Convert_Abstraction_Factory_PNG.php

<?php
class Abstract_Factory_Convert_PNG extends Convert_Abstraction_Factory {

    const EXTENSION = '.png';

    public function __construct() {
        parent::__construct();
    }
    
    public function image_convert($img) {
        $name = $this->to_pnm($img);
        exec('pnmtopng ' . self::TMP_PATH . DIRECTORY_SEPARATOR . $name .  '.pnm > ' . self::CONV_PATH . DIRECTORY_SEPARATOR . $name . self::EXTENSION);
    }
    
}