Added willRenderFeature() and symbolsForFeature() utility methods.

Author: wonder-sk

python/core/symbology-ng-core.sip

@@ -77,6 +77,17 @@ public:
 
   virtual QString dump();
 
+  enum Capabilities
+  {
+    SymbolLevels = 1,     // rendering with symbol levels (i.e. implements symbols(), symbolForFeature())
+    RotationField = 2,    // rotate symbols by attribute value
+    MoreSymbolsPerFeature = 4  // may use more than one symbol to render a feature: symbolsForFeature() will return them
+  };
+
+  //! returns bitwise OR-ed capabilities of the renderer
+  //! \note added in 2.0
+  virtual int capabilities();
+
   virtual QgsFeatureRendererV2* clone()=0 /Factory/;
 
   virtual QgsSymbolV2List symbols()=0;
@@ -105,6 +116,18 @@ public:
   //! @note added in 1.9
   virtual void setRotationField( QString fieldName );
 
+  //! return whether the renderer will render a feature or not.
+  //! Must be called between startRender() and stopRender() calls.
+  //! Default implementation uses symbolForFeature().
+  //! @note added in 1.9
+  virtual bool willRenderFeature( QgsFeature& feat );
+
+  //! return list of symbols used for rendering the feature.
+  //! For renderers that do not support MoreSymbolsPerFeature it is more efficient
+  //! to use symbolForFeature()
+  //! @note added in 1.9
+  virtual QgsSymbolV2List symbolsForFeature( QgsFeature& feat );
+
 protected:
   QgsFeatureRendererV2(QString type);
 
@@ -154,6 +177,10 @@ public:
 
   virtual QString dump();
 
+  //! returns bitwise OR-ed capabilities of the renderer
+  //! \note added in 2.0
+  virtual int capabilities();
+
   virtual QgsFeatureRendererV2* clone() /Factory/;
 
   virtual QgsSymbolV2List symbols();
@@ -221,6 +248,10 @@ public:
 
   virtual QString dump();
 
+  //! returns bitwise OR-ed capabilities of the renderer
+  //! \note added in 2.0
+  virtual int capabilities();
+
   virtual QgsFeatureRendererV2* clone() /Factory/;
 
   virtual QgsSymbolV2List symbols();
@@ -320,6 +351,10 @@ public:
 
   virtual QString dump();
 
+  //! returns bitwise OR-ed capabilities of the renderer
+  //! \note added in 2.0
+  virtual int capabilities();
+
   virtual QgsFeatureRendererV2* clone() /Factory/;
 
   virtual QgsSymbolV2List symbols();
@@ -410,27 +445,76 @@ class QgsRuleBasedRendererV2 : QgsFeatureRendererV2
     class Rule
     {
       public:
-        //! Constructor takes ownership of the symbol
-        Rule( QgsSymbolV2* symbol /Transfer/, int scaleMinDenom = 0, int scaleMaxDenom = 0, QString filterExp = QString() );
-        //Rule( const QgsRuleBasedRendererV2::Rule& other );
+
+        Rule( QgsSymbolV2* symbol /Transfer/, int scaleMinDenom = 0, int scaleMaxDenom = 0, QString filterExp = QString(),
+              QString label = QString(), QString description = QString() );
         ~Rule();
-        QString dump() const;
-        //QStringList needsFields() const;
+        QString dump( int offset = 0 ) const;
+        QSet<QString> usedAttributes();
+        QgsSymbolV2List symbols();
+        // TODO QgsLegendSymbolList legendSymbolItems();
         bool isFilterOK( QgsFeature& f ) const;
         bool isScaleOK( double scale ) const;
 
         QgsSymbolV2* symbol();
+        QString label() const;
         bool dependsOnScale() const;
         int scaleMinDenom() const;
         int scaleMaxDenom() const;
-        QString filterExpression() const;
         QgsExpression* filter() const;
+        QString filterExpression() const;
+        QString description() const;
 
