upgrade

vendor/graphp/graphviz/.gitignore

@@ -0,0 +1,2 @@
+/vendor
+/composer.lock

vendor/graphp/graphviz/.travis.yml

@@ -0,0 +1,34 @@
+language: php
+
+php:
+# - 5.3 # requires old distro, see below
+  - 5.4
+  - 5.5
+  - 5.6
+  - 7.0
+  - 7.1
+  - 7.2
+  - hhvm # ignore errors, see below
+
+# lock distro so future defaults will not break the build
+dist: trusty
+
+matrix:
+  include:
+    - php: 5.3
+      dist: precise
+  allow_failures:
+    - php: hhvm
+
+sudo: false
+
+addons:
+  apt:
+    packages:
+      - graphviz
+
+install:
+  - composer install --no-interaction
+
+script:
+  - vendor/bin/phpunit --coverage-text

vendor/graphp/graphviz/CHANGELOG.md

@@ -0,0 +1,44 @@
+# Changelog
+
+## 0.2.2 (2019-10-04)
+
+*   Feature: Omit root graph name unless explicitly assigned via `graphviz.name` attribute.
+    (#28 by @rhelms and @clue)
+
+    ```php
+    $graph = new Graph();
+    $graph->setAttribute('graphviz.name', 'g');
+    ```
+
+*   Feature: Remove unneeded dependency on `graphp/algorithms`.
+    (#39 by @clue)
+
+*   Feature / Fix: Use UTF-8 encoding (Unicode) by default and respect charset attribute.
+    (#27 by @Ithilias and @clue)
+
+*   Fix: Fix representing directed loop edges as directed edge
+    (#37 by @clue)
+
+*   Add examples and documentation for GraphViz attributes, labels and record shapes.
+    (#26 by @clue)
+
+*   Update test suite to support PHPUnit 6 and PHPUnit 5 and support running on legacy PHP 5.3 through PHP 7.2 and HHVM.
+    (#24 by @clue)
+
+## 0.2.1 (2015-03-08)
+
+*   Support graph v0.9 (while keeping BC)
+    ([#9](https://github.com/graphp/graphviz/pull/9))
+
+## 0.2.0 (2015-01-19)
+
+*   BC break: Refactor to inject Graph into GraphViz on demand, inject GraphViz into exporters
+    ([#6](https://github.com/graphp/graphviz/pull/6))
+
+*   BC break: Remove legacy layout helper
+    ([#5](https://github.com/graphp/graphviz/pull/5))
+
+## 0.1.0 (2014-12-31)
+
+*   First tagged release, split off from [clue/graph](https://github.com/clue/graph) v0.8.0
+    ([#1](https://github.com/graphp/graphviz/issues/1))

vendor/graphp/graphviz/LICENSE

@@ -0,0 +1,22 @@
+The MIT License (MIT)
+
+Copyright (c) 2012+ Christian Lück (Maintainer)
+Copyright (c) 2012+ Fhaculty Core Team and our awesome contributors <https://github.com/clue/graph/graphs/contributors>
+
+Permission is hereby granted, free of charge, to any person obtaining a copy
+of this software and associated documentation files (the "Software"), to deal
+in the Software without restriction, including without limitation the rights
+to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+copies of the Software, and to permit persons to whom the Software is furnished
+to do so, subject to the following conditions:
+
+The above copyright notice and this permission notice shall be included in all
+copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+THE SOFTWARE.

