Check if imageflip is available

* imageflip() isn't available in PHP < 5.5
* fixes #14130

diff --git a/lib/private/image.php b/lib/private/image.php
index f5f9a04facce527dadb5f6b2afc52e3336e50653..317b6fde16058e97a4ea18dd64991c1543bfd0dd 100644 (file)
--- a/lib/private/image.php
+++ b/lib/private/image.php
@@ -391,7 +391,7 @@ class OC_Image {
                                $rotate = 90;
                                break;
                }
-               if($flip) {
+               if($flip && function_exists('imageflip')) {
                        imageflip($this->resource, IMG_FLIP_HORIZONTAL);
                }
                if ($rotate) {