CoreText: Modernize font smoothing and antialiasing threshold detection

The way macOS does font smoothing has changed in Mojave, and we need to
take both this new algorithm into account, as well as support users who
set legacy preferences to revert back to subpixel font smoothing.

As a followup to this patch we will tweak some of the existing logic
to take the new font smoothing algorithm into account, so this is
just a first step.

Change-Id: If37014c18515f406b8bb8194c9df7a75c2eb10fc
Reviewed-by: Simon Hausmann <simon.hausmann@qt.io>
Reviewed-by: Tor Arne Vestbø <tor.arne.vestbo@qt.io>
Reviewed-by: Allan Sandfeld Jensen <allan.jensen@qt.io>

1 files changed, 12 insertions, 3 deletions

diff --git a/src/platformsupport/fontdatabases/mac/qfontengine_coretext_p.h b/src/platformsupport/fontdatabases/mac/qfontengine_coretext_p.h
index 7ed2faff8e..2ce46a4706 100644
--- a/src/platformsupport/fontdatabases/mac/qfontengine_coretext_p.h
+++ b/src/platformsupport/fontdatabases/mac/qfontengine_coretext_p.h
@@ -53,6 +53,7 @@
 
 #include <private/qfontengine_p.h>
 #include <private/qcore_mac_p.h>
+#include <QtCore/qloggingcategory.h>
 
 #ifdef Q_OS_OSX
 #include <ApplicationServices/ApplicationServices.h>
@@ -63,8 +64,12 @@
 
 QT_BEGIN_NAMESPACE
 
+Q_DECLARE_LOGGING_CATEGORY(lcQpaFonts)
+
 class QCoreTextFontEngine : public QFontEngine
 {
+    Q_GADGET
+
 public:
     QCoreTextFontEngine(CTFontRef font, const QFontDef &def);
     QCoreTextFontEngine(CGFontRef font, const QFontDef &def);
@@ -118,13 +123,17 @@ public:
 
     QFontEngine::Properties properties() const override;
 
+    enum FontSmoothing { Disabled, Subpixel, Grayscale };
+    Q_ENUM(FontSmoothing);
+
+    static FontSmoothing fontSmoothing();
+    static int antialiasingThreshold();
+
     static bool ct_getSfntTable(void *user_data, uint tag, uchar *buffer, uint *length);
     static QFont::Weight qtWeightFromCFWeight(float value);
 
-    static int antialiasingThreshold;
-    static QFontEngine::GlyphFormat defaultGlyphFormat;
-
     static QCoreTextFontEngine *create(const QByteArray &fontData, qreal pixelSize, QFont::HintingPreference hintingPreference);
+
 protected:
     QCoreTextFontEngine(const QFontDef &def);
     void init();