Added QgsGeometry::buffer() function that returns buffer around the geometry.

wonder · wonder · commit 857ae41deeae · 2008-01-16T22:39:57.000Z
git-svn-id: http://svn.osgeo.org/qgis/trunk/qgis@7986 c8812cc2-4d05-0410-92ff-de0c093fc19c
diff --git a/python/core/qgsgeometry.sip b/python/core/qgsgeometry.sip
@@ -208,6 +208,10 @@ not disjoint with existing polygons of the feature*/
     /** Test for containment of a point (uses GEOS) */
     bool contains(QgsPoint* p);
 
+    /** 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) /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;
diff --git a/src/core/qgsgeometry.cpp b/src/core/qgsgeometry.cpp
@@ -5511,3 +5511,15 @@ double QgsGeometry::distance(QgsGeometry& geom)
 
   return mGeos->distance(geom.mGeos);
 }
+
+
+QgsGeometry* QgsGeometry::buffer(double distance, int segments)
+{
+  if (mGeos == NULL)
+    exportWkbToGeos();
+  GEOS_GEOM::Geometry* geos = mGeos->buffer(distance, segments);
+  QgsGeometry* g = new QgsGeometry;
+  g->setGeos(geos);
+  return g;
+}
+
diff --git a/src/core/qgsgeometry.h b/src/core/qgsgeometry.h
@@ -278,6 +278,10 @@ not disjoint with existing polygons of the feature*/
     /** Test for containment of a point (uses GEOS) */
     bool contains(QgsPoint* p);
 
+    /** 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);
+
     /** Exports the geometry to mWkt
         @return true in case of success and false else
      */
