babl: add ~ variants to gray color models

We do not add premultiplied sRGB trc variants even if this exists for RGB
since it is the type of premultiplied alpha cairo expects. The less code
that does non-linear compositing the better, excluding some possibilities
also reduces the combinatorial overhead of finding conversion paths in babl.

diff --git a/babl/babl-ids.h b/babl/babl-ids.h
index 324b240587c22042697b5673d6c2aff828bfee82..a35efd2dad1977a8a6b4b4cd793480a49e6acca5 100644 (file)
--- a/babl/babl-ids.h
+++ b/babl/babl-ids.h
@@ -47,10 +47,10 @@ enum {
   BABL_RGBA_PREMULTIPLIED,
   BABL_MODEL_GRAY_NONLINEAR,
   BABL_MODEL_GRAY_NONLINEAR_ALPHA,
-  BABL_GRAY_NONLINEAR_ALPHA_PREMULTIPLIED,
-  BABL_GRAY_PERCEPTUAL,
-  BABL_GRAY_PERCEPTUAL_ALPHA,
-  BABL_GRAY_PERCEPTUAL_ALPHA_PREMULTIPLIED,
+  BABL_MODEL_GRAY_NONLINEAR_ALPHA_PREMULTIPLIED,
+  BABL_MODEL_GRAY_PERCEPTUAL,
+  BABL_MODEL_GRAY_PERCEPTUAL_ALPHA,
+  BABL_MODEL_GRAY_PERCEPTUAL_ALPHA_PREMULTIPLIED,
   BABL_RGB_NONLINEAR,
   BABL_RGBA_NONLINEAR,
   BABL_RGBA_NONLINEAR_PREMULTIPLIED,
@@ -73,6 +73,7 @@ enum {
   BABL_RED_MUL_ALPHA,
   BABL_GREEN_MUL_ALPHA,
   BABL_BLUE_MUL_ALPHA,
+  BABL_GRAY_PERCEPTUAL,
   BABL_GRAY_NONLINEAR,
   BABL_GRAY_NONLINEAR_MUL_ALPHA,
   BABL_RED_NONLINEAR,

diff --git a/babl/base/formats.c b/babl/base/formats.c
index 97e6e8b28bced2026cf374c5e8d95c541fabda84..7affcc56158d613a036b4979b81d9352b8730fb1 100644 (file)
--- a/babl/base/formats.c
+++ b/babl/base/formats.c
@@ -111,7 +111,7 @@ babl_formats_init (void)
     babl_component_from_id (BABL_ALPHA),
     NULL);
   babl_format_new (
-    babl_model_from_id (BABL_GRAY_NONLINEAR_ALPHA_PREMULTIPLIED),
+    babl_model_from_id (BABL_MODEL_GRAY_NONLINEAR_ALPHA_PREMULTIPLIED),
     babl_type_from_id (BABL_FLOAT),
     babl_component_from_id (BABL_GRAY_NONLINEAR_MUL_ALPHA),
     babl_component_from_id (BABL_ALPHA),
@@ -128,7 +128,7 @@ babl_formats_init (void)
     babl_component_from_id (BABL_ALPHA),
     NULL);
   babl_format_new (
-    babl_model_from_id (BABL_GRAY_NONLINEAR_ALPHA_PREMULTIPLIED),
+    babl_model_from_id (BABL_MODEL_GRAY_NONLINEAR_ALPHA_PREMULTIPLIED),
     babl_type_from_id (BABL_U16),
     babl_component_from_id (BABL_GRAY_NONLINEAR_MUL_ALPHA),
     babl_component_from_id (BABL_ALPHA),
@@ -145,7 +145,7 @@ babl_formats_init (void)
     babl_component_from_id (BABL_ALPHA),
     NULL);
   babl_format_new (
-    babl_model_from_id (BABL_GRAY_NONLINEAR_ALPHA_PREMULTIPLIED),
+    babl_model_from_id (BABL_MODEL_GRAY_NONLINEAR_ALPHA_PREMULTIPLIED),
     babl_type_from_id (BABL_U8),
     babl_component_from_id (BABL_GRAY_NONLINEAR_MUL_ALPHA),
     babl_component_from_id (BABL_ALPHA),

diff --git a/babl/base/model-gray.c b/babl/base/model-gray.c
index 47a875b6f9e4d4c29be3dd14a811994930a15818..ea1ca98cb2c47321a721ac9641a128e7c45855cb 100644 (file)
--- a/babl/base/model-gray.c
+++ b/babl/base/model-gray.c
@@ -19,8 +19,7 @@
 #include "config.h"
 #include <stdlib.h>
 
