[gegl/gsoc2011-opencl: 11/18] Add gegl:display meta operation

[Victor Matheus de Araujo Oliveira <vmaolive src gnome org>]

commit 6bcd181347c6b3b7588043b1442228d600d9c7d5
Author: Jon Nordby <jononor gmail com>
Date:   Tue Jul 19 22:38:30 2011 +0200

    Add gegl:display meta operation

 operations/common/display.c |  143 +++++++++++++++++++++++++++++++++++++++++++
 1 files changed, 143 insertions(+), 0 deletions(-)
---
diff --git a/operations/common/display.c b/operations/common/display.c
new file mode 100644
index 0000000..bafd09d
--- /dev/null
+++ b/operations/common/display.c
@@ -0,0 +1,143 @@
+/* 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 2011 Jon Nordby <jononor gmail com>
+ */
+
+#include "config.h"
+#include <glib/gi18n-lib.h>
+
+#ifdef GEGL_CHANT_PROPERTIES
+gegl_chant_string  (window_title, _(""), "window_title",
+                    _("Title to be given to output window"))
+#else
+
+#define GEGL_CHANT_C_FILE       "display.c"
+
+#include "gegl-plugin.h"
+#include "gegl/graph/gegl-node.h"
+
+/* gegl:display
+ * Meta operation for displaying the output of a buffer.
+ * Will use one of several well-known display operations 
+ * to actually display the output. */
+
+struct _GeglChant
+{
+  GeglOperationSink parent_instance;
+  gpointer          properties;
+
+  GeglNode *input; /* The node to show the output of. */
+  GeglNode *display; /* The node actually acting as the display op. */
+};
+
+typedef struct
+{
+  GeglOperationSinkClass parent_class;
+} GeglChantClass;
+
+
+#include "gegl-chant.h"
+GEGL_DEFINE_DYNAMIC_OPERATION(GEGL_TYPE_OPERATION_SINK)
+
+/* Set the correct display handler operation. */
+static void
+set_display_handler (GeglOperation *operation)
+{
+  GeglChantO  *o    = GEGL_CHANT_PROPERTIES (operation);
+  GeglChant   *self = GEGL_CHANT (operation);
+  const gchar *known_handlers[] = {"gegl-gtk3:display", 
+				 "gegl-gtk2:display",
+                                 "gegl:sdl-display"};
+  char *handler = NULL;
+  gchar **operations = NULL;
+  guint   n_operations;
+  gint i, j;
+
+  /* FIXME: Allow operations to register as a display handler. */
+  operations = gegl_list_operations (&n_operations);
+
+  for (i=0; !handler && i < G_N_ELEMENTS(known_handlers); i++)
+    {
+      for (j=0; j < n_operations; j++)
+      {
+         if (g_strcmp0(operations[j], known_handlers[i]) == 0)
+           {
+             handler = operations[j];
+             break;
+           }
+      }
+    }
+
+  if (handler)
+      gegl_node_set (self->display, "operation", handler,
+                     "window-title", o->window_title, NULL);
+  else
+      g_warning ("No display handler operation found for gegl:display");
+
+  g_free (operations);
+}
+
+/* Create an input proxy, and initial display operation, and link together.
+ * These will be passed control when process is called later. */
+static void
+attach (GeglOperation *operation)
+{
+  GeglChant   *self = GEGL_CHANT (operation);
+
+  g_assert (!self->input);
+  g_assert (!self->display);
+
+  self->input   = gegl_node_get_input_proxy (operation->node, "input");
+  self->display = gegl_node_new_child (operation->node,
+                                      "operation", "gegl:nop",
+                                      NULL);
+  gegl_node_link (self->input, self->display);
+
+  set_display_handler (operation);
+}
+
+
+/* Forward processing to the handler operation. */
+static gboolean
+process (GeglOperation        *operation,
+         GeglOperationContext *context,
+         const gchar          *output_pad,
+         const GeglRectangle  *roi)
+{
+  GeglChantO   *o = GEGL_CHANT_PROPERTIES (operation);
+  GeglChant   *self = GEGL_CHANT (operation);
+
+  return gegl_operation_process (self->display->operation, 
+				 context, output_pad, roi);
+}
+
+static void
+gegl_chant_class_init (GeglChantClass *klass)
+{
+  GeglOperationClass     *operation_class = GEGL_OPERATION_CLASS (klass);
+  GeglOperationSinkClass *sink_class = GEGL_OPERATION_SINK_CLASS (klass);
+
+  operation_class->attach  = attach;
+  operation_class->process = process;
+
+  sink_class->needs_full = TRUE;
+
+  operation_class->name        = "gegl:display";
+  operation_class->categories  = "meta:display";
+  operation_class->description =
+        _("Display the input buffer in a window.");
+}
+#endif