From f4ec74a4c5338f1df4a3dbb58a19b946ab627005 Mon Sep 17 00:00:00 2001
From: Sam Sullivan <samsullivan09@gmail.com>
Date: Mon, 11 Apr 2016 12:49:18 -0500
Subject: [PATCH] imagesavealpha() in Element\Image

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

diff --git a/src/PhpWord/Element/Image.php b/src/PhpWord/Element/Image.php
index f5cc7ccc..64ddfd86 100644
--- a/src/PhpWord/Element/Image.php
+++ b/src/PhpWord/Element/Image.php
@@ -335,6 +335,10 @@ class Image extends AbstractElement
         // Read image binary data and convert to hex/base64 string
         if ($this->sourceType == self::SOURCE_GD) {
             $imageResource = call_user_func($this->imageCreateFunc, $actualSource);
+            if ($this->imageType === 'image/png') {
+                // PNG images need to preserve alpha channel information
+                imagesavealpha($imageResource, true);
+            }
             ob_start();
             call_user_func($this->imageFunc, $imageResource);
             $imageBinary = ob_get_contents();