[FEATURE] New $atlasfeature expression function for returning the cur…

…rent atlas feature. Also clean up the expression groups and move some unrelated functions out of the 'Record' group.

resources/function_help/$atlasfeature

@@ -0,0 +1,13 @@
+<h3>$atlasfeature function</h3>
+In atlas generation, returns the current feature that is iterated over on the coverage layer. This can be used with the 'attribute' function
+to return attribute values from the current atlas feature.
+
+<h4>Syntax</h4>
+<pre>$atlasfeature</pre>
+
+<h4>Arguments</h4>
+None
+
+<h4>Example</h4>
+<pre>attribute( $atlasfeature, 'name' ) &rarr; returns value stored in 'name' attribute for the current atlas feature</pre>
+

src/app/composer/qgscomposer.cpp

@@ -3491,6 +3491,7 @@ void QgsComposer::setAtlasFeature( QgsMapLayer* layer, QgsFeature * feat )
 {
   //update expression variables
   QgsExpression::setSpecialColumn( "$atlasfeatureid", feat->id() );
+  QgsExpression::setSpecialColumn( "$atlasfeature", QVariant::fromValue( *feat ) );
   QgsExpression::setSpecialColumn( "$atlasgeometry", QVariant::fromValue( *( feat->geometry() ) ) );
 
   emit atlasPreviewFeatureChanged();

src/core/composer/qgsatlascomposition.cpp

@@ -45,6 +45,7 @@ QgsAtlasComposition::QgsAtlasComposition( QgsComposition* composition ) :
   QgsExpression::setSpecialColumn( "$numpages", QVariant(( int )1 ) );
   QgsExpression::setSpecialColumn( "$numfeatures", QVariant(( int )0 ) );
   QgsExpression::setSpecialColumn( "$atlasfeatureid", QVariant(( int )0 ) );
+  QgsExpression::setSpecialColumn( "$atlasfeature", QVariant::fromValue( QgsFeature() ) );
   QgsExpression::setSpecialColumn( "$atlasgeometry", QVariant::fromValue( QgsGeometry() ) );
 }
 
@@ -73,6 +74,7 @@ void QgsAtlasComposition::setCoverageLayer( QgsVectorLayer* layer )
     layer->getFeatures().nextFeature( fet );
     QgsExpression::setSpecialColumn( "$atlasfeatureid", fet.id() );
     QgsExpression::setSpecialColumn( "$atlasgeometry", QVariant::fromValue( *fet.geometry() ) );
+    QgsExpression::setSpecialColumn( "$atlasfeature", QVariant::fromValue( fet ) );
   }
 
   emit coverageLayerChanged( layer );
@@ -357,6 +359,7 @@ bool QgsAtlasComposition::prepareForFeature( int featureI )
 
   QgsExpression::setSpecialColumn( "$atlasfeatureid", mCurrentFeature.id() );
   QgsExpression::setSpecialColumn( "$atlasgeometry", QVariant::fromValue( *mCurrentFeature.geometry() ) );
+  QgsExpression::setSpecialColumn( "$atlasfeature", QVariant::fromValue( mCurrentFeature ) );
   QgsExpression::setSpecialColumn( "$feature", QVariant(( int )featureI + 1 ) );
 
   // generate filename for current feature

src/core/qgsexpression.cpp

@@ -1680,14 +1680,14 @@ const QList<QgsExpression::Function*> &QgsExpression::Functions()
     << new StaticFunction( "geomToWKT", 1, fcnGeomToWKT, "Geometry" )
     << new StaticFunction( "$rownum", 0, fcnRowNumber, "Record" )
     << new StaticFunction( "$id", 0, fcnFeatureId, "Record" )
-    << new StaticFunction( "$currentfeature", 0, fcnFeature, "Features" )
+    << new StaticFunction( "$currentfeature", 0, fcnFeature, "Record" )
     << new StaticFunction( "$scale", 0, fcnScale, "Record" )
     << new StaticFunction( "$uuid", 0, fcnUuid, "Record" )
 
     //return all attributes string for referencedColumns - this is caught by
     // QgsFeatureRequest::setSubsetOfAttributes and causes all attributes to be fetched by the
     // feature request
-    << new StaticFunction( "attribute", 2, fcnAttribute, "Features", QString(), false, QStringList( QgsFeatureRequest::AllAttributes ) )
+    << new StaticFunction( "attribute", 2, fcnAttribute, "Record", QString(), false, QStringList( QgsFeatureRequest::AllAttributes ) )
 
     << new StaticFunction( "_specialcol_", 1, fcnSpecialColumn, "Special" )
     ;
@@ -1696,6 +1696,7 @@ const QList<QgsExpression::Function*> &QgsExpression::Functions()
 }
 
 QMap<QString, QVariant> QgsExpression::gmSpecialColumns;
+QMap<QString, QString> QgsExpression::gmSpecialColumnGroups;
 
 void QgsExpression::setSpecialColumn( const QString& name, QVariant variant )
 {
@@ -1742,10 +1743,23 @@ bool QgsExpression::hasSpecialColumn( const QString& name )
     // This is really sub-optimal, we should get rid of the special columns and instead have contexts in which some values
     // are defined and some are not ($rownum makes sense only in field calculator, $scale only when rendering, $page only for composer etc.)
 
-    QStringList lst;
-    lst << "$page" << "$feature" << "$numpages" << "$numfeatures" << "$atlasfeatureid" << "$atlasgeometry" << "$map";
-    foreach ( QString c, lst )
-      setSpecialColumn( c, QVariant() );
+    //pairs of column name to group name
+    QList< QPair<QString, QString> > lst;
+    lst << qMakePair( QString( "$page" ), QString( "Composer" ) );
+    lst << qMakePair( QString( "$feature" ), QString( "Atlas" ) );
+    lst << qMakePair( QString( "$numpages" ), QString( "Composer" ) );
+    lst << qMakePair( QString( "$numfeatures" ), QString( "Atlas" ) );
+    lst << qMakePair( QString( "$atlasfeatureid" ), QString( "Atlas" ) );
+    lst << qMakePair( QString( "$atlasgeometry" ), QString( "Atlas" ) );
+    lst << qMakePair( QString( "$atlasfeature" ), QString( "Atlas" ) );
+    lst << qMakePair( QString( "$map" ), QString( "Composer" ) );
+
+    QList< QPair<QString, QString> >::const_iterator it = lst.constBegin();
+    for ( ; it != lst.constEnd(); ++it )
+    {
+      setSpecialColumn(( *it ).first, QVariant() );
+      gmSpecialColumnGroups[( *it ).first ] = ( *it ).second;
+    }
 
     initialized = true;
   }
@@ -1768,7 +1782,9 @@ QList<QgsExpression::Function*> QgsExpression::specialColumns()
   QList<Function*> defs;
   for ( QMap<QString, QVariant>::const_iterator it = gmSpecialColumns.begin(); it != gmSpecialColumns.end(); ++it )
   {
-    defs << new StaticFunction( it.key(), 0, 0, "Record" );
+    //check for special column group name
+    QString group = gmSpecialColumnGroups.value( it.key(), "Record" );
+    defs << new StaticFunction( it.key(), 0, 0, group );
   }
   return defs;
 }

src/core/qgsexpression.h

@@ -629,6 +629,8 @@ class CORE_EXPORT QgsExpression
     QString mExp;
 
     static QMap<QString, QVariant> gmSpecialColumns;
+    static QMap<QString, QString> gmSpecialColumnGroups;
+
     QgsDistanceArea *mCalc;
 
     friend class QgsOgcUtils;