Add option to export graph into image file

bin/graph-composer

@@ -7,4 +7,9 @@ require_once __DIR__ . '/../vendor/autoload.php';
 $dir = isset($argv[1]) ? $argv[1] : '.';
 
 $graph = new Clue\GraphComposer($dir);
-$graph->displayGraph();
+
+if (isset($argv[2])) {
+    $graph->exportGraph($argv[2]);
+} else {
+    $graph->displayGraph();
+}

src/Clue/GraphComposer.php

@@ -87,4 +87,27 @@ public function displayGraph()
         $graphviz->setFormat('svg');
         $graphviz->display();
     }
+
+    public function exportGraph($target)
+    {
+        $graph = $this->createGraph();
+
+        if (is_dir($target)) {
+            $target = rtrim($target, '/') . '/graph-composer.svg';
+        }
+
+        $filename = basename($target);
+        $format = 'svg';
+        $pos = strrpos($filename, '.');
+        if ($pos !== false && isset($filename[$pos + 1])) {
+            // extension found and not empty
+            $format = substr($filename, $pos + 1);
+        }
+
+        $graphviz = new GraphViz($graph);
+        $graphviz->setFormat($format);
+        $temp = $graphviz->createImageFile();
+
+        rename($temp, $target);
+    }
 }