From 6a6c14626df1ccf7838f0b8dd82bc88a1c637d04 Mon Sep 17 00:00:00 2001
From: Eskil Abrahamsen Blomfeldt <eskil.abrahamsen-blomfeldt@theqtcompany.com>
Date: Mon, 2 Nov 2015 12:28:35 +0100
Subject: [PATCH] Windows: Default to vertical hinting when high-dpi scaling is
 enabled

Since hinted text layouts are not scalable, we should disable
hinting by default when the high-dpi scaling is active.

This is the Windows version of 0f7bc885aa7ae8cc3c448cc751aba4eba8c1c8b8,
which solved the same issue for the fontconfig database.

Change-Id: I48b5da5b045dec195fd257743175017f39cf9620
Reviewed-by: Paul Olav Tvete <paul.tvete@theqtcompany.com>
---
 .../platforms/windows/qwindowsfontdatabase.cpp        | 11 ++++++++---
 1 file changed, 8 insertions(+), 3 deletions(-)

diff --git a/src/plugins/platforms/windows/qwindowsfontdatabase.cpp b/src/plugins/platforms/windows/qwindowsfontdatabase.cpp
index 9531d30e06..c8eaccd956 100644
--- a/src/plugins/platforms/windows/qwindowsfontdatabase.cpp
+++ b/src/plugins/platforms/windows/qwindowsfontdatabase.cpp
@@ -40,6 +40,7 @@
 
 #include <QtGui/QFont>
 #include <QtGui/QGuiApplication>
+#include <QtGui/private/qhighdpiscaling_p.h>
 
 #include <QtCore/qmath.h>
 #include <QtCore/QDebug>
@@ -1100,8 +1101,11 @@ QFontEngine *QWindowsFontDatabase::fontEngine(const QByteArray &fontData, qreal
     QFontEngine *fontEngine = 0;
 
 #if !defined(QT_NO_DIRECTWRITE)
-    if (hintingPreference == QFont::PreferDefaultHinting
-        || hintingPreference == QFont::PreferFullHinting)
+    bool useDirectWrite = (hintingPreference == QFont::PreferNoHinting)
+                       || (hintingPreference == QFont::PreferVerticalHinting)
+                       || (QHighDpiScaling::isActive() && hintingPreference == QFont::PreferDefaultHinting);
+
+    if (!useDirectWrite)
 #endif
     {
         GUID guid;
@@ -1704,7 +1708,8 @@ QFontEngine *QWindowsFontDatabase::createEngine(const QFontDef &request,
 
 #if !defined(QT_NO_DIRECTWRITE)
     bool useDirectWrite = (request.hintingPreference == QFont::PreferNoHinting)
-                       || (request.hintingPreference == QFont::PreferVerticalHinting);
+                       || (request.hintingPreference == QFont::PreferVerticalHinting)
+                       || (QHighDpiScaling::isActive() && request.hintingPreference == QFont::PreferDefaultHinting);
     if (useDirectWrite && initDirectWrite(data.data())) {
         const QString fam = QString::fromWCharArray(lf.lfFaceName);
         const QString nameSubstitute = QWindowsFontEngineDirectWrite::fontNameSubstitute(fam);