Followup f9fa979, avoid expensive intersection calculation when

testing label candidates against polygon obstacles

Fix #13556

(cherry-picked from b384f18)

Author: nyalldawson

src/core/pal/labelposition.cpp

@@ -593,36 +593,47 @@ namespace pal
       polygon->createGeosGeom();
 
     GEOSContextHandle_t geosctxt = geosContext();
-
     double cost = 0;
-    //check the label center. if covered by polygon, initial cost of 4
-    if ( polygon->containsPoint(( x[0] + x[2] ) / 2.0, ( y[0] + y[2] ) / 2.0 ) )
-      cost += 4;
-
     try
     {
-      //calculate proportion of label candidate which is covered by polygon
-      GEOSGeometry* intersectionGeom = GEOSIntersection_r( geosctxt, mGeos, polygon->mGeos );
-      if ( intersectionGeom )
+      if ( GEOSPreparedIntersects_r( geosctxt, polygon->preparedGeom(), mGeos ) == 1 )
       {
-        double positionArea = 0;
-        if ( GEOSArea_r( geosctxt, mGeos, &positionArea ) == 1 )
+        //at least a partial intersection
+        cost += 1;
+
+        double px, py;
+
+        // check each corner
+        for ( int i = 0; i < 4; ++i )
         {
-          double intersectionArea = 0;
-          if ( GEOSArea_r( geosctxt, intersectionGeom, &intersectionArea ) == 1 )
+          px = x[i];
+          py = y[i];
+
+          for ( int a = 0; a < 2; ++a ) // and each middle of segment
           {
-            double portionCovered = intersectionArea / positionArea;
-            cost += portionCovered * 8.0; //cost of 8 if totally covered
+            if ( polygon->containsPoint( px, py ) )
+              cost++;
+            px = ( x[i] + x[( i+1 ) %4] ) / 2.0;
+            py = ( y[i] + y[( i+1 ) %4] ) / 2.0;
           }
         }
-        GEOSGeom_destroy_r( geosctxt, intersectionGeom );
+
+        px = ( x[0] + x[2] ) / 2.0;
+        py = ( y[0] + y[2] ) / 2.0;
+
+        //check the label center. if covered by polygon, cost of 4
+        if ( polygon->containsPoint( px, py ) )
+          cost += 4;
       }
     }
     catch ( GEOSException &e )
     {
       QgsMessageLog::logMessage( QObject::tr( "Exception: %1" ).arg( e.what() ), QObject::tr( "GEOS" ) );
     }
 
+    //maintain scaling from 0 -> 12
+    cost = 12.0 * cost / 13.0;
+
     if ( nextPart )
     {
       cost += nextPart->polygonIntersectionCostForParts( polygon );

src/core/pal/pointset.cpp

@@ -299,7 +299,7 @@ namespace pal
       GEOSCoordSeq_setX_r( geosctxt, seq, 0, x );
       GEOSCoordSeq_setY_r( geosctxt, seq, 0, y );
       GEOSGeometry* point = GEOSGeom_createPoint_r( geosctxt, seq );
-      bool result = ( GEOSPreparedContains_r( geosctxt, preparedGeom(), point ) == 1 );
+      bool result = ( GEOSPreparedContainsProperly_r( geosctxt, preparedGeom(), point ) == 1 );
       GEOSGeom_destroy_r( geosctxt, point );
 
       return result;
@@ -349,7 +349,7 @@ namespace pal
     try
     {
       GEOSGeometry* bboxGeos = GEOSGeom_createLinearRing_r( geosctxt, coord );
-      bool result = ( GEOSPreparedContains_r( geosctxt, preparedGeom(), bboxGeos ) == 1 );
+      bool result = ( GEOSPreparedContainsProperly_r( geosctxt, preparedGeom(), bboxGeos ) == 1 );
       GEOSGeom_destroy_r( geosctxt, bboxGeos );
       return result;
     }