Share FreeType font engine creation code between platforms

The FreeType font engine setup is spread out between factory functions,
constructors, and init() functions, so let's at least try to share as
much as possible of it to make it easier to reason about and possibly
refactor in the future.

Change-Id: Ic39353d2b3111024e0589a70211bac80feb8498e
Reviewed-by: Eskil Abrahamsen Blomfeldt <eskil.abrahamsen-blomfeldt@qt.io>

6 files changed, 51 insertions, 57 deletions

diff --git a/src/platformsupport/fontdatabases/fontconfig/qfontconfigdatabase.cpp b/src/platformsupport/fontdatabases/fontconfig/qfontconfigdatabase.cpp
index 4464e93bbd..a997bf0ba1 100644
--- a/src/platformsupport/fontdatabases/fontconfig/qfontconfigdatabase.cpp
+++ b/src/platformsupport/fontdatabases/fontconfig/qfontconfigdatabase.cpp
@@ -677,6 +677,7 @@ QFontEngine *QFontconfigDatabase::fontEngine(const QFontDef &f, void *usrPtr)
     fid.filename = QFile::encodeName(fontfile->fileName);
     fid.index = fontfile->indexValue;
 
+    // FIXME: Unify with logic in QFontEngineFT::create()
     QFontEngineFT *engine = new QFontEngineFT(f);
     engine->face_id = fid;
 
diff --git a/src/platformsupport/fontdatabases/freetype/qfontengine_ft.cpp b/src/platformsupport/fontdatabases/freetype/qfontengine_ft.cpp
index 03e72546eb..98bf91fa9d 100644
--- a/src/platformsupport/fontdatabases/freetype/qfontengine_ft.cpp
+++ b/src/platformsupport/fontdatabases/freetype/qfontengine_ft.cpp
@@ -44,6 +44,9 @@
 #include "qfontengine_ft_p.h"
 #include "private/qimage_p.h"
 #include <private/qstringiterator_p.h>
+#include <qguiapplication.h>
+#include <qscreen.h>
+#include <qpa/qplatformscreen.h>
 
 #ifndef QT_NO_FREETYPE
 
@@ -666,6 +669,43 @@ static void convoluteBitmap(const uchar *src, uchar *dst, int width, int height,
     }
 }
 
+static QFontEngine::SubpixelAntialiasingType subpixelAntialiasingTypeHint()
+{
+    static int type = -1;
+    if (type == -1) {
+        if (QScreen *screen = QGuiApplication::primaryScreen())
+            type = screen->handle()->subpixelAntialiasingTypeHint();
+    }
+    return static_cast<QFontEngine::SubpixelAntialiasingType>(type);
+}
+
+QFontEngineFT *QFontEngineFT::create(const QFontDef &fontDef, FaceId faceId, const QByteArray &fontData)
+{
+    QScopedPointer<QFontEngineFT> engine(new QFontEngineFT(fontDef));
+
+    QFontEngineFT::GlyphFormat format = QFontEngineFT::Format_Mono;
+    const bool antialias = !(fontDef.styleStrategy & QFont::NoAntialias);
+
+    if (antialias) {
+        QFontEngine::SubpixelAntialiasingType subpixelType = subpixelAntialiasingTypeHint();
+        if (subpixelType == QFontEngine::Subpixel_None || (fontDef.styleStrategy & QFont::NoSubpixelAntialias)) {
+            format = QFontEngineFT::Format_A8;
+            engine->subpixelType = QFontEngine::Subpixel_None;
+        } else {
+            format = QFontEngineFT::Format_A32;
+            engine->subpixelType = subpixelType;
+        }
+    }
+
+    if (!engine->init(faceId, antialias, format, fontData) || engine->invalid()) {
+        qWarning("QFontEngineFT: Failed to create FreeType font engine");
+        return nullptr;
+    }
+
+    engine->setQtDefaultHintStyle(static_cast<QFont::HintingPreference>(fontDef.hintingPreference));
+    return engine.take();
+}
+
 QFontEngineFT::QFontEngineFT(const QFontDef &fd)
     : QFontEngine(Freetype)
 {
diff --git a/src/platformsupport/fontdatabases/freetype/qfontengine_ft_p.h b/src/platformsupport/fontdatabases/freetype/qfontengine_ft_p.h
index 3fa0b2e7d6..fc923d196b 100644
--- a/src/platformsupport/fontdatabases/freetype/qfontengine_ft_p.h
+++ b/src/platformsupport/fontdatabases/freetype/qfontengine_ft_p.h
@@ -292,6 +292,9 @@ private:
     bool initFromFontEngine(const QFontEngineFT *fontEngine);
 
     HintStyle defaultHintStyle() const { return default_hint_style; }
+
+    static QFontEngineFT *create(const QFontDef &fontDef, FaceId faceId, const QByteArray &fontData = QByteArray());
+
 protected:
 
     QFreetypeFace *freetype;
@@ -312,7 +315,6 @@ private:
     friend class QFontEngineFTRawFont;
     friend class QFontconfigDatabase;
     friend class QFreeTypeFontDatabase;
-    friend class QCoreTextFontDatabase;
     friend class QFontEngineMultiFontConfig;
 
     int loadFlags(QGlyphSet *set, GlyphFormat format, int flags, bool &hsubpixel, int &vfactor) const;
diff --git a/src/platformsupport/fontdatabases/freetype/qfreetypefontdatabase.cpp b/src/platformsupport/fontdatabases/freetype/qfreetypefontdatabase.cpp
index 97be1606b4..764f2d8868 100644
--- a/src/platformsupport/fontdatabases/freetype/qfreetypefontdatabase.cpp
+++ b/src/platformsupport/fontdatabases/freetype/qfreetypefontdatabase.cpp
@@ -85,33 +85,12 @@ void QFreeTypeFontDatabase::populateFontDatabase()
 
