// For changing the current state of the diagram.
public MoveShapeCommand(Shape _shape, double _offsetX, double _offsetY)
{
shape = _shape;
offsetX = _offsetX;
offsetY = _offsetY;
}
// For changing the current state of the diagram.
public AddShapeCommand(ObservableCollection<Shape> _shapes, Shape _shape)
{
shapes = _shapes;
shape = _shape;
}