// define is in the wall by r
public bool InWall(Vector vector, double r)
{
var metaDir = End.Normalize(Begin).Multiply(r / 2.0);
var xBegin = Begin.NewSubtract(metaDir);
var xEnd = End.NewAdd(metaDir);
// x, y should > min && < max
return(vector.X > Math.Min(xBegin.X, xEnd.X) &&
vector.X < Math.Max(xBegin.X, xEnd.X) &&
vector.Y > Math.Min(xBegin.Y, xEnd.Y) &&
vector.Y < Math.Max(xBegin.Y, xEnd.Y));
}