[gimp] change the pow() workaround to be more HDR safe

[Simon Budig <simon src gnome org>]

commit 8f40eba70279730c072942af52fbcd5801656e90
Author: Simon Budig <simon budig de>
Date:   Thu May 10 21:26:48 2012 +0200

    change the pow() workaround to be more HDR safe

 app/operations/gimpoperationlevels.c |    5 +----
 1 files changed, 1 insertions(+), 4 deletions(-)
---
diff --git a/app/operations/gimpoperationlevels.c b/app/operations/gimpoperationlevels.c
index 8863d59..9ab9009 100644
--- a/app/operations/gimpoperationlevels.c
+++ b/app/operations/gimpoperationlevels.c
@@ -86,16 +86,13 @@ gimp_operation_levels_map (gdouble value,
                            gdouble low_output,
                            gdouble high_output)
 {
-  /* clamp to guard pow() against negative input */
-  value = MAX (value, low_input);
-
   /*  determine input intensity  */
   if (high_input != low_input)
     value = (value - low_input) / (high_input - low_input);
   else
     value = (value - low_input);
 
-  if (inv_gamma != 1.0)
+  if (inv_gamma != 1.0 && value > 0)
     value =  pow (value, inv_gamma);
 
   /*  determine the output intensity  */