[gnome-shell] st: Fix Gaussian kernel calculation

[Florian Müllner <fmuellner src gnome org>]

commit 9a7b47c23f676cdfc80758ee45a4bc0cada83243
Author: Florian Müllner <fmuellner gnome org>
Date:   Thu Nov 12 00:42:36 2015 +0100

    st: Fix Gaussian kernel calculation
    
    The result of subtracting unsigned operands is unsigned, which throws
    off our calculation in case it should be negative.
    
    This partly reverts 18b6f133952.
    
    https://bugzilla.gnome.org/show_bug.cgi?id=757779

 src/st/st-private.c |    6 +++---
 1 files changed, 3 insertions(+), 3 deletions(-)
---
diff --git a/src/st/st-private.c b/src/st/st-private.c
index 9ff469a..559336c 100644
--- a/src/st/st-private.c
+++ b/src/st/st-private.c
@@ -211,7 +211,7 @@ calculate_gaussian_kernel (gdouble   sigma,
 {
   gdouble *ret, sum;
   gdouble exp_divisor;
-  guint half, i;
+  int half, i;
 
   g_return_val_if_fail (sigma > 0, NULL);
 
@@ -223,14 +223,14 @@ calculate_gaussian_kernel (gdouble   sigma,
   exp_divisor = 2 * sigma * sigma;
 
   /* n_values of 1D Gauss function */
-  for (i = 0; i < n_values; i++)
+  for (i = 0; i < (int)n_values; i++)
     {
       ret[i] = exp (-(i - half) * (i - half) / exp_divisor);
       sum += ret[i];
     }
 
   /* normalize */
-  for (i = 0; i < n_values; i++)
+  for (i = 0; i < (int)n_values; i++)
     ret[i] /= sum;
 
   return ret;