{
  "name": "darker",
  "type": "function",
  "groups": ["Color"],
  "description": "Returns a darker (or lighter) color string",
  "arguments": [
               {"arg":"color", "description":"a color string"},
	{"arg":"factor", "description":"an integer corresponding to the darkening factor:<ul><li>if the factor is greater than 100, this function returns a darker color (e.g., setting factor to 200 returns a color that is half the brightness);</li><li>if the factor is less than 100, the return color is lighter, but using the lighter() function for this purpose is recommended;</li><li>if the factor is 0 or negative, the return value is unspecified.</li></ul>"}
	          ],
  "examples": [ { "expression":"darker('200,10,30', 200)", "returns":"'100,5,15,255'"}]
}