From adfcc62e644f1fe6ce24f5392803cebdf9a02760 Mon Sep 17 00:00:00 2001
From: Sam Sullivan <samsullivan09@gmail.com>
Date: Mon, 11 Apr 2016 12:48:43 -0500
Subject: [PATCH] imagesavealpha() in Writer\AbstractWriter

---
 src/PhpWord/Writer/AbstractWriter.php | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/src/PhpWord/Writer/AbstractWriter.php b/src/PhpWord/Writer/AbstractWriter.php
index 55b20232..c6b64c28 100644
--- a/src/PhpWord/Writer/AbstractWriter.php
+++ b/src/PhpWord/Writer/AbstractWriter.php
@@ -360,6 +360,10 @@ abstract class AbstractWriter implements WriterInterface
             // Retrive GD image content or get local media
             if (isset($element['isMemImage']) && $element['isMemImage']) {
                 $image = call_user_func($element['createFunction'], $element['source']);
+                if ($element['imageType'] === 'image/png') {
+                    // PNG images need to preserve alpha channel information
+                    imagesavealpha($image, true);
+                }
                 ob_start();
                 call_user_func($element['imageFunction'], $image);
                 $imageContents = ob_get_contents();