Gd::rotate

public function rotate($angle, Color $bgColor)
{
	if ($this->resource === null)
	{
		return false;
	}

	$angle = 360 - $angle;
	$alpha = (1.0 - $bgColor->getAlpha()) * 127;
	$color = imagecolorallocatealpha($this->resource, $bgColor->getRed(), $bgColor->getGreen(), $bgColor->getBlue(), $alpha);

	$resource = imagerotate($this->resource, $angle, $color);

	if ($resource === false)
	{
		return false;
	}

	$this->clear();
	$this->resource = $resource;

	return true;
}