ilog.views.graphlayout.topologicalmesh

Class IlvTopologicalMeshLayout

java.lang.Object

ilog.views.graphlayout.IlvGraphLayout

ilog.views.graphlayout.basic.IlvBasicLinkStyleLayout

ilog.views.graphlayout.topologicalmesh.IlvTopologicalMeshLayout

public class IlvTopologicalMeshLayout
extends ilog.views.graphlayout.basic.IlvBasicLinkStyleLayout

The main class for the Topological Mesh Layout (TML) algorithm.

The Topological Mesh Layout algorithm can be used to lay out cyclic graphs, both planar and nonplanar. Most of the time, if the graph is topologically symmetric, TML produces a symmetric drawing. The layout algorithm places the nodes of a cycle of the graph on a circle and the remaining nodes inside this circle. The size of the enclosing circle depends on the layout region settings (see #setLayoutRegion). For an optimal layout quality, the layout region needs to be large enough to have enough place for the nodes.

Sample drawings produced by the Topological Mesh Layout algorithm:

See the corresponding chapter of the User's Manual for details on the algorithm, the types of graphs for which this algorithm can be used, the features and limitations, code samples, parameters, and so on.

Note that the initial position of the nodes (at the moment you start the layout) does not affect the resulting layout. However, nodes specified as fixed are not moved if you call the method #setPreserveFixedNodes with a true argument.

CSS example:

SDM {
GraphLayout : true;
}

GraphLayout {
graphLayout : @#layout;
// optional settings for the graph layout renderer
}

Subobject#layout {
class : "ilog.views.graphlayout.topologicalmesh.IlvTopologicalMeshLayout";
allowedNodesPlacementTime : "3";
allowedNumberOfNodesPlacementIterations : "2";
allowedNumberOfOptimizationIterations : "2";
allowedOptimizationTime : "3";
coordinatesMode : "MANAGER_COORDINATES";
layoutOfConnectedComponentsEnabled : "false";
minBusyTime : "3";
nodesMoveThreshold : "3.0";
nodesPlacementAlgorithm : "SLOW_GOOD";
}

CSS specification of per-node and per-link layout parameters:

The following table lists the per-object rendering properties of the GraphLayout renderer:

Property	Type	Default	Description
GraphLayout	IlvGraphLayout	null	Lets you define a different graph layout algorithm for each subgraph. If one is not specified, the same algorithm is applied recursively to all subgraphs.
LayoutFixed	String	false	Deprecated, replaced by Fixed.
Fixed	String	false	Lets you specify that the node or link must not be moved or reshaped by the layout algorithm.
LayoutGroup	String	null	Lets you apply the algorithm to different groups of objects, one group after the other.
LayoutIgnored	boolean	false	If true, the object is ignored by the layout.

The per-node and per-link layout parameters are specified in the style sheet through the CSS rules for nodes and links, not through the CSS rule for graph layout. For instance:

link.tag {
LinkStyle : "ORTHOGONAL_STYLE";
}

Note that the names of the node and link layout parameters use an initial capital, unlike the regular properties. See also the documentation of the class IlvGraphLayoutRenderer.

Property Summary

Properties

Modifier and Type	Property and Description
long	allowedNodesPlacementTime Sets the allowed maximum time (in milliseconds) for the topological optimization step of the layout.
int	allowedNumberOfNodesPlacementIterations Sets the maximum number of iterations of the drawing algorithm.
int	allowedNumberOfOptimizationIterations Sets the maximum number of iterations of the topological optimization algorithm.
long	allowedOptimizationTime Sets the allowed maximum time (in milliseconds) for the topological optimization step of the layout.
java.lang.String	class Default constructor.
int	coordinatesMode Sets the coordinates mode to be used during layout.
boolean	layoutOfConnectedComponentsEnabled Sets whether the generic connected component layout mechanism is enabled.
long	minBusyTime Sets the minimal time that the layout algorithm can be busy.
double	nodesMoveThreshold Sets the convergence criteria of the node placement algorithm (the second step of the layout algorithm).
int	nodesPlacementAlgorithm Sets the choice of the node placement algorithm (the second step of the layout algorithm).

Properties inherited from class ilog.views.graphlayout.basic.IlvBasicLinkStyleLayout

connectLinksToNodeCenters, linkStyle, multiLinkMaxSpread, multiLinkMode, multiLinkOffset, multiSelfLinkDistribution, multiSelfLinkMaxSpread, multiSelfLinkOffset, selfLinkAbsoluteAttachPosition, selfLinkAllowedCorners, selfLinkConnectToNodeCenter, selfLinkMode, selfLinkOrientation, selfLinkRelativeAttachPosition, selfLinkSpacing

Method Summary

Methods inherited from class java.lang.Object

equals, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Property Detail

class

public java.lang.String class

Default constructor.

CSS example: class : "ilog.views.graphlayout.topologicalmesh.IlvTopologicalMeshLayout";

allowedNodesPlacementTime

public long allowedNodesPlacementTime

Sets the allowed maximum time (in milliseconds) for the topological optimization step of the layout.

CSS example: allowedNodesPlacementTime : "3";

allowedNumberOfNodesPlacementIterations

public int allowedNumberOfNodesPlacementIterations

Sets the maximum number of iterations of the drawing algorithm.

