qgsmapthemecollection.cpp

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/***************************************************************************
  qgsmapthemecollection.cpp
  --------------------------------------
  Date                 : September 2014
  Copyright            : (C) 2014 by Martin Dobias
  Email                : wonder dot sk at gmail dot com
 ***************************************************************************
 *                                                                         *
 *   This program is free software; you can redistribute it and/or modify  *
 *   it under the terms of the GNU General Public License as published by  *
 *   the Free Software Foundation; either version 2 of the License, or     *
 *   (at your option) any later version.                                   *
 *                                                                         *
 ***************************************************************************/
 
#include "qgsmapthemecollection.h"
 
#include "qgslayertree.h"
#include "qgslayertreemodel.h"
#include "qgslayertreemodellegendnode.h"
#include "qgsmaplayerstylemanager.h"
#include "qgsproject.h"
#include "qgsrenderer.h"
#include "qgsvectorlayer.h"
#include "moc_qgsmapthemecollection.cpp"
 
QgsMapThemeCollection::QgsMapThemeCollection( QgsProject *project )
  : mProject( project )
{
  connect( project, static_cast<void ( QgsProject::* )( const QStringList & )>( &QgsProject::layersWillBeRemoved ), this, &QgsMapThemeCollection::registryLayersRemoved );
}
 
QgsMapThemeCollection::MapThemeLayerRecord QgsMapThemeCollection::createThemeLayerRecord( QgsLayerTreeLayer *nodeLayer, QgsLayerTreeModel *model )
{
  MapThemeLayerRecord layerRec( nodeLayer->layer() );
  layerRec.isVisible = nodeLayer->isVisible();
  layerRec.usingCurrentStyle = true;
  layerRec.currentStyle = nodeLayer->layer()->styleManager()->currentStyle();
  layerRec.expandedLayerNode = nodeLayer->isExpanded();
  const QStringList expandedLegendNodes = nodeLayer->customProperty( QStringLiteral( "expandedLegendNodes" ) ).toStringList();
  layerRec.expandedLegendItems = QSet<QString>( expandedLegendNodes.begin(), expandedLegendNodes.end() );
 
  // get checked legend items
  bool hasCheckableItems = false;
  bool someItemsUnchecked = false;
  QSet<QString> checkedItems;
  const QList<QgsLayerTreeModelLegendNode *> layerLegendNodes = model->layerLegendNodes( nodeLayer, true );
  for ( QgsLayerTreeModelLegendNode *legendNode : layerLegendNodes )
  {
    if ( legendNode->flags() & Qt::ItemIsUserCheckable )
    {
      hasCheckableItems = true;
 
      if ( legendNode->data( Qt::CheckStateRole ).toInt() == Qt::Checked )
        checkedItems << legendNode->data( static_cast< int >( QgsLayerTreeModelLegendNode::CustomRole::RuleKey ) ).toString();
      else
        someItemsUnchecked = true;
    }
  }
 
  if ( hasCheckableItems && someItemsUnchecked )
  {
    layerRec.usingLegendItems = true;
    layerRec.checkedLegendItems = checkedItems;
  }
  return layerRec;
}
 
static QString _groupId( QgsLayerTreeNode *node )
{
  QStringList lst;
  while ( node->parent() )
  {
    lst.prepend( node->name() );
    node = node->parent();
  }
  return lst.join( '/' );
}
 
void QgsMapThemeCollection::createThemeFromCurrentState( QgsLayerTreeGroup *parent, QgsLayerTreeModel *model, QgsMapThemeCollection::MapThemeRecord &rec )
{
  const QList<QgsLayerTreeNode *> constChildren = parent->children();
  for ( QgsLayerTreeNode *node : constChildren )
  {
    if ( QgsLayerTree::isGroup( node ) )
    {
      createThemeFromCurrentState( QgsLayerTree::toGroup( node ), model, rec );
      if ( node->isExpanded() )
        rec.mExpandedGroupNodes.insert( _groupId( node ) );
      if ( node->itemVisibilityChecked() != Qt::Unchecked )
        rec.mCheckedGroupNodes.insert( _groupId( node ) );
    }
    else if ( QgsLayerTree::isLayer( node ) )
    {
      QgsLayerTreeLayer *nodeLayer = QgsLayerTree::toLayer( node );
      if ( node->itemVisibilityChecked() != Qt::Unchecked && nodeLayer->layer() )
        rec.mLayerRecords << createThemeLayerRecord( nodeLayer, model );
    }
  }
}
 
