/// <summary>
/// Gets hypotenuse from a known side and the angle adjacent to that side.
/// </summary>
/// <param name="side">Length of the known side.</param>
/// <param name="angleAdjacentToSide">The angle adjacent to the known side in degrees.</param>
public static decimal GetHypFromSideAdjAngle(decimal side, decimal angleAdjacentToSide)
{
// cos(a) = s / h
// h * cos(a) = s
// h = s / cos(a)
return(side / DecimalEx.Cos(DecimalEx.ToRad(angleAdjacentToSide)));
}
/// <summary>
/// Gets a line segment of length 1 starting at the point on the circle
/// and extending either clockwise or counterclockwise.
/// </summary>
/// <param name="degrees">An angle.</param>
public LineSeg2D TangentAt(decimal degrees, decimal length, bool clockwise)
{
var r = RightTriangleAbstract.FromTwoSides(_radius, length);
decimal rad = DecimalEx.ToRad(degrees + r.AngleA);
LineSeg2D ret = default(LineSeg2D);
Debug.Assert(r.AngleA == RightTriangle.GetAngleFromSides(length, _radius));
Debug.Assert(r.Hypotenuse == RightTriangle.GetHypFromSides(length, _radius));
ret.Pt1 = PointAt(degrees);
if (!clockwise)
{
ret.Pt2 = new Point2D(_center.X + r.Hypotenuse * DecimalEx.Cos(rad), _center.Y + r.Hypotenuse * DecimalEx.Sin(rad));
}
else
{
ret.Pt2 = new Point2D(ret.Pt1.X - (_center.X + r.Hypotenuse * DecimalEx.Cos(rad) - ret.Pt1.X), ret.Pt1.Y - (_center.Y + r.Hypotenuse * DecimalEx.Sin(rad) - ret.Pt1.Y));
}
return(ret);
}
/// <summary>
/// Gets the coordinates of the point on the circle at the given angle.
/// </summary>
/// <param name="degrees">The angle in degrees.</param>
public Point2D PointAt(decimal degrees)
{
decimal rad = DecimalEx.ToRad(degrees);
return(new Point2D(_center.X + _radius * DecimalEx.Cos(rad), _center.Y + _radius * DecimalEx.Sin(rad)));
}
/// <summary>
/// Gets a side from the adjacent angle and the length of the hypotenuse.
/// </summary>
/// <param name="adjacentAngle">Angle adjacent to the side to calculate in degrees.</param>
/// <param name="hypotenuse">Length of the hypotenuse.</param>
public static decimal GetSideFromAdjAngleHyp(decimal adjacentAngle, decimal hypotenuse)
{
// cos(adjacentAngle) = x / hypotenuse
// x = hypotenuse * cos(adjacentAngle)
return(hypotenuse * Convert.ToDecimal(DecimalEx.Cos(DecimalEx.ToRad(adjacentAngle))));
}
/// <summary>
/// Gets a side from the opposite angle and the length of the opposite side.
/// </summary>
/// <param name="oppositeAngle">Angle opposite the side to calculate in degrees.</param>
/// <param name="oppositeSide">Length of the opposite side.</param>
public static decimal GetSideFromOppAngleOppSide(decimal oppositeAngle, decimal oppositeSide)
{
// tan(oppositeAngle) = x / oppositeSide
// x = oppositeSide * tan(oppositeAngle)
return(oppositeSide * Convert.ToDecimal(DecimalEx.Tan(DecimalEx.ToRad(oppositeAngle))));
}
/// <summary>
/// Gets a side from the adjacent angle and the length of the opposite side.
/// </summary>
/// <param name="adjacentAngle">Angle adjacent to the side to calculate in degrees.</param>
/// <param name="oppositeSide">Length of the opposite side.</param>
public static decimal GetSideFromAdjAngleOppSide(decimal adjacentAngle, decimal oppositeSide)
{
// tan(adjacentAngle) = oppositeSide / x
// x = oppositeSide / tan(adjacentAngle)
return(oppositeSide / Convert.ToDecimal(DecimalEx.Tan(DecimalEx.ToRad(adjacentAngle))));
}
/// <summary>
/// Gets hypotenuse from a known side and the angle opposite to it.
/// </summary>
/// <param name="side">Length of the known side.</param>
/// <param name="angleOppositeToSide">Angle opposite to the known side in degrees.</param>
public static decimal GetHypFromSideOppAngle(decimal side, decimal angleOppositeToSide)
{
// sin(a) = s / h
// h = s / sin(a)
return(side / DecimalEx.Sin(DecimalEx.ToRad(angleOppositeToSide)));
}
/// <summary>
/// Gets a side from the opposite angle and the length of the hypotenuse.
/// </summary>
/// <param name="oppositeAngle">Angle opposite to the side to calculate in degrees.</param>
/// <param name="hypotenuse">Length of the hypotenuse.</param>
public static decimal GetSideFromOppAngleHyp(decimal oppositeAngle, decimal hypotenuse)
{
// sin(oppositeAngle) = x / hypotenuse
// x = hypotenuse * sin(oppositeAngle)
return(hypotenuse * Convert.ToDecimal(DecimalEx.Sin(DecimalEx.ToRad(oppositeAngle))));
}
