/// <summary>
/// Returns a line segment with the coordinates of a chord centered on
/// the given angle with the given length.
/// </summary>
/// <param name="angleThroughCenter">The angle that passes through the
/// center of the chord, in degrees.</param>
/// <param name="chordLength">The length of the chord.</param>
public LineSeg2D GetChord(decimal angleThroughCenter, decimal chordLength)
{
LineSeg2D l = default(LineSeg2D);
decimal a = 0m;
// Create a right triangle where one side is half the chord length,
// the other side is from the center of the circle to the midpoint
// of the chord, and the hypotenuse is from the center of the circle
// to the chord start point
a = RightTriangle.GetAngleFromOppSideHyp(0.5m * chordLength, _radius);
l.Pt1 = PointAt(angleThroughCenter - a);
l.Pt2 = PointAt(angleThroughCenter + a);
return(l);
}
/// <summary>
/// Gets the total angle on a circle of the given radius from one side of the chord to the other.
/// </summary>
/// <param name="chordLength">The length of the chord.</param>
/// <param name="circleRadius">The radius of the circle.</param>
public static decimal GetChordTotalAngle(decimal chordLength, decimal circleRadius)
{
if (chordLength == 0)
{
return(0m);
}
else if (chordLength > circleRadius * 2m)
{
throw new Exception("Chord can't fit inside a circle with the specified radius!");
}
else if (chordLength == circleRadius * 2m)
{
return(180m);
}
else
{
return(RightTriangle.GetAngleFromOppSideHyp(0.5m * chordLength, circleRadius) * 2m);
}
}
