[gimp] app: add mono-mix layer mode

[N/A <ell src gnome org>]

commit c6c0899655740869ef401599e16d9c8e16853f80
Author: Ell <ell_se yahoo com>
Date:   Fri Mar 10 16:33:14 2017 -0500

    app: add mono-mix layer mode
    
    Calculates the dot product of the two input colors, and uses that
    as the value for all the output color's components.  Basically,
    a per-pixel mono mixer.
    
    Useful for custom desaturation, component extraction, and crazier
    stuff (bump mapping!)

 app/core/gimpimage.c                               |    1 +
 app/operations/layer-modes/gimp-layer-modes.c      |   18 +++++++++++-
 .../layer-modes/gimpoperationlayermode.c           |   30 ++++++++++++++++++++
 app/operations/operations-enums.c                  |    2 +
 app/operations/operations-enums.h                  |    1 +
 libgimp/gimpenums.h                                |    3 +-
 tools/pdbgen/enums.pl                              |    6 ++-
 7 files changed, 57 insertions(+), 4 deletions(-)
---
diff --git a/app/core/gimpimage.c b/app/core/gimpimage.c
index f936b8d..cd2e487 100644
--- a/app/core/gimpimage.c
+++ b/app/core/gimpimage.c
@@ -2464,6 +2464,7 @@ gimp_image_get_xcf_version (GimpImage    *image,
         case GIMP_LAYER_MODE_LUMINANCE:
         case GIMP_LAYER_MODE_COLOR_ERASE:
         case GIMP_LAYER_MODE_ERASE:
+        case GIMP_LAYER_MODE_MONO_MIX:
           version = MAX (10, version);
           break;
 
diff --git a/app/operations/layer-modes/gimp-layer-modes.c b/app/operations/layer-modes/gimp-layer-modes.c
index fd37a7b..1a61e50 100644
--- a/app/operations/layer-modes/gimp-layer-modes.c
+++ b/app/operations/layer-modes/gimp-layer-modes.c
@@ -825,6 +825,17 @@ static const GimpLayerModeInfo layer_mode_infos[] =
     .composite_space      = GIMP_LAYER_COLOR_SPACE_RGB_LINEAR
   },
 
+  { GIMP_LAYER_MODE_MONO_MIX,
+
+    .op_name              = "gimp:layer-mode",
+    .function             = gimp_operation_layer_mode_process_pixels,
+    .context              = GIMP_LAYER_MODE_CONTEXT_ALL,
+    .paint_composite_mode = GIMP_LAYER_COMPOSITE_SRC_OVER,
+    .composite_mode       = GIMP_LAYER_COMPOSITE_SRC_ATOP,
+    .composite_space      = GIMP_LAYER_COLOR_SPACE_RGB_LINEAR,
+    .blend_space          = GIMP_LAYER_COLOR_SPACE_RGB_LINEAR
+  },
+
   { GIMP_LAYER_MODE_REPLACE,
 
     .op_name              = "gimp:replace",
@@ -909,7 +920,8 @@ static const GimpLayerMode layer_mode_group_default[] =
   GIMP_LAYER_MODE_SEPARATOR,
 
   GIMP_LAYER_MODE_EXCLUSION,
-  GIMP_LAYER_MODE_LINEAR_BURN
+  GIMP_LAYER_MODE_LINEAR_BURN,
+  GIMP_LAYER_MODE_MONO_MIX
 };
 
 static const GimpLayerMode layer_mode_group_legacy[] =
@@ -1088,6 +1100,10 @@ static const GimpLayerMode layer_mode_groups[][2] =
     [GIMP_LAYER_MODE_GROUP_LEGACY ] = -1
   },
 
+  { [GIMP_LAYER_MODE_GROUP_DEFAULT] = GIMP_LAYER_MODE_MONO_MIX,
+    [GIMP_LAYER_MODE_GROUP_LEGACY ] = -1
+  },
+
   { [GIMP_LAYER_MODE_GROUP_DEFAULT] = GIMP_LAYER_MODE_REPLACE,
     [GIMP_LAYER_MODE_GROUP_LEGACY ] = -1
   },
diff --git a/app/operations/layer-modes/gimpoperationlayermode.c 
b/app/operations/layer-modes/gimpoperationlayermode.c
index ee2bf8a..dd3b863 100644
--- a/app/operations/layer-modes/gimpoperationlayermode.c
+++ b/app/operations/layer-modes/gimpoperationlayermode.c
@@ -2241,6 +2241,35 @@ blendfun_color_erase (const float *dest,
 }
 
 static inline void
+blendfun_mono_mix (const float *dest,
+                   const float *src,
+                   float       *out,
+                   int          samples)
+{
+  while (samples--)
+    {
+      if (dest[ALPHA] != 0.0f && src[ALPHA] != 0.0f)
+        {
+          gfloat value = 0.0f;
+          gint   c;
+
+          for (c = 0; c < 3; c++)
+            {
+              value += dest[c] * src[c];
+            }
+
+          out[RED] = out[GREEN] = out[BLUE] = value;
+        }
+
+      out[ALPHA] = src[ALPHA];
+
+      out  += 4;
+      src  += 4;
+      dest += 4;
+    }
+}
+
+static inline void
 blendfun_dummy (const float *dest,
                 const float *src,
                 float       *out,
@@ -2289,6 +2318,7 @@ gimp_layer_mode_get_blend_fun (GimpLayerMode mode)
     case GIMP_LAYER_MODE_LINEAR_BURN:    return blendfun_linear_burn;
     case GIMP_LAYER_MODE_COLOR_ERASE_LEGACY:
     case GIMP_LAYER_MODE_COLOR_ERASE:    return blendfun_color_erase;
+    case GIMP_LAYER_MODE_MONO_MIX:       return blendfun_mono_mix;
 
