The most natural transformer value that
could be chosen is the “identity” transformer.
An identity transformer has no translation, zoom, or rotation
factors. This means that the geometry of the
IlvManager
instance is considered in the manager coordinates, not in the
manager view coordinates (transformed coordinates). However, the
special case of nonzoomable graphic
objects must be taken into account. For this case, the idea of
simply using the geometry of the grapher in manager coordinates is
not pertinent.
Label layout algorithms have to deal with the geometry of labels
and obstacles. In a manager, labels and obstacles can be any
graphic objects, that is, any subclass of IlvGraphic. Their position and size are
given by their
boundingBox(IlvTransformer t)
method and usually depend on the transformer used for their
display. Therefore, when you need to perform layout on a IlvManagerLayer object, you need to consider
the geometry of the manager for a specified value of the
transformer.