system/Images/Handlers/ImageMagickHandler.php
protected function _rotate(int $angle)
	{
		$angle = '-rotate ' . $angle;

		$source      = ! empty($this->resource) ? $this->resource : $this->image->getPathname();
		$destination = $this->getResourcePath();

		$action = ' ' . $angle . ' "' . $source . '" "' . $destination . '"';

		$this->process($action);

		return $this;
	}
protected function _rotate(int $angle)
	{
		$angle = '-rotate ' . $angle;

		$source      = ! empty($this->resource) ? $this->resource : $this->image->getPathname();
		$destination = $this->getResourcePath();

		$action = ' ' . $angle . ' "' . $source . '" "' . $destination . '"';

		$this->process($action);

		return $this;
	}
Handles the rotation of an image resource.
Doesn't save the image, but replaces the current resource.

@param integer $angle

@return $this
@throws \Exception