[FEATURE][labeling] Allow data defined control of label priority

Previously only the priority for the entire layer could be specified
(fix #4606)

Author: nyalldawson

python/core/qgspallabeling.sip

@@ -278,6 +278,7 @@ class QgsPalLayerSettings
       Rotation, //data defined rotation
       RepeatDistance,
       RepeatDistanceUnit,
+      Priority,
 
       // rendering
       ScaleVisibility,

src/app/qgslabelinggui.cpp

@@ -831,6 +831,7 @@ QgsPalLayerSettings QgsLabelingGui::layerSettings()
   setDataDefinedProperty( mMaxCharAngleDDBtn, QgsPalLayerSettings::CurvedCharAngleInOut, lyr );
   setDataDefinedProperty( mRepeatDistanceDDBtn, QgsPalLayerSettings::RepeatDistance, lyr );
   setDataDefinedProperty( mRepeatDistanceUnitDDBtn, QgsPalLayerSettings::RepeatDistanceUnit, lyr );
+  setDataDefinedProperty( mPriorityDDBtn, QgsPalLayerSettings::Priority, lyr );
 
   // data defined-only
   setDataDefinedProperty( mCoordXDDBtn, QgsPalLayerSettings::PositionX, lyr );
@@ -1051,6 +1052,9 @@ void QgsLabelingGui::populateDataDefinedButtons( QgsPalLayerSettings& s )
                             QgsDataDefinedButton::AnyType, QgsDataDefinedButton::doublePosDesc() );
   mLineDistanceUnitDDBtn->init( mLayer, s.dataDefinedProperty( QgsPalLayerSettings::DistanceUnits ),
                                 QgsDataDefinedButton::String, QgsDataDefinedButton::unitsMmMuDesc() );
+  mPriorityDDBtn->init( mLayer, s.dataDefinedProperty( QgsPalLayerSettings::Priority ),
+                        QgsDataDefinedButton::AnyType, tr( "double [0.0-10.0]" ) );
+
   // TODO: is this necessary? maybe just use the data defined-only rotation?
   //mPointAngleDDBtn->init( mLayer, s.dataDefinedProperty( QgsPalLayerSettings::OffsetRotation ),
   //                        QgsDataDefinedButton::AnyType, QgsDataDefinedButton::double180RotDesc() );

src/core/pal/feature.cpp

@@ -77,6 +77,7 @@ namespace pal
       , repeatDist( 0.0 )
       , alwaysShow( false )
       , mFixedQuadrant( false )
+      , mPriority( -1.0 )
   {
     assert( finite( lx ) && finite( ly ) );
   }
@@ -86,6 +87,11 @@ namespace pal
 
   }
 
+  double Feature::calculatePriority() const
+  {
+    return mPriority >= 0 ? mPriority : layer->getPriority();
+  }
+
   ////////////
 
   FeaturePart::FeaturePart( Feature *feat, const GEOSGeometry* geom )

src/core/pal/feature.h

@@ -85,24 +85,55 @@ namespace pal
 
       void setLabelInfo( LabelInfo* info ) { labelInfo = info; }
       void setDistLabel( double dist ) { distlabel = dist; }
-      //Set label position of the feature to fixed x/y values
+      /** Set label position of the feature to fixed x/y values */
       void setFixedPosition( double x, double y ) { fixedPos = true; fixedPosX = x; fixedPosY = y;}
       void setQuadOffset( double x, double y ) { quadOffset = true; quadOffsetX = x; quadOffsetY = y;}
 
       /** Sets whether the quadrant for the label must be respected. This can be used
        * to fix the quadrant for specific features when using an "around point" placement.
+       * @see fixedQuadrant
        */
       void setFixedQuadrant( bool fixed ) { mFixedQuadrant = fixed; }
+
+      /** Returns whether the quadrant for the label is fixed.
+       * @see setFixedQuadrant
+       */
       bool fixedQuadrant() const { return mFixedQuadrant; }
 
       void setPosOffset( double x, double y ) { offsetPos = true; offsetPosX = x; offsetPosY = y;}
       bool fixedPosition() const { return fixedPos; }
-      //Set label rotation to fixed value
+
+      /** Set label rotation to fixed value
+      */
       void setFixedAngle( double a ) { fixedRotation = true; fixedAngle = a; }
       void setRepeatDistance( double dist ) { repeatDist = dist; }
       double repeatDistance() const { return repeatDist; }
       void setAlwaysShow( bool bl ) { alwaysShow = bl; }
 
