[babl] extensions: add a double extension

[Øyvind Kolås <ok src gnome org>]

commit 240cd0b99485fb9de00a63ad254bf55a5fa75aea
Author: Øyvind Kolås <pippin gimp org>
Date:   Thu Apr 5 23:24:31 2018 +0200

    extensions: add a double extension
    
    This will permit slightly faster than the generic fast paths for some possibly
    desired intermediate conversions. This also adds alpha stripping - which fills
    in the last babl fast path currently reported missing on every launch of GIMP.

 extensions/Makefile.am       |    3 +-
 extensions/double.c          |  264 ++++++++++++++++++++++++++++++++++++++++++
 extensions/gggl-table-lies.c |   52 ++++++++
 extensions/gggl-table.c      |    1 +
 extensions/meson.build       |    1 +
 extensions/two-table.c       |   11 ++
 6 files changed, 331 insertions(+), 1 deletions(-)
---
diff --git a/extensions/Makefile.am b/extensions/Makefile.am
index b103c93..06d6bea 100644
--- a/extensions/Makefile.am
+++ b/extensions/Makefile.am
@@ -18,7 +18,7 @@ ext_LTLIBRARIES = \
        16bit.la        \
        cairo.la        \
        CIE.la          \
-    float-half.la   \
+       float-half.la   \
        gegl-fixups.la  \
        gggl-lies.la    \
        gggl-table.la   \
@@ -26,6 +26,7 @@ ext_LTLIBRARIES = \
        gggl.la         \
        gimp-8bit.la    \
        grey.la         \
+       double.la       \
        float.la        \
        fast-float.la   \
        naive-CMYK.la   \
diff --git a/extensions/double.c b/extensions/double.c
new file mode 100644
index 0000000..f592cb9
--- /dev/null
+++ b/extensions/double.c
@@ -0,0 +1,264 @@
+/* babl - dynamically extendable universal pixel conversion library.
+ * Copyright (C) 2012, Øyvind Kolås
+ *
+ * This library is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public
+ * License as published by the Free Software Foundation; either
+ * version 3 of the License, or (at your option) any later version.
+ *
+ * This library is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General
+ * Public License along with this library; if not, see
+ * <http://www.gnu.org/licenses/>.
+ */
+
+#include "config.h"
+
+#include <stdint.h>
+#include <stdlib.h>
+
+#include "babl-internal.h"
+#include "babl-cpuaccel.h"
+#include "extensions/util.h"
+#include "base/util.h"
+
+
+#define INLINE inline
+
+
+static INLINE void
+conv_rgbaD_linear_rgbAD_gamma (const Babl *conversion,unsigned char *src,
+                               unsigned char *dst,
+                               long           samples)
+{
+   const Babl  *space = babl_conversion_get_destination_space (conversion);
+   const Babl **trc   = (void*)space->space.trc;
+
+   double *fsrc = (double *) src;
+   double *fdst = (double *) dst;
+   int n = samples;
+
+   while (n--)
+     {
+       double alpha = fsrc[3];
+       *fdst++ = babl_trc_from_linear (trc[0], *fsrc++) * alpha;
+       *fdst++ = babl_trc_from_linear (trc[1], *fsrc++) * alpha;
+       *fdst++ = babl_trc_from_linear (trc[2], *fsrc++) * alpha;
+       *fdst++ = *fsrc++;
+     }
+}
+
+static INLINE void
+conv_rgbAD_linear_rgbAD_gamma (const Babl    *conversion,
+                               unsigned char *src,
+                               unsigned char *dst,
+                               long           samples)
+{
+   const Babl  *space = babl_conversion_get_destination_space (conversion);
+   const Babl **trc   = (void*)space->space.trc;
+
+   double *fsrc = (double *) src;
+   double *fdst = (double *) dst;
+   int n = samples;
+
+   while (n--)
+     {
+       double alpha = fsrc[3];
+       if (alpha < BABL_ALPHA_THRESHOLD)
+         {
+           *fdst++ = 0.0;
+           *fdst++ = 0.0;
+           *fdst++ = 0.0;
+           *fdst++ = 0.0;
+           fsrc+=4;
+         }
+       else if (alpha >= 1.0)
+         {
+           *fdst++ = babl_trc_from_linear (trc[0], *fsrc++) * alpha;
+           *fdst++ = babl_trc_from_linear (trc[1], *fsrc++) * alpha;
+           *fdst++ = babl_trc_from_linear (trc[2], *fsrc++) * alpha;
+           *fdst++ = *fsrc++;
+         }
+       else
+         {
+           double alpha_recip = 1.0 / alpha;
+           *fdst++ = babl_trc_from_linear (trc[0], *fsrc++ * alpha_recip) * alpha;
+           *fdst++ = babl_trc_from_linear (trc[1], *fsrc++ * alpha_recip) * alpha;
+           *fdst++ = babl_trc_from_linear (trc[2], *fsrc++ * alpha_recip) * alpha;
+           *fdst++ = *fsrc++;
+         }
+     }
+}
+
+static INLINE void
+conv_rgbaD_linear_rgbaD_gamma (const Babl *conversion,unsigned char *src, 
+                               unsigned char *dst, 
+                               long           samples)
+{
+   const Babl  *space = babl_conversion_get_destination_space (conversion);
+   const Babl **trc   = (void*)space->space.trc;
+
+   double *fsrc = (double *) src;
