atan2 function

Input type	Output type
complex	float

This function calculates the angle (or complex argument) of the argument and returns the result. The return value is always in the correct quadrant. This function is very useful for many transformations and coloring algorithms, and acts the same as the atan2 function in the C programming language library.

Here is some sample code to illustrate the behaviour of atan2:

angle = atan2(arg)

is equivalent to

if real(arg) > 0
  angle = atan(imag(arg) / real(arg))
elseif real(arg) == 0
  if imag(arg) > 0
    angle = 0.5 * #pi
  else
    angle = -0.5 * #pi
  endif
else
  if imag(arg) > 0
    angle = #pi + atan(imag(arg) / real(arg))
  else
    angle = -#pi + atan(imag(arg) / real(arg))
  endif
endif

Examples:

atan2((1, 1))    ; 0.25 * pi
atan2((-1, -1))  ; -0.75 * pi