+      /** Sets the priority for labeling the feature.
+       * @param priority feature's priority, as a value between 0 (highest priority)
+       * and 1 (lowest priority). Set to -1.0 to use the layer's default priority
+       * for this feature.
+       * @see priority
+       * @see calculatePriority
+       */
+      void setPriority( double priority ) { mPriority = priority; }
+
+      /** Returns the feature's labeling priority.
+       * @returns feature's priority, as a value between 0 (highest priority)
+       * and 1 (lowest priority). Returns -1.0 if feature will use the layer's default priority.
+       * @see setPriority
+       * @see calculatePriority
+       */
+      double priority() const { return mPriority; }
+
+      /** Calculates the priority for the feature. This will be the feature's priority if set,
+       * otherwise the layer's default priority.
+       * @see setPriority
+       * @see priority
+       */
+      double calculatePriority() const;
+
     protected:
       Layer *layer;
       PalGeometry *userGeom;
@@ -136,6 +167,9 @@ namespace pal
     private:
 
       bool mFixedQuadrant;
+
+      //-1 if layer priority should be used
+      double mPriority;
   };
 
   /**

src/core/pal/layer.h

@@ -192,7 +192,6 @@ namespace pal
        * \ brief set the layer priority
        *
        * The best priority is 0, the worst is 1
-       * Should be links with a slider in a nice gui
        */
       void setPriority( double priority );
 

src/core/pal/pal.cpp

@@ -206,7 +206,6 @@ namespace pal
     QLinkedList<Feats*>* fFeats;
     RTree<PointSet*, double, 2, double> *obstacles;
     RTree<LabelPosition*, double, 2, double> *candidates;
-    double priority;
     double bbox_min[2];
     double bbox_max[2];
   } FeatCallBackCtx;
@@ -275,7 +274,7 @@ namespace pal
       ft->shape = NULL;
       ft->nblp = nblp;
       ft->lPos = lPos;
-      ft->priority = context->priority;
+      ft->priority = ft_ptr->getFeature()->calculatePriority();
       context->fFeats->append( ft );
     }
     else
@@ -320,7 +319,7 @@ namespace pal
     return true;
   }
 
-  Problem* Pal::extract( int nbLayers, const QStringList& layersName, double *layersFactor, double lambda_min, double phi_min, double lambda_max, double phi_max, double scale )
+  Problem* Pal::extract( int nbLayers, const QStringList& layersName, double lambda_min, double phi_min, double lambda_max, double phi_max, double scale )
   {
     // to store obstacles
     RTree<PointSet*, double, 2, double> *obstacles = new RTree<PointSet*, double, 2, double>();
@@ -399,7 +398,6 @@ namespace pal
 
 
             context->layer = layer;
-            context->priority = layersFactor[i];
             // lookup for feature (and generates candidates list)
 
             context->layer->mMutex.lock();
@@ -614,29 +612,26 @@ namespace pal
     int nbLayers = layers->size();
 
     QStringList layersName;
-    double *priorities = new double[nbLayers];
     Layer *layer;
     i = 0;
     for ( QList<Layer*>::iterator it = layers->begin(); it != layers->end(); ++it )
     {
       layer = *it;
       layersName << layer->name;
-      priorities[i] = layer->defaultPriority;
       i++;
     }
     mMutex.unlock();
 
-    std::list<LabelPosition*> * solution = labeller( nbLayers, layersName, priorities, scale, bbox, stats, displayAll );
+    std::list<LabelPosition*> * solution = labeller( nbLayers, layersName, scale, bbox, stats, displayAll );
 
-    delete[] priorities;
     return solution;
   }
 
 
   /*
    * BIG MACHINE
    */
-  std::list<LabelPosition*>* Pal::labeller( int nbLayers, const QStringList& layersName, double *layersFactor, double scale, double bbox[4], PalStat **stats, bool displayAll )
+  std::list<LabelPosition*>* Pal::labeller( int nbLayers, const QStringList& layersName, double scale, double bbox[4], PalStat **stats, bool displayAll )
   {
 #ifdef _DEBUG_
     std::cout << "LABELLER (selection)" << std::endl;
@@ -662,7 +657,7 @@ namespace pal
 
     // First, extract the problem
     // TODO which is the minimum scale? (> 0, >= 0, >= 1, >1 )
-    if ( scale < 1 || ( prob = extract( nbLayers, layersName, layersFactor, bbox[0], bbox[1], bbox[2], bbox[3], scale ) ) == NULL )
+    if ( scale < 1 || ( prob = extract( nbLayers, layersName, bbox[0], bbox[1], bbox[2], bbox[3], scale ) ) == NULL )
     {
 
 #ifdef _VERBOSE_
@@ -750,21 +745,17 @@ namespace pal
     int nbLayers = layers->size();
 
