[gimp] Bug 736232 - Strange result using transparent layer, blending modes...

[Michael Natterer <mitch src gnome org>]

commit dbfbc221a5bdbab1530ec6ab018b6e57301f6c7c
Author: Thomas Manni <thomas manni free fr>
Date:   Thu Oct 2 19:04:05 2014 +0200

    Bug 736232 - Strange result using transparent layer, blending modes...
    
    ...and layer opacity
    
    Use a temporary variable to store intermediate result instead of
    writting 2 times to the output buffer, because input and output
    buffer might be the same.

 app/operations/gimpoperationcolormode.c      |    9 +++++----
 app/operations/gimpoperationhuemode.c        |    9 +++++----
 app/operations/gimpoperationsaturationmode.c |    9 +++++----
 app/operations/gimpoperationvaluemode.c      |    9 +++++----
 4 files changed, 20 insertions(+), 16 deletions(-)
---
diff --git a/app/operations/gimpoperationcolormode.c b/app/operations/gimpoperationcolormode.c
index 4d4dc20..5f5a7ef 100644
--- a/app/operations/gimpoperationcolormode.c
+++ b/app/operations/gimpoperationcolormode.c
@@ -111,6 +111,7 @@ gimp_operation_color_mode_process_pixels (gfloat              *in,
       if (comp_alpha && new_alpha)
         {
           gint   b;
+          gfloat out_tmp[3];
           gfloat ratio = comp_alpha / new_alpha;
 
           gimp_rgb_to_hsl (&layer_rgb, &layer_hsl);
@@ -120,13 +121,13 @@ gimp_operation_color_mode_process_pixels (gfloat              *in,
           out_hsl.s = layer_hsl.s;
           gimp_hsl_to_rgb (&out_hsl, &out_rgb);
 
-          out[0] = out_rgb.r;
-          out[1] = out_rgb.g;
-          out[2] = out_rgb.b;
+          out_tmp[0] = out_rgb.r;
+          out_tmp[1] = out_rgb.g;
+          out_tmp[2] = out_rgb.b;
 
           for (b = RED; b < ALPHA; b++)
             {
-              out[b] = out[b] * ratio + in[b] * (1.0 - ratio);
+              out[b] = out_tmp[b] * ratio + in[b] * (1.0 - ratio);
             }
         }
       else
diff --git a/app/operations/gimpoperationhuemode.c b/app/operations/gimpoperationhuemode.c
index 985a80c..a43e519 100644
--- a/app/operations/gimpoperationhuemode.c
+++ b/app/operations/gimpoperationhuemode.c
@@ -111,6 +111,7 @@ gimp_operation_hue_mode_process_pixels (gfloat              *in,
       if (comp_alpha && new_alpha)
         {
           gint   b;
+          gfloat out_tmp[3];
           gfloat ratio = comp_alpha / new_alpha;
 
           gimp_rgb_to_hsv (&layer_rgb, &layer_hsv);
@@ -125,13 +126,13 @@ gimp_operation_hue_mode_process_pixels (gfloat              *in,
             }
           gimp_hsv_to_rgb (&out_hsv, &out_rgb);
 
-          out[0] = out_rgb.r;
-          out[1] = out_rgb.g;
-          out[2] = out_rgb.b;
+          out_tmp[0] = out_rgb.r;
+          out_tmp[1] = out_rgb.g;
+          out_tmp[2] = out_rgb.b;
 
           for (b = RED; b < ALPHA; b++)
             {
-              out[b] = out[b] * ratio + in[b] * (1.0 - ratio);
+              out[b] = out_tmp[b] * ratio + in[b] * (1.0 - ratio);
             }
         }
       else
diff --git a/app/operations/gimpoperationsaturationmode.c b/app/operations/gimpoperationsaturationmode.c
index 688eaf9..9297df2 100644
--- a/app/operations/gimpoperationsaturationmode.c
+++ b/app/operations/gimpoperationsaturationmode.c
@@ -111,6 +111,7 @@ gimp_operation_saturation_mode_process_pixels (gfloat              *in,
       if (comp_alpha && new_alpha)
         {
           gint   b;
+          gfloat out_tmp[3];
           gfloat ratio = comp_alpha / new_alpha;
 
           gimp_rgb_to_hsv (&layer_rgb, &layer_hsv);
@@ -119,13 +120,13 @@ gimp_operation_saturation_mode_process_pixels (gfloat              *in,
           out_hsv.s = layer_hsv.s;
           gimp_hsv_to_rgb (&out_hsv, &out_rgb);
 
-          out[0] = out_rgb.r;
-          out[1] = out_rgb.g;
-          out[2] = out_rgb.b;
+          out_tmp[0] = out_rgb.r;
+          out_tmp[1] = out_rgb.g;
+          out_tmp[2] = out_rgb.b;
 
           for (b = RED; b < ALPHA; b++)
             {
-              out[b] = out[b] * ratio + in[b] * (1.0 - ratio);
+              out[b] = out_tmp[b] * ratio + in[b] * (1.0 - ratio);
             }
         }
       else
diff --git a/app/operations/gimpoperationvaluemode.c b/app/operations/gimpoperationvaluemode.c
index 05416ab..21cca08 100644
--- a/app/operations/gimpoperationvaluemode.c
+++ b/app/operations/gimpoperationvaluemode.c
@@ -111,6 +111,7 @@ gimp_operation_value_mode_process_pixels (gfloat              *in,
       if (comp_alpha && new_alpha)
         {
           gint   b;
+          gfloat out_tmp[3];
           gfloat ratio = comp_alpha / new_alpha;
 
           gimp_rgb_to_hsv (&layer_rgb, &layer_hsv);
@@ -119,13 +120,13 @@ gimp_operation_value_mode_process_pixels (gfloat              *in,
           out_hsv.v = layer_hsv.v;
           gimp_hsv_to_rgb (&out_hsv, &out_rgb);
 
-          out[0] = out_rgb.r;
-          out[1] = out_rgb.g;
-          out[2] = out_rgb.b;
+          out_tmp[0] = out_rgb.r;
+          out_tmp[1] = out_rgb.g;
+          out_tmp[2] = out_rgb.b;
 
           for (b = RED; b < ALPHA; b++)
             {
-              out[b] = out[b] * ratio + in[b] * (1.0 - ratio);
+              out[b] = out_tmp[b] * ratio + in[b] * (1.0 - ratio);
             }
         }
       else