QgsMapThemeCollection::MapThemeRecord QgsMapThemeCollection::createThemeFromCurrentState( QgsLayerTreeGroup *root, QgsLayerTreeModel *model )
{
  QgsMapThemeCollection::MapThemeRecord rec;
  rec.setHasExpandedStateInfo( true );  // all newly created theme records have expanded state info
  rec.setHasCheckedStateInfo( true );  // all newly created theme records have checked state info
  createThemeFromCurrentState( root, model, rec );
  return rec;
}
 
bool QgsMapThemeCollection::findRecordForLayer( QgsMapLayer *layer, const QgsMapThemeCollection::MapThemeRecord &rec, QgsMapThemeCollection::MapThemeLayerRecord &layerRec )
{
  for ( const QgsMapThemeCollection::MapThemeLayerRecord &lr : std::as_const( rec.mLayerRecords ) )
  {
    if ( lr.layer() == layer )
    {
      layerRec = lr;
      return true;
    }
  }
  return false;
}
 
void QgsMapThemeCollection::applyThemeToLayer( QgsLayerTreeLayer *nodeLayer, QgsLayerTreeModel *model, const QgsMapThemeCollection::MapThemeRecord &rec )
{
  MapThemeLayerRecord layerRec;
  const bool recordExists = findRecordForLayer( nodeLayer->layer(), rec, layerRec );
 
  // Make sure the whole tree is visible
  if ( recordExists )
  {
    if ( rec.hasCheckedStateInfo() )
      nodeLayer->setItemVisibilityChecked( true );
    else
      nodeLayer->setItemVisibilityCheckedParentRecursive( true );
  }
  else
    nodeLayer->setItemVisibilityChecked( false );
 
  if ( !recordExists )
    return;
 
  if ( layerRec.usingCurrentStyle )
  {
    // apply desired style first
    nodeLayer->layer()->styleManager()->setCurrentStyle( layerRec.currentStyle );
  }
 
  if ( layerRec.usingLegendItems )
  {
    // some nodes are not checked
    const QList<QgsLayerTreeModelLegendNode *> constLayerLegendNodes = model->layerLegendNodes( nodeLayer, true );
    for ( QgsLayerTreeModelLegendNode *legendNode : constLayerLegendNodes )
    {
      QString ruleKey = legendNode->data( static_cast< int >( QgsLayerTreeModelLegendNode::CustomRole::RuleKey ) ).toString();
      Qt::CheckState shouldHaveState = layerRec.checkedLegendItems.contains( ruleKey ) ? Qt::Checked : Qt::Unchecked;
      if ( ( legendNode->flags() & Qt::ItemIsUserCheckable ) &&
           legendNode->data( Qt::CheckStateRole ).toInt() != shouldHaveState )
        legendNode->setData( shouldHaveState, Qt::CheckStateRole );
    }
  }
  else
  {
    // all nodes should be checked
    const QList<QgsLayerTreeModelLegendNode *> constLayerLegendNodes = model->layerLegendNodes( nodeLayer, true );
    for ( QgsLayerTreeModelLegendNode *legendNode : constLayerLegendNodes )
    {
      if ( ( legendNode->flags() & Qt::ItemIsUserCheckable ) &&
           legendNode->data( Qt::CheckStateRole ).toInt() != Qt::Checked )
        legendNode->setData( Qt::Checked, Qt::CheckStateRole );
    }
  }
 
