[gegl] Set correctly shifted extent on sub-buffers

[Daniel Sabo <daniels src gnome org>]

commit 6a4ef10cd89db4d3623376e17ca60ed4faf24200
Author: Daniel Sabo <DanielSabo gmail com>
Date:   Tue Oct 8 04:46:54 2013 -0700

    Set correctly shifted extent on sub-buffers

 gegl/buffer/gegl-buffer.c |    4 ++--
 1 files changed, 2 insertions(+), 2 deletions(-)
---
diff --git a/gegl/buffer/gegl-buffer.c b/gegl/buffer/gegl-buffer.c
index 1107eee..c61980c 100644
--- a/gegl/buffer/gegl-buffer.c
+++ b/gegl/buffer/gegl-buffer.c
@@ -651,8 +651,8 @@ gegl_buffer_constructor (GType                  type,
     {
       if (GEGL_IS_BUFFER (source))
         {
-          buffer->extent.x = GEGL_BUFFER (source)->extent.x;
-          buffer->extent.y = GEGL_BUFFER (source)->extent.y;
+          buffer->extent.x = GEGL_BUFFER (source)->extent.x - buffer->shift_x;
+          buffer->extent.y = GEGL_BUFFER (source)->extent.y - buffer->shift_y;
           buffer->extent.width  = GEGL_BUFFER (source)->extent.width;
           buffer->extent.height = GEGL_BUFFER (source)->extent.height;
         }