FocusModel fires PropertyChangeEvents when the viewer
focused state changes.ViewportModel that is manipulated by this operation.ViewportModel stores viewport width and height, horizontal and
vertical translation, and a general contents transformation.ViewportModel.ViewportState with
tx = ty = width = height = 0 and an identity transform.ViewportModel.ViewportState for the given translation, size,
and transform.VisualOutlineGeometryProvider can be registered on an
IVisualPart to provide an IGeometry based on the outline of
the part's visualization.Copyright (c) 2014 itemis AG and others. All rights reserved.