[gegl] buffer: document some specifics of gegl_buffer_copy

[Michael Henning <mhenning src gnome org>]

commit 483bef20e8a753fd9343fe3a12737f1d4e08ede2
Author: Michael Henning <drawoc darkrefraction com>
Date:   Mon Aug 12 22:08:34 2013 -0400

    buffer: document some specifics of gegl_buffer_copy

 gegl/buffer/gegl-buffer.h |    3 +++
 1 files changed, 3 insertions(+), 0 deletions(-)
---
diff --git a/gegl/buffer/gegl-buffer.h b/gegl/buffer/gegl-buffer.h
index ad233a0..ec31c7f 100644
--- a/gegl/buffer/gegl-buffer.h
+++ b/gegl/buffer/gegl-buffer.h
@@ -378,6 +378,9 @@ void            gegl_buffer_clear             (GeglBuffer          *buffer,
  *
  * If the babl_formats of the buffers are the same, and the tile boundaries
  * align, this will create copy-on-write tiles in the destination buffer.
+ *
+ * This function never does any scaling. When src_rect and dst_rect do not have
+ * the same width and height, the size of src_rect is used.
  */
 void            gegl_buffer_copy              (GeglBuffer          *src,
                                                const GeglRectangle *src_rect,