Adapt a plugin in php with CodeIgniter

How to adapt the Croppic plugin for cropping images? I have two files that I have made into libraries, but I can not pass the parameters to this library .

The plugin is this: link

Code used below.

Controller:

public function cropimg() {

    if($_POST) {
        $imgUrl = $_POST['imgUrl'];
        $imgInitW = $_POST['imgInitW'];
        $imgInitH = $_POST['imgInitH'];
        $imgW = $_POST['imgW'];
        $imgH = $_POST['imgH'];
        $imgY1 = $_POST['imgY1'];
        $imgX1 = $_POST['imgX1'];
        $cropW = $_POST['cropW'];
        $cropH = $_POST['cropH']; 
    }

    $this->cropfile->imgCrop($imgUrl, $imgInitW, $imgInitH, $imgW, $imgH, $imgY1, $imgX1, $cropW, $cropH);
}

Library:

class CropFile {

public function imgCrop($imgUrl, $imgInitW, $imgInitH, $imgW, $imgH, $imgY1, $imgX1, $cropW, $cropH)
{
    $CI =& get_instance();
    $CI->load->helper('url');
    $CI->load->library('session');
    $CI->config->item('base_url');


    $jpeg_quality = 100;

    $output_filename = base_url() . "public/croppedImg_".rand();

    $what = getimagesize($imgUrl);
    switch(strtolower($what['mime']))
    {
        case 'image/png':
            $img_r = imagecreatefrompng($imgUrl);
            $source_image = imagecreatefrompng($imgUrl);
            $type = '.png';
            break;
        case 'image/jpeg':
            $img_r = imagecreatefromjpeg($imgUrl);
            $source_image = imagecreatefromjpeg($imgUrl);
            $type = '.jpeg';
            break;
        case 'image/gif':
            $img_r = imagecreatefromgif($imgUrl);
            $source_image = imagecreatefromgif($imgUrl);
            $type = '.gif';
            break;
        default: die('image type not supported');
    }

        $resizedImage = imagecreatetruecolor($imgW, $imgH);
        imagecopyresampled($resizedImage, $source_image, 0, 0, 0, 0, $imgW, 
                    $imgH, $imgInitW, $imgInitH);   


        $dest_image = imagecreatetruecolor($cropW, $cropH);
        imagecopyresampled($dest_image, $resizedImage, 0, 0, $imgX1, $imgY1, $cropW, 
                    $cropH, $cropW, $cropH);    


        imagejpeg($dest_image, $output_filename.$type, $jpeg_quality);

        $response = array(
                "status" => 'success',
                "url" => $output_filename.$type 
              );
         print json_encode($response);

}