transformation.php

См. документацию.

<?php
 
namespace Bitrix\Main\UI\Viewer\Transformation;
 
use Bitrix\Transformer\FileTransformer;
 
abstract class Transformation
{
    public static function getInputContentTypes()
    {
        return [];
    }
 
    abstract public function getOutputContentType();
    abstract public function getOutputExtension();

    abstract public function buildTransformer();

    public function getInputMaxSize()
    {
        return 0;
    }
}