From 13d95e415e0870fd13ebef8b888364d8b9ebb9e5 Mon Sep 17 00:00:00 2001
From: Friedemann Kleint <Friedemann.Kleint@qt.io>
Date: Tue, 2 Jun 2020 10:19:06 +0200
Subject: [PATCH] High DPI/Windows style: Fix potential crash when drawing
 buttons of maximized QMdiSubWindow

In QWindowsXPStylePrivate::drawBackgroundThruNativeBuffer(),
pass the correct rectangle (reflecting the correction factor)
to the function fixAlphaChannel().

Amends e56b8e1e59b6df7c7abd48b163abe6846849eb7a.

Pick-to: 5.15
Fixes: QTBUG-84613
Task-number: QTBUG-75927
Change-Id: I5357bb8c55ed26a50cc322ea7a05df4487212fb8
Reviewed-by: Oliver Wolff <oliver.wolff@qt.io>
---
 src/plugins/styles/windowsvista/qwindowsxpstyle.cpp | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/src/plugins/styles/windowsvista/qwindowsxpstyle.cpp b/src/plugins/styles/windowsvista/qwindowsxpstyle.cpp
index 67198e701c7..e57ebfeeffc 100644
--- a/src/plugins/styles/windowsvista/qwindowsxpstyle.cpp
+++ b/src/plugins/styles/windowsvista/qwindowsxpstyle.cpp
@@ -972,7 +972,7 @@ bool QWindowsXPStylePrivate::drawBackgroundThruNativeBuffer(XPThemeData &themeDa
 
         // Fix alpha values, if needed
         if (potentialInvalidAlpha)
-            wasAlphaFixed = fixAlphaChannel(rect);
+            wasAlphaFixed = fixAlphaChannel(drawRect);
 
         QImage::Format format;
         if ((partIsTransparent && !wasAlphaSwapped) || (!partIsTransparent && hasAlpha)) {