[gegl] operations: add gegl:color-exchange

[Michael Natterer <mitch src gnome org>]

commit 2217e4f95577943355b976b9189af2ddecc5f100
Author: Thomas Manni <thomas manni free fr>
Date:   Mon Nov 3 19:43:55 2014 +0100

    operations: add gegl:color-exchange

 operations/common/Makefile.am                   |    1 +
 operations/common/color-exchange.c              |  200 +++++++++++++++++++++++
 tests/compositions/Makefile.am                  |    1 +
 tests/compositions/color-exchange.xml           |   18 ++
 tests/compositions/reference/color-exchange.png |  Bin 0 -> 192726 bytes
 5 files changed, 220 insertions(+), 0 deletions(-)
---
diff --git a/operations/common/Makefile.am b/operations/common/Makefile.am
index 27956d5..1feba4a 100644
--- a/operations/common/Makefile.am
+++ b/operations/common/Makefile.am
@@ -24,6 +24,7 @@ op_LTLIBRARIES = \
        cartoon.la \
        channel-mixer.la \
        checkerboard.la \
+       color-exchange.la \
        color-reduction.la \
        color-rotate.la \
        color-temperature.la \
diff --git a/operations/common/color-exchange.c b/operations/common/color-exchange.c
new file mode 100644
index 0000000..a13d62d
--- /dev/null
+++ b/operations/common/color-exchange.c
@@ -0,0 +1,200 @@
+/* This file is an image processing operation for GEGL
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program 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 General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ *
+ *
+ * Exchange one color with the other (settable threshold to convert from
+ * one color-shade to another...might do wonders on certain images, or be
+ * totally useless on others).
+ *
+ * Author: robert experimental net
+ *
+ * GEGL port: Thomas Manni <thomas manni free fr>
+ *
+ */
+
+#include "config.h"
+#include <glib/gi18n-lib.h>
+
+#ifdef GEGL_PROPERTIES
+
+property_color (from_color, _("From Color"), "white")
+    description(_("The color to change."))
+
+property_double (red_threshold, _("Red Threshold"), 0.0)
+    description (_("Red threshold of the input color"))
+    value_range (0.0, 1.0)
+
+property_double (green_threshold, _("Green Threshold"), 0.0)
+    description (_("Green threshold of the input color"))
+    value_range (0.0, 1.0)
+
+property_double (blue_threshold, _("Blue Threshold"), 0.0)
+    description (_("Blue threshold of the input color"))
+    value_range (0.0, 1.0)
+
+property_color (to_color, _("To Color"), "black")
+    description(_("Replacement color."))
+
+#else
+
+#define GEGL_OP_POINT_FILTER
+#define GEGL_OP_C_FILE "color-exchange.c"
+
+#include "gegl-op.h"
+
+typedef struct
+{
+  gfloat color_in[3];
+  gfloat color_out[3];
+  gfloat min[3];
+  gfloat max[3];
+} CeParamsType;
+
+static void
+prepare (GeglOperation *operation)
+{
+  GeglProperties *o      = GEGL_PROPERTIES (operation);
+  const Babl     *format = babl_format ("R'G'B'A float");
+  const Babl     *colorformat = babl_format ("R'G'B' float");
+  CeParamsType *params;
+
+  if (o->user_data == NULL)
+    o->user_data = g_slice_new0 (CeParamsType);
+
+  params = (CeParamsType*) o->user_data;
+
+  gegl_color_get_pixel (o->from_color, colorformat, &(params->color_in));
+  gegl_color_get_pixel (o->to_color, colorformat, &(params->color_out));
+
+  params->min[0] = CLAMP (params->color_in[0] - o->red_threshold,
+                          0.0, 1.0);
+  params->max[0] = CLAMP (params->color_in[0] + o->red_threshold,
+                          0.0, 1.0);
+  params->min[1] = CLAMP (params->color_in[1] - o->green_threshold,
+                          0.0, 1.0);
+  params->max[1] = CLAMP (params->color_in[1] + o->green_threshold,
+                          0.0, 1.0);
+  params->min[2] = CLAMP (params->color_in[2] - o->blue_threshold,
+                          0.0, 1.0);
+  params->max[2] = CLAMP (params->color_in[2] + o->blue_threshold,
+                          0.0, 1.0);
+
+  gegl_operation_set_format (operation, "input", format);
+  gegl_operation_set_format (operation, "output", format);
+}
+
+static void
+finalize (GObject *object)
+{
+  GeglOperation *op = (void*) object;
+  GeglProperties *o = GEGL_PROPERTIES (op);
+
+  if (o->user_data)
+    {
+      g_slice_free (CeParamsType, o->user_data);
+      o->user_data = NULL;
