gegl: Add photos_gegl_pixbuf_new_from_buffer
This is part of a new set of APIs for GeglBuffer that don't require the creation of a graph. These will allow decoding and encoding image file formats to and from a GeglBuffer through asynchronous and cancellable methods with error handling. These will follow GIO idioms and be similar to the codec APIs for GdkPixbuf. There will be a compatibility layer to convert a GeglBuffer to and from GdkPixbuf for legacy reasons. These APIs will address the current lack of cancellation and error handling in gegl:load, and make it easier to port existing code away from GdkPixbuf. Bump minimum GdkPixbuf version to 2.36.8.
Showing with 44 additions and 2 deletions