/// <summary>
/// Removes all the connections from this shape to others. Also removes
/// connections from substroke endpoints, if there are any.
///
/// Preconditions:
/// - For every shape "s" in ConnectedShapes, s.ConnectedShapes
/// contains this shape.
///
/// Postconditions:
/// - For every shape "s" in the old ConnectedShapes, s.ConnectedShapes
/// does not contain this shape and there is no endpoint in
/// s.Endpoints connected to this shape.
/// - ConnectedShapes is empty
/// - for every endpoint of every substroke, ConnectedShape is null
/// </summary>
public void ClearConnections()
{
foreach (Shape s in ConnectedShapes)
{
/* NOTE: shapes are allowed to be connected to themselves.
* If this is the case, then the connection will be removed
* below when we call ConnectedShapes.Clear(). Removing this
* if-check can cause the ConnectedShapes collection to be
* modified in the middle of this loop when s == this,
* causing an InvalidOperationException. */
if (s != this)
{
s.ConnectedShapes.Remove(this);
}
// Remove endpoint connections referencing this shape
foreach (EndPoint endpoint in s.Endpoints)
{
if (endpoint.ConnectedShape == this)
{
endpoint.ConnectedShape = null;
}
}
}
ConnectedShapes.Clear();
foreach (Substroke substroke in Substrokes)
{
foreach (EndPoint endpoint in substroke.Endpoints)
{
endpoint.ConnectedShape = null;
}
}
}
/// <summary>
/// Called when a substroke is added to this shape, and before it is added
/// to the list of substrokes. By default this does the following:
/// - updates the substroke's parent shape
/// - connects this shape to everything the substroke is connected to
/// </summary>
/// <param name="substroke">the substroke to acquire</param>
protected virtual void AcquireSubstroke(Substroke substroke)
{
if (substroke.ParentShape != null && substroke.ParentShape != this)
{
throw new ArgumentException("Cannot add a substroke belonging to a different shape!");
}
substroke.ParentShape = this;
foreach (EndPoint endpoint in substroke.Endpoints)
{
Shape connected = endpoint.ConnectedShape;
if (connected != null)
{
ConnectedShapes.Add(connected);
connected.ConnectedShapes.Add(this);
}
}
}
/// <summary>
/// Disconnect two shapes.
///
/// Note that this.disconnectFrom(shape) should be equivalent to
/// shape.disconnectFrom(this).
/// </summary>
/// <param name="other"></param>
public void disconnectFrom(Shape other)
{
ConnectedShapes.Remove(other);
other.ConnectedShapes.Remove(this);
foreach (EndPoint endpoint in Endpoints)
{
if (endpoint.ConnectedShape == other)
{
endpoint.ConnectedShape = null;
}
}
foreach (EndPoint endpoint in other.Endpoints)
{
if (endpoint.ConnectedShape == this)
{
endpoint.ConnectedShape = null;
}
}
}
