babl: use hashtable approach in double reference

Strictly speaking we should be doing the reference using
conversions to R'G'B'A double and using the distance metric
there; possibly getting a slight difference in result at
comparison ties.

In use GEGL ends up using both the really fast 8bit code paths
and the quite fast floating point code paths that use 8bit
hashtables for the lookup of conversion.

Progress on bug #787237 missing fast-paths.

diff --git a/babl/babl-palette.c b/babl/babl-palette.c
index a22ea584bf88c88494021639b182b6d9c9d866f6..ca375c9bcef8a0e97a9fef1f485c444259c02328 100644 (file)
--- a/babl/babl-palette.c
+++ b/babl/babl-palette.c
@@ -28,13 +28,11 @@
 
 #define HASH_TABLE_SIZE 1111
 
-//#define SHOW_PATH
-
 /* A default palette, containing standard ANSI / EGA colors
  *
  */
-static unsigned char defpal_data[4*16] = 
-{  
+static unsigned char defpal_data[4*16] =
+{
 0  ,0  ,0  ,255,
 127,0  ,0  ,255,
 0  ,127,0  ,255,
@@ -77,6 +75,8 @@ babl_palette_reset_hash (BablPalette *pal)
     }
 }
 
+#define BABL_IDX_FACTOR 255.5
+
 static int
 babl_palette_lookup (BablPalette *pal, int r, int g, int b, int a)
 {
@@ -180,108 +180,92 @@ static BablPalette *default_palette (void)
 
 static void
 rgba_to_pal (Babl *conversion,
-             char *src,
+             char *src_b,
              char *dst,
              long  n,
              void *dst_model_data)
 {
+  const Babl *space = babl_conversion_get_source_space (conversion);
   BablPalette **palptr = dst_model_data;
-  BablPalette *pal = *palptr;
-#ifdef SHOW_PATH
-  fprintf (stderr, "d");
-#endif
+  BablPalette *pal;
+  assert (palptr);
+  pal = *palptr;
+  assert(pal);
+
   while (n--)
     {
-      int idx;
-
-      int best_idx = 0;
-      double best_diff = 100000;
-      double srcf[4];
+      double *src_d = (void*) src_b;
+      unsigned char src[4];
       int c;
-      for (c = 0; c < 4; c++)
+      for (c = 0; c < 3; c++)
       {
-        srcf[c] = ((double *) src)[c];
-        if (srcf[c] < 0.0)
-         srcf[c] = 0.0;
-        if (srcf[c] > 1.0)
-         srcf[c] = 1.0;
+        if (src_d[c] >= 1.0f)
+          src[c] = 255;
+        else if (src_d[c] <= 0.0f)
+          src[c] = 0;
+        else
+          src[c] = babl_trc_from_linear (space->space.trc[0],
+                                         src_d[c]) * 255 + 0.5f;
       }
+      if (src_d[3] >= 1.0f)
+        src[3] = 255;
+      else if (src_d[3] <= 0.0f)
+        src[3] = 0;
+      else
+        src[3] = src_d[3] * 255 + 0.5f;
 
-      for (idx = 0; idx<pal->count; idx++)
-        {
-          double diff;
-          double *palpx = ((double *)pal->data_double) + idx * 4;
-
-          diff = (palpx[0] - srcf[0]) * (palpx[0] - srcf[0]) +
-                 (palpx[1] - srcf[1]) * (palpx[1] - srcf[1]) +
-                 (palpx[2] - srcf[2]) * (palpx[2] - srcf[2]);
-          if (diff <= best_diff)
-            {
-              best_diff = diff;
-              best_idx = idx;
-            }
-        }
-
-      ((double *) dst)[0] = best_idx / 255.5;
+      ((double *) dst)[0] =
+        babl_palette_lookup (pal, src[0], src[1], src[2], src[3]) /
+           BABL_IDX_FACTOR;
 
-      src += sizeof (double) * 4;
+      src_b += sizeof (double) * 4;
       dst += sizeof (double) * 1;
     }
+
 }
 
