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angle class

base_angle

A template class base_angle provides functions to handle angles in different scales. The base_angle class requires the angle_range class as a template parameter, which defines the domain of the class. There are four angle_range options defined.

enum class angle_range
{
  zero_to_twopi,       /** range [0, 2pi)      (w/wrap)   */
  minus_pi_to_pi,      /** range [-pi, pi)     (w/wrap)   */
  zero_to_pi,          /** range [0, pi]       (w/o wrap) */
  minus_pi_2_to_pi_2   /** range [-pi/2, pi/2] (w/o wrap) */
};

zero_to_twopi is a default option. It produces the base_angle with the domain of [0, 2π). If one requires the angle symmetric about zero, minus_pi_to_pi is available, which produces the base_angle with the domain of [-π, π). zero_to_pi generates the base_angle with the domain of [0, π]. It is useful to define the angle between two directions. minus_pi_2_to_pi_2 gives the domain of [-π/2, π/2] to define the latitude.

Constructor

base_angle<angle_range range>(double r)

Create a base_angle instance with r radian.

range
the domain of base_angle.
r
an angle in degree.

Attributes

radian
(double) angle in radian.
degree
(double) angle in degree.
arcmin
(double) angle in arcminute.
arcsec
(double) angle in arcsecond.

Operators

operator double() const

A cast of an angle instance always provides an angle in degree.

const base_angle<range>
operator-() const

Returns an instance with an negative angle.

const base_angle<range>
operator+(const base_angle<range>& ang, const double val)

Define the add operator between base_angle and double.

const base_angle<range>
operator+(const double val, const base_angle<range>& ang)

Define the add operator between double and base_angle.

const base_angle<range>
operator-(const base_angle<range>& ang, const double val)

Define the subtract operator between base_angle and double.

const base_angle<range>
operator-(const double val, const base_angle<range>& ang)

Define the subtract operator between double and base_angle.

const base_angle<range>
operator*(const base_angle<range>& ang, const double val)

Define the product operator between base_angle and double.

const base_angle<range>
operator*(const double val, const base_angle<range>& ang)

Define the product operator between double and base_angle.

const base_angle<range>
operator/(const base_angle<range>& ang, const double val)

Define the divide operator between base_angle and double.

const base_angle<range>
operator/(const double val, const base_angle<range>& ang)

Define the divide operator between double and base_angle.

const base_angle<range>
operator+(const base_angle<_range>& ang) const

Define the add operator with another base_angle instance.

const base_angle<range>
operator-(const base_angle<_range>& ang) const

Define the subtract operator with another base_angle instance.

const bool
operator==(const base_angle<_range>& ang) const

Define equality operator to anotehr base_angle instance.

const bool
operator!=(const base_angle<_range>& ang) const

Define inequality operator to anotehr base_angle instance.

const bool
operator<(const base_angle<_range>& ang) const

Define less operator to anotehr base_angle instance.

const bool
operator<=(const base_angle<_range>& ang) const

Define less-or-equal operator to anotehr base_angle instance.

const bool
operator>(const base_angle<_range>& ang) const

Define greater operator to anotehr base_angle instance.

const bool
operator>=(const base_angle<_range>& ang) const

Define greater-or-equal operator to anotehr base_angle instance.

Some specializations of base_angle are defined as follows.

  • angle
  • longitude
  • latitude

angle

/** general purpose angle class. */
using angle = base_angle<angle_range::zero_to_twopi>;
The angle is a general-purpose specialization of base_angle. The domain of the angle is 0 to 2π. The argument outside of the domain is automatically wrapped into [0, 2π).

longitude

/** `longitude` is an alias to `angle`. */
using longitude = base_angle<angle_range::zero_to_twopi>;
The longitude is just an alias of angle. The domain of the longitude is 0 to 2π.

latitude

/** `latitude` is defined within [-pi/2,pi/2]. */
using latitude = base_angle<angle_range::minus_pi_2_to_pi_2>;

The latitude is another specialization of base_angle. The domain of the latitude is -π/2 to π/2. The argument outside of the domain throws an exception.