Add Img.php view helper

refs #4301

application/views/helpers/Img.php

@@ -0,0 +1,29 @@
+<?php
+
+// TODO: Search for the best and safest quoting
+// TODO: Check whether attributes are safe. Script, title in combination with
+//       Hover-Tips etc. Eventually create a whitelist for a few options only.
+class Zend_View_Helper_Img extends Zend_View_Helper_Abstract
+{
+    public function img($url, array $properties = array())
+    {
+        $attributes = array();
+        $has_alt = false;
+        foreach ($properties as $key => $val) {
+            if ($key === 'alt') $has_alt = true;
+            $attributes[] = sprintf(
+                '%s="%s"',
+                filter_var($key, FILTER_SANITIZE_URL),
+                filter_var($val, FILTER_SANITIZE_FULL_SPECIAL_CHARS)
+            );
+        }
+        if (! $has_alt) $attributes[] = 'alt=""';
+
+        return sprintf(
+            '<img src="%s"%s />',
+            $this->view->baseUrl($url),
+            !empty($attributes) ? ' ' . implode(' ', $attributes) : ''
+        );
+    }
+}
+