Specified provider mode

The specified provider mode can be used if you want to perform graph layout on a nested graph and either you want individual global layout parameters for specific subgraphs or you want to lay out different subgraphs with different styles. It is your responsibility to manage the specified layout provider (unlike the case with the internal provider mode), but this is probably only necessary in very advanced applications.

Specified provider mode has no reference layout. You allocate the Recursive Layout by using the constructor with your layout provider as argument:

IlvRecursiveLayout(IlvLayoutProvider specifiedProvider) 

IlvLayoutProvider getLayoutProvider() 

You should implement your layout provider in such a way that it delivers a different layout instance for each subgraph. The delivered layout instance must be attached to the graph model of the corresponding subgraph.

Because there is no reference layout, global layout parameters are independent for each subgraph. It is recommended that the implementation of the layout provider takes care of the setting of global and local layout parameters. Theoretically, you can use the method:

IlvGraphLayout getLayout(Object subgraph) 

which will return the layout instance that the specified layout provider delivers for the graph model of the input subgraph. If you pass null as subgraph, you get the layout instance of the top-level graph. The effect of this method depends on the implementation of the layout provider that was passed to the constructor of Recursive Layout.

The layout instances of the subgraphs used during recursive layout should be attached by the layout provider. They are usually not automatically detached when the Recursive Layout is detached.