Introduce blur effect (contao#9)

src/Effects.php

@@ -0,0 +1,65 @@
+<?php
+
+
+namespace Contao\ImagineSvg;
+
+
+use Imagine\Effects\EffectsInterface;
+use Imagine\Exception\RuntimeException;
+use Imagine\Image\Palette\Color\ColorInterface;
+
+class Effects implements EffectsInterface
+{
+
+    /** @var Image */
+    private $image;
+
+    public function __construct(Image $image)
+    {
+        $this->image = $image;
+    }
+
+    public function gamma($correction)
+    {
+        throw new RuntimeException('This method is not implemented');
+
+        // TODO: Implement gamma() method.
+    }
+
+    public function negative()
+    {
+        throw new RuntimeException('This method is not implemented');
+        // TODO: Implement negative() method.
+    }
+
+    public function grayscale()
+    {
+        throw new RuntimeException('This method is not implemented');
+        // TODO: Implement grayscale() method.
+    }
+
+    public function colorize(ColorInterface $color)
+    {
+        throw new RuntimeException('This method is not implemented');
+        // TODO: Implement colorize() method.
+    }
+
+    public function sharpen()
+    {
+        throw new RuntimeException('This method is not implemented');
+        // TODO: Implement sharpen() method.
+    }
+
+    public function blur($sigma)
+    {
+
+        $dom = $this->image->getDomDocument();
+        $dom->documentElement->setAttribute("filter", "url(#rokkaBlur)");
+        $filter = $dom->createDocumentFragment();
+        $filter->appendXML('<filter id="rokkaBlur">
+                <feGaussianBlur in="SourceGraphic" stdDeviation="'.$sigma.'" />
+        </filter>');
+        $dom->documentElement->insertBefore($filter, $dom->documentElement->firstChild);
+    }
+
+}

src/Image.php

@@ -292,7 +292,7 @@ public function draw()
      */
     public function effects()
     {
-        throw new RuntimeException('This method is not implemented');
+        return new Effects($this);
     }
 
     /**