- renamed QgsGeometry::difference to QgsGeometry::makeDifference

- more geoprocessing in QgsGeometry: convexHull, intersection, Union, difference, symDifference


git-svn-id: http://svn.osgeo.org/qgis/trunk/qgis@7994 c8812cc2-4d05-0410-92ff-de0c093fc19c

Author: wonder

python/core/qgsgeometry.sip

@@ -195,7 +195,7 @@ not disjoint with existing polygons of the feature*/
  /**Changes this geometry such that it does not intersect the other geometry
        @param other geometry that should not be intersect
        @return 0 in case of success*/
-    int difference(QgsGeometry* other);	
+    int makeDifference(QgsGeometry* other);	
 
     /**Returns the bounding box of this feature*/
     QgsRect boundingBox();
@@ -212,6 +212,21 @@ not disjoint with existing polygons of the feature*/
         of segments used to approximate curves */
     QgsGeometry* buffer(double distance, int segments) /Factory/;
 
+    /** Returns the smallest convex polygon that contains all the points in the geometry. */
+    QgsGeometry* convexHull() /Factory/;
+    
+    /** Returns a geometry representing the points shared by this geometry and other. */
+    QgsGeometry* intersection(QgsGeometry* geometry) /Factory/;
+    
+    /** Returns a geometry representing all the points in this geometry and other. */
+    QgsGeometry* Union(QgsGeometry* geometry) /Factory/;
+    
+    /** Returns a geometry representing the points making up this geometry that do not make up other. */
+    QgsGeometry* difference(QgsGeometry* geometry) /Factory/;
+    
+    /** Returns a Geometry representing the points making up this Geometry that do not make up other. */
+    QgsGeometry* symDifference(QgsGeometry* geometry) /Factory/;
+    
     /**Creates a geos geometry from this features geometry. Note, that the returned object needs to be deleted*/
     // TODO: unsupported class... would be possible to use PyGEOS?
     //geos::Geometry* geosGeometry() const;

src/core/qgsgeometry.cpp

@@ -2934,7 +2934,7 @@ int QgsGeometry::splitGeometry(const QList<QgsPoint>& splitLine, QList<QgsGeomet
   return returnCode;
 }
 
-int QgsGeometry::difference(QgsGeometry* other)
+int QgsGeometry::makeDifference(QgsGeometry* other)
 {
   //make sure geos geometry is up to date
   if(!mGeos || mDirtyGeos)
@@ -5523,3 +5523,68 @@ QgsGeometry* QgsGeometry::buffer(double distance, int segments)
   return g;
 }
 
+QgsGeometry* QgsGeometry::convexHull()
+{
+  if (mGeos == NULL)
+    exportWkbToGeos();
+  GEOS_GEOM::Geometry* geos = mGeos->convexHull();
+  QgsGeometry* g = new QgsGeometry;
+  g->setGeos(geos);
+  return g;
+}
+
+QgsGeometry* QgsGeometry::intersection(QgsGeometry* geometry)
+{
+  if (geometry == NULL)
+    return NULL;
+  if (mGeos == NULL)
+    exportWkbToGeos();
+  if (geometry->mGeos == NULL)
+    geometry->exportWkbToGeos();
+  GEOS_GEOM::Geometry* geos = mGeos->intersection(geometry->mGeos);
+  QgsGeometry* g = new QgsGeometry;
+  g->setGeos(geos);
+  return g;
+}
+
+QgsGeometry* QgsGeometry::Union(QgsGeometry* geometry)
+{
+  if (geometry == NULL)
+    return NULL;
+  if (mGeos == NULL)
+    exportWkbToGeos();
+  if (geometry->mGeos == NULL)
+    geometry->exportWkbToGeos();
+  GEOS_GEOM::Geometry* geos = mGeos->Union(geometry->mGeos);
+  QgsGeometry* g = new QgsGeometry;
+  g->setGeos(geos);
+  return g;
+}
+
+QgsGeometry* QgsGeometry::difference(QgsGeometry* geometry)
+{
+  if (geometry == NULL)
+    return NULL;
+  if (mGeos == NULL)
+    exportWkbToGeos();
+  if (geometry->mGeos == NULL)
+    geometry->exportWkbToGeos();
+  GEOS_GEOM::Geometry* geos = mGeos->difference(geometry->mGeos);
+  QgsGeometry* g = new QgsGeometry;
+  g->setGeos(geos);
+  return g;
+}
+
+QgsGeometry* QgsGeometry::symDifference(QgsGeometry* geometry)
+{
+  if (geometry == NULL)
+    return NULL;
+  if (mGeos == NULL)
+    exportWkbToGeos();
+  if (geometry->mGeos == NULL)
+    geometry->exportWkbToGeos();
+  GEOS_GEOM::Geometry* geos = mGeos->symDifference(geometry->mGeos);
+  QgsGeometry* g = new QgsGeometry;
+  g->setGeos(geos);
+  return g;
+}

src/core/qgsgeometry.h

@@ -265,7 +265,7 @@ not disjoint with existing polygons of the feature*/
     /**Changes this geometry such that it does not intersect the other geometry
        @param other geometry that should not be intersect
        @return 0 in case of success*/
-    int difference(QgsGeometry* other);
+    int makeDifference(QgsGeometry* other);
 
     /**Returns the bounding box of this feature*/
     QgsRect boundingBox();
@@ -281,6 +281,21 @@ not disjoint with existing polygons of the feature*/
     /** Returns a buffer region around this geometry having the given width and with a specified number
         of segments used to approximate curves */
     QgsGeometry* buffer(double distance, int segments);
+    
+    /** Returns the smallest convex polygon that contains all the points in the geometry. */
+    QgsGeometry* convexHull();
+    
+    /** Returns a geometry representing the points shared by this geometry and other. */
+    QgsGeometry* intersection(QgsGeometry* geometry);
+    
+    /** Returns a geometry representing all the points in this geometry and other. */
+    QgsGeometry* Union(QgsGeometry* geometry);
+    
+    /** Returns a geometry representing the points making up this geometry that do not make up other. */
+    QgsGeometry* difference(QgsGeometry* geometry);
+    
+    /** Returns a Geometry representing the points making up this Geometry that do not make up other. */
+    QgsGeometry* symDifference(QgsGeometry* geometry);
 
     /** Exports the geometry to mWkt
         @return true in case of success and false else

src/core/qgsvectorlayer.cpp

@@ -1781,11 +1781,11 @@ int QgsVectorLayer::removePolygonIntersections(QgsGeometry* geom)
 
   for(; it != featureList.end(); ++it)
     {
-      //call geometry->difference for each feature
+      //call geometry->makeDifference for each feature
       currentGeom = it->geometry();
       if(currentGeom)
 	{
-	  if(geom->difference(it->geometry()) != 0)
+	  if(geom->makeDifference(it->geometry()) != 0)
 	    {
 	      returnValue = 2;
 	    }