/// <summary>
/// 判断画布中某个位置是否在某个圆弧附近;
/// </summary>
/// <param name="arc2D"></param>
/// <param name="point"></param>
/// <param name="canvasProxy"></param>
/// <returns></returns>
public static bool PointInArc(Arc2D arc2D, Vector2D point, ICanvasScreenConvertable canvasProxy)
{
if (canvasProxy == null)
{
return(false);
}
if (arc2D == null)
{
return(false);
}
//以视图单位为标准进行判断;
var screenPoint = canvasProxy.ToScreen(point);
var arcCenterScreenPoint = canvasProxy.ToScreen(arc2D.Center);
var screenRadius = canvasProxy.ToScreen(arc2D.Radius);
if (Math.Abs(arcCenterScreenPoint.Distance(screenPoint) - screenRadius) > TolerantedScreenLength)
{
return(false);
}
var centerToPointDirection = new Line2D(arc2D.Center, point).Direction;
if (Extension.AreEqual(centerToPointDirection.Modulus(), 0))
{
return(false);
}
var centerToPointAngle = Extension.AngleFrom(
new Vector3D(centerToPointDirection.X, centerToPointDirection.Y, 0),
Vector3D.BasisX
);
if (arc2D.Angle > 0)
{
return(centerToPointAngle < arc2D.StartAngle + arc2D.Angle && centerToPointAngle > arc2D.StartAngle);
}
else
{
return(centerToPointAngle < arc2D.StartAngle && centerToPointAngle > arc2D.StartAngle + arc2D.Angle);
}
}