streams/Code/Thumbs/Epubthumb.php

<?php

namespace Code\Thumbs;

require_once 'library/epub-meta/epub.php';

use Epub;

/**
 * @brief Thumbnail creation for epub files.
 *
 */
class Epubthumb
{

    /**
     * @brief Match for application/epub+zip.
     *
     * @param string $type MimeType
     * @return bool
     */

    public function Match($type)
    {
        return (($type === 'application/epub+zip') ? true : false);
    }

    /**
     * @brief
     *
     * @param array $attach
     * @param number $preview_style unused
     * @param number $height (optional) default 300
     * @param number $width (optional) default 300
     */

    public function Thumb($attach, $preview_style, $height = 300, $width = 300)
    {

        $photo = false;

        $ep = new EPub(dbunescbin($attach['content']));
        $data = $ep->Cover();

        if ($data['found']) {
            $photo = $data['data'];
        }

        if ($photo) {
            $image = imagecreatefromstring($photo);
            $dest = imagecreatetruecolor($width, $height);
            $srcwidth = imagesx($image);
            $srcheight = imagesy($image);

            imagealphablending($dest, false);
            imagesavealpha($dest, true);
            imagecopyresampled($dest, $image, 0, 0, 0, 0, $width, $height, $srcwidth, $srcheight);
            imagedestroy($image);
            imagejpeg($dest, dbunescbin($attach['content']) . '.thumb');
        }
    }
}