gegl r2249 - in trunk: . operations/common

[ok svn gnome org]

Author: ok
Date: Sun Apr 27 15:06:46 2008
New Revision: 2249
URL: http://svn.gnome.org/viewvc/gegl?rev=2249&view=rev

Log:
* operations/common/open-buffer.c: added new operation for opening
an existing GeglBuffer on disk.


Added:
   trunk/operations/common/open-buffer.c
Modified:
   trunk/ChangeLog

Added: trunk/operations/common/open-buffer.c
==============================================================================
--- (empty file)
+++ trunk/operations/common/open-buffer.c	Sun Apr 27 15:06:46 2008
@@ -0,0 +1,123 @@
+/* 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 2006 Ãyvind KolÃs <pippin gimp org>
+ */
+#ifdef GEGL_CHANT_PROPERTIES
+
+gegl_chant_string(path, "File", "", "a GeglBuffer on disk to open")
+
+#else
+
+#define GEGL_CHANT_TYPE_SOURCE
+#define GEGL_CHANT_C_FILE       "open-buffer.c"
+
+#include "gegl-chant.h"
+
+static GeglRectangle
+get_bounding_box (GeglOperation *operation)
+{
+  GeglRectangle result = {0,0,0,0};
+  GeglChantO   *o = GEGL_CHANT_PROPERTIES (operation);
+  GeglBuffer   *buffer = o->chant_data; /* since we only have one member
+                                         * of extra state data we want to
+                                         * carry we use the chant_data provided
+                                         * for all chanted ops.
+                                         */
+
+  if (!buffer)
+    {
+      buffer = gegl_buffer_open (o->path);
+      o->chant_data = buffer;
+    }
+  result = *gegl_buffer_get_extent (GEGL_BUFFER (buffer));
+  return result;
+}
+
+
+static GeglRectangle
+get_cached_region (GeglOperation       *self,
+                   const GeglRectangle *roi)
+{
+  return get_bounding_box (self);
+}
+
+static gboolean
+process (GeglOperation       *operation,
+         GeglNodeContext     *context,
+         const gchar         *output_pad,
+         const GeglRectangle *result)
+{
+  GeglChantO *o = GEGL_CHANT_PROPERTIES (operation);
+  GeglBuffer *buffer = o->chant_data;
+
+  if (!buffer)
+    {
+      buffer = gegl_buffer_open (o->path);
+      o->chant_data = buffer;
+    }
+  if (buffer)
+    {
+      g_object_ref (buffer); /* Add an extra reference, since
+		              * gegl_operation_set_data is
+		              * stealing one.
+		              */
+
+      /* override core behaviour, by resetting the buffer in the node_context */
+      gegl_node_context_set_object (context, "output", G_OBJECT (buffer));
+      return TRUE;
+    }
+  return FALSE;
+}
+
+static void
+dispose (GObject *object)
+{
+  GeglChantO *o = GEGL_CHANT_PROPERTIES (object);
+  GeglBuffer *buffer = o->chant_data;
+
+  if (buffer)
+    {
+      g_object_unref (buffer);
+      o->chant_data = NULL;
+    }
+
+  G_OBJECT_CLASS (g_type_class_peek_parent (G_OBJECT_GET_CLASS (object)))->dispose (object);
+}
+
+
+static void
+gegl_chant_class_init (GeglChantClass *klass)
+{
+  GeglOperationClass       *operation_class;
+  GeglOperationSourceClass *source_class;
+
+  operation_class = GEGL_OPERATION_CLASS (klass);
+  source_class    = GEGL_OPERATION_SOURCE_CLASS (klass);
+
+  operation_class->process = process;
+  operation_class->get_bounding_box = get_bounding_box;
+  operation_class->get_cached_region = get_cached_region;
+
+  G_OBJECT_CLASS (klass)->dispose = dispose;
+
+  operation_class->name        = "open-buffer";
+  operation_class->categories  = "input";
+  operation_class->description = "A source that uses an on-disk GeglBuffer.";
+
+  operation_class->no_cache = TRUE;
+}
+
+#endif