/// <summary>
/// Adds the specified Node to this Diagram.
/// </summary>
/// <param name="node">The Node to add to the diagram.</param>
/// <returns>True if the node was added, false if the node is already on this Diagram.</returns>
public bool AddNode(Node node)
{
if (node == null) throw new ArgumentNullException("node");
if (!mNodes.Contains(node)) {
// add node, associate with diagram, then add all connected nodes
mNodes.Add(node);
node.Diagram = this;
foreach (Node child in node.Connections) AddNode(child);
return true;
}
else {
return false;
}
}
/// <summary>
/// Calculates the repulsion force between any two nodes in the diagram space.
/// </summary>
/// <param name="x">The node that the force is acting on.</param>
/// <param name="y">The node creating the force.</param>
/// <returns>A Vector representing the repulsion force.</returns>
private Vector CalcRepulsionForce(Node x, Node y)
{
int proximity = Math.Max(CalcDistance(x.Location, y.Location), 1);
// Coulomb's Law: F = k(Qq/r^2)
double force = -(REPULSION_CONSTANT / Math.Pow(proximity, 2));
double angle = GetBearingAngle(x.Location, y.Location);
return new Vector(force, angle);
}
public Vector Velocity; // the node's current velocity, expressed in vector form
#endregion Fields
#region Constructors
/// <summary>
/// Initialises a new instance of the Diagram.NodeLayoutInfo class, using the specified parameters.
/// </summary>
/// <param name="node"></param>
/// <param name="velocity"></param>
/// <param name="nextPosition"></param>
public NodeLayoutInfo(Node node, Vector velocity, Point nextPosition)
{
Node = node;
Velocity = velocity;
NextPosition = nextPosition;
}
/// <summary>
/// Removes the specified node from the diagram. Any connected nodes will remain on the diagram.
/// </summary>
/// <param name="node">The node to remove from the diagram.</param>
/// <returns>True if the node belonged to the diagram.</returns>
public bool RemoveNode(Node node)
{
node.Diagram = null;
foreach (Node other in mNodes) {
if ((other != node) && other.Connections.Contains(node)) other.Disconnect(node);
}
return mNodes.Remove(node);
}
/// <summary>
/// Calculates the attraction force between two connected nodes, using the specified spring length.
/// </summary>
/// <param name="x">The node that the force is acting on.</param>
/// <param name="y">The node creating the force.</param>
/// <param name="springLength">The length of the spring, in pixels.</param>
/// <returns>A Vector representing the attraction force.</returns>
private Vector CalcAttractionForce(Node x, Node y, double springLength)
{
int proximity = Math.Max(CalcDistance(x.Location, y.Location), 1);
// Hooke's Law: F = -kx
double force = ATTRACTION_CONSTANT * Math.Max(proximity - springLength, 0);
double angle = GetBearingAngle(x.Location, y.Location);
return new Vector(force, angle);
}
/// <summary>
/// Determines whether the diagram contains the specified node.
/// </summary>
/// <param name="node">The node to test.</param>
/// <returns>True if the diagram contains the node.</returns>
public bool ContainsNode(Node node)
{
return mNodes.Contains(node);
}
/// <summary>
/// Draws a connector between this node and the specified child node using GDI+.
/// The source and destination coordinates (relative to the Graphics surface) are also specified.
/// </summary>
/// <param name="graphics">GDI+ Graphics surface.</param>
/// <param name="from">Source coodinate.</param>
/// <param name="to">Destination coordinate.</param>
/// <param name="other">The other node.</param>
public virtual void DrawConnector(Graphics graphics, Point from, Point to, Node other)
{
graphics.DrawLine(Pens.Gray, from, to);
}
/// <summary>
/// Removes any connection between this node and the specified node.
/// </summary>
/// <param name="other">The other node whose connection is to be removed.</param>
/// <returns>True if a connection existed.</returns>
public bool Disconnect(Node other)
{
bool c = this.mConnections.Remove(other);
bool p = other.mConnections.Remove(this);
return c || p;
}
/// <summary>
/// Connects this node to the specified parent node.
/// </summary>
/// <param name="parent">The node to connect to this node.</param>
/// <returns>True if the other node was connected to this node.</returns>
public bool AddParent(Node parent)
{
if (parent == null) throw new ArgumentNullException("parent");
return parent.AddChild(this);
}
/// <summary>
/// Connects the specified child node to this node.
/// </summary>
/// <param name="child">The child node to add.</param>
/// <returns>True if the node was connected to this node.</returns>
public bool AddChild(Node child)
{
if (child == null) throw new ArgumentNullException("child");
if ((child != this) && !this.mConnections.Contains(child)) {
child.Diagram = this.Diagram;
this.mConnections.Add(child);
return true;
}
else {
return false;
}
}
