From fef6b31b994befac0ee14391572ebc2b9b33e104 Mon Sep 17 00:00:00 2001
From: J-P Nurmi <jpnurmi@qt.io>
Date: Thu, 1 Feb 2018 14:40:46 +0100
Subject: GTK: fix menu positioning on high-DPI

The target position is passed in physical native pixels, so call
QPlatformWindow::mapToGlobal() instead of QWindow::mapToGlobal().
The latter operates on logical pixels.

Task-number: QTBUG-55251
Change-Id: I789128a0a345d4113fced82ed1b215fe14044634
Reviewed-by: Friedemann Kleint <Friedemann.Kleint@qt.io>
---
 src/plugins/platformthemes/gtk3/qgtk3menu.cpp | 6 ++++--
 1 file changed, 4 insertions(+), 2 deletions(-)

diff --git a/src/plugins/platformthemes/gtk3/qgtk3menu.cpp b/src/plugins/platformthemes/gtk3/qgtk3menu.cpp
index 99407a21de..cdd1abaf7d 100644
--- a/src/plugins/platformthemes/gtk3/qgtk3menu.cpp
+++ b/src/plugins/platformthemes/gtk3/qgtk3menu.cpp
@@ -41,6 +41,7 @@
 
 #include <QtGui/qwindow.h>
 #include <QtGui/qpa/qplatformtheme.h>
+#include <QtGui/qpa/qplatformwindow.h>
 
 #undef signals
 #include <gtk/gtk.h>
@@ -450,8 +451,9 @@ void QGtk3Menu::showPopup(const QWindow *parentWindow, const QRect &targetRect,
 
     m_targetPos = QPoint(targetRect.x(), targetRect.y() + targetRect.height());
 
-    if (parentWindow)
-        m_targetPos = parentWindow->mapToGlobal(m_targetPos);
+    QPlatformWindow *pw = parentWindow ? parentWindow->handle() : nullptr;
+    if (pw)
+        m_targetPos = pw->mapToGlobal(m_targetPos);
 
     gtk_menu_popup(GTK_MENU(m_menu), NULL, NULL, qt_gtk_menu_position_func, this, 0, gtk_get_current_event_time());
 }
-- 
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