/// <summary>
/// Gets geometric information for a edge and a route</summary>
/// <param name="edge">Edge</param>
/// <param name="route">Edge's route</param>
/// <param name="startPoint">Calculated starting point for edge</param>
/// <param name="endPoint">Calculated ending point for edge</param>
/// <param name="circle">Calculated embedding circle for edge</param>
/// <param name="moreThan180">Calculated sweep angle hint</param>
/// <returns>True iff edge is straight line</returns>
private bool GetEdgeGeometry(
TEdge edge,
int route,
ref Vec2F startPoint,
ref Vec2F endPoint,
ref CircleF circle,
ref bool moreThan180)
{
bool straightLine = false;
if (edge.FromNode == edge.ToNode)
{
CircleF c = GetBoundary(edge.FromNode);
circle = c;
circle.Center.X -= circle.Radius;
circle.Radius *= 0.85f;
float offset = route * m_routeOffset / 2;
circle.Center.X -= offset;
circle.Radius += offset;
CircleF.Intersect(circle, c, ref startPoint, ref endPoint);
moreThan180 = true;
}
else
{
CircleF c1 = GetBoundary(edge.FromNode);
CircleF c2 = GetBoundary(edge.ToNode);
Vec2F d = Vec2F.Sub(c2.Center, c1.Center);
float length = d.Length;
if (length < c1.Radius + c2.Radius)
{
// overlapping nodes, don't try to draw arcs
d = Vec2F.XAxis;
straightLine = true;
}
else if (route == 0)
{
d *= 1.0f / length;
straightLine = true;
}
else
{
Vec2F routePoint = c1.Center + d * 0.5f;
float dLength = d.Length;
Vec2F offset = d.Perp * (1.0f / dLength);
routePoint -= offset * m_routeOffset * route;
circle = new CircleF(c1.Center, routePoint, c2.Center);
Vec2F dummy = new Vec2F();
CircleF.Intersect(circle, c1, ref startPoint, ref dummy);
CircleF.Intersect(circle, c2, ref dummy, ref endPoint);
Vec2F startToEnd = startPoint - endPoint;
Vec2F centerToEnd = circle.Center - endPoint;
moreThan180 = Vec2F.PerpDot(centerToEnd, startToEnd) < 0;
}
if (straightLine)
{
startPoint = Vec2F.Add(c1.Center, Vec2F.Mul(d, c1.Radius));
endPoint = Vec2F.Sub(c2.Center, Vec2F.Mul(d, c2.Radius));
}
}
return(straightLine);
}