Graph layout algorithms have to deal with the geometry of the graph, that is, the position and shape of the nodes and links. In addition, they must deal with the layout of an IlvGrapher. The nodes of a Views IlvGrapher can be any graphic object, that is, any subclass of IlvGraphic. The position and size of the nodes are given by their boundingBox(IlvTransformer t) method and usually depend on the transformer used for their display. Therefore, when an IlvGrapher has to be laid out, the geometry of the grapher must be considered for a given value of the transformer.

The most natural transformer value that could be chosen is the “identity” transformer. An identity transformer has no translation, zoom, or rotation factors. In terms of Views, this would mean that the geometry of the IlvGrapher would be 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.