vendor/graphp/graphviz/README.md

@@ -0,0 +1,425 @@
+# graphp/graphviz [![Build Status](https://travis-ci.org/graphp/graphviz.svg?branch=master)](https://travis-ci.org/graphp/graphviz)
+
+GraphViz graph drawing for the mathematical graph/network library GraPHP.
+
+The library supports visualizing graph images, including them into webpages,
+opening up images from within CLI applications and exporting them
+as PNG, JPEG or SVG file formats (among many others).
+Because [graph drawing](http://en.wikipedia.org/wiki/Graph_drawing) is a complex area on its own,
+the actual layouting of the graph is left up to the excelent [GraphViz](http://www.graphviz.org/)
+"Graph Visualization Software" and we merely provide some convenient APIs to interface with GraphViz.
+
+> Note: This project is in beta stage! Feel free to report any issues you encounter.
+
+**Table of contents**
+
+* [Quickstart examples](#quickstart-examples)
+* [Attributes](#attributes)
+  * [Graph attributes](#graph-attributes)
+  * [Vertex attributes](#vertex-attributes)
+  * [Edge attributes](#edge-attributes)
+* [Labels](#labels)
+  * [Vertex labels](#vertex-labels)
+  * [Edge labels](#edge-labels)
+  * [HTML-like labels](#html-like-labels)
+  * [Record-based nodes](#record-based-nodes)
+* [Install](#install)
+* [Tests](#tests)
+* [License](#license)
+
+## Quickstart examples
+
+Once [installed](#install), let's build and display a sample graph:
+
+````php
+$graph = new Fhaculty\Graph\Graph();
+
+$blue = $graph->createVertex('blue');
+$blue->setAttribute('graphviz.color', 'blue');
+
+$red = $graph->createVertex('red');
+$red->setAttribute('graphviz.color', 'red');
+
+$edge = $blue->createEdgeTo($red);
+$edge->setAttribute('graphviz.color', 'grey');
+
+$graphviz = new Graphp\GraphViz\GraphViz();
+$graphviz->display($graph);
+````
+
+The above code will open your default image viewer with the following image:
+
+![red-blue](examples/01-simple.png)
+
+See also the [examples](examples/).
+
+## Attributes
+
+GraphViz supports a number of attributes on the graph instance itself, each
+vertex instance (GraphViz calls these "nodes") and edge instance. Any of these
+GraphViz attributes are supported by this library and have to be assigned using
+GraPHP attributes as documented below.
+
+For the full list of all GraphViz attributes, please refer to the
+[GraphViz documentation](https://graphviz.gitlab.io/_pages/doc/info/attrs.html).
+
+Note that all attributes use UTF-8 encoding (Unicode) and will be quoted and
+escaped by default, so a `ö` and `>` will appear as-is and will not be
+interpreted as HTML. See also [HTML-like labels](#html-like-labels) below for
+more details.
+
+### Graph attributes
+
+GraphViz supports a number of attributes on the graph instance itself. Any of
+these GraphViz attributes are supported by this library and have to be assigned
+on the graph instance with the `graphviz.graph.` prefix like this:
+
+```php
+$graph = new Fhaculty\Graph\Graph();
+$graph->setAttribute('graphviz.graph.bgcolor', 'transparent');
+```
+
+> Note how this uses the `graphviz.graph.` prefix and not just `graphviz.`. This
+  is done for consistency reasons with respect to default vertex and edge
+  attributes as documented below.
+
+For example, the `rankdir` attribute can be used to change the orientation to
+horizontal mode (left to right) like this:
+
+```php
+$graph = new Fhaculty\Graph\Graph();
+$graph->setAttribute('graphviz.graph.rankdir', 'LR');
+
+$hello = $graph->createVertex('hello');
+$world = $graph->createVertex('wörld');
+$hello->createEdgeTo($world);
+```
+
+![html graph example](examples/02-html.png)
+
+See also the [examples](examples/).
+
+Additionally, this library accepts an optional `graphviz.name` attribute that
+will be used as the name (or ID) for the root graph object in the DOT output if
+given. Unless explicitly assigned, this will be omitted by default. It is common
+to assign a `G` here, but usually there should be no need to assign this. Among
+others, this may be used as the title or tooltip in SVG output.
+
+```php
+$graph = new Fhaculty\Graph\Graph();
+$graph->setAttribute('graphviz.name', 'G');
+
+$graph->createVertex('first');
+```
+
+### Vertex attributes
+
+GraphViz supports a number of attributes on each vertex instance (GraphViz calls
+these "node" attributes). Any of these GraphViz attributes are supported by this
+library and have to be assigned on the respective vertex instance with the
+`graphviz.` prefix like this:
+
+```php
+$graph = new Fhaculty\Graph\Graph();
+
+$blue = $graph->createVertex('blue');
+$blue->setAttribute('graphviz.color', 'blue');
+```
+
+Additionally, GraphViz also supports default attributes for all vertices. Any of
+these GraphViz attributes are supported by this library and have to be assigned
+on the graph instance with the `graphviz.node.` prefix like this:
+
+```php
+$graph = new Fhaculty\Graph\Graph();
+$graph->setAttribute('graphviz.node.color', 'grey');
+
+$grey = $graph->createVertex('grey');
+```
+
+These default attributes can be overriden on each vertex instance by explicitly
+assigning the same attribute on the respective vertex instance like this:
+
+```php
+$graph = new Fhaculty\Graph\Graph();
+$graph->setAttribute('graphviz.node.color', 'grey');
+
+$blue = $graph->createVertex('blue');
+$blue->setAttribute('graphviz.color', 'blue');
+```
+
+> Note how this uses the `graphviz.node.` prefix and not `graphviz.vertex.`. This
+  is done for consistency reasons with respect to how GraphViz assigns these
+  default attributes in its DOT output.
+
+### Edge attributes
+
+GraphViz supports a number of attributes on each edge instance. Any of these
+GraphViz attributes are supported by this library and have to be assigned on the
+respective edge instance with the `graphviz.` prefix like this:
+
+```php
+$graph = new Fhaculty\Graph\Graph();
+
+$a = $graph->createVertex('a');
+$b = $graph->createVertex('b');
+
+$blue = $a->createEdgeTo($b);
+$blue->setAttribute('graphviz.color', 'blue');
+```
+
+Additionally, GraphViz also supports default attributes for all edges. Any of
+these GraphViz attributes are supported by this library and have to be assigned
+on the graph instance with the `graphviz.edge.` prefix like this:
+
+```php
+$graph = new Fhaculty\Graph\Graph();
+$graph->setAttribute('graphviz.edge.color', 'grey');
+
+$a = $graph->createVertex('a');
+$b = $graph->createVertex('b');
+
+$grey = $a->createEdgeTo($b);
+```
+
+These default attributes can be overriden on each edge instance by explicitly
+assigning the same attribute on the respective edge instance like this:
+
+```php
+$graph = new Fhaculty\Graph\Graph();
+$graph->setAttribute('graphviz.edge.color', 'grey');
+
+$a = $graph->createVertex('a');
+$b = $graph->createVertex('b');
+
+$blue = $a->createEdgeTo($b);
+$blue->setAttribute('graphviz.color', 'blue');
+```
+
+## Labels
+
+### Vertex labels
+
+By default, GraphViz will always render the vertex ID as the label:
