Penalize small lines/polygons with additional cost for all candidates of the feature part.

This has the effect that larger objects get higher chance of being labeled.


git-svn-id: http://svn.osgeo.org/qgis/branches/symbology-ng-branch@11317 c8812cc2-4d05-0410-92ff-de0c093fc19c

Author: wonder

src/core/pal/costcalculator.cpp

@@ -188,6 +188,9 @@ namespace pal
           setPolygonCandidatesCost( stop, (LabelPosition**) feat->lPos, max_p, obstacles, bbx, bby );
       }
 
+      // add size penalty (small lines/polygons get higher cost)
+      feat->feature->addSizePenalty(max_p, feat->lPos, bbx, bby);
+
       return max_p;
    }
 

src/core/pal/feature.cpp

@@ -1279,6 +1279,44 @@ void FeaturePart::removeDuplicatePoints()
     return rnbp;
   }
 
+  void FeaturePart::addSizePenalty( int nbp, LabelPosition** lPos, double bbx[4], double bby[4])
+  {
+    int geomType = GEOSGeomTypeId(the_geom);
+
+    double sizeCost = 0;
+    if (geomType == GEOS_LINESTRING)
+    {
+      double length;
+      if (GEOSLength(the_geom, &length) != 1)
+        return; // failed to calculate length
+      double bbox_length = max(bbx[2]-bbx[0], bby[2]-bby[0]);
+      if (length >= bbox_length/4)
+        return; // the line is longer than quarter of height or width - don't penalize it
+
+      sizeCost = 1 - (length / (bbox_length/4)); // < 0,1 >
+    }
+    else if (geomType == GEOS_POLYGON)
+    {
+      double area;
+      if (GEOSArea(the_geom, &area) != 1)
+        return;
+      double bbox_area = (bbx[2]-bbx[0])*(bby[2]-bby[0]);
+      if (area >= bbox_area/16)
+        return; // covers more than 1/16 of our view - don't penalize it
+
+      sizeCost = 1 - (area / (bbox_area/16)); // < 0, 1 >
+    }
+    else
+      return; // no size penalty for points
+
+    std::cout << "size cost " << sizeCost << std::endl;
+
+    // apply the penalty
+    for (int i = 0; i < nbp; i++)
+    {
+      lPos[i]->setCost( lPos[i]->getCost() + sizeCost / 100 );
+    }
+  }
 
   bool FeaturePart::isConnected(FeaturePart* p2)
   {

src/core/pal/feature.h

@@ -266,6 +266,9 @@ namespace pal
       /** merge other (connected) part with this one and save the result in this part (other is unchanged).
        * Return true on success, false if the feature wasn't modified */
       bool mergeWithFeaturePart(FeaturePart* other);
+
+      void addSizePenalty( int nbp, LabelPosition** lPos, double bbx[4], double bby[4]);
+
   };
 
 } // end namespace pal