com.yworks.yfiles.layout.tree

Interface INodePlacer

All Known Subinterfaces:

IFromSketchNodePlacer

All Known Implementing Classes:

AbstractNodePlacer, AbstractRotatableNodePlacer, AspectRatioNodePlacer, AssistantNodePlacer, BusNodePlacer, DefaultNodePlacer, DelegatingNodePlacer, DendrogramNodePlacer, DoubleLineNodePlacer, FreeNodePlacer, GridNodePlacer, GroupedNodePlacer, LayeredNodePlacer, LeafNodePlacer, LeftRightNodePlacer, SimpleNodePlacer

public interface INodePlacer

A INodePlacer is responsible for the arrangement of a local root node and all of its subtrees.

Subtrees are represented as SubtreeShapes with a connecting edge to the root of the subtree.

Implementations of this interface have to:

• arrange the SubtreeShapes and the root node (only the relative position matters, shapes can be placed at any absolute location, TreeLayout will perform the final alignment).
• perform the edge routing from the root node to all child nodes with respect to the connector provided by the SubtreeShapes
• calculate the union of the SubtreeShapes and the shape of the root node as well as any added edges
• initialize the connector of the root node with respect to the preferred connection direction
• return the SubtreeShape for the subtree including the local root

Method Summary

Modifier and Type	Method and Description
IProcessor	createProcessor(TreeLayout layouter, LayoutGraph graph, Node currentRoot) Creates an optional IProcessor for pre- and post-processing.
void	determineChildConnectors(Node localRoot, IDataMap connectorMap) Provides the direction of the connector to the SubtreeShape for each child node.
TreeLayout.SubtreeShape	placeSubtree(IDataProvider nodeShapeProvider, IDataProvider subtreeShapeProvider, LayoutGraph graph, Node localRoot, ParentConnectorDirection parentConnectorDirection) Arranges the SubtreeShapes of the local root and its children and routes the edges that connect them.

Method Detail

createProcessor

IProcessor createProcessor(TreeLayout layouter,
                           LayoutGraph graph,
                           Node currentRoot)

Creates an optional IProcessor for pre- and post-processing.

This method is called by TreeLayout before arranging the SubtreeShapes. If no pre- or post-processing is needed, this method may return null.

Parameters:

layouter - the current TreeLayout instance

graph - the input graph

currentRoot - the root node handled by this INodePlacer

Returns:

a IProcessor instance or null

determineChildConnectors

void determineChildConnectors(Node localRoot,
                              IDataMap connectorMap)

Provides the direction of the connector to the SubtreeShape for each child node.

This method is called by TreeLayout before the SubtreeShapes for the children of the local root node are calculated. The direction specifiers are stored in the given map for all child nodes of the local root.

Parameters:

localRoot - the local root node

connectorMap - the map that must be used for storing the direction specifiers of the child nodes

placeSubtree

TreeLayout.SubtreeShape placeSubtree(IDataProvider nodeShapeProvider,
                                     IDataProvider subtreeShapeProvider,
                                     LayoutGraph graph,
                                     Node localRoot,
                                     ParentConnectorDirection parentConnectorDirection)

Arranges the SubtreeShapes of the local root and its children and routes the edges that connect them.

This method is the main method of the tree layout algorithm. It is called by TreeLayout in each recursion step to place the local root in relation to its children. Their shapes will be merged into one SubtreeShape, which is returned by this method.

The SubtreeShape for the local root can be obtained from the nodeShapeProvider. subtreeShapeProvider contains the SubtreeShapes assigned to the child nodes.

Due to the order in which the tree nodes are processed, it is guaranteed that at the time of the invocation of this method the SubtreeShape of every descendant node has already been calculated.

Parameters:

nodeShapeProvider - the IDataProvider for obtaining an initial shape of the root node

subtreeShapeProvider - the IDataProvider for accessing the pre-calculated shapes of the subtrees

graph - the input graph

localRoot - the root of the subtree that should be arranged by this method

parentConnectorDirection - the direction specifier for the connector of the local root node to its parent node

Returns:

the combined shape of the whole subtree