added an "auto_rotate" filter based on exif data

Imagine/Filter/Loader/AutoRotateFilterLoader.php

@@ -0,0 +1,58 @@
+<?php
+
+namespace Liip\ImagineBundle\Imagine\Filter\Loader;
+
+use Imagine\Image\ImageInterface;
+
+/**
+ * AutoRotateFilterLoader - rotates an Image based on its EXIF Data
+ *
+ * @author Robert Schönthal <robert.schoenthal@gmail.com>
+ */
+class AutoRotateFilterLoader implements LoaderInterface
+{
+    /**
+     * {@inheritDoc}
+     */
+    public function load(ImageInterface $image, array $options = array())
+    {
+        $exifData = exif_read_data("data://image/jpeg;base64," . base64_encode($image->get('jpg')));
+
+        if (isset($exifData['Orientation'])) {
+            $orientation = (int) $exifData['Orientation'];
+            $degree = $this->calculateRotation($orientation);
+
+            if ($degree !== 0) {
+                $image->rotate($degree);
+            }
+        }
+
+        return $image;
+    }
+
+    /**
+     * calculates to rotation degree from the EXIF Orientation
+     *
+     * @param  int $orientation
+     * @return int
+     */
+    private function calculateRotation($orientation)
+    {
+        switch ($orientation) {
+            case 8:
+                $degree = -90;
+                break;
+            case 3:
+                $degree = 180;
+                break;
+            case 6:
+                $degree = 90;
+                break;
+            default:
+                $degree = 0;
+                break;
+        }
+
+        return $degree;
+    }
+}

Resources/config/imagine.xml

@@ -42,6 +42,7 @@
         <parameter key="liip_imagine.filter.loader.strip.class">Liip\ImagineBundle\Imagine\Filter\Loader\StripFilterLoader</parameter>
         <parameter key="liip_imagine.filter.loader.background.class">Liip\ImagineBundle\Imagine\Filter\Loader\BackgroundFilterLoader</parameter>
         <parameter key="liip_imagine.filter.loader.upscale.class">Liip\ImagineBundle\Imagine\Filter\Loader\UpscaleFilterLoader</parameter>
+        <parameter key="liip_imagine.filter.loader.auto_rotate.class">Liip\ImagineBundle\Imagine\Filter\Loader\AutoRotateFilterLoader</parameter>
 
         <!-- Data loaders' classes -->
 
@@ -165,6 +166,10 @@
             <tag name="liip_imagine.filter.loader" loader="upscale" />
         </service>
 
+        <service id="liip_imagine.filter.loader.auto_rotate" class="%liip_imagine.filter.loader.auto_rotate.class%">
+            <tag name="liip_imagine.filter.loader" loader="auto_rotate" />
+        </service>
+
         <!-- Data loaders -->
 
         <service id="liip_imagine.data.loader.filesystem" class="%liip_imagine.data.loader.filesystem.class%">

Resources/doc/filters.md

@@ -125,6 +125,18 @@ liip_image:
                 position: center
 ```
 
+### The `auto_rotate` filter
+
+The auto_rotate filter rotates the image based on its EXIF data. **(this filter should be called as early as possible)**
+Configuration looks like this:
+
+``` yaml
+liip_imagine:
+    filter_sets:
+        my_thumb:
+            filters:
+                auto_rotate: ~
+```
 ## Load your Custom Filters
 
 The ImagineBundle allows you to load your own custom filter classes. The only