Added watermark functionality and unit tests

src/FFMpeg/Filters/Video/VideoFilters.php

@@ -103,4 +103,17 @@ class VideoFilters extends AudioFilters
 
         return $this;
     }
+
+    /**
+     * @param string $imagePath
+     * @param array $coordinates
+     *
+     * @return $this
+     */
+    public function watermark($imagePath, array $coordinates = array())
+    {
+        $this->media->addFilter(new WatermarkFilter($imagePath, $coordinates));
+
+        return $this;
+    }
 }

src/FFMpeg/Filters/Video/WatermarkFilter.php

@@ -0,0 +1,81 @@
+<?php
+
+/*
+ * This file is part of PHP-FFmpeg.
+ *
+ * (c) Alchemy <dev.team@alchemy.fr>
+ *
+ * For the full copyright and license information, please view the LICENSE
+ * file that was distributed with this source code.
+ */
+
+namespace FFMpeg\Filters\Video;
+
+use FFMpeg\Format\VideoInterface;
+use FFMpeg\Media\Video;
+use FFMpeg\Coordinate\TimeCode;
+
+class WatermarkFilter implements VideoFilterInterface
+{
+    /** @var string */
+    private $watermarkPath;
+    /** @var array */
+    private $coordinates;
+    /** @var integer */
+    private $priority;
+
+
+    public function __construct($watermarkPath, array $coordinates = array(), $priority = 0)
+    {
+        $this->watermarkPath = $watermarkPath;
+        $this->coordinates = $coordinates;
+        $this->priority = $priority;
+    }
+
+    /**
+     * {@inheritdoc}
+     */
+    public function getPriority()
+    {
+        return $this->priority;
+    }
+
+    /**
+     * {@inheritdoc}
+     */
+    public function apply(Video $video, VideoInterface $format)
+    {
+        $position = isset($this->coordinates['position']) ? $this->coordinates['position'] : 'absolute';
+
+        switch($position) {
+            case 'relative':
+                if (isset($this->coordinates['top'])) {
+                    $y = $this->coordinates['top'];
+                }
+                elseif (isset($this->coordinates['bottom'])) {
+                    $y = sprintf('main_h - %d - overlay_h', $this->coordinates['bottom']);
+                }
+                else {
+                    $y = 0;
+                }
+
+                if (isset($this->coordinates['left'])) {
+                    $x = $this->coordinates['left'];
+                }
+                elseif (isset($this->coordinates['right'])) {
+                    $x = sprintf('main_w - %d - overlay_w', $this->coordinates['right']);
+                }
+                else {
+                    $x = 0;
+                }
+
+                break;
+            default:
+                $x = isset($this->coordinates['x']) ? $this->coordinates['x'] : 0;
+                $y = isset($this->coordinates['y']) ? $this->coordinates['y'] : 0;
+                break;
+        }
+
+        return array('-vf', sprintf('overlay %s:%s', $x, $y));
+    }
+}