[gegl] Add a saturation filter

[Debarshi Ray <debarshir src gnome org>]

commit f885ca324f1b4c7fa20470d5b68b480953367301
Author: Debarshi Ray <debarshir gnome org>
Date:   Fri Jan 8 10:36:18 2016 +0100

    Add a saturation filter
    
    https://bugzilla.gnome.org/show_bug.cgi?id=760310

 operations/common/Makefile.am  |    1 +
 operations/common/saturation.c |  222 ++++++++++++++++++++++++++++++++++++++++
 po/POTFILES.in                 |    1 +
 3 files changed, 224 insertions(+), 0 deletions(-)
---
diff --git a/operations/common/Makefile.am b/operations/common/Makefile.am
index b7aa345..d95dde8 100644
--- a/operations/common/Makefile.am
+++ b/operations/common/Makefile.am
@@ -116,6 +116,7 @@ op_LTLIBRARIES = \
        reinhard05.la \
        remap.la \
        ripple.la \
+       saturation.la \
        save.la \
        sepia.la \
        shift.la \
diff --git a/operations/common/saturation.c b/operations/common/saturation.c
new file mode 100644
index 0000000..0165cdf
--- /dev/null
+++ b/operations/common/saturation.c
@@ -0,0 +1,222 @@
+/* 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 2016 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, 2.0)
+
+#else
+
+#define GEGL_OP_POINT_FILTER
+#define GEGL_OP_C_SOURCE saturation.c
+
+#include "gegl-op.h"
+
+typedef void (*ProcessFunc) (GeglOperation       *operation,
+                             void                *in_buf,
+                             void                *out_buf,
+                             glong                n_pixels,
+                             const GeglRectangle *roi,
+                             gint                 level);
+
+static void
+process_lab (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;
+  glong i;
+
+  for (i = 0; i < n_pixels; i++)
+    {
+      out[0] = in[0];
+      out[1] = in[1] * o->scale;
+      out[2] = in[2] * o->scale;
+
+      in += 3;
+      out += 3;
+    }
+}
+
+static void
+process_lab_alpha (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;
+  glong i;
+
+  for (i = 0; i < n_pixels; i++)
+    {
+      out[0] = in[0];
+      out[1] = in[1] * o->scale;
+      out[2] = in[2] * o->scale;
+      out[3] = in[3];
+
+      in += 4;
+      out += 4;
+    }
+}
+
+static void
+process_lch (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;
+  glong i;
+
+  for (i = 0; i < n_pixels; i++)
+    {
+      out[0] = in[0];
+      out[1] = in[1] * o->scale;
+      out[2] = in[2];
+
+      in += 3;
+      out += 3;
+    }
+}
+
+static void
+process_lch_alpha (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;
+  glong i;
+
+  for (i = 0; i < n_pixels; i++)
+    {
+      out[0] = in[0];
+      out[1] = in[1] * o->scale;
+      out[2] = in[2];
+      out[3] = in[3];
+
+      in += 4;
+      out += 4;
+    }
+}
+
+static void prepare (GeglOperation *operation)
+{
+  GeglProperties *o = GEGL_PROPERTIES (operation);
+  const Babl *format;
+  const Babl *input_format;
+  const Babl *input_model;
+  const Babl *lch_model;
+
+  input_format = gegl_operation_get_source_format (operation, "input");
+  if (input_format == NULL)
+    return;
+
+  input_model = babl_format_get_model (input_format);
+
+  if (babl_format_has_alpha (input_format))
+    {
+      lch_model = babl_model ("CIE LCH(ab) alpha");
+      if (input_model == lch_model)
+        {
+          format = babl_format ("CIE LCH(ab) alpha float");
+          o->user_data = process_lch_alpha;
+        }
+      else
+        {
+          format = babl_format ("CIE Lab alpha float");
+          o->user_data = process_lab_alpha;
+        }
+    }
+  else
+    {
+      lch_model = babl_model ("CIE LCH(ab)");
+      if (input_model == lch_model)
+        {
+          format = babl_format ("CIE LCH(ab) float");
+          o->user_data = process_lch;
+        }
+      else
+        {
+          format = babl_format ("CIE Lab float");
+          o->user_data = process_lab;
+        }
+    }
+
+  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);
+  ProcessFunc real_process = (ProcessFunc) o->user_data;
+
+  real_process (operation, in_buf, out_buf, n_pixels, roi, level);
+  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:saturation",
+    "title",       _("Saturation"),
+    "categories" , "color",
+    "description", _("Changes the saturation"),
+    NULL);
+}
+
+#endif
diff --git a/po/POTFILES.in b/po/POTFILES.in
index 6e373df..d89f585 100644
--- a/po/POTFILES.in
+++ b/po/POTFILES.in
@@ -108,6 +108,7 @@ operations/common/red-eye-removal.c
 operations/common/reinhard05.c
 operations/common/remap.c
 operations/common/ripple.c
+operations/common/saturation.c
 operations/common/save.c
 operations/common/sepia.c
 operations/common/shift.c