[gegl] operations: add gegl:cast-format which casts between two formats

[Michael Natterer <mitch src gnome org>]

commit f3e6ab47753be1c6970e8eb090461cf5a9647584
Author: Michael Natterer <mitch gimp org>
Date:   Mon May 5 19:17:01 2014 +0200

    operations: add gegl:cast-format which casts between two formats

 operations/core/Makefile.am   |    1 +
 operations/core/cast-format.c |  118 +++++++++++++++++++++++++++++++++++++++++
 po/POTFILES.in                |    1 +
 3 files changed, 120 insertions(+), 0 deletions(-)
---
diff --git a/operations/core/Makefile.am b/operations/core/Makefile.am
index 378553f..32985ce 100644
--- a/operations/core/Makefile.am
+++ b/operations/core/Makefile.am
@@ -9,6 +9,7 @@ LIBS = $(op_libs)
 opdir = $(ext_dir)
 op_LTLIBRARIES = \
        clone.la \
+       cast-format.la \
        convert-format.la \
        crop.la \
        nop.la
\ No newline at end of file
diff --git a/operations/core/cast-format.c b/operations/core/cast-format.c
new file mode 100644
index 0000000..991fa8d
--- /dev/null
+++ b/operations/core/cast-format.c
@@ -0,0 +1,118 @@
+/* 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 2007 Étienne Bersac <bersace03 laposte net>
+ * Copyright 2006 Øyvind Kolås <pippin gimp org>
+ * Copyright 2013 Daniel Sabo
+ *
+ */
+
+#include "config.h"
+#include <glib/gi18n-lib.h>
+
+#ifdef GEGL_CHANT_PROPERTIES
+
+gegl_chant_format (input_format, _("Input Format"),
+                   _("The babl format of the input"))
+gegl_chant_format (output_format, _("Output Format"),
+                   _("The babl format of the output"))
+
+#else
+
+#define GEGL_CHANT_TYPE_FILTER
+#define GEGL_CHANT_C_FILE "cast-format.c"
+
+#include "gegl-chant.h"
+
+static void
+prepare (GeglOperation *operation)
+{
+  GeglChantO *o = GEGL_CHANT_PROPERTIES (operation);
+
+  if (o->input_format)
+    gegl_operation_set_format (operation, "input", o->input_format);
+
+  if (o->output_format)
+    gegl_operation_set_format (operation, "output", o->output_format);
+}
+
+static gboolean
+process (GeglOperation        *operation,
+         GeglOperationContext *context,
+         const gchar          *output_prop,
+         const GeglRectangle  *roi,
+         gint                  level)
+{
+  GeglChantO *o = GEGL_CHANT_PROPERTIES (operation);
+  GeglBuffer *input;
+  GeglBuffer *output;
+
+  if (! o->input_format || ! o->output_format)
+    {
+      g_warning ("cast-format: input-format or output-format are not set");
+      return FALSE;
+    }
+
+  if (babl_format_get_bytes_per_pixel (o->input_format) !=
+      babl_format_get_bytes_per_pixel (o->output_format))
+    {
+      g_warning ("cast-format: input-format and output-format have different bpp");
+      return FALSE;
+    }
+
+  if (strcmp (output_prop, "output"))
+    {
+      g_warning ("cast-format: requested processing of %s pad", output_prop);
+      return FALSE;
+    }
+
+  input = gegl_operation_context_get_source (context, "input");
+  if (! input)
+    {
+      g_warning ("cast: received NULL input");
+      return FALSE;
+    }
+
+  output = gegl_buffer_new (roi, o->input_format);
+
+  gegl_buffer_copy (input,  roi,
+                    output, roi);
+  gegl_buffer_set_format (output, o->output_format);
+
+  g_object_unref (input);
+
+  gegl_operation_context_take_object (context, "output", G_OBJECT (output));
+
+  return TRUE;
+}
+
+static void
+gegl_chant_class_init (GeglChantClass *klass)
+{
+  GeglOperationClass *operation_class = GEGL_OPERATION_CLASS (klass);
+
+  operation_class->prepare  = prepare;
+  operation_class->process  = process;
+  operation_class->no_cache = FALSE;
+
+  gegl_operation_class_set_keys (operation_class,
+    "name",       "gegl:cast-format",
+    "categories", "core:color",
+    "description", _("Cast the data between input_format and output_format, "
+                     "both bormats must have the same bpp"),
+    NULL);
+}
+
+#endif
diff --git a/po/POTFILES.in b/po/POTFILES.in
index 088683f..6d1b72d 100644
--- a/po/POTFILES.in
+++ b/po/POTFILES.in
@@ -114,6 +114,7 @@ operations/common/whirl-pinch.c
 operations/common/wind.c
 operations/common/write-buffer.c
 operations/core/clone.c
+operations/core/cast-format.c
 operations/core/convert-format.c
 operations/core/crop.c
 operations/core/nop.c