 QFontEngine *QFreeTypeFontDatabase::fontEngine(const QFontDef &fontDef, void *usrPtr)
 {
-    FontFile *fontfile = static_cast<FontFile *> (usrPtr);
-    QFontEngine::FaceId fid;
-    fid.filename = QFile::encodeName(fontfile->fileName);
-    fid.index = fontfile->indexValue;
-
-    bool antialias = !(fontDef.styleStrategy & QFont::NoAntialias);
-    QFontEngineFT *engine = new QFontEngineFT(fontDef);
-    QFontEngineFT::GlyphFormat format = QFontEngineFT::Format_Mono;
-    if (antialias) {
-        QFontEngine::SubpixelAntialiasingType subpixelType = subpixelAntialiasingTypeHint();
-        if (subpixelType == QFontEngine::Subpixel_None || (fontDef.styleStrategy & QFont::NoSubpixelAntialias)) {
-            format = QFontEngineFT::Format_A8;
-            engine->subpixelType = QFontEngine::Subpixel_None;
-        } else {
-            format = QFontEngineFT::Format_A32;
-            engine->subpixelType = subpixelType;
-        }
-    }
-
-    if (!engine->init(fid, antialias, format) || engine->invalid()) {
-        delete engine;
-        engine = 0;
-    } else {
-        engine->setQtDefaultHintStyle(static_cast<QFont::HintingPreference>(fontDef.hintingPreference));
-    }
+    FontFile *fontfile = static_cast<FontFile *>(usrPtr);
+    QFontEngine::FaceId faceId;
+    faceId.filename = QFile::encodeName(fontfile->fileName);
+    faceId.index = fontfile->indexValue;
 
-    return engine;
+    return QFontEngineFT::create(fontDef, faceId);
 }
 
 namespace {
diff --git a/src/platformsupport/fontdatabases/mac/qcoretextfontdatabase.mm b/src/platformsupport/fontdatabases/mac/qcoretextfontdatabase.mm
index 3588948133..b8097702ed 100644
--- a/src/platformsupport/fontdatabases/mac/qcoretextfontdatabase.mm
+++ b/src/platformsupport/fontdatabases/mac/qcoretextfontdatabase.mm
@@ -890,28 +890,7 @@ QFontEngine *QCoreTextFontDatabase::freeTypeFontEngine(const QFontDef &fontDef,
 {
     QFontEngine::FaceId faceId;
     faceId.filename = filename;
-    const bool antialias = !(fontDef.styleStrategy & QFont::NoAntialias);
-
-    QScopedPointer<QFontEngineFT> engine(new QFontEngineFT(fontDef));
-    QFontEngineFT::GlyphFormat format = QFontEngineFT::Format_Mono;
-    if (antialias) {
-        QFontEngine::SubpixelAntialiasingType subpixelType = subpixelAntialiasingTypeHint();
-        if (subpixelType == QFontEngine::Subpixel_None || (fontDef.styleStrategy & QFont::NoSubpixelAntialias)) {
-            format = QFontEngineFT::Format_A8;
-            engine->subpixelType = QFontEngine::Subpixel_None;
-        } else {
-            format = QFontEngineFT::Format_A32;
-            engine->subpixelType = subpixelType;
-        }
-    }
-
-    if (!engine->init(faceId, antialias, format, fontData) || engine->invalid()) {
-        qWarning("QCoreTextFontDatabase::freeTypefontEngine Failed to create engine");
-        return Q_NULLPTR;
-    }
-    engine->setQtDefaultHintStyle(static_cast<QFont::HintingPreference>(fontDef.hintingPreference));
-
-    return engine.take();
+    return QFontEngineFT::create(fontDef, faceId, fontData);
 }
 #endif
 
diff --git a/src/platformsupport/fontdatabases/winrt/qwinrtfontdatabase.cpp b/src/platformsupport/fontdatabases/winrt/qwinrtfontdatabase.cpp
index 6ac092aa0e..2a95ca26a9 100644
--- a/src/platformsupport/fontdatabases/winrt/qwinrtfontdatabase.cpp
+++ b/src/platformsupport/fontdatabases/winrt/qwinrtfontdatabase.cpp
@@ -444,15 +444,8 @@ QFontEngine *QWinRTFontDatabase::fontEngine(const QFontDef &fontDef, void *handl
     const FontDescription description = m_fonts.value(fontFile);
     faceId.uuid = description.uuid;
     faceId.index = description.index;
-    const bool antialias = !(fontDef.styleStrategy & QFont::NoAntialias);
-    QFontEngineFT::GlyphFormat format = antialias ? QFontEngineFT::Format_A8 : QFontEngineFT::Format_Mono;
-    QFontEngineFT *engine = new QFontEngineFT(fontDef);
-    if (!engine->init(faceId, antialias, format, fontData) || engine->invalid()) {
-        delete engine;
-        return 0;
-    }
 
-    return engine;
+    return QFontEngineFT::create(fontDef, faceId, fontData);
 }
 
 QStringList QWinRTFontDatabase::fallbacksForFamily(const QString &family, QFont::Style style,