[gegl] map-relative: sample from the pixel centers for integer vectors.

[Simon Budig <simon src gnome org>]

commit 568306d968559067223d749f9ac2dec30bac45ae
Author: Simon Budig <simon budig de>
Date:   Sat Sep 24 12:50:08 2016 +0200

    map-relative: sample from the pixel centers for integer vectors.

 operations/common/map-relative.c |    4 ++--
 1 files changed, 2 insertions(+), 2 deletions(-)
---
diff --git a/operations/common/map-relative.c b/operations/common/map-relative.c
index 0cfae41..eaa8524 100644
--- a/operations/common/map-relative.c
+++ b/operations/common/map-relative.c
@@ -113,8 +113,8 @@ process (GeglOperation       *operation,
                 }
               else
                 {
-                  gegl_sampler_get (sampler, x+coords[0] * scaling,
-                                             y+coords[1] * scaling,
+                  gegl_sampler_get (sampler, x + coords[0] * scaling + 0.5,
+                                             y + coords[1] * scaling + 0.5,
                                              NULL, out,
                                              GEGL_ABYSS_NONE);
                 }