+
+```php
+$graph = new Fhaculty\Graph\Graph();
+
+$blue = $graph->createVertex('blue');
+```
+
+If you assign a vertex balance, this library will automatically include a
+`label` attribute that includes the balance value. The following example will
+automatically assign `blue (+10)` as the label:
+
+```php
+$graph = new Fhaculty\Graph\Graph();
+
+$blue = $graph->createVertex('blue');
+$blue->setBalance(10);
+```
+
+You can use [vertex attributes](#vertex-attributes) to explicitly assign a
+custom `label` attribute. Note that any balance value will still be appended
+like in the previous example.
+
+```php
+$graph = new Fhaculty\Graph\Graph();
+
+$blue = $graph->createVertex('blue');
+$blue->setAttribute('graphviz.label', 'Hello world!');
+```
+
+Note that all [attributes](#attributes) will be quoted and escaped by default,
+so a `>` will appear as-is and will not be interpreted as HTML. See also
+[HTML-like labels](#html-like-labels) below for more details.
+
+### Edge labels
+
+By default, GraphViz will not render any label on an edge:
+
+```php
+$graph = new Fhaculty\Graph\Graph();
+
+$a = $graph->createVertex('a');
+$b = $graph->createVertex('b');
+
+$edge = $a->createEdgeTo($b);
+```
+
+If you assign an edge flow, capacity or weight, this library will automatically
+include a `label` attribute that includes these values. The following example
+will automatically assign `100` as the label for the weighted edge:
+
+```php
+$graph = new Fhaculty\Graph\Graph();
+
+$a = $graph->createVertex('a');
+$b = $graph->createVertex('b');
+
+$edge = $a->createEdgeTo($b);
+$edge->setWeight(100);
+```
+
+The following example will automatically assign `4/10` as the label for an edge
+with both flow and maximum capacity set:
+
+```php
+$graph = new Fhaculty\Graph\Graph();
+
+$a = $graph->createVertex('a');
+$b = $graph->createVertex('b');
+
+$edge = $a->createEdgeTo($b);
+$edge->setFlow(4);
+$edge->setCapacity(10);
+```
+
+The following example will automatically assign `4/∞/100` as the label for a
+weighted edge with a flow and unlimited capacity:
+
+```php
+$graph = new Fhaculty\Graph\Graph();
+
+$a = $graph->createVertex('a');
+$b = $graph->createVertex('b');
+
+$edge = $a->createEdgeTo($b);
+$edge->setFlow(4);
+$edge->setCapacity(null);
+$edge->setWeight(100);
+```
+
+You can use [edge attributes](#edge-attributes) to explicitly assign any
+custom `label` attribute. Note that any flow, capacity or weight value will still
+be appended like in the previous examples.
+
+```php
+$graph = new Fhaculty\Graph\Graph();
+
+$a = $graph->createVertex('a');
+$b = $graph->createVertex('b');
+
+$edge = $a->createEdgeTo($b);
+$edge->setAttribute('graphviz.label', 'important');
+```
+
+### HTML-like labels
+
+Note that all [attributes](#attributes) will be quoted and escaped by default,
+so a `>` will appear as-is and will not be interpreted as HTML. GraphViz also
+supports [HTML-like labels](https://graphviz.gitlab.io/_pages/doc/info/shapes.html#html)
+that support a subset of HTML features.
+
+GraphViz requires any HTML-like label to be wrapped in `<` and `>` and only
+supports a limited subset of HTML features as documented above. In order to
+prevent automatic quoting and escaping, all attribute values have to be passed
+to the static `GraphViz::raw()` helper like this:
+
+```php
+$graph = new Fhaculty\Graph\Graph();
+
+$a = $graph->createVertex('Entity');
+$a->setAttribute('graphviz.shape', 'none');
+$a->setAttribute('graphviz.label', GraphViz::raw('<
+<table cellspacing="0" border="0" cellborder="1">
+    <tr><td bgcolor="#eeeeee"><b>\N</b></td></tr>
+    <tr><td></td></tr><tr>
+    <td>+ touch()</td></tr>
+</table>>'));
+
+$b = $graph->createVertex('Block');
+$b->createEdgeTo($a);
+$b->setAttribute('graphviz.shape', 'none');
+$b->setAttribute('graphviz.label', GraphViz::raw('<
+<table cellspacing="0" border="0" cellborder="1">
+    <tr><td bgcolor="#eeeeee"><b>\N</b></td></tr>
+    <tr><td>- size:int</td></tr>
+    <tr><td>+ touch()</td></tr>
+</table>>'));
+```
+
+![UML html graph example](examples/11-uml-html.png)
+
+See also the [examples](examples/).
+
+### Record-based nodes
+
+Note that all [attributes](#attributes) will be quoted and escaped by default,
+so a `>` will appear as-is and will not be interpreted as HTML. Similar to the
+above [HTML-like labels](#html-like-labels), GraphViz also supports simple
+[record-based nodes](https://graphviz.gitlab.io/_pages/doc/info/shapes.html#record)
+using the `record` and `Mrecord` shape attributes and structured label attributes.
+
+GraphViz requires any record-based node label to be quoted, but uses special
+syntax to mark record fields and optional port names. In order to prevent
+automatic quoting and escaping, all attribute values have to be quoted manually
+and passed to the static `GraphViz::raw()` helper like this:
+
+```php
+$graph = new Fhaculty\Graph\Graph();
+
+$a = $graph->createVertex();
+$a->setAttribute('graphviz.shape', 'Mrecord');
+$a->setAttribute('graphviz.label', GraphViz::raw('"<f0> left |<middle> middle |<f2> right"'));
+
+$b = $graph->createVertex();
+$b->setAttribute('graphviz.shape', 'Mrecord');
+$b->setAttribute('graphviz.label', GraphViz::raw('"<f0> left |<f1> middle |<right> right"'));
+
+// a:middle -> b:right
+$edge = $a->createEdgeTo($b);
+$edge->setAttribute('graphviz.tailport', 'middle');
+$edge->setAttribute('graphviz.headport', 'right');
+```
+
+![records with ports graph example](examples/13-record-ports.png)
+
+See also the [examples](examples/).
+
+## Install
+
+The recommended way to install this library is [through Composer](https://getcomposer.org).
+[New to Composer?](https://getcomposer.org/doc/00-intro.md)
+
+This will install the latest supported version:
+
+```bash
+$ composer require graphp/graphviz:^0.2.2
+```
+
+See also the [CHANGELOG](CHANGELOG.md) for details about version upgrades.
+
+This project aims to run on any platform and thus does not require any PHP
+extensions and supports running on legacy PHP 5.3 through current PHP 7+ and
+HHVM.
+It's *highly recommended to use PHP 7+* for this project.
+
+The graph drawing feature is powered by the excellent [GraphViz](https://www.graphviz.org)
+software. This means you'll have to install GraphViz (`dot` executable).
+The [Graphviz homepage](https://www.graphviz.org/download/) includes complete
+installation instructions for most common platforms, users of Debian/Ubuntu-based
+distributions may simply invoke:
+
+```bash
+$ sudo apt install graphviz
+```
+
+## Tests
+
+To run the test suite, you first need to clone this repo and then install all
+dependencies [through Composer](https://getcomposer.org):
+
+```bash
+$ composer install
+```
+
+To run the test suite, go to the project root and run:
+
+```bash
+$ php vendor/bin/phpunit
+```
+
+## License
+
+Released under the terms of the permissive [MIT license](http://opensource.org/licenses/MIT).