+    }
+
+  G_OBJECT_CLASS (gegl_op_parent_class)->finalize (object);
+}
+
+static gboolean
+process (GeglOperation       *operation,
+         void                *in_buf,
+         void                *out_buf,
+         glong                n_pixels,
+         const GeglRectangle *roi,
+         gint                 level)
+{
+  GeglProperties     *o      = GEGL_PROPERTIES (operation);
+  const CeParamsType *params = (CeParamsType*) o->user_data;
+  gint    chan;
+  gfloat *input  = in_buf;
+  gfloat *output = out_buf;
+
+  g_assert (params != NULL);
+
+  while (n_pixels--)
+    {
+      if ((GEGL_FLOAT_EQUAL (input[0], params->min[0]) ||
+          (input[0] > params->min[0])) &&
+          (GEGL_FLOAT_EQUAL (input[0], params->max[0]) ||
+          (input[0] < params->max[0])) &&
+          (GEGL_FLOAT_EQUAL (input[1], params->min[1]) ||
+          (input[1] > params->min[1])) &&
+          (GEGL_FLOAT_EQUAL (input[1], params->max[1]) ||
+          (input[1] < params->max[1])) &&
+          (GEGL_FLOAT_EQUAL (input[2], params->min[2]) ||
+          (input[2] > params->min[2])) &&
+          (GEGL_FLOAT_EQUAL (input[2], params->max[2]) ||
+          (input[2] < params->max[2])))
+        {
+          gfloat delta[3];
+
+          for (chan = 0; chan < 3 ; chan++)
+            {
+              delta[chan] = input[chan] > params->color_in[chan] ?
+                input[chan] - params->color_in[chan] :
+                params->color_in[chan] - input[chan];
+
+              output[chan] = CLAMP (params->color_out[chan] + delta[chan],
+                                    0.0, 1.0);
+            }
+        }
+      else
+        {
+          output[0] = input[0];
+          output[1] = input[1];
+          output[2] = input[2];
+        }
+
+      output[3] = input[3];
+
+      input  += 4;
+      output += 4;
+    }
+
+  return TRUE;
+}
+
+static void
+gegl_op_class_init (GeglOpClass *klass)
+{
+  GObjectClass                  *object_class;
+  GeglOperationClass            *operation_class;
+  GeglOperationPointFilterClass *filter_class;
+
+  object_class    = G_OBJECT_CLASS (klass);
+  operation_class = GEGL_OPERATION_CLASS (klass);
+  filter_class    = GEGL_OPERATION_POINT_FILTER_CLASS (klass);
+
+  object_class->finalize = finalize;
+
+  operation_class->prepare = prepare;
+  operation_class->opencl_support = FALSE;
+
+  filter_class->process    = process;
+
+  gegl_operation_class_set_keys (operation_class,
+    "name",        "gegl:color-exchange",
+    "title",       _("Exchange color"),
+    "categories",  "color",
+    "license",     "GPL3+",
+    "description", _("Exchange one color with another, optionally setting "
+                     "a threshold to convert from one shade to another."),
+    NULL);
+}
+
+#endif
diff --git a/tests/compositions/Makefile.am b/tests/compositions/Makefile.am
index e8b5fe5..db52448 100644
--- a/tests/compositions/Makefile.am
+++ b/tests/compositions/Makefile.am
@@ -21,6 +21,7 @@ TESTS = \
   checkerboard.xml                \
   clones.xml                      \
   colors.xml                      \
+  color-exchange.xml              \
   color-to-alpha.xml              \
   composite-transform.xml         \
   contrast-curve.xml              \
diff --git a/tests/compositions/color-exchange.xml b/tests/compositions/color-exchange.xml
new file mode 100644
index 0000000..7a9b064
--- /dev/null
+++ b/tests/compositions/color-exchange.xml
@@ -0,0 +1,18 @@
+<?xml version='1.0' encoding='UTF-8'?>
+<gegl>
+  <node operation='gegl:color-exchange'>
+    <params>
+      <param name='from-color'>rgba(1.0000, 1.0000, 0.0000, 1.0000)</param>
+      <param name='to-color'>rgba(0.0000, 1.0000, 0.0000, 1.0000)</param>
+      <param name='red-threshold'>0.500</param>
+      <param name='green-threshold'>0.500</param>
+      <param name='blue-threshold'>0.500</param>
+    </params>
+  </node>
+  <node operation='gegl:load'>
+    <params>
+      <param name='path'>data/duck.png</param>
+    </params>
+  </node>
+</gegl>
+
diff --git a/tests/compositions/reference/color-exchange.png b/tests/compositions/reference/color-exchange.png
new file mode 100644
index 0000000..8d524d4
Binary files /dev/null and b/tests/compositions/reference/color-exchange.png differ