Merge pull request #4239 from nyalldawson/layer_freakin_order

Allow retrieval of project layer order through QgsProject

Author: nyalldawson

doc/api_break.dox

@@ -1261,6 +1261,7 @@ QgsLayerTreeMapCanvasBridge        {#qgis_api_break_3_0_QgsLayerTreeMapCanvasBri
 -----------------
 
 - setAutoEnableCrsTransform() and autoEnableCrsTransform() were removed. CRS transformation is now always enabled.
+- setCanvasLayers() now requires a third map layer list argument for storage of all layers in the layer tree order.
 
 
 QgsLayerTreeModel        {#qgis_api_break_3_0_QgsLayerTreeMode}

python/core/layertree/qgslayertree.sip

@@ -12,11 +12,8 @@
  */
 namespace QgsLayerTree
 {
-  //! Check whether the node is a valid group node
-  bool isGroup( QgsLayerTreeNode* node );
-
-  //! Check whether the node is a valid layer node
-  bool isLayer( QgsLayerTreeNode* node );
+  bool isGroup( QgsLayerTreeNode *node );
+  bool isLayer( const QgsLayerTreeNode *node );
 
   //! Cast node to a group. No type checking is done - use isGroup() to find out whether this operation is legal.
   // PYTHON: automatic cast

python/core/layertree/qgslayertreenode.sip

@@ -70,7 +70,7 @@ class QgsLayerTreeNode : QObject
     ~QgsLayerTreeNode();
 
     //! Find out about type of the node. It is usually shorter to use convenience functions from QgsLayerTree namespace for that
-    NodeType nodeType();
+    NodeType nodeType() const;
     //! Get pointer to the parent. If parent is a null pointer, the node is a root node
     QgsLayerTreeNode *parent();
     //! Get list of children of the node. Children are owned by the parent
@@ -132,8 +132,7 @@ class QgsLayerTreeNode : QObject
     //! Return whether this node is unchecked and all its children.
     //! @note added in 3.0
     bool isItemVisibilityUncheckedRecursive() const;
-
-    //! Return whether the node should be shown as expanded or collapsed in GUI
+    QList< QgsMapLayer * > checkedLayers() const;
     bool isExpanded() const;
     //! Set whether the node should be shown as expanded or collapsed in GUI
     void setExpanded( bool expanded );

python/core/qgsmapthemecollection.sip

@@ -102,62 +102,23 @@ class QgsMapThemeCollection : QObject
     //! Returns a list of existing map theme names.
     QStringList mapThemes() const;
 
-    /**
-     * Returns the recorded state of a map theme.
-     */
-    MapThemeRecord mapThemeState( const QString& name ) const;
 
-    /**
-     * Returns the list of layer IDs that are visible for the specified map theme.
-     *
-     * @note The order of the returned list is not guaranteed to reflect the order of layers
-     * in the canvas.
-     * @note Added in QGIS 3.0
-     */
-    QStringList mapThemeVisibleLayerIds( const QString& name ) const;
 
-    /**
-     * Returns the list of layers that are visible for the specified map theme.
-     *
-     * @note The order of the returned list is not guaranteed to reflect the order of layers
-     * in the canvas.
-     * @note Added in QGIS 3.0
-     */
-    QList<QgsMapLayer*> mapThemeVisibleLayers( const QString& name ) const;
 
-    /**
-     * Get layer style overrides (for QgsMapSettings) of the visible layers for given map theme.
-     */
-    QMap<QString, QString> mapThemeStyleOverrides( const QString& name );
 
-    /**
-     * Reads the map theme collection state from XML
-     * @param doc DOM document
-     * @see writeXml
-     */
-    void readXml( const QDomDocument& doc );
+    MapThemeRecord mapThemeState( const QString &name ) const;
+    QStringList mapThemeVisibleLayerIds( const QString &name ) const;
+    QList<QgsMapLayer *> mapThemeVisibleLayers( const QString &name ) const;
+    QMap<QString, QString> mapThemeStyleOverrides( const QString &name );
+    void readXml( const QDomDocument &doc );
+    void writeXml( QDomDocument &doc );
+    static MapThemeRecord createThemeFromCurrentState( QgsLayerTreeGroup *root, QgsLayerTreeModel *model );
+    void applyTheme( const QString &name, QgsLayerTreeGroup *root, QgsLayerTreeModel *model );
+    QgsProject *project();
+    void setProject( QgsProject *project );
+    QList< QgsMapLayer * > masterLayerOrder() const;
+    QList< QgsMapLayer * > masterVisibleLayers() const;
 
