private void LayoutNode(GraphNode node) {
if (node.moveable) {
double dx = node.dx;
double dy = node.dy;
// The damper slows things down. It cuts down jiggling at the last moment, and optimizes
// layout. As an experiment, get rid of the damper in these lines, and make a
// long straight line of nodes. It wiggles too much and doesn't straighten out.
dx *= _damper;
dy *= _damper;
// Slow down, but dont stop. Nodes in motion store momentum. This helps when the force
// on a node is very low, but you still want to get optimal layout.
node.dx = dx / 2;
node.dy = dy / 2;
// How far did the node actually move?
double distanceMoved = Math.Sqrt(dx * dx + dy * dy);
// Don't move faster then 30 units at a time.
// Stops severed nodes from flying away?
node.x = node.x + Math.Max(-30, Math.Min(30, dx));
node.y = node.y + Math.Max(-30, Math.Min(30, dy));
_intermediateMaxMotion = Math.Max(distanceMoved, _intermediateMaxMotion);
}
}
public void AddNode(GraphNode node) {
_nodes.Add(node);
if (_updating == false) {
RaiseChangedEvent();
}
else {
_updated = true;
}
}
private void RemoveOverlap(GraphNode node1, GraphNode node2) {
double dx = 0;
double dy = 0;
double vx = node1.x - node2.x;
double vy = node1.y - node2.y;
double distance = vx * vx + vy * vy;
// TODO: 36 should be a property instead of hardcoded
// This is the radius of a node.
if (distance < 36 * 36 * 2) {
// If two nodes are right on top of each other, separate them
// apart randomly
dx = Math.Random();
dy = Math.Random();
}
else if (distance < 360000) {
// 600 * 600, because we don't want deleted nodes to fly too far away
// If it was sqrt(len) then a single node surrounded by many others will
// always look like a circle. This might look good at first, but I think
// it makes large graphs look ugly + it contributes to oscillation. A
// linear function does not fall off fast enough, so you get rough edges
// in the 'force field'
dx = vx / distance;
dy = vy / distance;
}
double totalRepulsion = DefaultRepulsion * DefaultRepulsion / 100;
double factor = totalRepulsion * _rigidity;
node1.dx += dx * factor;
node1.dy += dy * factor;
node2.dx -= dx * factor;
node2.dy -= dy * factor;
}
public GraphEdge(GraphNode fromNode, GraphNode toNode, int length) {
_fromNode = fromNode;
_toNode = toNode;
_length = length;
}
public void RemoveNode(GraphNode node) {
foreach (GraphEdge edge in node.Edges) {
RemoveEdge(edge);
}
_nodes.Remove(node);
if (_updating == false) {
RaiseChangedEvent();
}
else {
_updated = true;
}
}