<?php

private function convertDocToThumbnail(string $filename, string $fileExt)
{
    $thumbnail = '';
    $image = new \Imagick();
    $image->setSize(210, 298);
    $image->readImage(config('default.path.user.attachment.abs') . '/' . $filename . '[0]');
    $image->setImageBackgroundColor('#ffffff');
    $image->setImageAlphaChannel(11);
    $image->mergeImageLayers(\Imagick::LAYERMETHOD_FLATTEN);
    $image->setImageFormat("jpeg");
    $thumbnail = str_replace('.'.$fileExt, '', $filename) . '_thumbnail.jpg';
    file_put_contents(config('default.path.user.attachment.abs') . '/' . $thumbnail, $image->getImageBlob());
    return $thumbnail;
}