Rule-based renderer: dump meaningful debugging info

src/core/symbology-ng/qgsrulebasedrendererv2.cpp

@@ -62,7 +62,7 @@ void QgsRuleBasedRendererV2::Rule::initFilter()
 
 QString QgsRuleBasedRendererV2::Rule::dump() const
 {
-  return QString( "RULE %1 - scale [%2,%3] - filter %4 - symbol %5" )
+  return QString( "RULE %1 - scale [%2,%3] - filter %4 - symbol %5\n" )
          .arg( mLabel ).arg( mScaleMinDenom ).arg( mScaleMaxDenom )
          .arg( mFilterExp ).arg( mSymbol->dump() );
 
@@ -409,3 +409,13 @@ QList<QgsRuleBasedRendererV2::Rule> QgsRuleBasedRendererV2::refineRuleScales( Qg
   rules.append( Rule( initialRule.symbol()->clone(), oldScale, maxDenom, initialRule.filterExpression(), initialRule.label(), initialRule.description() ) );
   return rules;
 }
+
+QString QgsRuleBasedRendererV2::dump()
+{
+  QString msg( "Rule-based renderer:\n" );
+  foreach( const Rule& rule, mRules )
+  {
+    msg += rule.dump();
+  }
+  return msg;
+}

src/core/symbology-ng/qgsrulebasedrendererv2.h

@@ -113,6 +113,9 @@ class CORE_EXPORT QgsRuleBasedRendererV2 : public QgsFeatureRendererV2
     //! @note: this method was added in version 1.5
     virtual QgsLegendSymbolList legendSymbolItems();
 
+    //! for debugging
+    virtual QString dump();
+
     /////
 
     //! return the total number of rules