     QStringList layersName;
-    double *priorities = new double[nbLayers];
     Layer *layer;
     int i = 0;
     for ( QList<Layer*>::iterator it = layers->begin(); it != layers->end(); ++it )
     {
       layer = *it;
       layersName << layer->name;
-      priorities[i] = layer->defaultPriority;
       i++;
     }
     mMutex.unlock();
 
-    Problem* prob = extract( nbLayers, layersName, priorities, bbox[0], bbox[1], bbox[2], bbox[3], scale );
-
-    delete[] priorities;
+    Problem* prob = extract( nbLayers, layersName, bbox[0], bbox[1], bbox[2], bbox[3], scale );
 
     return prob;
   }

src/core/pal/pal.h

@@ -202,7 +202,6 @@ namespace pal
        *
        * @param nbLayers # layers
        * @param layersName names of layers to label
-       * @param layersFactor layers priorities array
        * @param scale map scale is  '1:scale'
        * @param bbox map extent
        * @param stat will be filled with labelling process statistics, can be NULL
@@ -214,7 +213,6 @@ namespace pal
        */
       std::list<LabelPosition*> *labeller( int nbLayers,
                                            const QStringList &layersName,
-                                           double *layersFactor,
                                            double scale, double bbox[4],
                                            PalStat **stat,
                                            bool displayAll );
@@ -380,14 +378,13 @@ namespace pal
        *
        * @param nbLayers  number of layers to extract
        * @param layersName layers name to be extracted
-       * @param layersFactor layer's factor (priority between layers, 0 is the best, 1 the worst)
        * @param lambda_min xMin bounding-box
        * @param phi_min yMin bounding-box
        * @param lambda_max xMax bounding-box
        * @param phi_max yMax bounding-box
        * @param scale the scale (1:scale)
        */
-      Problem* extract( int nbLayers, const QStringList& layersName, double *layersFactor,
+      Problem* extract( int nbLayers, const QStringList& layersName,
                         double lambda_min, double phi_min,
                         double lambda_max, double phi_max,
                         double scale );

src/core/qgspallabeling.cpp

@@ -292,6 +292,8 @@ QgsPalLayerSettings::QgsPalLayerSettings()
   mDataDefinedNames.insert( CurvedCharAngleInOut, QPair<QString, int>( "CurvedCharAngleInOut", -1 ) );
   mDataDefinedNames.insert( RepeatDistance, QPair<QString, int>( "RepeatDistance", -1 ) );
   mDataDefinedNames.insert( RepeatDistanceUnit, QPair<QString, int>( "RepeatDistanceUnit", -1 ) );
+  mDataDefinedNames.insert( Priority, QPair<QString, int>( "Priority", -1 ) );
+
   // (data defined only)
   mDataDefinedNames.insert( PositionX, QPair<QString, int>( "PositionX", 9 ) );
   mDataDefinedNames.insert( PositionY, QPair<QString, int>( "PositionY", 10 ) );
@@ -2173,6 +2175,19 @@ void QgsPalLayerSettings::registerFeature( QgsFeature& f, const QgsRenderContext
     feat->setFixedQuadrant( true );
   }
 
+  // data defined priority?
+  if ( dataDefinedEvaluate( QgsPalLayerSettings::Priority, exprVal ) )
+  {
+    bool ok;
+    double priorityD = exprVal.toDouble( &ok );
+    if ( ok )
+    {
+      priorityD = qBound( 0.0, priorityD, 10.0 );
+      priorityD = 1 - priorityD / 10.0; // convert 0..10 --> 1..0
+      feat->setPriority( priorityD );
+    }
+  }
+
   //add parameters for data defined labeling to QgsPalGeometry
   QMap< DataDefinedProperties, QVariant >::const_iterator dIt = dataDefinedValues.constBegin();
   for ( ; dIt != dataDefinedValues.constEnd(); ++dIt )

src/core/qgspallabeling.h

@@ -253,6 +253,7 @@ class CORE_EXPORT QgsPalLayerSettings
       Rotation = 14, //data defined rotation
       RepeatDistance = 84,
       RepeatDistanceUnit = 86,
+      Priority = 87,
 
       // rendering
       ScaleVisibility = 23,
@@ -556,7 +557,7 @@ class CORE_EXPORT QgsPalLayerSettings
 
     void parseDropShadow();
 
-    /**Checks if a feature is larger than a minimum size (in mm)
+    /** Checks if a feature is larger than a minimum size (in mm)
     @return true if above size, false if below*/
     bool checkMinimumSizeMM( const QgsRenderContext& ct, const QgsGeometry* geom, double minSize ) const;