-#include "babl-classes.h"
-#include "babl.h"
+#include "babl-internal.h"
 #include "babl-ids.h"
 #include "math.h"
 #include "babl-base.h"
@@ -64,6 +63,12 @@ components (void)
     "id", BABL_GRAY_NONLINEAR_MUL_ALPHA,
     "luma",
     NULL);
+
+  babl_component_new (
+    "Y~",
+    "id", BABL_GRAY_PERCEPTUAL,
+    "luma",
+    NULL);
 }
 
 static void
@@ -87,9 +92,8 @@ models (void)
     babl_component_from_id (BABL_ALPHA),
     NULL);
 
-
   babl_model_new (
-    "id", BABL_GRAY_NONLINEAR,
+    "id", BABL_MODEL_GRAY_NONLINEAR,
     babl_component_from_id (BABL_GRAY_NONLINEAR),
     NULL);
 
@@ -100,12 +104,23 @@ models (void)
     NULL);
 
   babl_model_new (
-    "id", BABL_GRAY_NONLINEAR_ALPHA_PREMULTIPLIED,
+    "id", BABL_MODEL_GRAY_NONLINEAR_ALPHA_PREMULTIPLIED,
     babl_component_from_id (BABL_GRAY_NONLINEAR_MUL_ALPHA),
     babl_component_from_id (BABL_ALPHA),
     NULL);
-}
 
+  babl_model_new (
+    "id", BABL_MODEL_GRAY_PERCEPTUAL,
+    babl_component_from_id (BABL_GRAY_PERCEPTUAL),
+    NULL);
+
+  babl_model_new (
+    "id", BABL_MODEL_GRAY_PERCEPTUAL_ALPHA,
+    babl_component_from_id (BABL_GRAY_PERCEPTUAL),
+    babl_component_from_id (BABL_ALPHA),
+    NULL);
+
+}
 
 static void
 rgba_to_graya (Babl *conversion,
@@ -171,6 +186,8 @@ rgba_to_gray (Babl *conversion,
     }
 }
 
+static const Babl *perceptual_trc = NULL;
+
 static void
 rgb_to_gray_nonlinear (Babl  *conversion,
                        int    src_bands,
@@ -254,6 +271,88 @@ gray_nonlinear_to_rgb (Babl *conversion,
     }
 }
 
+static void
+rgb_to_gray_perceptual (Babl  *conversion,
+                        int    src_bands,
+                        char **src,
+                        int   *src_pitch,
+                        int    dst_bands,
+                        char **dst,
+                        int   *dst_pitch,
+                        long   n)
+{
+  const Babl *space = babl_conversion_get_destination_space (conversion);
+  const Babl *trc = perceptual_trc;
+  double RGB_LUMINANCE_RED   = space->space.RGBtoXYZ[3];
+  double RGB_LUMINANCE_GREEN = space->space.RGBtoXYZ[4];
+  double RGB_LUMINANCE_BLUE  = space->space.RGBtoXYZ[5];
+
+  BABL_PLANAR_SANITY
+  while (n--)
+    {
+      double red, green, blue;
+      double luminance, alpha;
+
+      red   = *(double *) src[0];
+      green = *(double *) src[1];
+      blue  = *(double *) src[2];
+      if (src_bands > 3)
+        alpha = *(double *) src[3];
+      else
+        alpha = 1.0;
+
+      luminance = red   * RGB_LUMINANCE_RED +
+                  green * RGB_LUMINANCE_GREEN +
+                  blue  * RGB_LUMINANCE_BLUE;
+      *(double *) dst[0] = babl_trc_from_linear (trc, luminance);
+
+      if (dst_bands == 2)
+        *(double *) dst[1] = alpha;
+
+      BABL_PLANAR_STEP
+    }
+}
+
+static void
+gray_perceptual_to_rgb (Babl *conversion,
+                        int    src_bands,
+                        char **src,
+                        int   *src_pitch,
+                        int    dst_bands,
+                        char **dst,
+                        int   *dst_pitch,
+                        long   n)
+{
+  const Babl *trc = perceptual_trc;
+
+  BABL_PLANAR_SANITY
+  while (n--)
+    {
+      double luminance;
+      double red, green, blue;
+      double alpha;
+
+      luminance = babl_trc_to_linear (trc, *(double *) src[0]);
+      red       = luminance;
+      green     = luminance;
+      blue      = luminance;
+      if (src_bands > 1)
+        alpha = *(double *) src[1];
+      else
+        alpha = 1.0;
+
+      *(double *) dst[0] = red;
+      *(double *) dst[1] = green;
+      *(double *) dst[2] = blue;
+
+      if (dst_bands > 3)
+        *(double *) dst[3] = alpha;
+
+      BABL_PLANAR_STEP
+    }
+}
+
+
 static void
 graya_to_rgba (Babl *conversion,
                char *src,
@@ -516,10 +615,10 @@ gray_nonlinear_premultiplied2rgba (Babl *conversion,
     }
 }
 
