diff --git a/app/core/gimpbrush.c b/app/core/gimpbrush.c
index 75a58c3d4f..5cb2b4291c 100644
--- a/app/core/gimpbrush.c
+++ b/app/core/gimpbrush.c
@@ -531,6 +531,18 @@ gimp_brush_transform_pixmap (GimpBrush *brush,
                                                          angle, hardness);
 }
 
+GimpBezierDesc *
+gimp_brush_transform_boundary (GimpBrush *brush,
+                               gdouble    scale,
+                               gdouble    aspect_ratio,
+                               gdouble    angle,
+                               gdouble    hardness)
+{
+  g_return_val_if_fail (GIMP_IS_BRUSH (brush), NULL);
+
+  return NULL;
+}
+
 gdouble
 gimp_brush_clamp_scale (GimpBrush *brush,
                         gdouble    scale)
diff --git a/app/core/gimpbrush.h b/app/core/gimpbrush.h
index ebd69da0cc..31fcfbb5d7 100644
--- a/app/core/gimpbrush.h
+++ b/app/core/gimpbrush.h
@@ -47,78 +47,90 @@ struct _GimpBrush
 
 struct _GimpBrushClass
 {
-  GimpDataClass parent_class;
+  GimpDataClass  parent_class;
 
   /*  virtual functions  */
-  GimpBrush * (* select_brush)     (GimpBrush        *brush,
-                                    const GimpCoords *last_coords,
-                                    const GimpCoords *current_coords);
-  gboolean    (* want_null_motion) (GimpBrush        *brush,
-                                    const GimpCoords *last_coords,
-                                    const GimpCoords *current_coords);
-  void        (* transform_size)   (GimpBrush        *brush,
-                                    gdouble           scale,
-                                    gdouble           aspect_ratio,
-                                    gdouble           angle,
-                                    gint             *width,
-                                    gint             *height);
-  TempBuf   * (* transform_mask)   (GimpBrush        *brush,
-                                    gdouble           scale,
-                                    gdouble           aspect_ratio,
-                                    gdouble           angle,
-                                    gdouble           hardness);
-  TempBuf   * (* transform_pixmap) (GimpBrush        *brush,
-                                    gdouble           scale,
-                                    gdouble           aspect_ratio,
-                                    gdouble           angle,
-                                    gdouble           hardness);
+  GimpBrush      * (* select_brush)       (GimpBrush        *brush,
+                                           const GimpCoords *last_coords,
+                                           const GimpCoords *current_coords);
+  gboolean         (* want_null_motion)   (GimpBrush        *brush,
+                                           const GimpCoords *last_coords,
+                                           const GimpCoords *current_coords);
+  void             (* transform_size)     (GimpBrush        *brush,
+                                           gdouble           scale,
+                                           gdouble           aspect_ratio,
+                                           gdouble           angle,
+                                           gint             *width,
+                                           gint             *height);
+  TempBuf        * (* transform_mask)     (GimpBrush        *brush,
+                                           gdouble           scale,
+                                           gdouble           aspect_ratio,
+                                           gdouble           angle,
+                                           gdouble           hardness);
+  TempBuf        * (* transform_pixmap)   (GimpBrush        *brush,
+                                           gdouble           scale,
+                                           gdouble           aspect_ratio,
+                                           gdouble           angle,
+                                           gdouble           hardness);
+  GimpBezierDesc * (* transform_boundary) (GimpBrush        *brush,
+                                           gdouble           scale,
+                                           gdouble           aspect_ratio,
+                                           gdouble           angle,
+                                           gdouble           hardness);
 
   /*  signals  */
-  void        (* spacing_changed)  (GimpBrush        *brush);
+  void             (* spacing_changed)    (GimpBrush        *brush);
 };
 
 
-GType       gimp_brush_get_type         (void) G_GNUC_CONST;
+GType            gimp_brush_get_type           (void) G_GNUC_CONST;
 
