graph.php

<?php
require_once __DIR__.'/vendor/autoload.php';

use Example\Order\Process\Postpayment;
use Example\Order\Process\Prepayment;
use Metabor\NamedCollection;
use Metabor\Statemachine\Graph\GraphBuilder;
use Fhaculty\Graph\Graph;
use Graphp\GraphViz\GraphViz;

try {
 $processes = new NamedCollection();
 $processes->add(new Prepayment());
 $processes->add(new Postpayment());

 if (isset($_GET['process'])) {
 $processName = strtolower($_GET['process']);
 if ($processes->has($processName)) {
 $process = $processes->get($processName);
 }
 }
 if (!isset($process)) {
 $processNames = $processes->getNames();
 $processName = reset($processNames);
 $process = $processes->get($processName);
 }

 $graph = new Graph();
 $builder = new GraphBuilder($graph);
 $builder->addStateCollection($process);

 $viz = new GraphViz();
 $viz->setFormat('svg');
 echo file_get_contents($viz->createImageFile($graph));
} catch (Exception $e) {
 echo $e->getMessage();
}