  // apply expanded/collapsed state to the layer and its legend nodes
  if ( rec.hasExpandedStateInfo() )
  {
    nodeLayer->setExpanded( layerRec.expandedLayerNode );
    nodeLayer->setCustomProperty( QStringLiteral( "expandedLegendNodes" ), QStringList( layerRec.expandedLegendItems.constBegin(), layerRec.expandedLegendItems.constEnd() ) );
  }
}
 
 
void QgsMapThemeCollection::applyThemeToGroup( QgsLayerTreeGroup *parent, QgsLayerTreeModel *model, const QgsMapThemeCollection::MapThemeRecord &rec )
{
  const QList<QgsLayerTreeNode *> constChildren = parent->children();
  for ( QgsLayerTreeNode *node : constChildren )
  {
    if ( QgsLayerTree::isGroup( node ) )
    {
      applyThemeToGroup( QgsLayerTree::toGroup( node ), model, rec );
      if ( rec.hasExpandedStateInfo() )
        node->setExpanded( rec.expandedGroupNodes().contains( _groupId( node ) ) );
      if ( rec.hasCheckedStateInfo() )
        node->setItemVisibilityChecked( rec.checkedGroupNodes().contains( _groupId( node ) ) );
    }
    else if ( QgsLayerTree::isLayer( node ) )
      applyThemeToLayer( QgsLayerTree::toLayer( node ), model, rec );
  }
}
 
 
void QgsMapThemeCollection::applyTheme( const QString &name, QgsLayerTreeGroup *root, QgsLayerTreeModel *model )
{
  applyThemeToGroup( root, model, mapThemeState( name ) );
 
  // also make sure that the preset is up-to-date (not containing any non-existent legend items)
  update( name, createThemeFromCurrentState( root, model ) );
}
 
QgsProject *QgsMapThemeCollection::project()
{
  return mProject;
}
 
void QgsMapThemeCollection::setProject( QgsProject *project )
{
  if ( project == mProject )
    return;
 
  disconnect( mProject, static_cast<void ( QgsProject::* )( const QStringList & )>( &QgsProject::layersWillBeRemoved ), this, &QgsMapThemeCollection::registryLayersRemoved );
  mProject = project;
  connect( mProject, static_cast<void ( QgsProject::* )( const QStringList & )>( &QgsProject::layersWillBeRemoved ), this, &QgsMapThemeCollection::registryLayersRemoved );
  emit projectChanged();
}
 
QList<QgsMapLayer *> QgsMapThemeCollection::masterLayerOrder() const
{
  if ( !mProject )
    return QList< QgsMapLayer * >();
 
  return mProject->layerTreeRoot()->layerOrder();
}
 
QList<QgsMapLayer *> QgsMapThemeCollection::masterVisibleLayers() const
{
  const QList< QgsMapLayer *> allLayers = masterLayerOrder();
  const QList< QgsMapLayer * > visibleLayers = mProject->layerTreeRoot()->checkedLayers();
 
  if ( allLayers.isEmpty() )
  {
    // no project layer order set
    return visibleLayers;
  }
  else
  {
    QList< QgsMapLayer * > orderedVisibleLayers;
    for ( QgsMapLayer *layer : allLayers )
    {
      if ( visibleLayers.contains( layer ) )
        orderedVisibleLayers << layer;
    }
    return orderedVisibleLayers;
  }
}
 
 
bool QgsMapThemeCollection::hasMapTheme( const QString &name ) const
{
  return mMapThemes.contains( name );
}
 
void QgsMapThemeCollection::insert( const QString &name, const QgsMapThemeCollection::MapThemeRecord &state )
{
  mMapThemes.insert( name, state );
 
  reconnectToLayersStyleManager();
  emit mapThemeChanged( name );
  emit mapThemesChanged();
}
 
void QgsMapThemeCollection::update( const QString &name, const MapThemeRecord &state )
{
  if ( !mMapThemes.contains( name ) )
    return;
 
  mMapThemes[name] = state;
 
  reconnectToLayersStyleManager();
  emit mapThemeChanged( name );
  emit mapThemesChanged();
}
 
bool QgsMapThemeCollection::renameMapTheme( const QString &name,  const QString &newName )
{
  if ( !mMapThemes.contains( name ) || mMapThemes.contains( newName ) )
    return false;
 