+        //! set a new symbol (or NULL). Deletes old symbol.
+        void setSymbol( QgsSymbolV2* sym /Transfer/ );
+        void setLabel( QString label );
         void setScaleMinDenom( int scaleMinDenom );
         void setScaleMaxDenom( int scaleMaxDenom );
         void setFilterExpression( QString filterExp );
+        void setDescription( QString description );
+
+        //! clone this rule, return new instance
+        QgsRuleBasedRendererV2::Rule* clone() const /Factory/;
+
+        QDomElement save( QDomDocument& doc, QgsSymbolV2Map& symbolMap );
+
+        //! prepare the rule for rendering and its children (build active children array)
+        bool startRender( QgsRenderContext& context, const QgsVectorLayer *vlayer );
+        //! get all used z-levels from this rule and children
+        QSet<int> collectZLevels();
+        //! assign normalized z-levels [0..N-1] for this rule's symbol for quick access during rendering
+        // TODO void setNormZLevels( const QMap<int, int>& zLevelsToNormLevels );
+
+        // TODO bool renderFeature( FeatureToRender& featToRender, QgsRenderContext& context, RenderQueue& renderQueue );
+
+        //! only tell whether a feature will be rendered without actually rendering it
+        //! @note added in 1.9
+        bool willRenderFeature( QgsFeature& feat );
+
+        //! tell which symbols will be used to render the feature
+        //! @note added in 1.9
+        QgsSymbolV2List symbolsForFeature( QgsFeature& feat );
+
+        void stopRender( QgsRenderContext& context );
+
+        static QgsRuleBasedRendererV2::Rule* create( QDomElement& ruleElem, QgsSymbolV2Map& symbolMap ) /Factory/;
+
+        QList<QgsRuleBasedRendererV2::Rule*>& children();
+        QgsRuleBasedRendererV2::Rule* parent();
+
+        //! add child rule, take ownership, sets this as parent
+        void appendChild( QgsRuleBasedRendererV2::Rule* rule /Transfer/ );
+        //! add child rule, take ownership, sets this as parent
+        void insertChild( int i, QgsRuleBasedRendererV2::Rule* rule /Transfer/ );
+        //! delete child rule
+        void removeChild( QgsRuleBasedRendererV2::Rule* rule );
+        //! delete child rule
+        void removeChildAt( int i );
+        //! take child rule out, set parent as null
+        void takeChild( QgsRuleBasedRendererV2::Rule* rule );
+        //! take child rule out, set parent as null
+        QgsRuleBasedRendererV2::Rule* takeChildAt( int i );
 
-        //Rule& operator=( const Rule& other );
     };
 
     /////
@@ -453,6 +537,12 @@ class QgsRuleBasedRendererV2 : QgsFeatureRendererV2
 
     virtual QList<QString> usedAttributes();
 
+    virtual QString dump();
+
+    //! returns bitwise OR-ed capabilities of the renderer
+    //! \note added in 2.0
+    virtual int capabilities();
+
     virtual QgsFeatureRendererV2* clone() /Factory/;
 
     virtual QgsSymbolV2List symbols();
@@ -463,6 +553,17 @@ class QgsRuleBasedRendererV2 : QgsFeatureRendererV2
     //! return a list of symbology items for the legend 
     virtual QgsLegendSymbologyList legendSymbologyItems( QSize iconSize ); 
 
+    //! return whether the renderer will render a feature or not.
+    //! Must be called between startRender() and stopRender() calls.
+    //! @note added in 1.9
+    virtual bool willRenderFeature( QgsFeature& feat );
+
+    //! return list of symbols used for rendering the feature.
+    //! For renderers that do not support MoreSymbolsPerFeature it is more efficient
+    //! to use symbolForFeature()
+    //! @note added in 1.9
+    virtual QgsSymbolV2List symbolsForFeature( QgsFeature& feat );
+
     /////
 
 

src/core/symbology-ng/qgsrendererv2.cpp

@@ -417,3 +417,11 @@ void QgsFeatureRendererV2::renderVertexMarkerPolygon( QPolygonF& pts, QList<QPol
     }
   }
 }
+
+QgsSymbolV2List QgsFeatureRendererV2::symbolsForFeature( QgsFeature& feat )
+{
+  QgsSymbolV2List lst;
+  QgsSymbolV2* s = symbolForFeature( feat );
+  if ( s ) lst.append( s );
+  return lst;
+}

src/core/symbology-ng/qgsrendererv2.h

@@ -81,7 +81,8 @@ class CORE_EXPORT QgsFeatureRendererV2
     enum Capabilities
     {
       SymbolLevels = 1,     // rendering with symbol levels (i.e. implements symbols(), symbolForFeature())
-      RotationField = 1 <<  1    // rotate symbols by attribute value
+      RotationField = 1 <<  1,    // rotate symbols by attribute value
+      MoreSymbolsPerFeature = 1 << 2  // may use more than one symbol to render a feature: symbolsForFeature() will return them
     };
 
