Hi Robin! Sorry for answering late, but I had to catch-up with daily work after some short vacations…
In fact, the problem I’m facing is not the storage of the metadata into the output files, but the internal memory storage of the same data inside the processing pipeline, in a way that is understandable both by photoflow and GIMP.
An example: I load and develop a RAW file, and then later on in the processing pipeline I need to apply lens distortion corrections. For that I need to know the camera model, lens model, focal length, etc…
However, at this point of the pipeline the original RAW data is not accessible anymore, so I need to “propagate” the metadata together with the pixel data through the pipeline.
At the moment I am doing this by simply attaching an instance of the Exiv2 object to the pixel data, by this does not work when it comes to the point of transferring the metadata from PhF to GIMP…
As far as I understand, GIMP internally stores the metadata in the form of an XML-formatted text buffer. The relevant pieces of code that save and read back the XML buffer can be found here and here.
The GIMP code uses GExiv2 instead of Exiv2, but I guess one could achieve the same XML conversion directly with the Exiv2 API… would this be something that could be considered to be included in the Exiv2 library? If not, I will most likely stick to my current implementation and use the GIMP functions when outputting the metadata from the photoflow plug-in to GIMP itself…
Thanks!