/// <summary>
/// 返回矩形中心点与指定点的向量，与矩形相交的点。
/// 简单地认为，这个点即是矩形边上最靠近指定点的点。
/// </summary>
/// <param name="rect"></param>
/// <param name="point"></param>
/// <returns></returns>
public static Point NearestPointOnLine(Rect rect, Point point)
{
Point res = point;
if (rect.Contains(res))
{
var center = rect.GetCenterPoint();
//没有斜率
if (res.Y == center.Y)
{
if (res.X < center.X)
{
res = RectAlgorithm.GetRectAbsolute(rect, new Point(0, 0.5));
}
else
{
res = RectAlgorithm.GetRectAbsolute(rect, new Point(1, 0.5));
}
return(res);
}
else
{
//使用向量继续向该方向延长。
Vector v = new Vector(res.X - center.X, res.Y - center.Y);
v *= 10000;
while (true)
{
res += v;
if (!rect.Contains(res))
{
break;
}
}
}
}
res = CalcCrossPoint(rect, point);
return(res);
}