem *item = dynamic_cast< const QgsLayoutItem *>( graphicsItem ) )
+    {
+      if ( item->type() == QgsLayoutItemRegistry::LayoutPage
+           || item->type() == QgsLayoutItemRegistry::LayoutFrame )
+        continue;
+
+      item->writeXml( element, document, context );
+    }
+  }
+
+  //save multiframes
+  for ( QgsLayoutMultiFrame *mf : mMultiFrames )
+  {
+    mf->writeXml( element, document, context );
+  }
+
   writeXmlLayoutSettings( element, document, context );
   return element;
 }
@@ -623,6 +643,26 @@ void QgsLayout::deleteAndRemoveMultiFrames()
   mMultiFrames.clear();
 }
 
+QPointF QgsLayout::minPointFromXml( const QDomElement &elem ) const
+{
+  double minX = std::numeric_limits<double>::max();
+  double minY = std::numeric_limits<double>::max();
+  const QDomNodeList itemList = elem.elementsByTagName( QStringLiteral( "LayoutItem" ) );
+  bool found = false;
+  for ( int i = 0; i < itemList.size(); ++i )
+  {
+    const QDomElement currentItemElem = itemList.at( i ).toElement();
+
+    QgsLayoutPoint pos = QgsLayoutPoint::decodePoint( currentItemElem.attribute( QStringLiteral( "position" ) ) );
+    QPointF layoutPoint = convertToLayoutUnits( pos );
+
+    minX = std::min( minX, layoutPoint.x() );
+    minY = std::min( minY, layoutPoint.y() );
+    found = true;
+  }
+  return found ? QPointF( minX, minY ) : QPointF( 0, 0 );
+}
+
 void QgsLayout::updateZValues( const bool addUndoCommands )
 {
   int counter = mItemsModel->zOrderListSize();
@@ -671,10 +711,137 @@ bool QgsLayout::readXml( const QDomElement &layoutElement, const QDomDocument &d
   restore( mPageCollection.get() );
   restore( &mSnapper );
   restore( &mGridSettings );
+  addItemsFromXml( layoutElement, document, context );
 
   return true;
 }
 
+QVector< QgsLayoutItem * > QgsLayout::addItemsFromXml( const QDomElement &parentElement, const QDomDocument &document, const QgsReadWriteContext &context, QPointF *position, bool pasteInPlace )
+{
+  std::unique_ptr< QPointF > pasteInPlacePt;
+  QVector< QgsLayoutItem * > newItems;
+  QVector< QgsLayoutMultiFrame * > newMultiFrames;
+
+  //if we are adding items to a layout which already contains items, we need to make sure
+  //these items are placed at the top of the layout and that zValues are not duplicated
+  //so, calculate an offset which needs to be added to the zValue of created items
+  int zOrderOffset = mItemsModel->zOrderListSize();
+
+  QPointF pasteShiftPos;
+  if ( position )
+  {
+    //If we are placing items relative to a certain point, then calculate how much we need
+    //to shift the items by so that they are placed at this point
+    //First, calculate the minimum position from the xml
+    QPointF minItemPos = minPointFromXml( parentElement );
+    //next, calculate how much each item needs to be shifted from its original position
+    //so that it's placed at the correct relative position
+    pasteShiftPos = *position - minItemPos;
+
+#if 0 // TODO - move to gui
+    //since we are pasting items, clear the existing selection
+    setAllDeselected();
+#endif
+    if ( pasteInPlace )
+    {
+      int pageNumber = mPageCollection->pageNumberForPoint( *position );
+      pasteInPlacePt = qgis::make_unique< QPointF >( 0, mPageCollection->page( pageNumber )->pos().y() );
+    }
+  }
+
+  const QDomNodeList layoutItemList = parentElement.elementsByTagName( QStringLiteral( "LayoutItem" ) );
+  for ( int i = 0; i < layoutItemList.size(); ++i )
+  {
+    const QDomElement currentItemElem = layoutItemList.at( i ).toElement();
+    const int itemType = currentItemElem.attribute( QStringLiteral( "type" ) ).toInt();
+    std::unique_ptr< QgsLayoutItem > item( QgsApplication::layoutItemRegistry()->createItem( itemType, this ) );
+    if ( !item )
+    {
+      // e.g. plugin based item which is no longer available
+      continue;
+    }
+
+    item->readXml( currentItemElem, document, context );
+    if ( position )
+    {
+#if 0 //TODO
+      if ( pasteInPlacePt )
+      {
+        item->setItemPosition( newLabel->pos().x(), std::fmod( newLabel->pos().y(), ( paperHeight() + spaceBetweenPages() ) ) );
+        item->move( pasteInPlacePt->x(), pasteInPlacePt->y() );
+      }
+      else
+      {
+        item->move( pasteShiftPos.x(), pasteShiftPos.y() );
+      }
+#endif
+    }
+
+#if 0 //TODO - move to gui
+    newLabel->setSelected( true );
+#endif
+
+    QgsLayoutItem *layoutItem = item.get();
+    addLayoutItem( item.release() );
+    layoutItem->setZValue( layoutItem->zValue() + zOrderOffset );
+    newItems << layoutItem;
+  }
+
+  // multiframes
+
+  //TODO - fix this. pasting multiframe frame items has no effect
+  const QDomNodeList multiFrameList = parentElement.elementsByTagName( QStringLiteral( "LayoutMultiFrame" ) );
+  for ( int i = 0; i < multiFrameList.size(); ++i )
+  {
+    const QDomElement multiFrameElem = multiFrameList.at( i ).toElement();
+    const int itemType = multiFrameElem.attribute( QStringLiteral( "type" ) ).toInt();
+    std::unique_ptr< QgsLayoutMultiFrame > mf( QgsApplication::layoutItemRegistry()->createMultiFrame( itemType, this ) );
+    if ( !mf )
+    {
+      // e.g. plugin based item which is no longer available
+      continue;
+    }
+    mf->readXml( multiFrameElem, document, context );
+
+#if 0 //TODO?
+    mf->setCreateUndoCommands( true );
+#endif
+
+    QgsLayoutMultiFrame *m = mf.get();
+    this->addMultiFrame( mf.release() );
+
+    //offset z values for frames
+    //TODO - fix this after fixing multiframe item paste
+    /*for ( int frameIdx = 0; frameIdx < mf->frameCount(); ++frameIdx )
+    {
+      QgsLayoutItemFrame * frame = mf->frame( frameIdx );
+      frame->setZValue( frame->zValue() + zOrderOffset );
+    }*/
+    newMultiFrames << m;
+  }
+
+
+  // we now allow items to "post-process", e.g. if they need to setup connections
+  // to other items in the layout, which may not have existed at the time the
+  // item's state was restored. E.g. a scalebar may have been restored before the map
+  // it is linked to
+  for ( QgsLayoutItem *item : qgis::as_const( newItems ) )
+  {
+    item->finalizeRestoreFromXml();
+  }
+  for ( QgsLayoutMultiFrame *mf : qgis::as_const( newMultiFrames ) )
+  {
+    mf->finalizeRestoreFromXml();
+  }
+
+  //Since this function adds items in an order which isn't the z-order, and each item is added to end of
+  //z order list in turn, it will now be inconsistent with the actual order of items in the scene.
+  //Make sure z order list matches the actual order of items in the scene.
+  mItemsModel->rebuildZList();
+
+  return newItems;
+}
+
 void QgsLayout::updateBounds()
 {
   setSceneRect( layoutBounds( false, 0.05 ) );