+   double *fdst = (double *) dst;
+   int n = samples;
+
+   while (n--)
+     {
+       *fdst++ = babl_trc_from_linear (trc[0], *fsrc++);
+       *fdst++ = babl_trc_from_linear (trc[1], *fsrc++);
+       *fdst++ = babl_trc_from_linear (trc[2], *fsrc++);
+       *fdst++ = *fsrc++;
+     }
+}
+
+#define conv_rgbaD_linear_rgbD_linear conv_rgbaD_gamma_rgbD_gamma
+
+static void
+conv_rgbaD_linear_rgbD_linear (const Babl *conversion,unsigned char *src,
+                               unsigned char *dst,
+                               long           samples)
+{
+   double *fsrc = (double *) src;
+   double *fdst = (double *) dst;
+   int n = samples;
+
+   while (n--)
+     {
+       *fdst++ = *fsrc++;
+       *fdst++ = *fsrc++;
+       *fdst++ = *fsrc++;
+       fsrc++;
+     }
+}
+
+
+static INLINE void
+conv_rgbD_linear_rgbD_gamma (const Babl *conversion,unsigned char *src, 
+                             unsigned char *dst, 
+                             long           samples)
+{
+   const Babl  *space = babl_conversion_get_destination_space (conversion);
+   const Babl **trc   = (void*)space->space.trc;
+   double *fsrc = (double *) src;
+   double *fdst = (double *) dst;
+   int n = samples;
+
+   while (n--)
+     {
+       *fdst++ = babl_trc_from_linear (trc[0], *fsrc++);
+       *fdst++ = babl_trc_from_linear (trc[1], *fsrc++);
+       *fdst++ = babl_trc_from_linear (trc[2], *fsrc++);
+     }
+}
+
+
+static INLINE void
+conv_rgbaD_gamma_rgbaD_linear (const Babl *conversion,unsigned char *src, 
+                               unsigned char *dst, 
+                               long           samples)
+{
+   const Babl  *space = babl_conversion_get_destination_space (conversion);
+   const Babl **trc   = (void*)space->space.trc;
+   double *fsrc = (double *) src;
+   double *fdst = (double *) dst;
+   int n = samples;
+
+   while (n--)
+     {
+       *fdst++ = babl_trc_to_linear (trc[0], *fsrc++);
+       *fdst++ = babl_trc_to_linear (trc[1], *fsrc++);
+       *fdst++ = babl_trc_to_linear (trc[2], *fsrc++);
+       *fdst++ = *fsrc++;
+     }
+}
+
+static INLINE void
+conv_rgbD_gamma_rgbD_linear (const Babl *conversion,unsigned char *src, 
+                             unsigned char *dst, 
+                             long           samples)
+{
+   const Babl  *space = babl_conversion_get_destination_space (conversion);
+   const Babl **trc   = (void*)space->space.trc;
+   double *fsrc = (double *) src;
+   double *fdst = (double *) dst;
+   int n = samples;
+
+   while (n--)
+     {
+       *fdst++ = babl_trc_to_linear (trc[0], *fsrc++);
+       *fdst++ = babl_trc_to_linear (trc[1], *fsrc++);
+       *fdst++ = babl_trc_to_linear (trc[2], *fsrc++);
+     }
+}
+
+#define o(src, dst) \
+  babl_conversion_new (src, dst, "linear", conv_ ## src ## _ ## dst, NULL)
+
+int init (void);
+
+int
+init (void)
+{
+  const Babl *rgbaD_linear = babl_format_new (
+    babl_model ("RGBA"),
+    babl_type ("double"),
+    babl_component ("R"),
+    babl_component ("G"),
+    babl_component ("B"),
+    babl_component ("A"),
+    NULL);
+  const Babl *rgbAD_linear = babl_format_new (
+    babl_model ("RaGaBaA"),
+    babl_type ("double"),
+    babl_component ("Ra"),
+    babl_component ("Ga"),
+    babl_component ("Ba"),
+    babl_component ("A"),
+    NULL);
+  const Babl *rgbaD_gamma = babl_format_new (
+    babl_model ("R'G'B'A"),
+    babl_type ("double"),
+    babl_component ("R'"),
+    babl_component ("G'"),
+    babl_component ("B'"),
+    babl_component ("A"),
+    NULL);
+  const Babl *rgbAD_gamma = babl_format_new (
+    babl_model ("R'aG'aB'aA"),
+    babl_type ("double"),
+    babl_component ("R'a"),
+    babl_component ("G'a"),
+    babl_component ("B'a"),
+    babl_component ("A"),
+    NULL);
+  const Babl *rgbD_linear = babl_format_new (
+    babl_model ("RGB"),
+    babl_type ("double"),
+    babl_component ("R"),
+    babl_component ("G"),
+    babl_component ("B"),
+    NULL);
+  const Babl *rgbD_gamma = babl_format_new (
+    babl_model ("R'G'B'"),
+    babl_type ("double"),
+    babl_component ("R'"),
+    babl_component ("G'"),
+    babl_component ("B'"),
+    NULL);
+
+  o (rgbAD_linear, rgbAD_gamma);
+  o (rgbaD_linear, rgbAD_gamma);
+  o (rgbaD_linear, rgbaD_gamma);
+  o (rgbaD_gamma,  rgbaD_linear);
+  o (rgbD_linear, rgbD_gamma);
+  o (rgbD_gamma,  rgbD_linear);
+  o (rgbaD_linear, rgbD_linear);
+  o (rgbaD_gamma,  rgbD_gamma);
+
+  return 0;
+}
+
diff --git a/extensions/gggl-table-lies.c b/extensions/gggl-table-lies.c
index 6cce2ba..88da9b6 100644
--- a/extensions/gggl-table-lies.c
+++ b/extensions/gggl-table-lies.c
@@ -302,6 +302,38 @@ conv_ga16_gaF (const Babl *conversion,unsigned char *src, unsigned char *dst, lo
 #define conv_gA16_gAF        conv_ga16_gaF
 #define conv_g16_gF          conv_16_F
 
