[gimp] app: cache fishes per operation instance in layer-modes

[Øyvind "pippin" Kolås <ok src gnome org>]

commit 4dd3e2197a182f3b3cdccb5ebef758b1363a1e68
Author: Øyvind Kolås <pippin gimp org>
Date:   Fri Nov 30 01:20:27 2018 +0100

    app: cache fishes per operation instance in layer-modes
    
    There was a global 3x3 array of babl fishes used for converting between
    blending and compositing pixel representations, these were all hard-coded to
    operate within the sRGB babl-space family. This commit updates a per-instance
    array during operation prepare instead, that comes preconfigured with fishes
    derived from the correct space. Since the same operation instance might get
    different space input during its life time we store and compare the cached
    fishes with the current format (which is unique depending on space).
    
    This should address the problem seen in issue #2592

 .../layer-modes/gimpoperationlayermode.c           | 74 ++++++++++++----------
 .../layer-modes/gimpoperationlayermode.h           |  2 +
 2 files changed, 43 insertions(+), 33 deletions(-)
---
diff --git a/app/operations/layer-modes/gimpoperationlayermode.c 
b/app/operations/layer-modes/gimpoperationlayermode.c
index 3ebb2f698b..05df9b9253 100644
--- a/app/operations/layer-modes/gimpoperationlayermode.c
+++ b/app/operations/layer-modes/gimpoperationlayermode.c
@@ -117,9 +117,6 @@ G_DEFINE_TYPE (GimpOperationLayerMode, gimp_operation_layer_mode,
 
 #define parent_class gimp_operation_layer_mode_parent_class
 
-
-static const Babl *gimp_layer_color_space_fish[3 /* from */][3 /* to */];
-
 static CompositeFunc composite_union                = gimp_operation_layer_mode_composite_union;
 static CompositeFunc composite_clip_to_backdrop     = gimp_operation_layer_mode_composite_clip_to_backdrop;
 static CompositeFunc composite_clip_to_layer        = gimp_operation_layer_mode_composite_clip_to_layer;
@@ -192,32 +189,6 @@ gimp_operation_layer_mode_class_init (GimpOperationLayerModeClass *klass)
                                                       GIMP_PARAM_READWRITE |
                                                       G_PARAM_CONSTRUCT));
 
-  gimp_layer_color_space_fish
-    /* from */ [GIMP_LAYER_COLOR_SPACE_RGB_LINEAR     - 1]
-    /* to   */ [GIMP_LAYER_COLOR_SPACE_RGB_PERCEPTUAL - 1] =
-      babl_fish ("RGBA float", "R'G'B'A float");
-  gimp_layer_color_space_fish
-    /* from */ [GIMP_LAYER_COLOR_SPACE_RGB_LINEAR     - 1]
-    /* to   */ [GIMP_LAYER_COLOR_SPACE_LAB            - 1] =
-      babl_fish ("RGBA float", "CIE Lab alpha float");
-
-  gimp_layer_color_space_fish
-    /* from */ [GIMP_LAYER_COLOR_SPACE_RGB_PERCEPTUAL - 1]
-    /* to   */ [GIMP_LAYER_COLOR_SPACE_RGB_LINEAR     - 1] =
-      babl_fish ("R'G'B'A float", "RGBA float");
-  gimp_layer_color_space_fish
-    /* from */ [GIMP_LAYER_COLOR_SPACE_RGB_PERCEPTUAL - 1]
-    /* to   */ [GIMP_LAYER_COLOR_SPACE_LAB            - 1] =
-      babl_fish ("R'G'B'A float", "CIE Lab alpha float");
-
-  gimp_layer_color_space_fish
-    /* from */ [GIMP_LAYER_COLOR_SPACE_LAB            - 1]
-    /* to   */ [GIMP_LAYER_COLOR_SPACE_RGB_LINEAR     - 1] =
-      babl_fish ("CIE Lab alpha float", "RGBA float");
-  gimp_layer_color_space_fish
-    /* from */ [GIMP_LAYER_COLOR_SPACE_LAB            - 1]
-    /* to   */ [GIMP_LAYER_COLOR_SPACE_RGB_PERCEPTUAL - 1] =
-      babl_fish ("CIE Lab alpha float", "R'G'B'A float");
 