  const MapThemeRecord state = mMapThemes[name];
  const MapThemeRecord newState = state;
  insert( newName, newState );
  emit mapThemeRenamed( name, newName );
  removeMapTheme( name );
  return true;
}
 
void QgsMapThemeCollection::removeMapTheme( const QString &name )
{
  if ( !mMapThemes.contains( name ) )
    return;
 
  mMapThemes.remove( name );
 
  reconnectToLayersStyleManager();
  emit mapThemesChanged();
}
 
void QgsMapThemeCollection::clear()
{
  mMapThemes.clear();
 
  reconnectToLayersStyleManager();
  emit mapThemesChanged();
}
 
QStringList QgsMapThemeCollection::mapThemes() const
{
  return mMapThemes.keys();
}
 
QStringList QgsMapThemeCollection::mapThemeVisibleLayerIds( const QString &name ) const
{
  QStringList layerIds;
  const QList<QgsMapLayer *> constMapThemeVisibleLayers = mapThemeVisibleLayers( name );
  for ( QgsMapLayer *layer : constMapThemeVisibleLayers )
  {
    layerIds << layer->id();
  }
  return layerIds;
}
 
QList<QgsMapLayer *> QgsMapThemeCollection::mapThemeVisibleLayers( const QString &name ) const
{
  QList<QgsMapLayer *> layers;
  const QList<MapThemeLayerRecord> recs = mMapThemes.value( name ).mLayerRecords;
  const QList<QgsMapLayer *> layerOrder = masterLayerOrder();
  if ( layerOrder.isEmpty() )
  {
    // no master layer order - so we have to just use the stored theme layer order as a fallback
    const QList<MapThemeLayerRecord> records { mMapThemes.value( name ).mLayerRecords };
    for ( const MapThemeLayerRecord &layerRec : records )
    {
      if ( layerRec.isVisible && layerRec.layer() )
        layers << layerRec.layer();
    }
  }
  else
  {
    for ( QgsMapLayer *layer : layerOrder )
    {
      for ( const MapThemeLayerRecord &layerRec : recs )
      {
        if ( layerRec.isVisible && layerRec.layer() == layer )
          layers << layerRec.layer();
      }
    }
  }
 
  return layers;
}
 
 
void QgsMapThemeCollection::applyMapThemeCheckedLegendNodesToLayer( const MapThemeLayerRecord &layerRec, QgsMapLayer *layer )
{
  QgsVectorLayer *vlayer = qobject_cast<QgsVectorLayer *>( layer );
  if ( !vlayer || !vlayer->renderer() )
    return;
 
  QgsFeatureRenderer *renderer = vlayer->renderer();
  if ( !renderer->legendSymbolItemsCheckable() )
    return; // no need to do anything
 
  bool someNodesUnchecked = layerRec.usingLegendItems;
 
  const auto constLegendSymbolItems = vlayer->renderer()->legendSymbolItems();
  for ( const QgsLegendSymbolItem &item : constLegendSymbolItems )
  {
    bool checked = renderer->legendSymbolItemChecked( item.ruleKey() );
    bool shouldBeChecked = someNodesUnchecked ? layerRec.checkedLegendItems.contains( item.ruleKey() ) : true;
    if ( checked != shouldBeChecked )
      renderer->checkLegendSymbolItem( item.ruleKey(), shouldBeChecked );
  }
}
 
 
QMap<QString, QString> QgsMapThemeCollection::mapThemeStyleOverrides( const QString &presetName )
{
  QMap<QString, QString> styleOverrides;
  if ( !mMapThemes.contains( presetName ) )
    return styleOverrides;
 
  const QList<MapThemeLayerRecord> records {mMapThemes.value( presetName ).mLayerRecords};
  for ( const MapThemeLayerRecord &layerRec : records )
  {
    if ( !layerRec.layer() )
      continue;
 
    if ( layerRec.usingCurrentStyle )
    {
      QgsMapLayer *layer = layerRec.layer();
      QgsMapLayerStyleOverride styleOverride( layer );
      styleOverride.setOverrideStyle( layerRec.currentStyle );
 
      // set the checked legend nodes
      applyMapThemeCheckedLegendNodesToLayer( layerRec, layer );
 