-
 static void
 conversions (void)
 {
+  perceptual_trc = babl_trc ("sRGB");
   babl_conversion_new (
     babl_model_from_id (BABL_MODEL_GRAY_NONLINEAR),
     babl_model_from_id (BABL_RGBA),
@@ -550,7 +649,7 @@ conversions (void)
 
 
   babl_conversion_new (
-    babl_model_from_id (BABL_GRAY_NONLINEAR_ALPHA_PREMULTIPLIED),
+    babl_model_from_id (BABL_MODEL_GRAY_NONLINEAR_ALPHA_PREMULTIPLIED),
     babl_model_from_id (BABL_RGBA),
     "linear", gray_nonlinear_premultiplied2rgba,
     NULL
@@ -558,11 +657,42 @@ conversions (void)
 
   babl_conversion_new (
     babl_model_from_id (BABL_RGBA),
-    babl_model_from_id (BABL_GRAY_NONLINEAR_ALPHA_PREMULTIPLIED),
+    babl_model_from_id (BABL_MODEL_GRAY_NONLINEAR_ALPHA_PREMULTIPLIED),
     "linear", rgba2gray_nonlinear_premultiplied,
     NULL
   );
 
+
+
+  babl_conversion_new (
+    babl_model_from_id (BABL_MODEL_GRAY_PERCEPTUAL),
+    babl_model_from_id (BABL_RGBA),
+    "planar", gray_perceptual_to_rgb,
+    NULL
+  );
+
+  babl_conversion_new (
+    babl_model_from_id (BABL_RGBA),
+    babl_model_from_id (BABL_MODEL_GRAY_PERCEPTUAL),
+    "planar", rgb_to_gray_perceptual,
+    NULL
+  );
+
+  babl_conversion_new (
+    babl_model_from_id (BABL_MODEL_GRAY_PERCEPTUAL_ALPHA),
+    babl_model_from_id (BABL_RGBA),
+    "planar", gray_perceptual_to_rgb,
+    NULL
+  );
+
+  babl_conversion_new (
+    babl_model_from_id (BABL_RGBA),
+    babl_model_from_id (BABL_MODEL_GRAY_PERCEPTUAL_ALPHA),
+    "planar", rgb_to_gray_perceptual,
+    NULL
+  );
+
+
   babl_conversion_new (
     babl_model_from_id (BABL_GRAY),
     babl_model_from_id (BABL_RGBA),
@@ -647,7 +777,7 @@ formats (void)
     babl_component_from_id (BABL_ALPHA),
     NULL);
   babl_format_new (
-    babl_model_from_id (BABL_GRAY_NONLINEAR_ALPHA_PREMULTIPLIED),
+    babl_model_from_id (BABL_MODEL_GRAY_NONLINEAR_ALPHA_PREMULTIPLIED),
     babl_type_from_id (BABL_HALF),
     babl_component_from_id (BABL_GRAY_NONLINEAR_MUL_ALPHA),
     babl_component_from_id (BABL_ALPHA),
@@ -683,7 +813,7 @@ formats (void)
     babl_component_from_id (BABL_ALPHA),
     NULL);
   babl_format_new (
-    babl_model_from_id (BABL_GRAY_NONLINEAR_ALPHA_PREMULTIPLIED),
+    babl_model_from_id (BABL_MODEL_GRAY_NONLINEAR_ALPHA_PREMULTIPLIED),
     babl_type ("u15"),
     babl_component_from_id (BABL_GRAY_NONLINEAR_MUL_ALPHA),
     babl_component_from_id (BABL_ALPHA),
@@ -718,7 +848,7 @@ formats (void)
     babl_component_from_id (BABL_ALPHA),
     NULL);
   babl_format_new (
-    babl_model_from_id (BABL_GRAY_NONLINEAR_ALPHA_PREMULTIPLIED),
+    babl_model_from_id (BABL_MODEL_GRAY_NONLINEAR_ALPHA_PREMULTIPLIED),
     babl_type_from_id (BABL_U32),
     babl_component_from_id (BABL_GRAY_NONLINEAR_MUL_ALPHA),
     babl_component_from_id (BABL_ALPHA),