direct2d: Work around ClearType rendering bug in translucent mode

This switches the font rendering to use gray scale antialiasing when in
translucent rendering mode. It does so by adding a flags argument to the
paint engine, allowing for future expansion in communicating render hints
from the device to the engine.

Task-number: QTBUG-41002
Change-Id: I0265154716a12060e851b603a109e9c693f5e843
Reviewed-by: Louai Al-Khanji <louai.al-khanji@digia.com>
Reviewed-by: Friedemann Kleint <Friedemann.Kleint@digia.com>

1 files changed, 5 insertions, 3 deletions

diff --git a/src/plugins/platforms/direct2d/qwindowsdirect2dplatformpixmap.cpp b/src/plugins/platforms/direct2d/qwindowsdirect2dplatformpixmap.cpp
index d9f7c595ca..88b440f857 100644
--- a/src/plugins/platforms/direct2d/qwindowsdirect2dplatformpixmap.cpp
+++ b/src/plugins/platforms/direct2d/qwindowsdirect2dplatformpixmap.cpp
@@ -62,10 +62,11 @@ public:
         , devicePixelRatio(1.0)
     {}
 
-    QWindowsDirect2DPlatformPixmapPrivate(QWindowsDirect2DBitmap *bitmap)
+    QWindowsDirect2DPlatformPixmapPrivate(QWindowsDirect2DBitmap *bitmap,
+                                          QWindowsDirect2DPaintEngine::Flags flags)
         : owns_bitmap(false)
         , bitmap(bitmap)
-        , device(new QWindowsDirect2DPaintDevice(bitmap, QInternal::Pixmap))
+        , device(new QWindowsDirect2DPaintDevice(bitmap, QInternal::Pixmap, flags))
         , devicePixelRatio(1.0)
     {}
 
@@ -91,9 +92,10 @@ QWindowsDirect2DPlatformPixmap::QWindowsDirect2DPlatformPixmap(PixelType pixelTy
 }
 
 QWindowsDirect2DPlatformPixmap::QWindowsDirect2DPlatformPixmap(QPlatformPixmap::PixelType pixelType,
+                                                               QWindowsDirect2DPaintEngine::Flags flags,
                                                                QWindowsDirect2DBitmap *bitmap)
     : QPlatformPixmap(pixelType, Direct2DClass)
-    , d_ptr(new QWindowsDirect2DPlatformPixmapPrivate(bitmap))
+    , d_ptr(new QWindowsDirect2DPlatformPixmapPrivate(bitmap, flags))
 {
     setSerialNumber(qt_d2dpixmap_serno++);