2008-10-09  Michael Natterer  <mitch@gimp.org>

	Address Bug 554983 – Layers Projection using GEGL

	* app/gegl/gimp-gegl-utils.[ch]: add (imcomplete) function
	gimp_layer_mode_to_gegl_operation() from bug #554983.

	* app/core/gimpdrawable.[ch]: add gimp_drawable_get_source_node()
	which returns a GimpOperationTileSource for the drawable's
	tiles.

	(gimp_drawable_real_set_tiles)
	(gimp_drawable_configure): set the node's "tiles" property.

	* app/core/gimplayer.[ch]: add gimp_layer_get_node() which returns
	a GeglNode with proxy "input" and "output" pads to be plugged
	into the projection graph. The node has children for opacity,
	mask, layer mode and layer offset.

	(gimp_layer_translate)
	(gimp_layer_add_mask)
	(gimp_layer_apply_mask)
	(gimp_layer_set_opacity)
	(gimp_layer_set_mode): reconfigure the respective nodes.

	* app/core/gimpimage.[ch]: keep a "graph" node around and destroy
	it in finalize(). Not even a stub, just a silly GEGL dependency.


svn path=/trunk/; revision=27204