[gegl] Add doc comments for TileBackend and TileHandler

[Daniel Sabo <daniels src gnome org>]

commit abc95c8298046525d8d4781bf9816892c2631a69
Author: Daniel Sabo <DanielSabo gmail com>
Date:   Sun Jun 2 21:17:19 2013 -0700

    Add doc comments for TileBackend and TileHandler

 gegl/buffer/gegl-tile-backend.h |   38 +++++++++++++++++++++++++++++++++-----
 gegl/buffer/gegl-tile-handler.h |   24 ++++++++++++++++++++++++
 2 files changed, 57 insertions(+), 5 deletions(-)
---
diff --git a/gegl/buffer/gegl-tile-backend.h b/gegl/buffer/gegl-tile-backend.h
index c727b5a..0951057 100644
--- a/gegl/buffer/gegl-tile-backend.h
+++ b/gegl/buffer/gegl-tile-backend.h
@@ -50,18 +50,46 @@ struct _GeglTileBackendClass
   gpointer            padding[4];
 };
 
+/**
+ * gegl_tile_backend_get_tile_size:
+ * @tile_backend: a #GeglTileBackend
+ *
+ * Return value: the size in bytes for a tile from this backend
+ */
 gint        gegl_tile_backend_get_tile_size (GeglTileBackend *tile_backend);
+
+/**
+ * gegl_tile_backend_get_format:
+ * @tile_backend: a #GeglTileBackend
+ *
+ * Gets pixel format of @tile_backend
+ *
+ * Return value: (transfer none): the #Babl format
+ */
 const Babl *gegl_tile_backend_get_format    (GeglTileBackend *tile_backend);
 
-/* gets a pointer to the GeglTileStorage that uses the backend */
-GeglTileSource *gegl_tile_backend_peek_storage  (GeglTileBackend *backend);
+/**
+ * gegl_tile_backend_peek_storage:
+ * @tile_backend: a #GeglTileBackend
+ *
+ * Gets a pointer to the GeglTileStorage that uses the backend
+ *
+ * Return value: (transfer none): the #GeglTileStorage
+ */
+GeglTileSource *gegl_tile_backend_peek_storage  (GeglTileBackend *tile_backend);
 
-/* specify the extent of the backend, can be used to
- * pre-prime the backend with the width/height information when
- * constructing proxy GeglBuffers to interact with other systems
+/**
+ * gegl_tile_backend_set_extent:
+ * @tile_backend: a #GeglTileBackend
+ * @rectangle: the new extent
+ *
+ * Specify the extent of the backend, can be used to pre-prime the
+ * backend with the width/height information when constructing proxy
+ * GeglBuffers to interact with other systems
  */
 void  gegl_tile_backend_set_extent    (GeglTileBackend *tile_backend,
                                        GeglRectangle   *rectangle);
+
 GeglRectangle gegl_tile_backend_get_extent (GeglTileBackend *tile_backend);
 
 GType gegl_tile_backend_get_type (void) G_GNUC_CONST;
diff --git a/gegl/buffer/gegl-tile-handler.h b/gegl/buffer/gegl-tile-handler.h
index 8d6f192..2145274 100644
--- a/gegl/buffer/gegl-tile-handler.h
+++ b/gegl/buffer/gegl-tile-handler.h
@@ -67,10 +67,34 @@ void    gegl_tile_handler_set_source (GeglTileHandler *handler,
 
 #define gegl_tile_handler_source_command(handler,command,x,y,z,data) 
(gegl_tile_handler_get_source(handler)?gegl_tile_source_command(gegl_tile_handler_get_source(handler), 
command, x, y, z, data):NULL)
 
+/**
+ * gegl_tile_handler_create_tile: (skip)
+ * @handler: a #GeglTileHandler
+ * @x: The tile space x coordinate for the tile
+ * @y: The tile space y coordinate for the tile
+ * @z: The tile space z coordinate for the tile
+ *
+ * Create a new tile associated with this tile handler.
+ *
+ * Return value: the new tile
+ */
 GeglTile * gegl_tile_handler_create_tile (GeglTileHandler *handler,
                                           gint             x,
                                           gint             y,
                                           gint             z);
+
+/**
+ * gegl_tile_handler_dup_tile: (skip)
+ * @handler: a #GeglTileHandler
+ * @tile: the #GeglTile to copy
+ * @x: The tile space x coordinate for the tile
+ * @y: The tile space y coordinate for the tile
+ * @z: The tile space z coordinate for the tile
+ *
+ * Create a duplicate of @tile, associated with this tile handler.
+ *
+ * Return value: the new tile
+ */
 GeglTile * gegl_tile_handler_dup_tile    (GeglTileHandler *handler,
                                           GeglTile        *tile,
                                           gint             x,