Commit 72a9161e authored by Committed by Øyvind "pippin" Kolås
gegl, operations: add meta-data API
This adds GeglResolutionUnit, GeglMetaDataStore interface and a hashtable implementation, as suggested and refined in issue #222. Image loading and saving operations can now implement the "metadata" property. For loading ops this means extracting known metadata keys when processing, and for saving ops storing the applicable and set key. The file operations can register maps of names of keys between its own naming scheme and the GeglMetaDataStore naming scheme, as well as provide conversion functions for rewriting formats, for instance for timestamps.