Enablers for shared graphics cache in raster paint engine

Required changes for using shared graphics cache for distance field
raster glyph rendering. Most of the logic is in platform plugins.

Platform plugins should implement
QPlatformIntegration::createImagePaintEngine() to create a subclass
of QRasterEngine.

Change-Id: Icf0a396e722e43b4caa2c1849aae38753cde38f1
Reviewed-by: Eskil Abrahamsen Blomfeldt <eskil.abrahamsen-blomfeldt@nokia.com>

1 files changed, 52 insertions, 15 deletions

diff --git a/src/gui/text/qdistancefield.cpp b/src/gui/text/qdistancefield.cpp
index fb06a26c8f..a1deb47175 100644
--- a/src/gui/text/qdistancefield.cpp
+++ b/src/gui/text/qdistancefield.cpp
@@ -692,17 +692,8 @@ static QImage makeDistanceField(int imgSize, const QPainterPath &path, int dfSca
     return image;
 }
 
-bool qt_fontHasNarrowOutlines(const QRawFont &f)
+static bool imageHasNarrowOutlines(const QImage &im)
 {
-    QRawFont font = f;
-    font.setPixelSize(QT_DISTANCEFIELD_DEFAULT_BASEFONTSIZE);
-    Q_ASSERT(font.isValid());
-
-    QVector<quint32> glyphIndices = font.glyphIndexesForString(QLatin1String("O"));
-    if (glyphIndices.size() < 1)
-        return false;
-
-    QImage im = font.alphaMapForGlyph(glyphIndices.at(0), QRawFont::PixelAntialiasing);
     if (im.isNull())
         return false;
 
@@ -742,6 +733,56 @@ bool qt_fontHasNarrowOutlines(const QRawFont &f)
     return minHThick == 1 || minVThick == 1;
 }
 
+bool qt_fontHasNarrowOutlines(QFontEngine *fontEngine)
+{
+    QFontEngine *fe = fontEngine->cloneWithSize(QT_DISTANCEFIELD_DEFAULT_BASEFONTSIZE);
+
+    QGlyphLayout glyphs;
+    glyph_t glyph;
+    glyphs.glyphs = &glyph;
+    int numGlyphs;
+    QChar *chars = QString(QLatin1String("O")).data();
+    fe->stringToCMap(chars, 1, &glyphs, &numGlyphs, QTextEngine::GlyphIndicesOnly);
+    QImage im = fe->alphaMapForGlyph(glyph, QFixed(), QTransform());
+    delete fe;
+
+    return imageHasNarrowOutlines(im);
+}
+
+bool qt_fontHasNarrowOutlines(const QRawFont &f)
+{
+    QRawFont font = f;
+    font.setPixelSize(QT_DISTANCEFIELD_DEFAULT_BASEFONTSIZE);
+    Q_ASSERT(font.isValid());
+
+    QVector<quint32> glyphIndices = font.glyphIndexesForString(QLatin1String("O"));
+    if (glyphIndices.size() < 1)
+        return false;
+
+    return imageHasNarrowOutlines(font.alphaMapForGlyph(glyphIndices.at(0),
+                                                        QRawFont::PixelAntialiasing));
+}
+
+static QImage renderDistanceFieldPath(const QPainterPath &path, bool doubleResolution)
+{
+    QImage im = makeDistanceField(QT_DISTANCEFIELD_TILESIZE(doubleResolution),
+                                  path,
+                                  QT_DISTANCEFIELD_SCALE(doubleResolution),
+                                  QT_DISTANCEFIELD_RADIUS(doubleResolution) / QT_DISTANCEFIELD_SCALE(doubleResolution));
+    return im;
+}
+
+QImage qt_renderDistanceFieldGlyph(QFontEngine *fe, glyph_t glyph, bool doubleResolution)
+{
+    QFixedPoint position;
+    QPainterPath path;
+    fe->addGlyphsToPath(&glyph, &position, 1, &path, 0);
+    path.translate(-path.boundingRect().topLeft());
+    path.setFillRule(Qt::WindingFill);
+
+    return renderDistanceFieldPath(path, doubleResolution);
+}
+
 QImage qt_renderDistanceFieldGlyph(const QRawFont &font, glyph_t glyph, bool doubleResolution)
 {
     QRawFont renderFont = font;
@@ -751,11 +792,7 @@ QImage qt_renderDistanceFieldGlyph(const QRawFont &font, glyph_t glyph, bool dou
     path.translate(-path.boundingRect().topLeft());
     path.setFillRule(Qt::WindingFill);
 
-    QImage im = makeDistanceField(QT_DISTANCEFIELD_TILESIZE(doubleResolution),
-                                  path,
-                                  QT_DISTANCEFIELD_SCALE(doubleResolution),
-                                  QT_DISTANCEFIELD_RADIUS(doubleResolution) / QT_DISTANCEFIELD_SCALE(doubleResolution));
-    return im;
+    return renderDistanceFieldPath(path, doubleResolution);
 }
 
 QT_END_NAMESPACE