      // save to overrides
      QgsMapLayerStyle layerStyle;
      layerStyle.readFromLayer( layer );
      styleOverrides[layer->id()] = layerStyle.xmlData();
    }
  }
  return styleOverrides;
}
 
void QgsMapThemeCollection::reconnectToLayersStyleManager()
{
  // disconnect( 0, 0, this, SLOT( layerStyleRenamed( QString, QString ) ) );
 
  QSet<QgsMapLayer *> layers;
  for ( const MapThemeRecord &rec : std::as_const( mMapThemes ) )
  {
    for ( const MapThemeLayerRecord &layerRec : std::as_const( rec.mLayerRecords ) )
    {
      if ( auto *lLayer = layerRec.layer() )
        layers << lLayer;
    }
  }
 
  const QSet<QgsMapLayer *> constLayers = layers;
  for ( QgsMapLayer *ml : constLayers )
  {
    connect( ml->styleManager(), &QgsMapLayerStyleManager::styleRenamed, this, &QgsMapThemeCollection::layerStyleRenamed );
  }
}
 
void QgsMapThemeCollection::readXml( const QDomDocument &doc )
{
  clear();
 
  QDomElement visPresetsElem = doc.firstChildElement( QStringLiteral( "qgis" ) ).firstChildElement( QStringLiteral( "visibility-presets" ) );
  if ( visPresetsElem.isNull() )
    return;
 
  QDomElement visPresetElem = visPresetsElem.firstChildElement( QStringLiteral( "visibility-preset" ) );
  while ( !visPresetElem.isNull() )
  {
    QHash<QString, MapThemeLayerRecord> layerRecords; // key = layer ID
 
    bool expandedStateInfo = false;
    if ( visPresetElem.hasAttribute( QStringLiteral( "has-expanded-info" ) ) )
      expandedStateInfo = visPresetElem.attribute( QStringLiteral( "has-expanded-info" ) ).toInt();
 
    bool checkedStateInfo = false;
    if ( visPresetElem.hasAttribute( QStringLiteral( "has-checked-group-info" ) ) )
      checkedStateInfo = visPresetElem.attribute( QStringLiteral( "has-checked-group-info" ) ).toInt();
 
    QString presetName = visPresetElem.attribute( QStringLiteral( "name" ) );
    QDomElement visPresetLayerElem = visPresetElem.firstChildElement( QStringLiteral( "layer" ) );
    while ( !visPresetLayerElem.isNull() )
    {
      QString layerID = visPresetLayerElem.attribute( QStringLiteral( "id" ) );
      if ( QgsMapLayer *layer = mProject->mapLayer( layerID ) )
      {
        layerRecords[layerID] = MapThemeLayerRecord( layer );
        layerRecords[layerID].isVisible = visPresetLayerElem.attribute( QStringLiteral( "visible" ), QStringLiteral( "1" ) ).toInt();
 
        if ( visPresetLayerElem.hasAttribute( QStringLiteral( "style" ) ) )
        {
          layerRecords[layerID].usingCurrentStyle = true;
          layerRecords[layerID].currentStyle = visPresetLayerElem.attribute( QStringLiteral( "style" ) );
        }
 
        if ( visPresetLayerElem.hasAttribute( QStringLiteral( "expanded" ) ) )
          layerRecords[layerID].expandedLayerNode = visPresetLayerElem.attribute( QStringLiteral( "expanded" ) ).toInt();
      }
      visPresetLayerElem = visPresetLayerElem.nextSiblingElement( QStringLiteral( "layer" ) );
    }
 
    QDomElement checkedLegendNodesElem = visPresetElem.firstChildElement( QStringLiteral( "checked-legend-nodes" ) );
    while ( !checkedLegendNodesElem.isNull() )
    {
      QSet<QString> checkedLegendNodes;
 