vendor/graphp/graphviz/composer.json

@@ -0,0 +1,18 @@
+{
+    "name": "graphp/graphviz",
+    "type": "library",
+    "description": "GraphViz graph drawing for the mathematical graph/network library GraPHP.",
+    "keywords": ["GraphViz", "graph drawing", "graph image", "dot output", "GraPHP"],
+    "homepage": "https://github.com/graphp/graphviz",
+    "license": "MIT",
+    "autoload": {
+        "psr-4": {"Graphp\\GraphViz\\": "src/"}
+    },
+    "require": {
+        "php": ">=5.3.0",
+        "clue/graph": "~0.9.0|~0.8.0"
+    },
+    "require-dev": {
+        "phpunit/phpunit": "^6.4 || ^5.7 || ^4.8.35"
+    }
+}

vendor/graphp/graphviz/examples/01-simple.php

@@ -0,0 +1,17 @@
+<?php
+
+require __DIR__ . '/../vendor/autoload.php';
+
+$graph = new Fhaculty\Graph\Graph();
+
+$blue = $graph->createVertex('blue');
+$blue->setAttribute('graphviz.color', 'blue');
+
+$red = $graph->createVertex('red');
+$red->setAttribute('graphviz.color', 'red');
+
+$edge = $blue->createEdgeTo($red);
+$edge->setAttribute('graphviz.color', 'grey');
+
+$graphviz = new Graphp\GraphViz\GraphViz();
+$graphviz->display($graph);