     case GIMP_LAYER_MODE_DISSOLVE:
     case GIMP_LAYER_MODE_BEHIND_LEGACY:
diff --git a/app/operations/operations-enums.c b/app/operations/operations-enums.c
index 5dfec3a..75fb2b2 100644
--- a/app/operations/operations-enums.c
+++ b/app/operations/operations-enums.c
@@ -140,6 +140,7 @@ gimp_layer_mode_get_type (void)
     { GIMP_LAYER_MODE_LUMINANCE, "GIMP_LAYER_MODE_LUMINANCE", "luminance" },
     { GIMP_LAYER_MODE_COLOR_ERASE, "GIMP_LAYER_MODE_COLOR_ERASE", "color-erase" },
     { GIMP_LAYER_MODE_ERASE, "GIMP_LAYER_MODE_ERASE", "erase" },
+    { GIMP_LAYER_MODE_MONO_MIX, "GIMP_LAYER_MODE_MONO_MIX", "mono-mix" },
     { GIMP_LAYER_MODE_REPLACE, "GIMP_LAYER_MODE_REPLACE", "replace" },
     { GIMP_LAYER_MODE_ANTI_ERASE, "GIMP_LAYER_MODE_ANTI_ERASE", "anti-erase" },
     { 0, NULL, NULL }
@@ -206,6 +207,7 @@ gimp_layer_mode_get_type (void)
     { GIMP_LAYER_MODE_LUMINANCE, NC_("layer-mode", "Luminance"), NULL },
     { GIMP_LAYER_MODE_COLOR_ERASE, NC_("layer-mode", "Color erase"), NULL },
     { GIMP_LAYER_MODE_ERASE, NC_("layer-mode", "Erase"), NULL },
+    { GIMP_LAYER_MODE_MONO_MIX, NC_("layer-mode", "Mono mix"), NULL },
     { GIMP_LAYER_MODE_REPLACE, NC_("layer-mode", "Replace"), NULL },
     { GIMP_LAYER_MODE_ANTI_ERASE, NC_("layer-mode", "Anti erase"), NULL },
     { 0, NULL, NULL }
diff --git a/app/operations/operations-enums.h b/app/operations/operations-enums.h
index 2a80ce8..ef863b2 100644
--- a/app/operations/operations-enums.h
+++ b/app/operations/operations-enums.h
@@ -118,6 +118,7 @@ typedef enum
   GIMP_LAYER_MODE_LUMINANCE,             /*< desc="Luminance"                >*/
   GIMP_LAYER_MODE_COLOR_ERASE,           /*< desc="Color erase"              >*/
   GIMP_LAYER_MODE_ERASE,                 /*< desc="Erase"                    >*/
+  GIMP_LAYER_MODE_MONO_MIX,              /*< desc="Mono mix"                 >*/
 
   /*  Internal modes, not available to the PDB, must be kept at the end  */
   GIMP_LAYER_MODE_REPLACE,               /*< pdb-skip, desc="Replace"        >*/
diff --git a/libgimp/gimpenums.h b/libgimp/gimpenums.h
index 85e4f11..8a4c105 100644
--- a/libgimp/gimpenums.h
+++ b/libgimp/gimpenums.h
@@ -153,7 +153,8 @@ typedef enum
   GIMP_LAYER_MODE_LUMA_LIGHTEN_ONLY,
   GIMP_LAYER_MODE_LUMINANCE,
   GIMP_LAYER_MODE_COLOR_ERASE,
-  GIMP_LAYER_MODE_ERASE
+  GIMP_LAYER_MODE_ERASE,
+  GIMP_LAYER_MODE_MONO_MIX
 } GimpLayerMode;
 
 
diff --git a/tools/pdbgen/enums.pl b/tools/pdbgen/enums.pl
index dfb3618..93512e1 100644
--- a/tools/pdbgen/enums.pl
+++ b/tools/pdbgen/enums.pl
@@ -747,7 +747,8 @@ package Gimp::CodeGen::enums;
                          GIMP_LAYER_MODE_LUMA_DARKEN_ONLY
                          GIMP_LAYER_MODE_LUMA_LIGHTEN_ONLY
                          GIMP_LAYER_MODE_LUMINANCE
-                         GIMP_LAYER_MODE_COLOR_ERASE GIMP_LAYER_MODE_ERASE) ],
+                         GIMP_LAYER_MODE_COLOR_ERASE GIMP_LAYER_MODE_ERASE
+                         GIMP_LAYER_MODE_MONO_MIX) ],
          mapping => { GIMP_LAYER_MODE_NORMAL_LEGACY => '0',
                       GIMP_LAYER_MODE_DISSOLVE => '1',
                       GIMP_LAYER_MODE_BEHIND_LEGACY => '2',
@@ -806,7 +807,8 @@ package Gimp::CodeGen::enums;
                       GIMP_LAYER_MODE_LUMA_LIGHTEN_ONLY => '55',
                       GIMP_LAYER_MODE_LUMINANCE => '56',
                       GIMP_LAYER_MODE_COLOR_ERASE => '57',
-                      GIMP_LAYER_MODE_ERASE => '58' }
+                      GIMP_LAYER_MODE_ERASE => '58',
+                      GIMP_LAYER_MODE_MONO_MIX => '59' }
        },
     GimpConvertDitherType =>
        { contig => 1,