Added possibility to choose mode when labeling a layer: label per feature (default) or label per feature part.

Label per feature uses longest line resp. largest polygon, for multipoint features fallback to label per feature part.


git-svn-id: http://svn.osgeo.org/qgis/branches/symbology-ng-branch@11209 c8812cc2-4d05-0410-92ff-de0c093fc19c

Author: wonder

src/core/pal/layer.cpp

@@ -62,7 +62,7 @@ namespace pal
       :  pal( pal ), obstacle( obstacle ), active( active ),
          toLabel( toLabel ), label_unit( label_unit ),
          min_scale( min_scale ), max_scale( max_scale ),
-         arrangement( arrangement ), arrangementFlags( 0 )
+         arrangement( arrangement ), arrangementFlags( 0 ), mode(LabelPerFeature)
   {
 
     this->name = new char[strlen( lyrName ) +1];
@@ -240,6 +240,9 @@ bool Layer::registerFeature( const char *geom_id, PalGeometry *userGeom, double
 
   bool first_feat = true;
 
+  double geom_size, biggest_size = -1;
+  FeaturePart* biggest_part = NULL;
+
   // break the (possibly multi-part) geometry into simple geometries
   LinkedList <const GEOSGeometry*> *simpleGeometries = unmulti( the_geom );
 
@@ -276,17 +279,25 @@ bool Layer::registerFeature( const char *geom_id, PalGeometry *userGeom, double
       continue;
     }
 
-    // feature part is ready!
-
-    double bmin[2];
-    double bmax[2];
-    fpart->getBoundingBox(bmin, bmax);
+    if (mode == LabelPerFeature && (type == GEOS_POLYGON || type == GEOS_LINESTRING))
+    {
+      if (type == GEOS_LINESTRING)
+        GEOSLength(geom, &geom_size);
+      else if (type == GEOS_POLYGON)
+        GEOSArea(geom, &geom_size);
 
-    // add to list of layer's feature parts
-    featureParts->push_back( fpart );
+      if (geom_size > biggest_size)
+      {
+        biggest_size = geom_size;
+        delete biggest_part; // safe with NULL part
+        biggest_part = fpart;
+      }
+      continue; // don't add the feature part now, do it later
+      // TODO: we should probably add also other parts to act just as obstacles
+    }
 
-    // add to r-tree for fast spatial access
-    rtree->Insert( bmin, bmax, fpart );
+    // feature part is ready!
+    addFeaturePart(fpart);
 
     first_feat = false;
   }
@@ -296,16 +307,40 @@ bool Layer::registerFeature( const char *geom_id, PalGeometry *userGeom, double
 
   modMutex->unlock();
 
+  // if using only biggest parts...
+  if (mode == LabelPerFeature && biggest_part != NULL)
+  {
+    addFeaturePart(biggest_part);
+    first_feat = false;
+  }
+
   // add feature to layer if we have added something
   if (!first_feat)
   {
     features->push_back( f );
     hashtable->insertItem( geom_id, f );
   }
+  else
+  {
+    delete f;
+  }
 
   return !first_feat; // true if we've added something
 }
 
+void Layer::addFeaturePart( FeaturePart* fpart )
+{
+  double bmin[2];
+  double bmax[2];
+  fpart->getBoundingBox(bmin, bmax);
+
+  // add to list of layer's feature parts
+  featureParts->push_back( fpart );
+
+  // add to r-tree for fast spatial access
+  rtree->Insert( bmin, bmax, fpart );
+}
+
 
 void Layer::setLabelUnit( Units label_unit )
 {

src/core/pal/layer.h

@@ -73,6 +73,9 @@ namespace pal
       friend bool extractFeatCallback( FeaturePart *ft_ptr, void *ctx );
       friend void toSVGPath( int nbPoints, double *x, double *y, int dpi, Layer *layer, int type, char *uid, std::ostream &out, double scale, int xmin, int ymax, bool exportInfo, char *color );
 
+    public:
+      enum LabelMode { LabelPerFeature, LabelPerFeaturePart };
+
     protected:
       char *name; /* unique */
 
@@ -97,6 +100,8 @@ namespace pal
 
       Arrangement arrangement;
 
+      LabelMode mode;
+
       /** optional flags used for some placement methods */
       unsigned long arrangementFlags;
 
@@ -134,6 +139,9 @@ namespace pal
        */
       bool isScaleValid( double scale );
 
+      /** add newly creted feature part into r tree and to the list */
+      void addFeaturePart( FeaturePart* fpart );
+
     public:
       /**
        * \brief get the number of features into layer
@@ -260,6 +268,9 @@ namespace pal
        */
       double getPriority();
 
+      void setLabelMode( LabelMode m ) { mode = m; }
+      LabelMode getLabelMode() const { return mode; }
+
       /**
        * \brief register a feature in the layer
        *

src/plugins/labeling/labelinggui.cpp

@@ -111,6 +111,7 @@ LabelingGui::LabelingGui( PalLabeling* lbl, QString layerId, QWidget* parent )
     chkEnableLabeling->setChecked( lyr.enabled );
     sliderPriority->setValue( lyr.priority );
     chkNoObstacle->setChecked( !lyr.obstacle );
+    chkLabelPerFeaturePart->setChecked( lyr.labelPerPart );
 
     bool scaleBased = (lyr.scaleMin != 0 && lyr.scaleMax != 0);
     chkScaleBasedVisibility->setChecked(scaleBased);
@@ -222,6 +223,7 @@ LayerSettings LabelingGui::layerSettings()
   lyr.enabled = chkEnableLabeling->isChecked();
   lyr.priority = sliderPriority->value();
   lyr.obstacle = !chkNoObstacle->isChecked();
+  lyr.labelPerPart = chkLabelPerFeaturePart->isChecked();
   if (chkScaleBasedVisibility->isChecked())
   {
     lyr.scaleMin = spinScaleMin->value();

src/plugins/labeling/labelingguibase.ui

@@ -648,6 +648,13 @@
      </item>
     </layout>
    </item>
+   <item>
+    <widget class="QCheckBox" name="chkLabelPerFeaturePart">
+     <property name="text">
+      <string>label every part of multi-part features</string>
+     </property>
+    </widget>
+   </item>
    <item>
     <layout class="QHBoxLayout" name="horizontalLayout_2">
      <item>

src/plugins/labeling/pallabeling.cpp

@@ -109,6 +109,7 @@ LayerSettings::LayerSettings(const LayerSettings& s)
   scaleMax = s.scaleMax;
   bufferSize = s.bufferSize;
   bufferColor = s.bufferColor;
+  labelPerPart = s.labelPerPart;
 
   fontMetrics = NULL;
   ct = NULL;
@@ -287,6 +288,9 @@ int PalLabeling::prepareLayerHook(void* context, void* layerContext, int& attrIn
   if ( lyr->placementFlags )
     l->setArrangementFlags( lyr->placementFlags );
 
+  // set label mode (label per feature is the default)
+  l->setLabelMode( lyr->labelPerPart ? Layer::LabelPerFeaturePart : Layer::LabelPerFeature );
+
   // save the pal layer to our layer context (with some additional info)
   lyr->palLayer = l;
   lyr->fieldIndex = fldIndex;

src/plugins/labeling/pallabeling.h

@@ -63,6 +63,7 @@ class LayerSettings
   int scaleMin, scaleMax; // disabled if both are zero
   int bufferSize;
   QColor bufferColor;
+  bool labelPerPart; // whether to label every feature's part or only the biggest one
 
   // called from register feature hook
   void calculateLabelSize(QString text, double& labelX, double& labelY);