vendor/graphp/graphviz/examples/02-html.php

@@ -0,0 +1,25 @@
+<?php
+
+// $ php -S localhost:8080 examples/02-html.php
+
+require __DIR__ . '/../vendor/autoload.php';
+
+$graph = new Fhaculty\Graph\Graph();
+$graph->setAttribute('graphviz.graph.rankdir', 'LR');
+
+$hello = $graph->createVertex('hello');
+$world = $graph->createVertex('wörld');
+$hello->createEdgeTo($world);
+
+$graphviz = new Graphp\GraphViz\GraphViz();
+$graphviz->setFormat('svg');
+
+echo '<!DOCTYPE html>
+<html>
+<head>
+<title>hello wörld</title>
+<body>
+' . $graphviz->createImageHtml($graph) . '
+</body>
+</html>
+';

vendor/graphp/graphviz/examples/11-uml-html.php

@@ -0,0 +1,30 @@
+<?php
+
+use Graphp\GraphViz\GraphViz;
+
+require __DIR__ . '/../vendor/autoload.php';
+
+$graph = new Fhaculty\Graph\Graph();
+
+$a = $graph->createVertex('Entity');
+$a->setAttribute('graphviz.shape', 'none');
+$a->setAttribute('graphviz.label', GraphViz::raw('<
+<table cellspacing="0" border="0" cellborder="1">
+    <tr><td bgcolor="#eeeeee"><b>\N</b></td></tr>
+    <tr><td></td></tr><tr>
+    <td>+ touch()</td></tr>
+</table>>'));
+
+$b = $graph->createVertex('Block');
+$b->createEdgeTo($a);
+$b->setAttribute('graphviz.shape', 'none');
+$b->setAttribute('graphviz.label', GraphViz::raw('<
+<table cellspacing="0" border="0" cellborder="1">
+    <tr><td bgcolor="#eeeeee"><b>\N</b></td></tr>
+    <tr><td>- size:int</td></tr>
+    <tr><td>+ touch()</td></tr>
+</table>>'));
+
+$graphviz = new GraphViz();
+echo $graphviz->createScript($graph);
+$graphviz->display($graph);

vendor/graphp/graphviz/examples/12-uml-records.php

@@ -0,0 +1,20 @@
+<?php
+
+use Graphp\GraphViz\GraphViz;
+
+require __DIR__ . '/../vendor/autoload.php';
+
+$graph = new Fhaculty\Graph\Graph();
+
+$a = $graph->createVertex('Entity');
+$a->setAttribute('graphviz.shape', 'record');
+$a->setAttribute('graphviz.label', GraphViz::raw('"{\N||+ touch()}"'));
+
+$b = $graph->createVertex('Block');
+$b->createEdgeTo($a);
+$b->setAttribute('graphviz.shape', 'record');
+$b->setAttribute('graphviz.label', GraphViz::raw('"{\N|- size:int|+ touch()}"'));
+
+$graphviz = new GraphViz();
+echo $graphviz->createScript($graph);
+$graphviz->display($graph);

vendor/graphp/graphviz/examples/13-record-ports.php

@@ -0,0 +1,24 @@
+<?php
+
+use Graphp\GraphViz\GraphViz;
+
+require __DIR__ . '/../vendor/autoload.php';
+
+$graph = new Fhaculty\Graph\Graph();
+
+$a = $graph->createVertex();
+$a->setAttribute('graphviz.shape', 'Mrecord');
+$a->setAttribute('graphviz.label', GraphViz::raw('"<f0> left |<middle> middle |<f2> right"'));
+
+$b = $graph->createVertex();
+$b->setAttribute('graphviz.shape', 'Mrecord');
+$b->setAttribute('graphviz.label', GraphViz::raw('"<f0> left |<f1> middle |<right> right"'));
+
+// a:middle -> b:right
+$edge = $a->createEdgeTo($b);
+$edge->setAttribute('graphviz.tailport', 'middle');
+$edge->setAttribute('graphviz.headport', 'right');
+
+$graphviz = new GraphViz();
+echo $graphviz->createScript($graph);
+$graphviz->display($graph);

vendor/graphp/graphviz/phpunit.xml.dist

@@ -0,0 +1,19 @@
+<?xml version="1.0" encoding="UTF-8"?>
+
+<phpunit bootstrap="vendor/autoload.php"
+         colors="true"
+         convertErrorsToExceptions="true"
+         convertNoticesToExceptions="true"
+         convertWarningsToExceptions="true"
+>
+    <testsuites>
+        <testsuite name="GraphViz Test Suite">
+            <directory>./tests/</directory>
+        </testsuite>
+    </testsuites>
+    <filter>
+        <whitelist>
+            <directory>./src</directory>
+        </whitelist>
+    </filter>
+</phpunit>

vendor/graphp/graphviz/src/Dot.php

@@ -0,0 +1,26 @@
+<?php
+
+namespace Graphp\GraphViz;
+
+use Graphp\GraphViz\GraphViz;
+use Fhaculty\Graph\Graph;
+use Fhaculty\Graph\Exporter\ExporterInterface;
+
+class Dot implements ExporterInterface
+{
+    private $graphviz;
+
+    public function __construct(GraphViz $graphviz = null)
+    {
+        if ($graphviz === null) {
+            $graphviz = new GraphViz();
+        }
+
+        $this->graphviz = $graphviz;
+    }
+
+    public function getOutput(Graph $graph)
+    {
+        return $this->graphviz->createScript($graph);
+    }
+}

