From d45f050e46c6c1483eb67b423de132e4afb84d6e Mon Sep 17 00:00:00 2001
From: Uwe Steinmann <steinm@debian.org>
Date: Wed, 15 Feb 2023 08:27:37 +0100
Subject: [PATCH] conversion from pdf to png replaces alpha channel with white

---
 CHANGELOG                                    | 1 +
 inc/inc.ClassConversionServicePdfToImage.php | 4 ++++
 2 files changed, 5 insertions(+)

diff --git a/CHANGELOG b/CHANGELOG
index 7627a500a..d396fba11 100644
--- a/CHANGELOG
+++ b/CHANGELOG
@@ -1,6 +1,7 @@
 --------------------------------------------------------------------------------
                      Changes in version 5.1.30
 --------------------------------------------------------------------------------
+- conversion from pdf to png replaces alpha channel with white
 
 --------------------------------------------------------------------------------
                      Changes in version 5.1.29
diff --git a/inc/inc.ClassConversionServicePdfToImage.php b/inc/inc.ClassConversionServicePdfToImage.php
index 349565232..4a7f1ce2e 100644
--- a/inc/inc.ClassConversionServicePdfToImage.php
+++ b/inc/inc.ClassConversionServicePdfToImage.php
@@ -64,6 +64,10 @@ class SeedDMS_ConversionServicePdfToImage extends SeedDMS_ConversionServiceBase
 			if($imagick->readImage($infile.'['.$page.']')) {
 				if(!empty($params['width']))
 					$imagick->scaleImage(min((int) $params['width'], $imagick->getImageWidth()), 0);
+				/* Remove alpha channel and set to white */
+        $imagick->setImageBackgroundColor('white');
+        $imagick->setImageAlphaChannel(Imagick::ALPHACHANNEL_REMOVE);
+        $imagick->mergeImageLayers(Imagick::LAYERMETHOD_FLATTEN);
 				$imagick->setImageFormat('png');
 				$end = microtime(true);
 				if($this->logger) {