      QDomElement checkedLegendNodeElem = checkedLegendNodesElem.firstChildElement( QStringLiteral( "checked-legend-node" ) );
      while ( !checkedLegendNodeElem.isNull() )
      {
        checkedLegendNodes << checkedLegendNodeElem.attribute( QStringLiteral( "id" ) );
        checkedLegendNodeElem = checkedLegendNodeElem.nextSiblingElement( QStringLiteral( "checked-legend-node" ) );
      }
 
      QString layerID = checkedLegendNodesElem.attribute( QStringLiteral( "id" ) );
      if ( mProject->mapLayer( layerID ) ) // only use valid IDs
      {
        layerRecords[layerID].usingLegendItems = true;
        layerRecords[layerID].checkedLegendItems = checkedLegendNodes;
      }
      checkedLegendNodesElem = checkedLegendNodesElem.nextSiblingElement( QStringLiteral( "checked-legend-nodes" ) );
    }
 
    QSet<QString> expandedGroupNodes;
    if ( expandedStateInfo )
    {
      // expanded state of legend nodes
      QDomElement expandedLegendNodesElem = visPresetElem.firstChildElement( QStringLiteral( "expanded-legend-nodes" ) );
      while ( !expandedLegendNodesElem.isNull() )
      {
        QSet<QString> expandedLegendNodes;
 
        QDomElement expandedLegendNodeElem = expandedLegendNodesElem.firstChildElement( QStringLiteral( "expanded-legend-node" ) );
        while ( !expandedLegendNodeElem.isNull() )
        {
          expandedLegendNodes << expandedLegendNodeElem.attribute( QStringLiteral( "id" ) );
          expandedLegendNodeElem = expandedLegendNodeElem.nextSiblingElement( QStringLiteral( "expanded-legend-node" ) );
        }
 
        QString layerID = expandedLegendNodesElem.attribute( QStringLiteral( "id" ) );
        if ( mProject->mapLayer( layerID ) ) // only use valid IDs
        {
          layerRecords[layerID].expandedLegendItems = expandedLegendNodes;
        }
        expandedLegendNodesElem = expandedLegendNodesElem.nextSiblingElement( QStringLiteral( "expanded-legend-nodes" ) );
      }
 
      // expanded state of group nodes
      QDomElement expandedGroupNodesElem = visPresetElem.firstChildElement( QStringLiteral( "expanded-group-nodes" ) );
      if ( !expandedGroupNodesElem.isNull() )
      {
        QDomElement expandedGroupNodeElem = expandedGroupNodesElem.firstChildElement( QStringLiteral( "expanded-group-node" ) );
        while ( !expandedGroupNodeElem.isNull() )
        {
          expandedGroupNodes << expandedGroupNodeElem.attribute( QStringLiteral( "id" ) );
          expandedGroupNodeElem = expandedGroupNodeElem.nextSiblingElement( QStringLiteral( "expanded-group-node" ) );
        }
      }
    }
 
    QSet<QString> checkedGroupNodes;
    if ( checkedStateInfo )
    {
      // expanded state of legend nodes
      QDomElement checkedGroupNodesElem = visPresetElem.firstChildElement( QStringLiteral( "checked-group-nodes" ) );
      if ( !checkedGroupNodesElem.isNull() )
      {
        QDomElement checkedGroupNodeElem = checkedGroupNodesElem.firstChildElement( QStringLiteral( "checked-group-node" ) );
        while ( !checkedGroupNodeElem.isNull() )
        {
          checkedGroupNodes << checkedGroupNodeElem.attribute( QStringLiteral( "id" ) );
          checkedGroupNodeElem = checkedGroupNodeElem.nextSiblingElement( QStringLiteral( "checked-group-node" ) );
        }
      }
    }
 
    MapThemeRecord rec;
    rec.setLayerRecords( layerRecords.values() );
    rec.setHasExpandedStateInfo( expandedStateInfo );
    rec.setExpandedGroupNodes( expandedGroupNodes );
    rec.setHasCheckedStateInfo( checkedStateInfo );
    rec.setCheckedGroupNodes( checkedGroupNodes );
    mMapThemes.insert( presetName, rec );
    emit mapThemeChanged( presetName );
 
    visPresetElem = visPresetElem.nextSiblingElement( QStringLiteral( "visibility-preset" ) );
  }
 
  reconnectToLayersStyleManager();
  emit mapThemesChanged();
}
 
void QgsMapThemeCollection::writeXml( QDomDocument &doc )
{
  QDomElement visPresetsElem = doc.createElement( QStringLiteral( "visibility-presets" ) );
 