vendor/graphp/graphviz/src/GraphViz.php

@@ -0,0 +1,446 @@
+<?php
+
+namespace Graphp\GraphViz;
+
+use Fhaculty\Graph\Attribute\AttributeBagNamespaced;
+use Fhaculty\Graph\Edge\Base as Edge;
+use Fhaculty\Graph\Edge\Directed as EdgeDirected;
+use Fhaculty\Graph\Exception\UnexpectedValueException;
+use Fhaculty\Graph\Graph;
+use Fhaculty\Graph\Vertex;
+
+class GraphViz
+{
+    /**
+     * file output format to use
+     *
+     * @var string
+     * @see GraphViz::setFormat()
+     */
+    private $format = 'png';
+
+    /**
+     * Either the name of full path to GraphViz layout.
+     *
+     * @var string
+     * @see GraphViz::setExecutable()
+     */
+    private $executable = 'dot';
+
+    /**
+     * string to use as indentation for dot output
+     *
+     * @var string
+     * @see GraphViz::createScript()
+     */
+    private $formatIndent = '  ';
+
+    const DELAY_OPEN = 2.0;
+
+    const EOL = PHP_EOL;
+
+    public function __construct()
+    {
+        if (strtoupper(substr(PHP_OS, 0, 3)) === 'WIN') {
+            $this->executable = 'dot.exe';
+        }
+    }
+
+    /**
+     * Change the executable to use.
+     *
+     * Usually, your graphviz executables should be located in your $PATH
+     * environment variable and invoking a mere `dot` is sufficient. If you
+     * have no access to your $PATH variable, use this method to set the path
+     * to your graphviz dot executable.
+     *
+     * This should contain '.exe' on windows.
+     * - /full/path/to/bin/dot
+     * - neato
+     * - dot.exe
+     * - c:\path\to\bin\dot.exe
+     *
+     * @param string $executable
+     * @return GraphViz $this (chainable)
+     */
+    public function setExecutable($executable) {
+        $this->executable = $executable;
+
+        return $this;
+    }
+
+    /**
+     * return executable to use
+     *
+     * @return string
+     * @see GraphViz::setExecutable()
+     */
+    public function getExecutable() {
+        return $this->executable;
+    }
+
+    /**
+     * set graph image output format
+     *
+     * @param  string   $format png, svg, ps2, etc. (see 'man dot' for details on parameter '-T')
+     * @return GraphViz $this (chainable)
+     */
+    public function setFormat($format)
+    {
+        $this->format = $format;
+
+        return $this;
+    }
+
+    /**
+     * create and display image for this graph
+     *
+     * @param Graph $graph graph to display
+     * @return void
+     * @uses GraphViz::createImageFile()
+     */
+    public function display(Graph $graph)
+    {
+        // echo "Generate picture ...";
+        $tmp = $this->createImageFile($graph);
+
+        static $next = 0;
+        if ($next > microtime(true)) {
+            // wait some time between calling xdg-open because earlier calls will be ignored otherwise
+            //echo '[delay flooding xdg-open]' . PHP_EOL;
+            sleep(self::DELAY_OPEN);
+        }
+
+        if (strtoupper(substr(PHP_OS, 0, 3)) === 'WIN') {
+            // open image in untitled, temporary background shell
+            exec('start "" ' . escapeshellarg($tmp) . ' >NUL');
+        } elseif (strtoupper(PHP_OS) === 'DARWIN') {
+            // open image in background (redirect stdout to /dev/null, sterr to stdout and run in background)
+            exec('open ' . escapeshellarg($tmp) . ' > /dev/null 2>&1 &');
+        } else {
+            // open image in background (redirect stdout to /dev/null, sterr to stdout and run in background)
+            exec('xdg-open ' . escapeshellarg($tmp) . ' > /dev/null 2>&1 &');
+        }
+
+        $next = microtime(true) + self::DELAY_OPEN;
+        // echo "... done\n";
+    }
+
+    /**
+     * create image file data contents for this graph
+     *
+     * @param Graph $graph graph to display
+     * @return string
+     * @uses GraphViz::createImageFile()
+     */
+    public function createImageData(Graph $graph)
+    {
+        $file = $this->createImageFile($graph);
+        $data = file_get_contents($file);
+        unlink($file);
+
+        return $data;
+    }
+
+    /**
+     * create base64-encoded image src target data to be used for html images
+     *
+     * @param Graph $graph graph to display
+     * @return string
+     * @uses GraphViz::createImageData()
+     */
+    public function createImageSrc(Graph $graph)
+    {
+        $format = $this->format;
+        if ($this->format === 'svg' || $this->format === 'svgz') {
+            $format = 'svg+xml;charset=' . $graph->getAttribute('graphviz.graph.charset', 'UTF-8');
+        }
+
+        return 'data:image/' . $format . ';base64,' . base64_encode($this->createImageData($graph));
+    }
+
+    /**
+     * create image html code for this graph
+     *
+     * @param Graph $graph graph to display
+     * @return string
+     * @uses GraphViz::createImageSrc()
+     */
+    public function createImageHtml(Graph $graph)
+    {
+        if ($this->format === 'svg' || $this->format === 'svgz') {
+            return '<object type="image/svg+xml" data="' . $this->createImageSrc($graph) . '"></object>';
+        }
+
+        return '<img src="' . $this->createImageSrc($graph) . '" />';
+    }
+
+    /**
+     * create image file for this graph
+     *
+     * @param Graph $graph graph to display
+     * @return string                   filename
+     * @throws UnexpectedValueException on error
+     * @uses GraphViz::createScript()
+     */
+    public function createImageFile(Graph $graph)
+    {
+        $script = $this->createScript($graph);
+        // var_dump($script);
+
+        $tmp = tempnam(sys_get_temp_dir(), 'graphviz');
+        if ($tmp === false) {
+            throw new UnexpectedValueException('Unable to get temporary file name for graphviz script');
+        }
+
+        $ret = file_put_contents($tmp, $script, LOCK_EX);
+        if ($ret === false) {
+            throw new UnexpectedValueException('Unable to write graphviz script to temporary file');
+        }
+
+        $ret = 0;
+
+        $executable = $this->getExecutable();
+        system(escapeshellarg($executable) . ' -T ' . escapeshellarg($this->format) . ' ' . escapeshellarg($tmp) . ' -o ' . escapeshellarg($tmp . '.' . $this->format), $ret);
+        if ($ret !== 0) {
+            throw new UnexpectedValueException('Unable to invoke "' . $executable .'" to create image file (code ' . $ret . ')');
+        }
+
+        unlink($tmp);
+
+        return $tmp . '.' . $this->format;
+    }
+
+    /**
+     * create graphviz script representing this graph
+     *
+     * @param Graph $graph graph to display
+     * @return string
+     * @uses Directed::hasDirected()
+     * @uses Graph::getVertices()
+     * @uses Graph::getEdges()
+     */
+    public function createScript(Graph $graph)
+    {
+        $directed = false;
+        foreach ($graph->getEdges() as $edge) {
+            if ($edge instanceof EdgeDirected) {
+                $directed = true;
+                break;
+            }
+        }
+
+        /*
+         * The website [http://www.graphviz.org/content/dot-language] uses the term `ID` when displaying
+         * the abstract grammar for the DOT language.
+         * But the man pages for dot use the term `name` when describing the graph file language.
