public function trimPerc($coords)
{
list($x1, $y1, $x2, $y2) = $coords;
$size = (object) $this->thumb->getCurrentDimensions();
// Convert percentage values to what GdThumb expects
$x = round($x1 * $size->width);
$y = round($y1 * $size->height);
$width = round($x2 * $size->width - $x);
$height = round($y2 * $size->height - $y);
$this->thumb->crop($x, $y, $width, $height);
return $this;
}