 static void
 rgba_to_pala (Babl *conversion,
-              char *src,
+              char *src_i,
               char *dst,
               long  n,
               void *dst_model_data)
 {
+  const Babl *space = babl_conversion_get_destination_space (conversion);
   BablPalette **palptr = dst_model_data;
-  BablPalette *pal = *palptr;
-
-#ifdef SHOW_PATH
-  fprintf (stderr, "D");
-#endif
+  BablPalette *pal;
+  assert (palptr);
+  pal = *palptr;
   assert(pal);
+
   while (n--)
     {
-      int idx;
-
-      int best_idx = 0;
-      double best_diff = 100000;
-      double srcf[4];
-      double alpha;
+      double *src_d = (void*) src_i;
+      unsigned char src[4];
       int c;
-      for (c = 0; c < 4; c++)
+      for (c = 0; c < 3; c++)
       {
-        srcf[c] = ((double *) src)[c];
-        if (srcf[c] < 0.0)
-         srcf[c] = 0.0;
-        if (srcf[c] > 1.0)
-         srcf[c] = 1.0;
+        if (src_d[c] >= 1.0f)
+          src[c] = 255;
+        else if (src_d[c] <= 0.0f)
+          src[c] = 0;
+        else
+          src[c] = babl_trc_from_linear (space->space.trc[0],
+                                         src_d[c]) * 255 + 0.5f;
       }
+      if (src_d[3] >= 1.0f)
+        src[3] = 255;
+      else if (src_d[3] <= 0.0f)
+        src[3] = 0;
+      else
+        src[3] = src_d[3] * 255 + 0.5f;
 
-      alpha = srcf[3];
-
-      for (idx = 0; idx<pal->count; idx++)
-        {
-          double diff;
-          double *palpx = ((double *)pal->data_double) + idx * 4;
-
-          diff = (palpx[0] - srcf[0]) * (palpx[0] - srcf[0]) +
-                 (palpx[1] - srcf[1]) * (palpx[1] - srcf[1]) +
-                 (palpx[2] - srcf[2]) * (palpx[2] - srcf[2]);
-          if (diff <= best_diff)
-            {
-              best_diff = diff;
-              best_idx = idx;
-            }
-        }
 
-      ((double *) dst)[0] = best_idx / 255.5;
-      ((double *) dst)[1] = alpha;
+      ((double *) dst)[0] = babl_palette_lookup (pal, src[0], src[1], src[2],
+                                                 src[3]) / BABL_IDX_FACTOR;
+      ((double *) dst)[1] = src_d[3];
 
-      src += sizeof (double) * 4;
+      src_i += sizeof (double) * 4;
       dst += sizeof (double) * 2;
     }
 }
@@ -298,7 +282,7 @@ pal_to_rgba (Babl *conversion,
   assert(pal);
   while (n--)
     {
-      int idx = (((double *) src)[0]) * 255.5;
+      int idx = (((double *) src)[0]) * BABL_IDX_FACTOR;
       double *palpx;
 
       if (idx < 0) idx = 0;
@@ -325,7 +309,7 @@ pala_to_rgba (Babl *conversion,
   assert(pal);
   while (n--)
     {
-      int idx      = (((double *) src)[0]) * 255.5;
+      int idx      = (((double *) src)[0]) * BABL_IDX_FACTOR;
       double alpha = (((double *) src)[1]);
       double *palpx;
 
@@ -354,9 +338,7 @@ rgba_u8_to_pal (Babl          *conversion,
   assert (palptr);
   pal = *palptr;
   assert(pal);
-#ifdef SHOW_PATH
-  fprintf (stderr, "8");
-#endif
+
   while (n--)
     {
       dst[0] = babl_palette_lookup (pal, src[0], src[1], src[2], src[3]);
@@ -380,9 +362,6 @@ rgba_float_to_pal_a (Babl          *conversion,
   pal = *palptr;
   assert(pal);
 
-#ifdef SHOW_PATH
-  fprintf (stderr, "f");
-#endif
   while (n--)
     {
       float *src_f = (void*) src_b;
@@ -428,9 +407,7 @@ rgba_float_to_pal (Babl          *conversion,
   assert (palptr);
   pal = *palptr;
   assert(pal);
-#ifdef SHOW_PATH
-  fprintf (stderr, "F");
-#endif
+
   while (n--)
     {
       float *src_f = (void*) src_b;
@@ -630,7 +607,6 @@ const Babl *babl_new_palette (const char  *name,
     "chroma",
     NULL);
   alpha = babl_component ("A");
-  
   model = babl_model_new ("name", name, component, alpha, NULL);
   palptr = malloc (sizeof (void*));
   *palptr = default_palette ();;
@@ -678,30 +654,24 @@ const Babl *babl_new_palette (const char  *name,
      "data", palptr,
      NULL
   );
-
   babl_conversion_new (
      f_pal_u8,
      f_pal_a_u8,
      "linear", conv_pal8_pala8,
      NULL
   );
-
   babl_conversion_new (
      f_pal_a_u8,
      f_pal_u8,
      "linear", conv_pala8_pal8,
      NULL
   );
-
-
   babl_conversion_new (
      f_pal_u8,
      babl_format ("R'G'B'A u8"),
      "linear", pal_u8_to_rgba_u8,
      "data", palptr,
      NULL);
-
-
   babl_conversion_new (
      f_pal_a_u8,
      babl_format ("R'G'B'A u8"),