+         */
+        $name = $graph->getAttribute('graphviz.name');
+        if ($name !== null) {
+            $name = $this->escapeId($name) . ' ';
+        }
+
+        $script = ($directed ? 'di':'') . 'graph ' . $name . '{' . self::EOL;
+
+        // add global attributes
+        $globals = array(
+            'graph' => 'graphviz.graph.',
+            'node'  => 'graphviz.node.',
+            'edge'  => 'graphviz.edge.',
+        );
+
+        foreach ($globals as $key => $prefix) {
+            $bag = new AttributeBagNamespaced($graph, $prefix);
+
+            if ($layout = $bag->getAttributes()) {
+                $script .= $this->formatIndent . $key . ' ' . $this->escapeAttributes($layout) . self::EOL;
+            }
+        }
+
+        $groups = array();
+        foreach ($graph->getVertices()->getMap() as $vid => $vertex) {
+            $groups[$vertex->getGroup()][$vid] = $vertex;
+        }
+
+        // only cluster vertices into groups if there are at least 2 different groups
+        if (count($groups) > 1) {
+            $indent = str_repeat($this->formatIndent, 2);
+            // put each group of vertices in a separate subgraph cluster
+            foreach ($groups as $group => $vertices) {
+                $script .= $this->formatIndent . 'subgraph cluster_' . $group . ' {' . self::EOL .
+                           $indent . 'label = ' . $this->escape($group) . self::EOL;
+                foreach ($vertices as $vid => $vertex) {
+                    $layout = $this->getLayoutVertex($vertex);
+
+                    $script .= $indent . $this->escapeId($vid);
+                    if ($layout) {
+                        $script .= ' ' . $this->escapeAttributes($layout);
+                    }
+                    $script .= self::EOL;
+                }
+                $script .= '  }' . self::EOL;
+            }
+        } else {
+            // explicitly add all isolated vertices (vertices with no edges) and vertices with special layout set
+            // other vertices wil be added automatically due to below edge definitions
+            foreach ($graph->getVertices()->getMap() as $vid => $vertex){
+                $layout = $this->getLayoutVertex($vertex);
+
+                if ($layout || $vertex->getEdges()->isEmpty()) {
+                    $script .= $this->formatIndent . $this->escapeId($vid);
+                    if ($layout) {
+                        $script .= ' ' . $this->escapeAttributes($layout);
+                    }
+                    $script .= self::EOL;
+                }
+            }
+        }
+
+        $edgeop = $directed ? ' -> ' : ' -- ';
+
+        // add all edges as directed edges
+        foreach ($graph->getEdges() as $currentEdge) {
+            $both = $currentEdge->getVertices()->getVector();
+            $currentStartVertex = $both[0];
+            $currentTargetVertex = $both[1];
+
+            $script .= $this->formatIndent . $this->escapeId($currentStartVertex->getId()) . $edgeop . $this->escapeId($currentTargetVertex->getId());
+
+            $layout = $this->getLayoutEdge($currentEdge);
+
+            // this edge is not a loop and also points to the opposite direction => this is actually an undirected edge
+            if ($directed && $currentStartVertex !== $currentTargetVertex && $currentEdge->isConnection($currentTargetVertex, $currentStartVertex)) {
+                $layout['dir'] = 'none';
+            }
+            if ($layout) {
+                $script .= ' ' . $this->escapeAttributes($layout);
+            }
+
+            $script .= self::EOL;
+        }
+        $script .= '}' . self::EOL;
+
+        return $script;
+    }
+
+    /**
+     * escape given id string and wrap in quotes if needed
+     *
+     * @param  string $id
+     * @return string
+     * @link http://graphviz.org/content/dot-language
+     */
+    private function escapeId($id)
+    {
+        return self::escape($id);
+    }
+
+    public static function escape($id)
+    {
+        // see raw()
+        if ($id instanceof \stdClass && isset($id->string)) {
+            return $id->string;
+        }
+        // see @link: There is no semantic difference between abc_2 and "abc_2"
+        // numeric or simple string, no need to quote (only for simplicity)
+        if (preg_match('/^(?:\-?(?:\.\d+|\d+(?:\.\d+)?))$/i', $id)) {
+            return $id;
+        }
+
+        return '"' . str_replace(array('&', '<', '>', '"', "'", '\\', "\n"), array('&amp;', '&lt;', '&gt;', '&quot;', '&apos;', '\\\\', '\\l'), $id) . '"';
+    }
+
+    /**
+     * get escaped attribute string for given array of (unescaped) attributes
+     *
+     * @param  array  $attrs
+     * @return string
+     * @uses GraphViz::escapeId()
+     */
+    private function escapeAttributes($attrs)
+    {
+        $script = '[';
+        $first = true;
+        foreach ($attrs as $name => $value) {
+            if ($first) {
+                $first = false;
+            } else {
+                $script .= ' ';
+            }
+            $script .= $name . '=' . self::escape($value);
+        }
+        $script .= ']';
+
+        return $script;
+    }
+
+    /**
+     * create a raw string representation, i.e. do NOT escape the given string when used in graphviz output
+     *
+     * @param  string   $string
+     * @return \stdClass
+     * @see GraphViz::escape()
+     */
+    public static function raw($string)
+    {
+        return (object) array('string' => $string);
+    }
+
+    protected function getLayoutVertex(Vertex $vertex)
+    {
+        $bag = new AttributeBagNamespaced($vertex, 'graphviz.');
+        $layout = $bag->getAttributes();
+
+        $balance = $vertex->getBalance();
+        if($balance !== NULL){
+            if($balance > 0){
+                $balance = '+' . $balance;
+            }
+            if(!isset($layout['label'])){
+                $layout['label'] = $vertex->getId();
+            }
+            $layout['label'] .= ' (' . $balance . ')';
+        }
+
+        return $layout;
+    }
+
+    protected function getLayoutEdge(Edge $edge)
+    {
+        $bag = new AttributeBagNamespaced($edge, 'graphviz.');
+        $layout = $bag->getAttributes();
+
+        // use flow/capacity/weight as edge label
+        $label = NULL;
+
+        $flow = $edge->getFlow();
+        $capacity = $edge->getCapacity();
+        // flow is set
+        if ($flow !== NULL) {
+            // NULL capacity = infinite capacity
+            $label = $flow . '/' . ($capacity === NULL ? '∞' : $capacity);
+            // capacity set, but not flow (assume zero flow)
+        } elseif ($capacity !== NULL) {
+            $label = '0/' . $capacity;
+        }
+
+        $weight = $edge->getWeight();
+        // weight is set
+        if ($weight !== NULL) {
+            if ($label === NULL) {
+                $label = $weight;
+            } else {
+                $label .= '/' . $weight;
+            }
+        }
+
+        if ($label !== NULL) {
+            if (isset($layout['label'])) {
+                $layout['label'] .= ' ' . $label;
+            } else {
+                $layout['label'] = $label;
+            }
+        }
+        return $layout;
+    }
+}

