Refactor glyph pretransform check

Move paintEngineSupportsTransformations logic from QPainter to paint
engine subclasses. Simplify and consolidate checks for cached drawing
(pretransformed) and path drawing (untransformed) in raster paint
engine. Fix unnecessary transform when paint engines actually take
the path drawing track. Fix scaling and rotation transform in raster
engine for Mac.

Task-number: QTBUG-19086
Change-Id: I1c0c1800a5173d3db765b9fccfd0e7a3628e3815
Reviewed-on: http://codereview.qt.nokia.com/298
Reviewed-by: Qt Sanity Bot <qt_sanity_bot@ovi.com>
Reviewed-by: Eskil Abrahamsen Blomfeldt <eskil.abrahamsen-blomfeldt@nokia.com>
(cherry picked from commit 43c0e08ba2e3487840b4063b2099bc17cdd4dce2)

1 files changed, 33 insertions, 34 deletions

diff --git a/src/gui/painting/qpaintengine_raster.cpp b/src/gui/painting/qpaintengine_raster.cpp
index 71bbbb1..a1d728c 100644
--- a/src/gui/painting/qpaintengine_raster.cpp
+++ b/src/gui/painting/qpaintengine_raster.cpp
@@ -3062,11 +3062,8 @@ void QRasterPaintEngine::drawStaticTextItem(QStaticTextItem *textItem)
     ensurePen();
     ensureState();
 
-    QRasterPaintEngineState *s = state();
-
     QFontEngine *fontEngine = textItem->fontEngine();
-    const qreal pixelSize = fontEngine->fontDef.pixelSize;
-    if (pixelSize * pixelSize * qAbs(s->matrix.determinant()) < 64 * 64) {
+    if (!supportsTransformations(fontEngine)) {
         drawCachedGlyphs(textItem->numGlyphs, textItem->glyphs, textItem->glyphPositions,
                          fontEngine);
     } else {
@@ -3094,36 +3091,7 @@ void QRasterPaintEngine::drawTextItem(const QPointF &p, const QTextItem &textIte
 
 #if defined (Q_WS_WIN) || defined(Q_WS_MAC)
 
-    bool drawCached = true;
-
-    if (s->matrix.type() >= QTransform::TxProject)
-        drawCached = false;
-
-    // don't try to cache huge fonts
-    const qreal pixelSize = ti.fontEngine->fontDef.pixelSize;
-    if (pixelSize * pixelSize * qAbs(s->matrix.determinant()) >= 64 * 64)
-        drawCached = false;
-
-    // ### Remove the TestFontEngine and Box engine crap, in these
-    // ### cases we should delegate painting to the font engine
-    // ### directly...
-
-#if defined(Q_WS_WIN) && !defined(Q_WS_WINCE)
-    QFontEngine::Type fontEngineType = ti.fontEngine->type();
-    // qDebug() << "type" << fontEngineType << s->matrix.type();
-    if ((fontEngineType == QFontEngine::Win && !((QFontEngineWin *) ti.fontEngine)->ttf && s->matrix.type() > QTransform::TxTranslate)
-        || (s->matrix.type() <= QTransform::TxTranslate
-            && (fontEngineType == QFontEngine::TestFontEngine
-                || fontEngineType == QFontEngine::Box))) {
-            drawCached = false;
-    }
-#else
-    if (s->matrix.type() > QTransform::TxTranslate)
-        drawCached = false;
-#endif
-    if (drawCached) {
-        QRasterPaintEngineState *s = state();
-
+    if (!supportsTransformations(ti.fontEngine)) {
         QVarLengthArray<QFixedPoint> positions;
         QVarLengthArray<glyph_t> glyphs;
 
@@ -3444,6 +3412,37 @@ void QRasterPaintEngine::releaseDC(HDC) const
 
 #endif
 
+bool QRasterPaintEngine::supportsTransformations(const QFontEngine *fontEngine) const
+{
+    const QTransform &m = state()->matrix;
+#if defined(Q_WS_WIN) && !defined(Q_WS_WINCE)
+    QFontEngine::Type fontEngineType = ti.fontEngine->type();
+    if ((fontEngineType == QFontEngine::Win && !((QFontEngineWin *) ti.fontEngine)->ttf && m.type() > QTransform::TxTranslate)
+        || (m.type() <= QTransform::TxTranslate
+            && (fontEngineType == QFontEngine::TestFontEngine
+                || fontEngineType == QFontEngine::Box))) {
+            return true;
+    }
+#endif
+    return supportsTransformations(fontEngine->fontDef.pixelSize, m);
+}
+
+bool QRasterPaintEngine::supportsTransformations(qreal pixelSize, const QTransform &m) const
+{
+#if defined(Q_WS_MAC)
+    // Mac font engines don't support scaling and rotation
+    if (m.type() > QTransform::TxTranslate)
+#else
+    if (m.type() >= QTransform::TxProject)
+#endif
+        return true;
+
+    if (pixelSize * pixelSize * qAbs(m.determinant()) >= 64 * 64)
+        return true;
+
+    return false;
+}
+
 /*!
     \internal
 */