+static void
+conv_rgbafloat_linear_cairo32_le (const Babl *conversion,unsigned char *src_char,
+                                  unsigned char *dst,
+                                  long           samples)
+{
+  long   n    = samples;
+  float *src  = (float*)src_char;
+
+  while (n--)
+    {
+      float alpha = src[3] * 255;
+#define BABL_ALPHA_THRESHOLD 0.000000152590219
+
+      if (alpha < BABL_ALPHA_THRESHOLD)
+        {
+          *(int *)dst = 0;
+        }
+      else
+        {
+          if (alpha > 255) alpha = 255;
+#define div_255(a) ((((a)+128)+(((a)+128)>>8))>>8)
+          dst[0] = src[2] * alpha + 0.5f;
+          dst[1] = src[1] * alpha + 0.5f;
+          dst[2] = src[0] * alpha + 0.5f;
+          dst[3] = alpha + 0.5f;
+        }
+      src += 4;
+      dst += 4;
+    }
+}
+
+
 int init (void);
 
 int
@@ -428,6 +460,26 @@ init (void)
     babl_component ("Y"),
     NULL);
 
+  int   testint  = 23;
+  char *testchar = (char*) &testint;
+  int   littleendian = (testchar[0] == 23);
+
+  if (littleendian)
+    {
+      const Babl *f32 = babl_format_new (
+        "name", "cairo-ARGB32",
+        babl_model ("R'aG'aB'aA"),
+        babl_type ("u8"),
+        babl_component ("B'a"),
+        babl_component ("G'a"),
+        babl_component ("R'a"),
+        babl_component ("A"),
+        NULL
+      );
+      babl_conversion_new (babl_format ("RGBA float"), f32, "linear",
+                           conv_rgbafloat_linear_cairo32_le, NULL);
+  }
+
 #define o(src, dst) \
   babl_conversion_new (src, dst, "linear", conv_ ## src ## _ ## dst, NULL)
 
diff --git a/extensions/gggl-table.c b/extensions/gggl-table.c
index 0ce0353..37d68dc 100644
--- a/extensions/gggl-table.c
+++ b/extensions/gggl-table.c
@@ -164,6 +164,7 @@ conv_F_8 (const Babl *conversion,unsigned char *src, unsigned char *dst, long sa
     }
 }
 
+
 static void
 conv_F_16 (const Babl *conversion,unsigned char *src, unsigned char *dst, long samples)
 {
diff --git a/extensions/meson.build b/extensions/meson.build
index d04ad67..f452417 100644
--- a/extensions/meson.build
+++ b/extensions/meson.build
@@ -2,6 +2,7 @@ extension_names = [
   '16bit',
   'cairo',
   'CIE',
+  'double',
   'fast-float',
   'float-half',
   'float',
diff --git a/extensions/two-table.c b/extensions/two-table.c
index 4b263cc..880adff 100644
--- a/extensions/two-table.c
+++ b/extensions/two-table.c
@@ -205,6 +205,17 @@ init (void)
 
   if (littleendian)
     {
+      const Babl *f32 = babl_format_new (
+        "name", "cairo-ARGB32",
+        babl_model ("R'aG'aB'aA"),
+        babl_type ("u8"),
+        babl_component ("B'a"),
+        babl_component ("G'a"),
+        babl_component ("R'a"),
+        babl_component ("A"),
+        NULL
+      );
+
       const Babl *f24 = babl_format_new (
         "name", "cairo-RGB24",
         babl_model ("R'G'B'"),