code: function colorCoords(channel, color) {
    let x, y, xmax, ymax;
    switch (channel) {
      case 'r':
        xmax = 255;
        ymax = 255;
        x = color.b;
        y = ymax - color.g;
        break;
      case 'g':
        xmax = 255;
        ymax = 255;
        x = color.b;
        y = ymax - color.r;
        break;
      case 'b':
        xmax = 255;
        ymax = 255;
        x = color.r;
        y = ymax - color.g;
        break;
      case 'h':
        xmax = 100;
        ymax = 100;
        x = color.s;
        y = ymax - color.l;
        break;
      case 's':
        xmax = 360;
        ymax = 100;
        x = color.h;
        y = ymax - color.l;
        break;
      case 'l':
        xmax = 360;
        ymax = 100;
        x = color.h;
        y = ymax - color.s;
        break;
    }
  
    return { xmax, ymax, x, y };
  }
docs: Determine x y coordinates based on color channel.
  
  R: x = b, y = g
  G: x = b, y = r
  B: x = r, y = g
  
  H: x = s, y = l
  S: x = h, y = l
  L: x = h, y = s
  
  @param {string} channel one of `r`, `g`, `b`, `h`, `s`, or `l`
  @param {Object} color a color object of current values associated to key
  @return {Object} coordinates