-    /** Writes the map theme collection state to XML.
-     * @param doc DOM document
-     * @see readXml
-     */
-    void writeXml( QDomDocument& doc );
-
-    /**
-     * Static method to create theme from the current state of layer visibilities in layer tree,
-     * current style of layers and check state of legend items (from a layer tree model).
-     * @note added in QGIS 3.0
-     */
-    static MapThemeRecord createThemeFromCurrentState( QgsLayerTreeGroup* root, QgsLayerTreeModel* model );
-
-    /**
-     * Apply theme given by its name and modify layer tree, current style of layers and checked
-     * legend items of passed layer tree model.
-     * @note added in QGIS 3.0
-     */
-    void applyTheme( const QString& name, QgsLayerTreeGroup* root, QgsLayerTreeModel* model );
-    QgsProject* project();
-    void setProject( QgsProject* project );
   signals:
 
     void mapThemesChanged();

python/core/qgsproject.sip

@@ -487,6 +487,9 @@ class QgsProject : QObject, QgsExpressionContextGenerator
      */
     void reloadAllLayers();
 
+    QList< QgsMapLayer * > layerOrder() const;
+    void setLayerOrder( const QList< QgsMapLayer * > &order );
+
   signals:
     //! emitted when project is being read
     void readProject( const QDomDocument& );
@@ -623,12 +626,12 @@ class QgsProject : QObject, QgsExpressionContextGenerator
      */
     //TODO QGIS 3.0 - rename to past tense
     void removeAll();
+    void layersAdded( const QList<QgsMapLayer *> &layers );
 
-    void layersAdded( const QList<QgsMapLayer *>& layers );
-
-    void layerWasAdded( QgsMapLayer* layer );
+    void layerWasAdded( QgsMapLayer *layer );
+    void legendLayersAdded( const QList<QgsMapLayer *> &layers );
 
-    void legendLayersAdded( const QList<QgsMapLayer*>& layers );
+    void layerOrderChanged();
 
   public slots:
     /**

python/gui/layertree/qgslayertreemapcanvasbridge.sip

@@ -64,8 +64,8 @@ class QgsLayerTreeMapCanvasBridge : QObject
 
     void defaultLayerOrder( QgsLayerTreeNode* node, QStringList& order ) const;
 
-    //! Fill canvasLayers and overviewLayers lists from node and its descendants
-    void setCanvasLayers( QgsLayerTreeNode* node, QList<QgsMapLayer*> &canvasLayers, QList<QgsMapLayer*>& overviewLayers );
+    void setCanvasLayers( QgsLayerTreeNode *node, QList<QgsMapLayer *> &canvasLayers, QList<QgsMapLayer *> &overviewLayers,
+                          QList<QgsMapLayer *> &allLayers );
 
     void deferredSetCanvasLayers();
 

src/core/layertree/qgslayertree.h

@@ -37,7 +37,7 @@ namespace QgsLayerTree
   }
 
   //! Check whether the node is a valid layer node
-  inline bool isLayer( QgsLayerTreeNode *node )
+  inline bool isLayer( const QgsLayerTreeNode *node )
   {
     return node && node->nodeType() == QgsLayerTreeNode::NodeLayer;
   }
@@ -54,6 +54,12 @@ namespace QgsLayerTree
     return static_cast<QgsLayerTreeLayer *>( node );
   }
 
+  //! Cast node to a layer. No type checking is done - use isLayer() to find out whether this operation is legal.
+  inline const QgsLayerTreeLayer *toLayer( const QgsLayerTreeNode *node )
+  {
+    return static_cast< const QgsLayerTreeLayer *>( node );
+  }
+
 }
 
 #endif // QGSLAYERTREE_H

src/core/layertree/qgslayertreenode.cpp

@@ -126,6 +126,26 @@ bool QgsLayerTreeNode::isItemVisibilityUncheckedRecursive() const
   return true;
 }
 
+void fetchCheckedLayers( const QgsLayerTreeNode *node, QList<QgsMapLayer *> &layers )
+{
+  if ( QgsLayerTree::isLayer( node ) )
+  {
+    const QgsLayerTreeLayer *nodeLayer = QgsLayerTree::toLayer( node );
+    if ( nodeLayer->isVisible() )
+      layers << nodeLayer->layer();
+  }
+
+  Q_FOREACH ( QgsLayerTreeNode *child, node->children() )
+    fetchCheckedLayers( child, layers );
+}
+
+QList<QgsMapLayer *> QgsLayerTreeNode::checkedLayers() const
+{
+  QList<QgsMapLayer *> layers;
+  fetchCheckedLayers( this, layers );
+  return layers;
+}
+
 void QgsLayerTreeNode::setExpanded( bool expanded )
 {
   if ( mExpanded == expanded )

src/core/layertree/qgslayertreenode.h

@@ -24,6 +24,7 @@
 class QDomElement;
 
 class QgsProject;
+class QgsMapLayer;
 
 /** \ingroup core
  * This class is a base class for nodes in a layer tree.
@@ -80,7 +81,7 @@ class CORE_EXPORT QgsLayerTreeNode : public QObject
     ~QgsLayerTreeNode();
 