  QList< QString > keys = mMapThemes.keys();
 
  std::sort( keys.begin(), keys.end() );
 
  for ( const QString &grpName : std::as_const( keys ) )
  {
    const MapThemeRecord &rec = mMapThemes.value( grpName );
    QDomElement visPresetElem = doc.createElement( QStringLiteral( "visibility-preset" ) );
    visPresetElem.setAttribute( QStringLiteral( "name" ), grpName );
    if ( rec.hasExpandedStateInfo() )
      visPresetElem.setAttribute( QStringLiteral( "has-expanded-info" ), QStringLiteral( "1" ) );
    if ( rec.hasCheckedStateInfo() )
      visPresetElem.setAttribute( QStringLiteral( "has-checked-group-info" ), QStringLiteral( "1" ) );
    for ( const MapThemeLayerRecord &layerRec : std::as_const( rec.mLayerRecords ) )
    {
      if ( !layerRec.layer() )
        continue;
      QString layerID = layerRec.layer()->id();
      QDomElement layerElem = doc.createElement( QStringLiteral( "layer" ) );
      layerElem.setAttribute( QStringLiteral( "id" ), layerID );
      layerElem.setAttribute( QStringLiteral( "visible" ), layerRec.isVisible ? QStringLiteral( "1" ) : QStringLiteral( "0" ) );
      if ( layerRec.usingCurrentStyle )
        layerElem.setAttribute( QStringLiteral( "style" ), layerRec.currentStyle );
      visPresetElem.appendChild( layerElem );
 
      if ( layerRec.usingLegendItems )
      {
        QDomElement checkedLegendNodesElem = doc.createElement( QStringLiteral( "checked-legend-nodes" ) );
        checkedLegendNodesElem.setAttribute( QStringLiteral( "id" ), layerID );
        for ( const QString &checkedLegendNode : std::as_const( layerRec.checkedLegendItems ) )
        {
          QDomElement checkedLegendNodeElem = doc.createElement( QStringLiteral( "checked-legend-node" ) );
          checkedLegendNodeElem.setAttribute( QStringLiteral( "id" ), checkedLegendNode );
          checkedLegendNodesElem.appendChild( checkedLegendNodeElem );
        }
        visPresetElem.appendChild( checkedLegendNodesElem );
      }
 
      if ( rec.hasExpandedStateInfo() )
      {
        layerElem.setAttribute( QStringLiteral( "expanded" ), layerRec.expandedLayerNode ? QStringLiteral( "1" ) : QStringLiteral( "0" ) );
 
        QDomElement expandedLegendNodesElem = doc.createElement( QStringLiteral( "expanded-legend-nodes" ) );
        expandedLegendNodesElem.setAttribute( QStringLiteral( "id" ), layerID );
        for ( const QString &expandedLegendNode : std::as_const( layerRec.expandedLegendItems ) )
        {
          QDomElement expandedLegendNodeElem = doc.createElement( QStringLiteral( "expanded-legend-node" ) );
          expandedLegendNodeElem.setAttribute( QStringLiteral( "id" ), expandedLegendNode );
          expandedLegendNodesElem.appendChild( expandedLegendNodeElem );
        }
        visPresetElem.appendChild( expandedLegendNodesElem );
      }
    }
 
    if ( rec.hasCheckedStateInfo() )
    {
      QDomElement checkedGroupElems = doc.createElement( QStringLiteral( "checked-group-nodes" ) );
      const QSet<QString> checkedGroupNodes = rec.checkedGroupNodes();
      for ( const QString &groupId : checkedGroupNodes )
      {
        QDomElement checkedGroupElem = doc.createElement( QStringLiteral( "checked-group-node" ) );
        checkedGroupElem.setAttribute( QStringLiteral( "id" ), groupId );
        checkedGroupElems.appendChild( checkedGroupElem );
      }
      visPresetElem.appendChild( checkedGroupElems );
    }
 
