/**
* Returns the luma
*
* @return integer
*/
public function getLuma()
{
if ($this->luma !== null) {
return $this->luma;
}
// Y = 0.2126 R + 0.7152 G + 0.0722 B
$r = ILess_Math::multiply('0.2126', ILess_Math::divide($this->rgb[0], 255));
$g = ILess_Math::multiply('0.7152', ILess_Math::divide($this->rgb[1], 255));
$b = ILess_Math::multiply('0.0722', ILess_Math::divide($this->rgb[2], 255));
$this->luma = ILess_Math::add(ILess_Math::add($r, $g), $b);
return $this->luma;
}