     //! Find out about type of the node. It is usually shorter to use convenience functions from QgsLayerTree namespace for that
-    NodeType nodeType() { return mNodeType; }
+    NodeType nodeType() const { return mNodeType; }
     //! Get pointer to the parent. If parent is a null pointer, the node is a root node
     QgsLayerTreeNode *parent() { return mParent; }
     //! Get list of children of the node. Children are owned by the parent
@@ -145,6 +146,13 @@ class CORE_EXPORT QgsLayerTreeNode : public QObject
     //! @note added in 3.0
     bool isItemVisibilityUncheckedRecursive() const;
 
+    /**
+     * Returns a list of any checked layers which belong to this node or its
+     * children.
+     * @note added in QGIS 3.0
+     */
+    QList< QgsMapLayer * > checkedLayers() const;
+
     //! Return whether the node should be shown as expanded or collapsed in GUI
     bool isExpanded() const;
     //! Set whether the node should be shown as expanded or collapsed in GUI

src/core/qgsmapthemecollection.cpp

@@ -175,6 +175,37 @@ void QgsMapThemeCollection::setProject( QgsProject *project )
   emit projectChanged();
 }
 
+QList<QgsMapLayer *> QgsMapThemeCollection::masterLayerOrder() const
+{
+  if ( !mProject )
+    return QList< QgsMapLayer * >();
+
+  return mProject->layerOrder();
+}
+
+QList<QgsMapLayer *> QgsMapThemeCollection::masterVisibleLayers() const
+{
+  QList< QgsMapLayer *> allLayers = masterLayerOrder();
+  QList< QgsMapLayer * > visibleLayers = mProject->layerTreeRoot()->checkedLayers();
+
+  if ( allLayers.isEmpty() )
+  {
+    // no project layer order set
+    return visibleLayers;
+  }
+
+  else
+  {
+    QList< QgsMapLayer * > orderedVisibleLayers;
+    Q_FOREACH ( QgsMapLayer *layer, allLayers )
+    {
+      if ( visibleLayers.contains( layer ) )
+        orderedVisibleLayers << layer;
+    }
+    return orderedVisibleLayers;
+  }
+}
+
 
 bool QgsMapThemeCollection::hasMapTheme( const QString &name ) const
 {
@@ -229,23 +260,39 @@ QStringList QgsMapThemeCollection::mapThemes() const
 QStringList QgsMapThemeCollection::mapThemeVisibleLayerIds( const QString &name ) const
 {
   QStringList layerIds;
-  Q_FOREACH ( const MapThemeLayerRecord &layerRec, mMapThemes.value( name ).mLayerRecords )
+  Q_FOREACH ( QgsMapLayer *layer, mapThemeVisibleLayers( name ) )
   {
-    if ( layerRec.layer() )
-      layerIds << layerRec.layer()->id();
+    layerIds << layer->id();
   }
   return layerIds;
 }
 
-
 QList<QgsMapLayer *> QgsMapThemeCollection::mapThemeVisibleLayers( const QString &name ) const
 {
   QList<QgsMapLayer *> layers;
-  Q_FOREACH ( const MapThemeLayerRecord &layerRec, mMapThemes.value( name ).mLayerRecords )
+  const QList<MapThemeLayerRecord> &recs = mMapThemes.value( name ).mLayerRecords;
+  QList<QgsMapLayer *> layerOrder = masterLayerOrder();
+  if ( layerOrder.isEmpty() )
   {
-    if ( layerRec.layer() )
-      layers << layerRec.layer();
+    // no master layer order - so we have to just use the stored theme layer order as a fallback
+    Q_FOREACH ( const MapThemeLayerRecord &layerRec, mMapThemes.value( name ).mLayerRecords )
+    {
+      if ( layerRec.layer() )
+        layers << layerRec.layer();
+    }
   }
+  else
+  {
+    Q_FOREACH ( QgsMapLayer *layer, layerOrder )
+    {
+      Q_FOREACH ( const MapThemeLayerRecord &layerRec, recs )
+      {
+        if ( layerRec.layer() == layer )
+          layers << layerRec.layer();
+      }
+    }
+  }
+
   return layers;
 }
 

src/core/qgsmapthemecollection.h

@@ -242,6 +242,23 @@ class CORE_EXPORT QgsMapThemeCollection : public QObject
      */
     void setProject( QgsProject *project );
 
+    /**
+     * Returns the master layer order (this will always match the project's QgsProject::layerOrder() ).
+     * All map themes will maintain the same layer order as the master layer order.
+     * @note added in QGIS 3.0
+     * @see masterVisibleLayers()
+     */
+    QList< QgsMapLayer * > masterLayerOrder() const;
+
+    /**
+     * Returns the master list of visible layers. The order of returned layers will always match those
+     * of masterLayerOrder(), but the returned layers are filtered to only include those visible
+     * in the project's layer tree.
+     * @note added in QGIS 3.0
+     * @see masterLayerOrder()
+     */
+    QList< QgsMapLayer * > masterVisibleLayers() const;
+
   signals:
 
     /**