Parameters of the link shape policy

Graphers may be nested. In this case, links of different subgraphers may cross each other. Calculating the crossings therefore requires a complete traversal of the nested subgraphers. If the grapher is not nested, or if crossings of links of different subgraphers should not be displayed as tunnels or bridges, then it is useful to disable the nesting traversal of the link shape policy. This also speeds up the calculation of crossings.
To disable the nesting traversal, call
crossingPolicy.setNestingTraversal(false);
The nesting traversal is enabled by default.
To enable or disable the nesting traversal of all crossing link shape policies that occur in a nested grapher, it is more convenient to call:
IlvCrossingLinkShapePolicy.SetNestingTraversal(grapher, flag, traverse, 
redraw);
If the traverse parameter is set to true, this method iterates over all links of all subgraphers and sets the flag at all crossing shape policies of the links. If the redraw parameter is true, a redraw is automatically performed afterwards.
Tunnel and bridge crossing shapes can be horizontally or vertically oriented. To enable a horizontal orientation, call:
crossingPolicy.setHorizontalPreferred(true);
To enable a vertical orientation, call:
crossingPolicy.setHorizontalPreferred(false);
The horizontal orientation is the default.
HorizTunnelCrossing.gif
VertiTunnelCrossing.gif
Crossing orientations: horizontal and vertical
Crossing links only look nice if all link crossings are the same. This can be achieved by making all links share the same shape policy. Alternatively, you can also achieve this by calling the following method on the grapher:
IlvCrossingLinkShapePolicy.SetHorizontalPreferred(grapher, flag, traverse, 
redraw);
If the traverse parameter is true, the same preference is applied to all crossing shape policies of all the links in all the nested subgraphers. Changing the preference changes the shape of the links; therefore it may be necessary to redraw the links. If the redraw parameter is true, the redraw is automatically performed.