vendor/graphp/graphviz/src/Image.php

@@ -0,0 +1,40 @@
+<?php
+
+namespace Graphp\GraphViz;
+
+use Graphp\GraphViz\GraphViz;
+use Fhaculty\Graph\Graph;
+use Fhaculty\Graph\Exporter\ExporterInterface;
+
+class Image implements ExporterInterface
+{
+    private $graphviz;
+
+    public function __construct(GraphViz $graphviz = null)
+    {
+        if ($graphviz === null) {
+            $graphviz = new GraphViz();
+            $graphviz->setFormat('png');
+        }
+
+        $this->graphviz = $graphviz;
+    }
+
+    public function getOutput(Graph $graph)
+    {
+        return $this->graphviz->createImageData($graph);
+    }
+
+    /**
+     * set the image output format to use
+     *
+     * @param string $type png, svg
+     * @return self $this (chainable)
+     * @uses GraphViz::setFormat()
+     */
+    public function setFormat($type)
+    {
+        $this->graphviz->setFormat($type);
+        return $this;
+    }
+}

vendor/graphp/graphviz/tests/GraphVizTest.php

@@ -0,0 +1,386 @@
+<?php
+
+use Fhaculty\Graph\Graph;
+use Graphp\GraphViz\GraphViz;
+use PHPUnit\Framework\TestCase;
+
+class GraphVizTest extends TestCase
+{
+    private $graphViz;
+
+    public function setUp()
+    {
+        $this->graphViz = new GraphViz();
+    }
+
+    public function testGraphEmpty()
+    {
+        $graph = new Graph();
+
+        $expected = <<<VIZ
+graph {
+}
+
+VIZ;
+
+        $this->assertEquals($expected, $this->graphViz->createScript($graph));
+    }
+
+    public function testGraphWithName()
+    {
+        $graph = new Graph();
+        $graph->setAttribute('graphviz.name', 'G');
+
+                $expected = <<<VIZ
+graph "G" {
+}
+
+VIZ;
+
+        $this->assertEquals($expected, $this->graphViz->createScript($graph));
+    }
+
+    public function testGraphWithNameWithSpaces()
+    {
+        $graph = new Graph();
+        $graph->setAttribute('graphviz.name', 'My Graph Name');
+
+                $expected = <<<VIZ
+graph "My Graph Name" {
+}
+
+VIZ;
+
+        $this->assertEquals($expected, $this->graphViz->createScript($graph));
+    }
+
+    public function testGraphIsolatedVertices()
+    {
+        $graph = new Graph();
+        $graph->createVertex('a');
+        $graph->createVertex('b');
+
+        $expected = <<<VIZ
+graph {
+  "a"
+  "b"
+}
+
+VIZ;
+
+        $this->assertEquals($expected, $this->graphViz->createScript($graph));
+    }
+
+    public function testGraphIsolatedVerticesWithGroupsWillBeAddedToClusters()
+    {
+        $graph = new Graph();
+        $graph->createVertex('a')->setGroup(0);
+        $graph->createVertex('b')->setGroup(1)->setAttribute('graphviz.label', 'second');
+
+        $expected = <<<VIZ
+graph {
+  subgraph cluster_0 {
+    label = 0
+    "a"
+  }
+  subgraph cluster_1 {
+    label = 1
+    "b" [label="second"]
+  }
+}
+
+VIZ;
+
+        $this->assertEquals($expected, $this->graphViz->createScript($graph));
+    }
+
+    public function testGraphDefaultAttributes()
+    {
+        $graph = new Graph();
+        $graph->setAttribute('graphviz.graph.bgcolor', 'transparent');
+        $graph->setAttribute('graphviz.node.color', 'blue');
+        $graph->setAttribute('graphviz.edge.color', 'grey');
+
+        $expected = <<<VIZ
+graph {
+  graph [bgcolor="transparent"]
+  node [color="blue"]
+  edge [color="grey"]
+}
+
+VIZ;
+
+        $this->assertEquals($expected, $this->graphViz->createScript($graph));
+    }
+
+    public function testUnknownGraphAttributesWillBeDiscarded()
+    {
+        $graph = new Graph();
+        $graph->setAttribute('graphviz.vertex.color', 'blue');
+        $graph->setAttribute('graphviz.unknown.color', 'red');
+
+        $expected = <<<VIZ
+graph {
+}
+
+VIZ;
+
+        $this->assertEquals($expected, $this->graphViz->createScript($graph));
+    }
+
+    public function testEscaping()
+    {
+        $graph = new Graph();
+        $graph->createVertex('a');
+        $graph->createVertex('b¹²³ is; ok\\ay, "right"?');
+        $graph->createVertex(3);
+        $graph->createVertex(4)->setAttribute('graphviz.label', 'normal');
+        $graph->createVertex(5)->setAttribute('graphviz.label', GraphViz::raw('<raw>'));
+
+
+        $expected = <<<VIZ
+graph {
+  "a"
+  "b¹²³ is; ok\\\\ay, &quot;right&quot;?"
+  3
+  4 [label="normal"]
+  5 [label=<raw>]
+}
+
+VIZ;
+
+        $this->assertEquals($expected, $this->graphViz->createScript($graph));
+    }
+
+    public function testGraphWithSimpleEdgeUsesGraphWithSimpleEdgeDefinition()
+    {
+        // a -- b
+        $graph = new Graph();
+        $graph->createVertex('a')->createEdge($graph->createVertex('b'));
+
+        $expected = <<<VIZ
+graph {
+  "a" -- "b"
+}
+
+VIZ;
+
+        $this->assertEquals($expected, $this->graphViz->createScript($graph));
+    }
+
+    public function testGraphWithLoopUsesGraphWithSimpleLoopDefinition()
+    {
+        // a -- b -\
+        //      |  |
+        //      \--/
+        $graph = new Graph();
+        $graph->createVertex('a')->createEdge($graph->createVertex('b'));
+        $graph->getVertex('b')->createEdge($graph->getVertex('b'));
+
+        $expected = <<<VIZ
+graph {
+  "a" -- "b"
+  "b" -- "b"
+}
+
+VIZ;
+
+        $this->assertEquals($expected, $this->graphViz->createScript($graph));
+    }
+
+    public function testGraphDirectedUsesDigraph()
+    {
+        $graph = new Graph();
+        $graph->createVertex('a')->createEdgeTo($graph->createVertex('b'));
+
+        $expected = <<<VIZ
+digraph {
+  "a" -> "b"
+}
+
+VIZ;
+
+        $this->assertEquals($expected, $this->graphViz->createScript($graph));
+    }
+
+    public function testGraphDirectedWithLoopUsesDigraphWithSimpleLoopDefinition()
+    {
+        // a -> b -\
+        //      ^  |
+        //      \--/
+        $graph = new Graph();
+        $graph->createVertex('a')->createEdgeTo($graph->createVertex('b'));
+        $graph->getVertex('b')->createEdgeTo($graph->getVertex('b'));
+
+        $expected = <<<VIZ
+digraph {
+  "a" -> "b"
+  "b" -> "b"
+}
+
+VIZ;
+
+        $this->assertEquals($expected, $this->graphViz->createScript($graph));
+    }
+
+    public function testGraphMixedUsesDigraphWithExplicitDirectionNoneForUndirectedEdges()
+    {
+        // a -> b -- c
+        $graph = new Graph();
+        $graph->createVertex('a')->createEdgeTo($graph->createVertex('b'));
+        $graph->createVertex('c')->createEdge($graph->getVertex('b'));
+
+        $expected = <<<VIZ
+digraph {
+  "a" -> "b"
+  "c" -> "b" [dir="none"]
+}
+
+VIZ;
+
+        $this->assertEquals($expected, $this->graphViz->createScript($graph));
+    }
+
+    public function testGraphMixedWithDirectedLoopUsesDigraphWithoutDirectionForDirectedLoop()
+    {
+        // a -- b -\
+        //      ^  |
+        //      \--/
+        $graph = new Graph();
+        $graph->createVertex('a')->createEdge($graph->createVertex('b'));
+        $graph->getVertex('b')->createEdgeTo($graph->getVertex('b'));
+
+        $expected = <<<VIZ
+digraph {
+  "a" -> "b" [dir="none"]
+  "b" -> "b"
+}
+
+VIZ;
+
+        $this->assertEquals($expected, $this->graphViz->createScript($graph));
+    }
+
+    public function testGraphUndirectedWithIsolatedVerticesFirst()
+    {
+        // a -- b -- c   d
+        $graph = new Graph();
+        $graph->createVertices(array('a', 'b', 'c', 'd'));
+        $graph->getVertex('a')->createEdge($graph->getVertex('b'));
+        $graph->getVertex('b')->createEdge($graph->getVertex('c'));
+
+        $expected = <<<VIZ
+graph {
+  "d"
+  "a" -- "b"
+  "b" -- "c"
+}
+
+VIZ;
+
+        $this->assertEquals($expected, $this->graphViz->createScript($graph));
+    }
+
+    public function testVertexLabels()
+    {
+        $graph = new Graph();
+        $graph->createVertex('a')->setBalance(1);
+        $graph->createVertex('b')->setBalance(0);
+        $graph->createVertex('c')->setBalance(-1);
+        $graph->createVertex('d')->setAttribute('graphviz.label', 'test');
+        $graph->createVertex('e')->setBalance(2)->setAttribute('graphviz.label', 'unnamed');
+
+        $expected = <<<VIZ
+graph {
+  "a" [label="a (+1)"]
+  "b" [label="b (0)"]
+  "c" [label="c (-1)"]
+  "d" [label="test"]
+  "e" [label="unnamed (+2)"]
+}
+
+VIZ;
+
+        $this->assertEquals($expected, $this->graphViz->createScript($graph));
+    }
+
+    public function testEdgeLayoutAtributes()
+    {
+        $graph = new Graph();
+        $graph->createVertex('1a')->createEdge($graph->createVertex('1b'));
+        $graph->createVertex('2a')->createEdge($graph->createVertex('2b'))->setAttribute('graphviz.numeric', 20);
+        $graph->createVertex('3a')->createEdge($graph->createVertex('3b'))->setAttribute('graphviz.textual', "forty");
+        $graph->createVertex('4a')->createEdge($graph->createVertex('4b'))->getAttributeBag()->setAttributes(array('graphviz.1' => 1, 'graphviz.2' => 2));
+        $graph->createVertex('5a')->createEdge($graph->createVertex('5b'))->getAttributeBag()->setAttributes(array('graphviz.a' => 'b', 'graphviz.c' => 'd'));
+
+        $expected = <<<VIZ
+graph {
+  "1a" -- "1b"
+  "2a" -- "2b" [numeric=20]
+  "3a" -- "3b" [textual="forty"]
+  "4a" -- "4b" [1=1 2=2]
+  "5a" -- "5b" [a="b" c="d"]
+}
+
+VIZ;
+
+        $this->assertEquals($expected, $this->graphViz->createScript($graph));
+    }
+
+    public function testEdgeLabels()
+    {
+        $graph = new Graph();
+        $graph->createVertex('1a')->createEdge($graph->createVertex('1b'));
+        $graph->createVertex('2a')->createEdge($graph->createVertex('2b'))->setWeight(20);
+        $graph->createVertex('3a')->createEdge($graph->createVertex('3b'))->setCapacity(30);
+        $graph->createVertex('4a')->createEdge($graph->createVertex('4b'))->setFlow(40);
+        $graph->createVertex('5a')->createEdge($graph->createVertex('5b'))->setFlow(50)->setCapacity(60);
+        $graph->createVertex('6a')->createEdge($graph->createVertex('6b'))->setFlow(60)->setCapacity(70)->setWeight(80);
+        $graph->createVertex('7a')->createEdge($graph->createVertex('7b'))->setFlow(70)->setAttribute('graphviz.label', 'prefixed');
+
+        $expected = <<<VIZ
+graph {
+  "1a" -- "1b"
+  "2a" -- "2b" [label=20]
+  "3a" -- "3b" [label="0/30"]
+  "4a" -- "4b" [label="40/∞"]
+  "5a" -- "5b" [label="50/60"]
+  "6a" -- "6b" [label="60/70/80"]
+  "7a" -- "7b" [label="prefixed 70/∞"]
+}
+
+VIZ;
+
+        $this->assertEquals($expected, $this->graphViz->createScript($graph));
+    }
+
+    public function testCreateImageSrcWillExportPngDefaultFormat()
+    {
+        $graph = new Graph();
+
+        $src = $this->graphViz->createImageSrc($graph);
+
+        $this->assertStringStartsWith('data:image/png;base64,', $src);
+    }
+
+    public function testCreateImageSrcAsSvgWithUtf8DefaultCharset()
+    {
+        $graph = new Graph();
+
+        $this->graphViz->setFormat('svg');
+        $src = $this->graphViz->createImageSrc($graph);
+
+        $this->assertStringStartsWith('data:image/svg+xml;charset=UTF-8;base64,', $src);
+    }
+
+    public function testCreateImageSrcAsSvgzWithExplicitIsoCharsetLatin1()
+    {
+        $graph = new Graph();
+        $graph->setAttribute('graphviz.graph.charset', 'iso-8859-1');
+
+        $this->graphViz->setFormat('svgz');
+        $src = $this->graphViz->createImageSrc($graph);
+
+        $this->assertStringStartsWith('data:image/svg+xml;charset=iso-8859-1;base64,', $src);
+    }
+}