[gegl] Add a sepia filter

[Øyvind Kolås <ok src gnome org>]

commit 35b1d99716bca769889b67d8db75e9e9299a157b
Author: Debarshi Ray <debarshir gnome org>
Date:   Mon Jun 8 09:24:28 2015 +0200

    Add a sepia filter
    
    This implements the filer of the same name in the Filter Effects
    specification: http://dev.w3.org/fxtf/filters/
    
    The document says that filter functions must operate in the sRGB color
    space. However, it also describes the color-interpolation-filters
    property, which is set to linear by default, for the filtering
    primitives used to implement the functions. Since sepia is a thin
    wrapper around the feColorMatrix primitive, we ignore what the
    specification says about the filter function, and expose the
    color-interpolation-filters property on the filter operation.
    
    https://bugzilla.gnome.org/show_bug.cgi?id=750542

 operations/common/Makefile.am |    1 +
 operations/common/sepia.c     |  116 +++++++++++++++++++++++++++++++++++++++++
 po/POTFILES.in                |    1 +
 3 files changed, 118 insertions(+), 0 deletions(-)
---
diff --git a/operations/common/Makefile.am b/operations/common/Makefile.am
index d036571..836548a 100644
--- a/operations/common/Makefile.am
+++ b/operations/common/Makefile.am
@@ -116,6 +116,7 @@ op_LTLIBRARIES = \
        remap.la \
        ripple.la \
        save.la \
+       sepia.la \
        shift.la \
        sinus.la \
        snn-mean.la \
diff --git a/operations/common/sepia.c b/operations/common/sepia.c
new file mode 100644
index 0000000..47ed744
--- /dev/null
+++ b/operations/common/sepia.c
@@ -0,0 +1,116 @@
+/* This file is an image processing operation for GEGL
+ *
+ * GEGL 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.
+ *
+ * GEGL 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 GEGL; if not, see <http://www.gnu.org/licenses/>.
+ *
+ * Copyright 2015 Red Hat, Inc.
+ */
+
+#include "config.h"
+#include <glib/gi18n-lib.h>
+
+#ifdef GEGL_PROPERTIES
+
+property_double (scale, _("Scale"), 1.0)
+    description(_("Scale, strength of effect"))
+    value_range (0.0, 1.0)
+
+property_boolean (srgb, _("sRGB"), TRUE)
+    description (_("Use sRGB gamma instead of linear"))
+
+#else
+
+#define GEGL_OP_POINT_FILTER
+#define GEGL_OP_C_SOURCE sepia.c
+
+#include "gegl-op.h"
+
+static void prepare (GeglOperation *operation)
+{
+  GeglProperties *o = GEGL_PROPERTIES (operation);
+  const Babl *format;
+
+  if (o->srgb)
+    format = babl_format ("R'G'B'A float");
+  else
+    format = babl_format ("RGBA float");
+
+  gegl_operation_set_format (operation, "input", format);
+  gegl_operation_set_format (operation, "output", format);
+}
+
+static gboolean
+process (GeglOperation       *operation,
+         void                *in_buf,
+         void                *out_buf,
+         glong                n_pixels,
+         const GeglRectangle *roi,
+         gint                 level)
+{
+  GeglProperties *o = GEGL_PROPERTIES (operation);
+  gfloat *in = in_buf;
+  gfloat *out = out_buf;
+  gfloat m[25] = { 1.0, 0.0, 0.0, 0.0, 0.0,
+                   0.0, 1.0, 0.0, 0.0, 0.0,
+                   0.0, 0.0, 1.0, 0.0, 0.0,
+                   0.0, 0.0, 0.0, 1.0, 0.0,
+                   0.0, 0.0, 0.0, 0.0, 1.0 };
+  glong i;
+
+  m[0] = 0.393 + 0.607 * (1.0 - o->scale);
+  m[1] = 0.769 - 0.769 * (1.0 - o->scale);
+  m[2] = 0.189 - 0.189 * (1.0 - o->scale);
+
+  m[5] = 0.349 - 0.349 * (1.0 - o->scale);
+  m[6] = 0.686 + 0.314 * (1.0 - o->scale);
+  m[7] = 0.168 - 0.168 * (1.0 - o->scale);
+
+  m[10] = 0.272 - 0.272 * (1.0 - o->scale);
+  m[11] = 0.534 - 0.534 * (1.0 - o->scale);
+  m[12] = 0.131 + 0.869 * (1.0 - o->scale);
+
+  for (i = 0; i < n_pixels; i++)
+    {
+      out[0] = m[0] * in[0] + m[1] * in[1] + m[2] * in[2];
+      out[1] = m[5] * in[0] + m[6] * in[1] + m[7] * in[2];
+      out[2] = m[10] * in[0] + m[11] * in[1] + m[12] * in[2];
+      out[3] = in[3];
+
+      in += 4;
+      out += 4;
+    }
+
+  return TRUE;
+}
+
+static void
+gegl_op_class_init (GeglOpClass *klass)
+{
+  GeglOperationClass *operation_class = GEGL_OPERATION_CLASS (klass);
+  GeglOperationPointFilterClass *point_filter_class =
+    GEGL_OPERATION_POINT_FILTER_CLASS (klass);
+
+  operation_class->prepare = prepare;
+  operation_class->opencl_support = FALSE;
+
+  point_filter_class->process = process;
+
+  gegl_operation_class_set_keys (operation_class,
+    "name"       , "gegl:sepia",
+    "title",       _("Sepia"),
+    "categories" , "color",
+    "description", _("Converts the input image to sepia"),
+    NULL);
+}
+
+#endif
diff --git a/po/POTFILES.in b/po/POTFILES.in
index ff4d28c..45063dc 100644
--- a/po/POTFILES.in
+++ b/po/POTFILES.in
@@ -108,6 +108,7 @@ operations/common/reinhard05.c
 operations/common/remap.c
 operations/common/ripple.c
 operations/common/save.c
+operations/common/sepia.c
 operations/common/shift.c
 operations/common/sinus.c
 operations/common/snn-mean.c