From 1ba0cfab308fff363973c3a15aa7f52908edf7af Mon Sep 17 00:00:00 2001
From: Eskil Abrahamsen Blomfeldt <eskil.abrahamsen-blomfeldt@qt.io>
Date: Wed, 2 Nov 2016 12:07:42 +0100
Subject: Windows: Fix high-dpi text rendering

In change ce2ae6ebd8cfebf9edbb0b5653e80de029669548 we added support for
hinted rendering to the DirectWrite engine. Previously, we would just
use the DirectWrite engine for all text rendering in high-dpi and assume
we would get only vertical hinting, but since the default changed, we
ended up scaling hinted text and the resulting text layouts were a mess.

Task-number: QTBUG-56841
Change-Id: I52101ea264878138de41878d1677c0ef8b522e78
Reviewed-by: Lars Knoll <lars.knoll@qt.io>
---
 .../fontdatabases/windows/qwindowsfontenginedirectwrite.cpp           | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/src/platformsupport/fontdatabases/windows/qwindowsfontenginedirectwrite.cpp b/src/platformsupport/fontdatabases/windows/qwindowsfontenginedirectwrite.cpp
index f266e85126..6130107cc8 100644
--- a/src/platformsupport/fontdatabases/windows/qwindowsfontenginedirectwrite.cpp
+++ b/src/platformsupport/fontdatabases/windows/qwindowsfontenginedirectwrite.cpp
@@ -49,6 +49,7 @@
 #include <QtCore/private/qsystemlibrary_p.h>
 #include <QtGui/private/qguiapplication_p.h>
 #include <qpa/qplatformintegration.h>
+#include <QtGui/private/qhighdpiscaling_p.h>
 
 #if defined(QT_USE_DIRECTWRITE2)
 #  include <dwrite_2.h>
@@ -185,6 +186,9 @@ namespace {
 
 static DWRITE_RENDERING_MODE hintingPreferenceToRenderingMode(QFont::HintingPreference hintingPreference)
 {
+    if (QHighDpiScaling::isActive() && hintingPreference == QFont::PreferDefaultHinting)
+        hintingPreference = QFont::PreferVerticalHinting;
+
     switch (hintingPreference) {
     case QFont::PreferNoHinting:
         return DWRITE_RENDERING_MODE_CLEARTYPE_NATURAL_SYMMETRIC;
-- 
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