 #if COMPILE_SSE2_INTRINISICS
   if (gimp_cpu_accel_get_support () & GIMP_CPU_ACCEL_X86_SSE2)
@@ -362,6 +333,43 @@ gimp_operation_layer_mode_prepare (GeglOperation *operation)
                                        self->composite_space,
                                        self->blend_space,
                                        preferred_format);
+  if (self->cached_fish_format != format)
+    {
+      self->cached_fish_format = format;
+
+      self->space_fish
+        /* from */ [GIMP_LAYER_COLOR_SPACE_RGB_LINEAR     - 1]
+        /* to   */ [GIMP_LAYER_COLOR_SPACE_RGB_PERCEPTUAL - 1] =
+          babl_fish (babl_format_with_space ("RGBA float", format),
+                     babl_format_with_space ("R'G'B'A float", format));
+      self->space_fish
+        /* from */ [GIMP_LAYER_COLOR_SPACE_RGB_LINEAR     - 1]
+        /* to   */ [GIMP_LAYER_COLOR_SPACE_LAB            - 1] =
+          babl_fish (babl_format_with_space ("RGBA float", format),
+                     babl_format_with_space ("CIE Lab alpha float", format));
+
+      self->space_fish
+        /* from */ [GIMP_LAYER_COLOR_SPACE_RGB_PERCEPTUAL - 1]
+        /* to   */ [GIMP_LAYER_COLOR_SPACE_RGB_LINEAR     - 1] =
+          babl_fish (babl_format_with_space("R'G'B'A float", format),
+                     babl_format_with_space ( "RGBA float", format));
+      self->space_fish
+        /* from */ [GIMP_LAYER_COLOR_SPACE_RGB_PERCEPTUAL - 1]
+        /* to   */ [GIMP_LAYER_COLOR_SPACE_LAB            - 1] =
+          babl_fish (babl_format_with_space("R'G'B'A float", format),
+                     babl_format_with_space ( "CIE Lab alpha float", format));
+
+      self->space_fish
+        /* from */ [GIMP_LAYER_COLOR_SPACE_LAB            - 1]
+        /* to   */ [GIMP_LAYER_COLOR_SPACE_RGB_LINEAR     - 1] =
+          babl_fish (babl_format_with_space("CIE Lab alpha float", format),
+                     babl_format_with_space ( "RGBA float", format));
+      self->space_fish
+        /* from */ [GIMP_LAYER_COLOR_SPACE_LAB            - 1]
+        /* to   */ [GIMP_LAYER_COLOR_SPACE_RGB_PERCEPTUAL - 1] =
+          babl_fish (babl_format_with_space("CIE Lab alpha float", format),
+                     babl_format_with_space ( "R'G'B'A float", format));
+    }
 
   gegl_operation_set_format (operation, "input",  format);
   gegl_operation_set_format (operation, "output", format);
@@ -582,11 +590,11 @@ gimp_operation_layer_mode_real_process (GeglOperation       *operation,
       gimp_assert (composite_space >= 1 && composite_space < 4);
       gimp_assert (blend_space     >= 1 && blend_space     < 4);
 
-      composite_to_blend_fish = gimp_layer_color_space_fish [composite_space - 1]
-                                                            [blend_space     - 1];
+      composite_to_blend_fish = layer_mode->space_fish [composite_space - 1]
+                                                       [blend_space     - 1];
 
-      blend_to_composite_fish = gimp_layer_color_space_fish [blend_space     - 1]
-                                                            [composite_space - 1];
+      blend_to_composite_fish = layer_mode->space_fish [blend_space     - 1]
+                                                       [composite_space - 1];
     }
 
   /* if we need to convert the samples between the composite and blend
diff --git a/app/operations/layer-modes/gimpoperationlayermode.h 
b/app/operations/layer-modes/gimpoperationlayermode.h
index 2c193a92b1..851daae3ae 100644
--- a/app/operations/layer-modes/gimpoperationlayermode.h
+++ b/app/operations/layer-modes/gimpoperationlayermode.h
@@ -44,6 +44,8 @@ struct _GimpOperationLayerMode
   GimpLayerColorSpace          blend_space;
   GimpLayerColorSpace          composite_space;
   GimpLayerCompositeMode       composite_mode;
+  const Babl                  *cached_fish_format;
+  const Babl                  *space_fish[3 /* from */][3 /* to */];
 
   GimpLayerCompositeMode       real_composite_mode;
   GimpLayerModeFunc            function;