-GimpData  * gimp_brush_new              (GimpContext      *context,
-                                         const gchar      *name);
-GimpData  * gimp_brush_get_standard     (GimpContext      *context);
+GimpData       * gimp_brush_new                (GimpContext      *context,
+                                                const gchar      *name);
+GimpData       * gimp_brush_get_standard       (GimpContext      *context);
 
-GimpBrush * gimp_brush_select_brush     (GimpBrush        *brush,
-                                         const GimpCoords *last_coords,
-                                         const GimpCoords *current_coords);
-gboolean    gimp_brush_want_null_motion (GimpBrush        *brush,
-                                         const GimpCoords *last_coords,
-                                         const GimpCoords *current_coords);
+GimpBrush      * gimp_brush_select_brush       (GimpBrush        *brush,
+                                                const GimpCoords *last_coords,
+                                                const GimpCoords *current_coords);
+gboolean         gimp_brush_want_null_motion   (GimpBrush        *brush,
+                                                const GimpCoords *last_coords,
+                                                const GimpCoords *current_coords);
 
-/* Gets width and height of a transformed mask of the brush, for provided parameters. */
-void        gimp_brush_transform_size   (GimpBrush        *brush,
-                                         gdouble           scale,
-                                         gdouble           aspect_ratio,
-                                         gdouble           angle,
-                                         gint             *width,
-                                         gint             *height);
-TempBuf   * gimp_brush_transform_mask   (GimpBrush        *brush,
-                                         gdouble           scale,
-                                         gdouble           aspect_ratio,
-                                         gdouble           angle,
-                                         gdouble           hardness);
-TempBuf   * gimp_brush_transform_pixmap (GimpBrush        *brush,
-                                         gdouble           scale,
-                                         gdouble           aspect_ratio,
-                                         gdouble           angle,
-                                         gdouble           hardness);
+/* Gets width and height of a transformed mask of the brush, for
+ * provided parameters.
+ */
+void             gimp_brush_transform_size     (GimpBrush        *brush,
+                                                gdouble           scale,
+                                                gdouble           aspect_ratio,
+                                                gdouble           angle,
+                                                gint             *width,
+                                                gint             *height);
+TempBuf        * gimp_brush_transform_mask     (GimpBrush        *brush,
+                                                gdouble           scale,
+                                                gdouble           aspect_ratio,
+                                                gdouble           angle,
+                                                gdouble           hardness);
+TempBuf        * gimp_brush_transform_pixmap   (GimpBrush        *brush,
+                                                gdouble           scale,
+                                                gdouble           aspect_ratio,
+                                                gdouble           angle,
+                                                gdouble           hardness);
+GimpBezierDesc * gimp_brush_transform_boundary (GimpBrush        *brush,
+                                                gdouble           scale,
+                                                gdouble           aspect_ratio,
+                                                gdouble           angle,
+                                                gdouble           hardness);
 
-gdouble     gimp_brush_clamp_scale      (GimpBrush        *brush,
-                                         gdouble           scale);
+gdouble          gimp_brush_clamp_scale        (GimpBrush        *brush,
+                                                gdouble           scale);
 
-TempBuf   * gimp_brush_get_mask         (const GimpBrush  *brush);
-TempBuf   * gimp_brush_get_pixmap       (const GimpBrush  *brush);
+TempBuf        * gimp_brush_get_mask           (const GimpBrush  *brush);
+TempBuf        * gimp_brush_get_pixmap         (const GimpBrush  *brush);
 
-gint        gimp_brush_get_spacing      (const GimpBrush  *brush);
-void        gimp_brush_set_spacing      (GimpBrush        *brush,
-                                         gint              spacing);
-void        gimp_brush_spacing_changed  (GimpBrush        *brush);
+gint             gimp_brush_get_spacing        (const GimpBrush  *brush);
+void             gimp_brush_set_spacing        (GimpBrush        *brush,
+                                                gint              spacing);
+void             gimp_brush_spacing_changed    (GimpBrush        *brush);
 
 
 #endif /* __GIMP_BRUSH_H__ */