IIIF Image API 3 allows context extensions that should be added to the
info.json's @context property. Therefore, '@context' might be an array
instead of a string.
60: "Missing or invalid `size`."
Without at least a size, no IIIF can be displayed.
61: "Cannot determine IIIF Image API version from provided image
information JSON."
Without finding out the version information, one could only guess how to
use the image info JSON.
src/ol/source/IIIF.js contains a tile source for IIIF Image API services.
It supports Image API version 1 and 2 on compliance levels 0, 1 and 2.
To get working constructor options for IIIF from an IIIF image info.json,
use src/ol/format/IIIFInfo.js.
An example is available in examples/iiif.html respectivly examples/iiif.js.
The renderer now accesses the zDirection member directly if it exists.
This also has the advantage of not advertising any object methods that
hav no use for most tile sources.
The zDirection addition to the Zoomify tile source only takes effect through
the renderer, so these two renderer cases are added to test the behavior.
zoomify-no-zdirection expects the default behavior.
zoomify-zdirection expects the tiles for the next better resolution.
Via zDirection, the renderer's selection of a tile source's resolution can be
controlled if the view's resolution does not match any tile source resolution.
Currently the zDirection option is only available for Zoomify. The comment
https://github.com/openlayers/openlayers/issues/9343#issuecomment-474341033
describes why caution is advised when using zDirection for other sources.
ol/source/Tile~TileSource#getZDirection has been added to avoid having the
getZDirection method solely in the Zoomify source - just to document the
possibility.
Lutz Helm