Factory methods

gistfile1.php

<?php

class Image
{
    private $width;
    private $height;
    private $content;
    
    public static function createEmpty($width, $height, $bgcolor = null)
    {
        $image = new Image();
        $image->width = $width;
        $image->height = $height;
        $image->content = …;
        
        return $image;
    }
    
    public static function createFromFile($file)
    {
        $reader = new FileReader($file);
        return self::createFromString($file->getContent());
    }
    
    public static function createFromString($str)
    {
        $image = new Image();
        $image->width = $width;
        $image->height = $height;
        $image->content = …;
        
        return $image;
    }
    
    private function __construct()
    {
    }
}