private float GetAngle(Rectangle pRect, Point pPoint)
{
Point lCenter = DrawingTracker.GetCenter(pRect);
float lAngle = (float)(Math.Atan2(pPoint.Y - lCenter.Y, pPoint.X - lCenter.X) * (180.0 / Math.PI));
return(ArcTrackerAdjust.RectifyAngle(lAngle));
}
/// <summary>
/// get point on ellipse around pRect via specific angle.
/// use x^2/a^2 + y^2/b^2 = 1 to calculate point.
/// </summary>
/// <param name="pRect"></param>
/// <param name="pAngle"></param>
/// <returns></returns>
private Point GetPoint(Rectangle pRect, float pAngle)
{
pAngle = ArcTrackerAdjust.RectifyAngle(pAngle);
Point lRet = GetCenter(pRect);
double lRadians = pAngle * Math.PI / 180;
int a = pRect.Width / 2;
int b = pRect.Height / 2;
double lTan = Math.Tan(lRadians);
double lX = (a * b) / Math.Sqrt(Math.Pow(b, 2) + Math.Pow(lTan, 2) * Math.Pow(a, 2));
if (pAngle >= 90.0 && pAngle < 270.0)
{
lX = -lX;
}
double lY = lTan * lX;
lRet.Offset((int)lX, (int)lY);
return(lRet);
}
public ArcTracker(DrawingTool pTool)
: base(pTool)
{
Adjust = new ArcTrackerAdjust();
}