Derive text color depending on background brightness

color2text_brightness.coffee

#Color text change
rgb = [
  "255"
  "0"
  "0"
]
setInterval (->
  c = "rgb(" + rgb[0] + "," + rgb[1] + "," + rgb[2] + ")"
  
  #http://www.w3.org/TR/AERT#color-contrast
  o = Math.round(((parseInt(rgb[0]) * 299) + (parseInt(rgb[1]) * 587) + (parseInt(rgb[2]) * 114)) / 1000)
  
  #console.log(o);
  if o > 125
    $("#bg").css "color", "black"
  else
    $("#bg").css "color", "white"
  $("#bg").css "background-color", c
  r = Math.round(Math.random() * 255)
  g = Math.round(Math.random() * 255)
  b = Math.round(Math.random() * 255)
  rgb[0] = r
  rgb[1] = g
  rgb[2] = b
  return
), 500