EdgeDirectionPolicy

With this policy CreateEdgeInputMode queries both getAllSourcePortCandidates and getAllTargetPortCandidates for a port candidate to start edge creation from. If the chosen candidate has been returned by the latter method the edge will be created in reversed order.

This requires a custom IPortCandidateProvider which implements both getAllSourcePortCandidates and getAllTargetPortCandidates to return candidates to start edge creation at the source port and at the target port, respectively.

public class TagSensitivePortCandidateProvider : IPortCandidateProvider
{
  private readonly IPortOwner owner;

  public TagSensitivePortCandidateProvider(IPortOwner owner) {
    this.owner = owner;
  }

  public IEnumerable<IPortCandidate> GetSourcePortCandidates(IInputModeContext context) {
    return from port in owner.Ports where "Source".Equals(port.Tag) select new DefaultPortCandidate(port);
  }

  public IEnumerable<IPortCandidate> GetTargetPortCandidates(IInputModeContext context) {
    return from port in owner.Ports where "Target".Equals(port.Tag) select new DefaultPortCandidate(port);
  }

  ...

}