Orientation/rotation change in IIIF manifest for initial load in viewer

[snydman]

For the Player Piano roll project MASTER files will be produced and archived in SDR with an image orientation that corresponds to the way notation should be read. However, when they are rendered in a viewer, the image will need to rendered - conditionally - with a different orientation better suited to human reading.

I believe this can be done by declaring a rotation/mirroring value the IIIF Manifest.

The questions are:

1. where and how in ContentMD should the orientation flag should be expressed.
2. How will we will get that flag into ContentMD? (maybe like rtl reading on registration?)
3. How can we customize the IIIF manifest for player piano rolls to declare the correct rotation/mirroring value in the IIIF image URI?

@LynnMcRae @blalbrit

[LynnMcRae]

The current <imageData> tag at the resource level of <contentMetadata> currently carries just dimensions, but rotation was suggested in its original design (https://consul.stanford.edu/display/chimera/DOR+content+types%2C+resource+types+and+interpretive+metadata). I think that's the place to put it for action at the resource/file level, and we should just take the IIIF spec for rotation for an attribute definition, see http://iiif.io/api/image/2.1/#rotation.

If a object level declaration is needed, it could be expressed at the root level of the doc, similar to <bookData>, with implied action against all resources, but I understand that is not the requirement here.