A simple way to tell if your terminal supports truecolor.

colortest16777216

$ cat ~/bin/colortest16777216
#!/usr/bin/env python3
# pylint: disable=g-import-not-at-top,missing-docstring,g-wrong-blank-lines
from collections import namedtuple


class Color(namedtuple('Color', 'r g b')):
  """values are 0 to 1"""

  @classmethod
  def from_rgb(cls, r, g, b):
    return cls(r, g, b)

  @classmethod
  def from_hsl(cls, h, s, l):
    from colorsys import hls_to_rgb
    return cls(*hls_to_rgb(h, l, s))

  def show(color):  # pylint: disable=no-self-argument
    color = [int(x * 255) for x in color]
    code = ';'.join(str(x) for x in color)
    # #repr = ''.join(format(x, '02x') for x in color)
    return '\x1b[48;2;%sm ' % code

def white_fg():
  return '\x1b[1;38;5;231m'

def black_fg():
  return '\x1b[1;38;5;232m'

def reset(end='\n'):
  return '\x1b[0m' + end


def frange(start, stop, step):
  from sys import float_info
  curr = start
  while stop - curr > -float_info.epsilon:
    yield curr
    curr += step


def colortest_truecolor(outfile, rows, columns):
  for h in frange(0, 1.0, 1.0/(rows - 3)):
    for l in frange(0, 1.0, 1.0/(columns - 1)):
      outfile.write(Color.from_hsl(h, 1.0, l).show())
    outfile.write(reset())


def main():
  import shutil as S
  columns, rows = S.get_terminal_size((80, 20))

  import sys as S
  colortest_truecolor(S.stdout, rows - 3, columns - 1)


if __name__ == '__main__':
  exit(main())