/// <summary>
/// Returns a list that contains a port candidate for each of the node's
/// ports. Each candidate has the same location as the port. If a port
/// already has a connected edge, its port candidate is marked as invalid.
/// </summary>
/// <remarks>
/// Note that the various variants of getPortCandidates of
/// <see cref="PortCandidateProviderBase"/> delegate to this method.
/// This can be used to provide the same candidates for all use-cases.
/// </remarks>
protected override IEnumerable <IPortCandidate> GetPortCandidates(IInputModeContext context)
{
List <IPortCandidate> candidates = new List <IPortCandidate>();
var graph = context.GetGraph();
// Create the candidate for each port
if (graph != null)
{
foreach (IPort port in node.Ports)
{
DefaultPortCandidate portCandidate = new DefaultPortCandidate(port);
portCandidate.Validity = graph.Degree(port) == 0 ? PortCandidateValidity.Valid : PortCandidateValidity.Invalid;
candidates.Add(portCandidate);
}
}
// If no candidates have been created so far, create a single invalid candidate as fallback
if (candidates.Count == 0)
{
DefaultPortCandidate item = new DefaultPortCandidate(node, FreeNodePortLocationModel.NodeCenterAnchored);
item.Validity = PortCandidateValidity.Invalid;
candidates.Add(item);
}
return(candidates);
}
/// <summary>
/// Returns a list that contains a port candidate for each of the node's
/// ports. Each candidate has the same location as the port. If a port
/// already has a connected edge, its port candidate is marked as invalid.
/// </summary>
/// <remarks>
/// Note that the variants of getPortCandidates for target ports are all
/// implemented by this class. Therefore, this method is only used for
/// source ports.
/// </remarks>
protected override IEnumerable <IPortCandidate> GetPortCandidates(IInputModeContext context)
{
List <IPortCandidate> candidates = new List <IPortCandidate>();
bool hasValid = false;
var graph = context.GetGraph();
if (graph != null)
{
// Create a port candidate for each port on the node
foreach (IPort port in node.Ports)
{
DefaultPortCandidate portCandidate = new DefaultPortCandidate(port);
bool valid = graph.OutDegree(port) == 0;
hasValid |= valid;
portCandidate.Validity = valid ? PortCandidateValidity.Valid : PortCandidateValidity.Invalid;
candidates.Add(portCandidate);
}
}
// If no valid candidates have been created so far, use the ShapeGeometryPortCandidateProvider as fallback.
// This provides a candidate in the middle of each of the four sides of the node.
if (!hasValid)
{
candidates.AddRange(PortCandidateProviders.FromShapeGeometry(node).GetSourcePortCandidates(context));
}
return(candidates);
}
/// <summary>
/// Returns all port candidates that apply for the provided opposite port candidate.
/// </summary>
/// <remarks>
/// In this implementation only source ports with the same color and source ports of nodes
/// with the same color as the target port are accepted.
/// </remarks>
public override IEnumerable <IPortCandidate> GetTargetPortCandidates(IInputModeContext context, IPortCandidate source)
{
List <IPortCandidate> candidates = new List <IPortCandidate>();
var graph = context.GetGraph();
if (graph != null)
{
foreach (IPort port in node.Ports)
{
DefaultPortCandidate portCandidate = new DefaultPortCandidate(port);
var sourcePort = source.CreatePort(context);
bool valid = port.Tag.Equals(source.Owner.Tag) || sourcePort != null && port.Tag.Equals(sourcePort.Tag);
portCandidate.Validity = valid ? PortCandidateValidity.Valid : PortCandidateValidity.Invalid;
candidates.Add(portCandidate);
}
}
return(candidates);
}
/// <summary>
/// Returns the suitable candidates based on the specified <see cref="EdgeDirection"/>.
/// </summary>
private IEnumerable <IPortCandidate> GetCandidatesForDirection(EdgeDirection direction, IInputModeContext context)
{
// If EdgeDirectionPolicy.DetermineFromPortCandidates is used, CreateEdgeInputMode queries GetSourcePortCandidates
// as well as GetTargetPortCandidates to collect possible port candidates to start the edge creation.
// In this case this method is called twice (with EdgeDirection.In and EdgeDirection.Out) so for each call we
// should only return the *valid* port candidates of a port as otherwise for each port a valid as well as an invalid
// candidate is returned.
var provideAllCandidates = true;
var ceim = context.ParentInputMode as CreateEdgeInputMode;
if (ceim != null)
{
// check the edge direction policy as well as whether candidates are collected for starting or ending the edge creation
provideAllCandidates = ceim.EdgeDirectionPolicy != EdgeDirectionPolicy.DetermineFromPortCandidates ||
ceim.IsCreationInProgress;
}
var candidates = new List <IPortCandidate>();
// iterate over all available ports
foreach (var port in context.GetGraph().Ports)
{
// create a port candidate, invalidate it (so it is visible but not usable)
var candidate = new DefaultPortCandidate(port)
{
Validity = PortCandidateValidity.Invalid
};
// get the port descriptor
var portDescriptor = port.Tag as PortDescriptor;
// make the candidate valid if the direction is the same as the one supplied
if (portDescriptor != null && portDescriptor.EdgeDirection == direction)
{
candidate.Validity = PortCandidateValidity.Valid;
}
// add the candidate to the list
if (provideAllCandidates || candidate.Validity == PortCandidateValidity.Valid)
{
candidates.Add(candidate);
}
}
// and return the list
return(candidates);
}
/// <summary>
/// Creates an enumeration of possible port candidates, in this
/// case one port candidate for each of the node's
/// ports in the same location as the port.
/// </summary>
/// <remarks>
/// This method is used to provide the same candidates for all
/// use-cases. It is used as a fallback if methods <c>GetSourcePortCandidates()</c>
/// and <c>GetTargetPortCandidates()</c> aren't implemented.
/// </remarks>
protected override IEnumerable <IPortCandidate> GetPortCandidates(IInputModeContext context)
{
List <IPortCandidate> candidates = new List <IPortCandidate>();
var graph = context.GetGraph();
if (graph != null)
{
foreach (IPort port in node.Ports)
{
DefaultPortCandidate portCandidate = new DefaultPortCandidate(port);
candidates.Add(portCandidate);
}
}
if (candidates.Count == 0)
{
DefaultPortCandidate item = new DefaultPortCandidate(node, FreeNodePortLocationModel.NodeCenterAnchored);
item.Validity = PortCandidateValidity.Invalid;
candidates.Add(item);
}
return(candidates);
}
