[gimp] app: skip color calculation in the blend funcs if either dest or src ...

[N/A <ell src gnome org>]

commit 9128f3fc87c98a7086799018e2659aca33340564
Author: Ell <ell_se yahoo com>
Date:   Tue Jan 24 11:20:28 2017 -0500

    app: skip color calculation in the blend funcs if either dest or src ...
    
    ... is fully transparent, instead of just src.
    
    The blend func results only affect the intersection of dest and src.
    Run time is currently dominated by the compositing step for most modes,
    so the difference in performance is pretty negligible, but it does make
    a difference for the more expensive modes, like the HSV ones.

 .../layer-modes/gimpoperationlayermode.c           |   58 ++++++++++----------
 1 files changed, 29 insertions(+), 29 deletions(-)
---
diff --git a/app/operations/layer-modes/gimpoperationlayermode.c 
b/app/operations/layer-modes/gimpoperationlayermode.c
index f052615..1ae0934 100644
--- a/app/operations/layer-modes/gimpoperationlayermode.c
+++ b/app/operations/layer-modes/gimpoperationlayermode.c
@@ -681,7 +681,7 @@ blendfun_screen (const float *dest,
 {
   while (samples--)
     {
-      if (src[ALPHA] != 0.0f)
+      if (dest[ALPHA] != 0.0f && src[ALPHA] != 0.0f)
         {
           gint c;
 
@@ -705,7 +705,7 @@ blendfun_addition (const float *dest,
 {
   while (samples--)
     {
-      if (src[ALPHA] != 0.0f)
+      if (dest[ALPHA] != 0.0f && src[ALPHA] != 0.0f)
         {
           gint c;
 
@@ -730,7 +730,7 @@ blendfun_linear_burn (const float *dest,
 {
   while (samples--)
     {
-      if (src[ALPHA] != 0.0f)
+      if (dest[ALPHA] != 0.0f && src[ALPHA] != 0.0f)
         {
           gint c;
 
@@ -754,7 +754,7 @@ blendfun_subtract (const float *dest,
 {
   while (samples--)
     {
-      if (src[ALPHA] != 0.0f)
+      if (dest[ALPHA] != 0.0f && src[ALPHA] != 0.0f)
         {
           gint c;
 
@@ -778,7 +778,7 @@ blendfun_multiply (const float *dest,
 {
   while (samples--)
     {
-      if (src[ALPHA] != 0.0f)
+      if (dest[ALPHA] != 0.0f && src[ALPHA] != 0.0f)
         {
           gint c;
 
@@ -802,7 +802,7 @@ blendfun_normal (const float *dest,
 {
   while (samples--)
     {
-      if (src[ALPHA] != 0.0f)
+      if (dest[ALPHA] != 0.0f && src[ALPHA] != 0.0f)
         {
           gint c;
 
@@ -826,7 +826,7 @@ blendfun_burn (const float *dest,
 {
   while (samples--)
     {
-      if (src[ALPHA] != 0.0f)
+      if (dest[ALPHA] != 0.0f && src[ALPHA] != 0.0f)
         {
           gint c;
 
@@ -857,7 +857,7 @@ blendfun_darken_only (const float *dest,
 {
   while (samples--)
     {
-      if (src[ALPHA] != 0.0f)
+      if (dest[ALPHA] != 0.0f && src[ALPHA] != 0.0f)
         {
           gint c;
 
@@ -881,7 +881,7 @@ blendfun_lighten_only (const float *dest,
 {
   while (samples--)
     {
-      if (src[ALPHA] != 0.0f)
+      if (dest[ALPHA] != 0.0f && src[ALPHA] != 0.0f)
         {
           gint c;
 
@@ -905,7 +905,7 @@ blendfun_difference (const float *dest,
 {
   while (samples--)
     {
-      if (src[ALPHA] != 0.0f)
+      if (dest[ALPHA] != 0.0f && src[ALPHA] != 0.0f)
         {
           gint c;
 
@@ -934,7 +934,7 @@ blendfun_divide (const float *dest,
 {
   while (samples--)
     {
-      if (src[ALPHA] != 0.0f)
+      if (dest[ALPHA] != 0.0f && src[ALPHA] != 0.0f)
         {
           gint c;
 
@@ -970,7 +970,7 @@ blendfun_dodge (const float *dest,
 {
   while (samples--)
     {
-      if (src[ALPHA] != 0.0f)
+      if (dest[ALPHA] != 0.0f && src[ALPHA] != 0.0f)
         {
           gint c;
 
@@ -1000,7 +1000,7 @@ blendfun_grain_extract (const float *dest,
 {
   while (samples--)
     {
-      if (src[ALPHA] != 0.0f)
+      if (dest[ALPHA] != 0.0f && src[ALPHA] != 0.0f)
         {
           gint c;
 
@@ -1024,7 +1024,7 @@ blendfun_grain_merge (const float *dest,
 {
   while (samples--)
     {
-      if (src[ALPHA] != 0.0f)
+      if (dest[ALPHA] != 0.0f && src[ALPHA] != 0.0f)
         {
           gint c;
 