CSS example: allowedNumberOfNodesPlacementIterations : "2";

allowedNumberOfOptimizationIterations

public int allowedNumberOfOptimizationIterations

Sets the maximum number of iterations of the topological optimization algorithm.

CSS example: allowedNumberOfOptimizationIterations : "2";

allowedOptimizationTime

public long allowedOptimizationTime

Sets the allowed maximum time (in milliseconds) for the topological optimization step of the layout.

CSS example: allowedOptimizationTime : "3";

coordinatesMode

public int coordinatesMode

Sets the coordinates mode to be used during layout.

Valid values are:

• ilog.views.graphlayout.IlvGraphLayout#MANAGER_COORDINATES - The geometry of the graph is computed using the coordinate space of the manager (that is, the attached IlvGrapher) without applying any transformation.

  This mode should be used if you visualize the graph at zoom level 1, or you do not visualize it at all, or the graph contains only fully zoomable objects. In all these cases there is no need to take the transformer into account during the layout.

  Note that in this mode the dimensional parameters of the layout algorithms are considered as being specified in manager coordinates.

• ilog.views.graphlayout.IlvGraphLayout#VIEW_COORDINATES - The geometry of the graph is computed in the coordinate space of the manager view. More exactly, all the coordinates are transformed using the current reference transformer.

  This mode should be used if you want the dimensional parameters of the layout algorithms to be considered as being specified in manager view coordinates.

• ilog.views.graphlayout.IlvGraphLayout#INVERSE_VIEW_COORDINATES - The geometry of the graph is computed using the coordinate space of the manager view and then applying the inverse transformation. This mode is equivalent to the "manager coordinates" mode if the geometry of the graphic objects strictly obeys the transformer. (A small difference may exist because of the limited precision of the computations.)

  On the contrary, if some graphic objects are either nonzoomable (see IlvGraphic#zoomable) or semizoomable (for example, links with a maximum line width), this mode gives different results than the manager coordinates mode. These results are optimal if the graph is visualized using the same transformer as the one taken into account during the layout.

  Note that in this mode the dimensional parameters of the layout algorithms are considered as being specified in manager coordinates.

The default value is IlvGraphLayout#INVERSE_VIEW_COORDINATES.

This option is useful only if the attached graph model is an IlvGrapherAdapter (or a subclass). Otherwise, it has no effect. Note: the coordinates mode of the layout is used only while this layout is running. If layout is not running, operations on the grapher adapter use the coordinates mode that was set on the grapher adapter directly (see IlvGrapherAdapter#setCoordinatesMode).

CSS example: coordinatesMode : "MANAGER_COORDINATES";

Allowed values:

MANAGER_COORDINATES

VIEW_COORDINATES

INVERSE_VIEW_COORDINATES

layoutOfConnectedComponentsEnabled

public boolean layoutOfConnectedComponentsEnabled

Sets whether the generic connected component layout mechanism is enabled. If enabled on a layout class that supports this mechanism (see #supportsLayoutOfConnectedComponents()), the method #performLayout(boolean, boolean, boolean) cuts the attached graph model into connected components and lays out each connected component separately. Then the connected components are placed using the layout instance returned by the method #getLayoutOfConnectedComponents().

Notice that the connected component layout is not used if the graph is connected.

A RuntimeException is thrown if the layout does not support this mechanism.

The default value is the value returned by the method #isLayoutOfConnectedComponentsEnabledByDefault().

CSS example: layoutOfConnectedComponentsEnabled : "false";

minBusyTime

public long minBusyTime

Sets the minimal time that the layout algorithm can be busy. This is the time between two calls of #layoutStepPerformed() when the method #callLayoutStepPerformedIfNeeded() is used.

The objective is to avoid the overhead of #layoutStepPerformed() becoming too high if the method is called too often. Internal routines of layout algorithms usually call #callLayoutStepPerformedIfNeeded(), which calls #layoutStepPerformed() if the time since the last call was at least the minimal busy time.

The default value is 50 (milliseconds).

CSS example: minBusyTime : "3";

nodesMoveThreshold

public double nodesMoveThreshold

Sets the convergence criteria of the node placement algorithm (the second step of the layout algorithm). This iterative algorithm is stopped when the greatest movement of a node at a given iteration is smaller than threshold.

The default value is 1.

The value of the argument is in the same coordinate space as the nodes and links of the graph. When laying out an IlvGrapher, the value is in manager coordinates (without transformation into view coordinates). If it is necessary to provide a given value in the coordinate space of a particular IlvManagerView, the value in manager coordinates can be computed using the following code:

  IlvTransformer t = view.getTransformer();
  double zoomFactor = transformer != null ? transformer.zoomFactor() : 1;
  double managerValue = viewValue / zoomFactor;
  

CSS example: nodesMoveThreshold : "3.0";

nodesPlacementAlgorithm

public int nodesPlacementAlgorithm

Sets the choice of the node placement algorithm (the second step of the layout algorithm). The valid values are:
- #SLOW_GOOD The first node placement algorithm (the default), which provides more uniformity of the node distribution inside the exterior cycle, but is slightly slower.
- #QUICK_BAD The second node placement algorithm, which provides less uniformity of the node distribution inside the exterior cycle, but is slightly quicker.

CSS example: nodesPlacementAlgorithm : "SLOW_GOOD";

Allowed values:
SLOW_GOOD		Slow
QUICK_BAD		Quick