Overview (TL)
The ibm_ilog.graphlayout.tree.TreeLayout class supports the following generic features defined
in the ibm_ilog.graphlayout.GraphLayout class. (See also Base class parameters and features.)
The following subsections describe the particular way
in which these features are used by the Tree Layout subclass.
Allowed time (TL)
The layout algorithm stops if the allowed time setting
has elapsed. If the layout stops early because the allowed time has
elapsed, the nodes and links are not moved from their positions before
the layout call.
The result code in the layout report is ibm_ilog.graphlayout.GraphLayoutReport.STOPPED_AND_INVALID.
For a description of this layout parameter in the ibm_ilog.graphlayout.GraphLayout class, see Allowed time.
Layout of connected components (TL)
The layout algorithm can use the generic mechanism to
lay out connected components. (For more information about this mechanism,
see Layout of connected components). It has,
however, a specialized internal mechanism to lay out connected components
and, therefore, the generic mechanism is disabled by default.
The generic connected component layout mechanism has
the disadvantage that it moves connected components completely. Fixed
nodes within a component do not preserve their old position, and the
resulting layout can be unstable on incremental changes, depending
on which layout instance is used for the component layout.
If the generic connected component layout mechanism is
disabled, the algorithm uses its own specialized internal mechanism
instead of the generic mechanism to lay out each component as a separate
tree. It is faster and more stable on incremental changes than the
generic mechanism. Furthermore, it enables the user to set the position
of the layout.
Link connection box (TL)
The layout algorithm can use a link connection box interface
(see Link connection box). For details,
see Using a link connection box interface (TL).
Percentage of completion calculation (TL)
The layout algorithm calculates the estimated percentage
of completion. This value can be obtained from the layout report during
the run of layout. (For a detailed description of this feature, see Percentage of completion calculation and Graph layout event listeners.)
Preserve fixed links (TL)
The layout algorithm does not reshape the links that
are specified as fixed.
For more information about link parameters in the ibm_ilog.graphlayout.GraphLayout class, see Preserve fixed links and Link style (TL).
Preserve fixed nodes (TL)
The layout algorithm does not move the nodes that are
specified as fixed.
For more information about node parameters in the ibm_ilog.graphlayout.GraphLayout class, see Preserve fixed nodes.
The layout algorithm ignores fixed nodes completely and
also does not route the links that are incident to the fixed nodes.
It can result in unwanted overlapping nodes and link crossings. However,
this feature is useful for individual, disconnected components that
can be laid out independently.
Stop immediately (TL)
The layout algorithm stops after cleanup if the method stopImmediately is called. (For a description
of this method in the ibm_ilog.graphlayout.GraphLayout class, see Stop immediately.) If the layout
stops early because the allowed time has elapsed, the nodes and links
are not moved from their positions before the layout call, and the
result code in the layout report is ibm_ilog.graphlayout.GraphLayoutReport.STOPPED_AND_INVALID.