@@ -1048,7 +1048,7 @@ blendfun_hardlight (const float *dest,
 {
   while (samples--)
     {
-      if (src[ALPHA] != 0.0f)
+      if (dest[ALPHA] != 0.0f && src[ALPHA] != 0.0f)
         {
           gint c;
 
@@ -1086,7 +1086,7 @@ blendfun_softlight (const float *dest,
 {
   while (samples--)
     {
-      if (src[ALPHA] != 0.0f)
+      if (dest[ALPHA] != 0.0f && src[ALPHA] != 0.0f)
         {
           gint c;
 
@@ -1115,7 +1115,7 @@ blendfun_overlay (const float *dest,
 {
   while (samples--)
     {
-      if (src[ALPHA] != 0.0f)
+      if (dest[ALPHA] != 0.0f && src[ALPHA] != 0.0f)
         {
           gint c;
 
@@ -1151,7 +1151,7 @@ blendfun_hsv_color (const float *dest,
 {
   while (samples--)
     {
-      if (src[ALPHA] != 0.0f)
+      if (dest[ALPHA] != 0.0f && src[ALPHA] != 0.0f)
         {
           GimpRGB dest_rgb = { dest[0], dest[1], dest[2] };
           GimpRGB src_rgb  = { src[0], src[1], src[2] };
@@ -1186,7 +1186,7 @@ blendfun_hsv_hue (const float *dest,
 {
   while (samples--)
     {
-      if (src[ALPHA] != 0.0f)
+      if (dest[ALPHA] != 0.0f && src[ALPHA] != 0.0f)
         {
           GimpRGB dest_rgb = { dest[0], dest[1], dest[2] };
           GimpRGB src_rgb  = { src[0],  src[1],  src[2] };
@@ -1219,7 +1219,7 @@ blendfun_hsv_saturation (const float *dest,
 {
   while (samples--)
     {
-      if (src[ALPHA] != 0.0f)
+      if (dest[ALPHA] != 0.0f && src[ALPHA] != 0.0f)
         {
           GimpRGB dest_rgb = { dest[0], dest[1], dest[2] };
           GimpRGB src_rgb  = { src[0], src[1], src[2] };
@@ -1252,7 +1252,7 @@ blendfun_hsv_value (const float *dest,
 {
   while (samples--)
     {
-      if (src[ALPHA] != 0.0f)
+      if (dest[ALPHA] != 0.0f && src[ALPHA] != 0.0f)
         {
           GimpRGB dest_rgb = { dest[0], dest[1], dest[2] };
           GimpRGB src_rgb  = { src[0], src[1], src[2] };
@@ -1285,7 +1285,7 @@ blendfun_lch_chroma (const float *dest,
 {
   while (samples--)
     {
-      if (src[ALPHA] != 0.0f)
+      if (dest[ALPHA] != 0.0f && src[ALPHA] != 0.0f)
         {
           gfloat A1 = dest[1];
           gfloat B1 = dest[2];
@@ -1321,7 +1321,7 @@ blendfun_lch_color (const float *dest,
 {
   while (samples--)
     {
-      if (src[ALPHA] != 0.0f)
+      if (dest[ALPHA] != 0.0f && src[ALPHA] != 0.0f)
         {
           out[0] = dest[0];
           out[1] = src[1];
@@ -1344,7 +1344,7 @@ blendfun_lch_hue (const float *dest,
 {
   while (samples--)
     {
-      if (src[ALPHA] != 0.0f)
+      if (dest[ALPHA] != 0.0f && src[ALPHA] != 0.0f)
         {
           gfloat A2 = src[1];
           gfloat B2 = src[2];
@@ -1386,7 +1386,7 @@ blendfun_lch_lightness (const float *dest,
 {
   while (samples--)
     {
-      if (src[ALPHA] != 0.0f)
+      if (dest[ALPHA] != 0.0f && src[ALPHA] != 0.0f)
         {
           out[0] = src[0];
           out[1] = dest[1];
@@ -1432,7 +1432,7 @@ blendfun_vivid_light (const float *dest,
 {
   while (samples--)
     {
-      if (src[ALPHA] != 0.0f)
+      if (dest[ALPHA] != 0.0f && src[ALPHA] != 0.0f)
         {
           gint c;
 
@@ -1472,7 +1472,7 @@ blendfun_linear_light (const float *dest,
 {
   while (samples--)
     {
-      if (src[ALPHA] != 0.0f)
+      if (dest[ALPHA] != 0.0f && src[ALPHA] != 0.0f)
         {
           gint c;
 
@@ -1509,7 +1509,7 @@ blendfun_pin_light (const float *dest,
 {
   while (samples--)
     {
-      if (src[ALPHA] != 0.0f)
+      if (dest[ALPHA] != 0.0f && src[ALPHA] != 0.0f)
         {
           gint c;
 
@@ -1543,7 +1543,7 @@ blendfun_exclusion (const float *dest,
 {
   while (samples--)
     {
-      if (src[ALPHA] != 0.0f)
+      if (dest[ALPHA] != 0.0f && src[ALPHA] != 0.0f)
         {
           gint c;