the count of renderers (based on paper count of a document, for example).
If a selection is given, the count has to be calculated
based on this selection. The other methods of this interface
will rely on this value if called.
If the selection contains a valid XModel interface,
it is assumed that the whole document should be rendered.
If the selection is empty, nothing should be rendered.
returns the specific renderer properties based on the given selection.
If the selection contains a valid XModel interface,
it is assumed that the whole document should be rendered.
If the selection is empty, nothing should be rendered.
renders the object with the specific renderer based on the given selection.
If the selection contains a valid XModel interface,
it is assumed that the whole document should be rendered.
If the selection is empty, nothing should be rendered.
