Improves truncate twig filter (#12347)

* respect encoded entities in truncate filter

* adds some simple tests

1 files changed, 3 insertions, 3 deletions

diff --git a/core/Twig.php b/core/Twig.php
index c36452055b..24fd09eec2 100755
--- a/core/Twig.php
+++ b/core/Twig.php
@@ -25,11 +25,11 @@ use Twig_SimpleTest;
 
 function piwik_filter_truncate($string, $size)
 {
-    if (strlen($string) < $size) {
+    if (Common::mb_strlen(html_entity_decode($string)) <= $size) {
         return $string;
     } else {
-        $array = str_split($string, $size);
-        return array_shift($array) . "...";
+        preg_match('/^(&(?:[a-z\d]+|#\d+|#x[a-f\d]+);|.){'.$size.'}/i', $string, $shortenString);
+        return reset($shortenString) . "...";
     }
 }