     //! returns bitwise OR-ed capabilities of the renderer
@@ -117,7 +118,17 @@ class CORE_EXPORT QgsFeatureRendererV2
     //! @note added in 1.9
     virtual void setRotationField( QString fieldName ) { Q_UNUSED( fieldName ); }
 
+    //! return whether the renderer will render a feature or not.
+    //! Must be called between startRender() and stopRender() calls.
+    //! Default implementation uses symbolForFeature().
+    //! @note added in 1.9
+    virtual bool willRenderFeature( QgsFeature& feat ) { return symbolForFeature( feat ) != NULL; }
 
+    //! return list of symbols used for rendering the feature.
+    //! For renderers that do not support MoreSymbolsPerFeature it is more efficient
+    //! to use symbolForFeature()
+    //! @note added in 1.9
+    virtual QgsSymbolV2List symbolsForFeature( QgsFeature& feat );
 
   protected:
     QgsFeatureRendererV2( QString type );

src/core/symbology-ng/qgsrulebasedrendererv2.cpp

@@ -288,6 +288,38 @@ bool QgsRuleBasedRendererV2::Rule::renderFeature( QgsRuleBasedRendererV2::Featur
   return rendered;
 }
 
+bool QgsRuleBasedRendererV2::Rule::willRenderFeature( QgsFeature& feat )
+{
+  if ( !isFilterOK( feat ) )
+    return false;
+  if ( mSymbol )
+    return true;
+
+  for ( QList<Rule*>::iterator it = mActiveChildren.begin(); it != mActiveChildren.end(); ++it )
+  {
+    Rule* rule = *it;
+    if ( rule->willRenderFeature( feat ) )
+      return true;
+  }
+  return false;
+}
+
+QgsSymbolV2List QgsRuleBasedRendererV2::Rule::symbolsForFeature( QgsFeature& feat )
+{
+  QgsSymbolV2List lst;
+  if ( !isFilterOK( feat ) )
+    return lst;
+  if ( mSymbol )
+    lst.append( mSymbol );
+
+  for ( QList<Rule*>::iterator it = mActiveChildren.begin(); it != mActiveChildren.end(); ++it )
+  {
+    Rule* rule = *it;
+    lst += rule->symbolsForFeature( feat );
+  }
+  return lst;
+}
+
 
 void QgsRuleBasedRendererV2::Rule::stopRender( QgsRenderContext& context )
 {
@@ -581,3 +613,13 @@ QString QgsRuleBasedRendererV2::dump()
   msg += mRootRule->dump();
   return msg;
 }
+
+bool QgsRuleBasedRendererV2::willRenderFeature( QgsFeature& feat )
+{
+  return mRootRule->willRenderFeature( feat );
+}
+
+QgsSymbolV2List QgsRuleBasedRendererV2::symbolsForFeature( QgsFeature& feat )
+{
+  return mRootRule->symbolsForFeature( feat );
+}

src/core/symbology-ng/qgsrulebasedrendererv2.h

@@ -127,6 +127,14 @@ class CORE_EXPORT QgsRuleBasedRendererV2 : public QgsFeatureRendererV2
 
         bool renderFeature( FeatureToRender& featToRender, QgsRenderContext& context, RenderQueue& renderQueue );
 
+        //! only tell whether a feature will be rendered without actually rendering it
+        //! @note added in 1.9
+        bool willRenderFeature( QgsFeature& feat );
+
+        //! tell which symbols will be used to render the feature
+        //! @note added in 1.9
+        QgsSymbolV2List symbolsForFeature( QgsFeature& feat );
+
         void stopRender( QgsRenderContext& context );
 
         static Rule* create( QDomElement& ruleElem, QgsSymbolV2Map& symbolMap );
@@ -204,6 +212,21 @@ class CORE_EXPORT QgsRuleBasedRendererV2 : public QgsFeatureRendererV2
     //! for debugging
     virtual QString dump();
 
+    //! return whether the renderer will render a feature or not.
+    //! Must be called between startRender() and stopRender() calls.
+    //! @note added in 1.9
+    virtual bool willRenderFeature( QgsFeature& feat );
+
+    //! return list of symbols used for rendering the feature.
+    //! For renderers that do not support MoreSymbolsPerFeature it is more efficient
+    //! to use symbolForFeature()
+    //! @note added in 1.9
+    virtual QgsSymbolV2List symbolsForFeature( QgsFeature& feat );
+
+    //! returns bitwise OR-ed capabilities of the renderer
+    //! \note added in 2.0
+    virtual int capabilities() { return MoreSymbolsPerFeature; }
+
     /////
 
     Rule* rootRule() { return mRootRule; }