/// <summary>
/// 计算点到Voronoi Edge的距离
/// </summary>
/// <param name="pt"></param>
/// <param name="edge"></param>
/// <returns></returns>
internal static double Distance2ToMidPoint(GeoPoint pt, GraphEdge edge)
{
var midPt = new GeoPoint(
(edge.Start.X + edge.End.X) / 2,
(edge.Start.Y + edge.End.Y) / 2
);
var distance2 = Math.Pow((pt.X - midPt.X), 2)
+ Math.Pow((pt.Y - midPt.Y), 2);
return(distance2);
}
/// <summary>
/// 垂线距离
/// </summary>
/// <param name="pt"></param>
/// <param name="line"></param>
/// <returns></returns>
internal virtual double GetVerticalDistance
(GeoPoint pt, GraphEdge line) //所在点到AB线段的垂线长度
{
var x = pt.X;
var y = pt.Y;
var x1 = line.Start.X;
var y1 = line.Start.Y;
var x2 = line.End.X;
var y2 = line.End.Y;
var reVal = 0.0;
bool retData = false;
var cross = (x2 - x1) * (x - x1) + (y2 - y1) * (y - y1);
if (cross <= 0)
{
reVal = Math.Sqrt((x - x1) * (x - x1) + (y - y1) * (y - y1));
retData = true;
}
var d2 = (x2 - x1) * (x2 - x1) + (y2 - y1) * (y2 - y1);
if (cross >= d2)
{
reVal = Math.Sqrt((x - x2) * (x - x2) + (y - y2) * (y - y2));
retData = true;
}
if (!retData)
{
var r = cross / d2;
var px = x1 + (x2 - x1) * r;
var py = y1 + (y2 - y1) * r;
reVal = Math.Sqrt((x - px) * (x - px) + (py - y) * (py - y));
}
return(reVal);
}
