[gegl: 10/25] transform-core.c: absolute positions in gegl_transform_detect

[Nicolas Robidoux <nrobidoux src gnome org>]

commit 13d94e74bc5b18a54dc3c2b4d7fb00ae670b6015
Author: Nicolas Robidoux <nrobidoux git gnome org>
Date:   Fri Nov 23 21:56:19 2012 -0500

    transform-core.c: absolute positions in gegl_transform_detect

 operations/transform/transform-core.c |    4 ++--
 1 files changed, 2 insertions(+), 2 deletions(-)
---
diff --git a/operations/transform/transform-core.c b/operations/transform/transform-core.c
index 655092d..5885e90 100644
--- a/operations/transform/transform-core.c
+++ b/operations/transform/transform-core.c
@@ -571,8 +571,8 @@ gegl_transform_detect (GeglOperation *operation,
       return gegl_operation_detect (source_node->operation, x, y);
     }
 
-  need_points [0] = x;
-  need_points [1] = y;
+  need_points [0] = x - (gdouble) 0.5;
+  need_points [1] = y - (gdouble) 0.5;
 
   gegl_transform_create_matrix (transform, &inverse);
   gegl_matrix3_invert (&inverse);