    if ( rec.hasExpandedStateInfo() )
    {
      QDomElement expandedGroupElems = doc.createElement( QStringLiteral( "expanded-group-nodes" ) );
      const QSet<QString> expandedGroupNodes = rec.expandedGroupNodes();
      for ( const QString &groupId : expandedGroupNodes )
      {
        QDomElement expandedGroupElem = doc.createElement( QStringLiteral( "expanded-group-node" ) );
        expandedGroupElem.setAttribute( QStringLiteral( "id" ), groupId );
        expandedGroupElems.appendChild( expandedGroupElem );
      }
      visPresetElem.appendChild( expandedGroupElems );
    }
 
    visPresetsElem.appendChild( visPresetElem );
  }
 
  doc.firstChildElement( QStringLiteral( "qgis" ) ).appendChild( visPresetsElem );
}
 
void QgsMapThemeCollection::registryLayersRemoved( const QStringList &layerIDs )
{
  // while layers are stored as weak pointers, this triggers the mapThemeChanged signal for
  // affected themes
  QSet< QString > changedThemes;
  MapThemeRecordMap::iterator it = mMapThemes.begin();
  for ( ; it != mMapThemes.end(); ++it )
  {
    MapThemeRecord &rec = it.value();
    for ( int i = 0; i < rec.mLayerRecords.count(); ++i )
    {
      MapThemeLayerRecord &layerRec = rec.mLayerRecords[i];
      if ( layerRec.layer() && layerIDs.contains( layerRec.layer()->id() ) )
      {
        rec.mLayerRecords.removeAt( i-- );
        changedThemes << it.key();
      }
    }
  }
 
  for ( const QString &theme : std::as_const( changedThemes ) )
  {
    emit mapThemeChanged( theme );
  }
  emit mapThemesChanged();
}
 
void QgsMapThemeCollection::layerStyleRenamed( const QString &oldName, const QString &newName )
{
  QgsMapLayerStyleManager *styleMgr = qobject_cast<QgsMapLayerStyleManager *>( sender() );
  if ( !styleMgr )
    return;
 
  QSet< QString > changedThemes;
 
  MapThemeRecordMap::iterator it = mMapThemes.begin();
  for ( ; it != mMapThemes.end(); ++it )
  {
    MapThemeRecord &rec = it.value();
    for ( int i = 0; i < rec.mLayerRecords.count(); ++i )
    {
      MapThemeLayerRecord &layerRec = rec.mLayerRecords[i];
      if ( layerRec.layer() == styleMgr->layer() )
      {
        if ( layerRec.currentStyle == oldName )
        {
          layerRec.currentStyle = newName;
          changedThemes << it.key();
        }
      }
    }
  }
 
  for ( const QString &theme : std::as_const( changedThemes ) )
  {
    emit mapThemeChanged( theme );
  }
  emit mapThemesChanged();
}
 
void QgsMapThemeCollection::MapThemeRecord::removeLayerRecord( QgsMapLayer *layer )
{
  for ( int i = 0; i < mLayerRecords.length(); ++i )
  {
    if ( mLayerRecords.at( i ).layer() == layer )
      mLayerRecords.removeAt( i );
  }
}
 
void QgsMapThemeCollection::MapThemeRecord::addLayerRecord( const QgsMapThemeCollection::MapThemeLayerRecord &record )
{
  mLayerRecords.append( record );
}
 
QHash<QgsMapLayer *, QgsMapThemeCollection::MapThemeLayerRecord> QgsMapThemeCollection::MapThemeRecord::validLayerRecords() const
{
  QHash<QgsMapLayer *, MapThemeLayerRecord> validSet;
  for ( const MapThemeLayerRecord &layerRec : mLayerRecords )
  {
    if ( auto *lLayer = layerRec.layer() )
      validSet.insert( lLayer, layerRec );
  }
  return validSet;
}
 
void QgsMapThemeCollection::MapThemeLayerRecord::setLayer( QgsMapLayer *layer )
{
  mLayer = layer;
}