QCoreTextFontEngine: Cache face_id.

This involves a significant amount of memory allocation, which made it rather
more expensive than one would expect. The FT engine also caches face id, so this
seems like a reasonable prospect.

Increases delegates_text by another few ops/frame.

Change-Id: If31e6b54478e4caf46a3a12a9ac45254a1f01525
Reviewed-by: Konstantin Ritt <ritt.ks@gmail.com>
Reviewed-by: Morten Johan Sørvig <morten.sorvig@theqtcompany.com>

2 files changed, 6 insertions, 7 deletions

diff --git a/src/platformsupport/fontdatabases/mac/qfontengine_coretext.mm b/src/platformsupport/fontdatabases/mac/qfontengine_coretext.mm
index 48ec78951d..64de364bfb 100644
--- a/src/platformsupport/fontdatabases/mac/qfontengine_coretext.mm
+++ b/src/platformsupport/fontdatabases/mac/qfontengine_coretext.mm
@@ -162,6 +162,10 @@ void QCoreTextFontEngine::init()
     Q_ASSERT(ctfont != NULL);
     Q_ASSERT(cgFont != NULL);
 
+    face_id.index = 0;
+    QCFString name = CTFontCopyName(ctfont, kCTFontUniqueNameKey);
+    face_id.filename = QCFString::toQString(name).toUtf8();
+
     QCFString family = CTFontCopyFamilyName(ctfont);
     fontDef.family = family;
 
@@ -696,13 +700,7 @@ void QCoreTextFontEngine::recalcAdvances(QGlyphLayout *glyphs, QFontEngine::Shap
 
 QFontEngine::FaceId QCoreTextFontEngine::faceId() const
 {
-    FaceId result;
-    result.index = 0;
-
-    QCFString name = CTFontCopyName(ctfont, kCTFontUniqueNameKey);
-    result.filename = QCFString::toQString(name).toUtf8();
-
-    return result;
+    return face_id;
 }
 
 bool QCoreTextFontEngine::canRender(const QChar *string, int len) const
diff --git a/src/platformsupport/fontdatabases/mac/qfontengine_coretext_p.h b/src/platformsupport/fontdatabases/mac/qfontengine_coretext_p.h
index 4a6c8e57e6..88ce2c726d 100644
--- a/src/platformsupport/fontdatabases/mac/qfontengine_coretext_p.h
+++ b/src/platformsupport/fontdatabases/mac/qfontengine_coretext_p.h
@@ -135,6 +135,7 @@ private:
     int synthesisFlags;
     CGAffineTransform transform;
     QFixed avgCharWidth;
+    QFontEngine::FaceId face_id;
 };
 
 CGAffineTransform qt_transform_from_fontdef(const QFontDef &fontDef);