Implement QgsProject::snapSettingsForLayer as a convenient way to access snap properties for a layer

python/core/qgsproject.sip

@@ -240,6 +240,11 @@ public:
       @note added in 1.4 */
     void setBadLayerHandler( QgsProjectBadLayerHandler* handler );
 
+    void setSnapSettingsForLayer( const QString& layerId, bool enabled, QgsSnapper::SnappingType type, QgsTolerance::UnitType, double tolerance );
+
+    bool snapSettingsForLayer( const QString& layerId, bool& enabled /Out/, QgsSnapper::SnappingType& type /Out/, QgsTolerance::UnitType& units /Out/, double& tolerance /Out/,
+                               bool& avoidIntersection /Out/ );
+
   protected:
 
     /** Set error message from read/write operation

src/core/qgsproject.cpp

@@ -1621,7 +1621,81 @@ bool QgsProject::createEmbeddedLayer( const QString& layerId, const QString& pro
   return false;
 }
 
+void QgsProject::setSnapSettingsForLayer( const QString& layerId, bool enabled, QgsSnapper::SnappingType  type, QgsTolerance::UnitType, double tolerance )
+{
+  //soon...
+}
+
+bool QgsProject::snapSettingsForLayer( const QString& layerId, bool& enabled, QgsSnapper::SnappingType &type, QgsTolerance::UnitType& units, double& tolerance,
+                                       bool& avoidIntersection )
+{
+  QStringList layerIdList, enabledList, snapTypeList, toleranceUnitList, toleranceList, avoidIntersectionList;
+  snapSettings( layerIdList, enabledList, snapTypeList, toleranceUnitList, toleranceList, avoidIntersectionList );
+  int idx = layerIdList.indexOf( layerId );
+  if ( idx == -1 )
+  {
+    return false;
+  }
+
+  //make sure all lists are long enough
+  int minListEntries = idx + 1;
+  if ( layerIdList.size() < minListEntries || enabledList.size() < minListEntries || snapTypeList.size() < minListEntries ||
+       toleranceUnitList.size() < minListEntries || toleranceList.size() < minListEntries )
+  {
+    return false;
+  }
+
+  //enabled
+  enabled = enabledList.at( idx ) == "enabled";
+
+  //snap type
+  QString snapType = snapTypeList.at( idx );
+  if ( snapType == "to_segment" )
+  {
+    type = QgsSnapper::SnapToSegment;
+  }
+  else if ( snapType == "to_vertex_and_segment" )
+  {
+    type = QgsSnapper::SnapToVertexAndSegment;
+  }
+  else //to vertex
+  {
+    type = QgsSnapper::SnapToVertex;
+  }
+
+  //units
+  if ( toleranceUnitList.at( idx ) == "1" )
+  {
+    units = QgsTolerance::Pixels;
+  }
+  else
+  {
+    units = QgsTolerance::MapUnits;
+  }
+
+  //tolerance
+  tolerance = toleranceList.at( idx ).toDouble();
+
+  //avoid intersection
+  avoidIntersection = ( avoidIntersectionList.indexOf( layerId ) != -1 );
+
+  return true;
+}
+
+void QgsProject::snapSettings( QStringList& layerIdList, QStringList& enabledList, QStringList& snapTypeList, QStringList& toleranceUnitList, QStringList& toleranceList,
+                               QStringList& avoidIntersectionList )
+{
+  layerIdList = readListEntry( "Digitizing", "/LayerSnappingList" );
+  enabledList = readListEntry( "Digitizing", "/LayerSnappingEnabledList" );
+  toleranceList = readListEntry( "Digitizing", "/LayerSnappingToleranceList" );
+  toleranceUnitList = readListEntry( "Digitizing", "/LayerSnappingToleranceUnitList" );
+  snapTypeList = readListEntry( "Digitizing", "/LayerSnapToList" );
+  avoidIntersectionList = readListEntry( "Digitizing", "/AvoidIntersectionsList" );
+}
+
 void QgsProjectBadLayerDefaultHandler::handleBadLayers( QList<QDomNode> /*layers*/, QDomDocument /*projectDom*/ )
 {
   // just ignore any bad layers
 }
+
+

src/core/qgsproject.h

@@ -28,6 +28,10 @@
 #include <QObject>
 #include <QPair>
 
+//for the snap settings
+#include "qgssnapper.h"
+#include "qgstolerance.h"
+
 //#include <QDomDocument>
 
 class QFileInfo;
@@ -286,6 +290,12 @@ class CORE_EXPORT QgsProject : public QObject
     bool createEmbeddedLayer( const QString& layerId, const QString& projectFilePath, QList<QDomNode>& brokenNodes,
                               QList< QPair< QgsVectorLayer*, QDomElement > >& vectorLayerList, bool saveFlag = true );
 
+    //convenience interface for querying / modifying the project snap settings per layer
+    void setSnapSettingsForLayer( const QString& layerId, bool enabled, QgsSnapper::SnappingType type, QgsTolerance::UnitType, double tolerance );
+
+    bool snapSettingsForLayer( const QString& layerId, bool& enabled, QgsSnapper::SnappingType& type, QgsTolerance::UnitType& units, double& tolerance,
+                               bool& avoidIntersection );
+
   protected:
 
     /** Set error message from read/write operation
@@ -339,6 +349,9 @@ class CORE_EXPORT QgsProject : public QObject
        If the project file path is empty, QgsProject is going to ignore the layer for saving (e.g. because it is part and managed by an embedded group)*/
     QHash< QString, QPair< QString, bool> > mEmbeddedLayers;
 
+    void snapSettings( QStringList& layerIdList, QStringList& enabledList, QStringList& snapTypeList, QStringList& snapUnitList, QStringList& toleranceUnitList,
+                       QStringList& avoidIntersectionList );
+
 }; // QgsProject