5 files changed, 39 insertions, 16 deletions

diff --git a/src/opengl/gl2paintengineex/qpaintengineex_opengl2.cpp b/src/opengl/gl2paintengineex/qpaintengineex_opengl2.cpp
index e62af62..3ac759c 100644
--- a/src/opengl/gl2paintengineex/qpaintengineex_opengl2.cpp
+++ b/src/opengl/gl2paintengineex/qpaintengineex_opengl2.cpp
@@ -1436,19 +1436,30 @@ void QGL2PaintEngineEx::drawStaticTextItem(QStaticTextItem *textItem)
 
     ensureActive();
 
-    QFontEngineGlyphCache::Type glyphType = textItem->fontEngine()->glyphFormat >= 0
-                                            ? QFontEngineGlyphCache::Type(textItem->fontEngine()->glyphFormat)
-                                            : d->glyphCacheType;
-    if (glyphType == QFontEngineGlyphCache::Raster_RGBMask) {
-        if (d->device->alphaRequested() || state()->matrix.type() > QTransform::TxTranslate
-            || (state()->composition_mode != QPainter::CompositionMode_Source
-            && state()->composition_mode != QPainter::CompositionMode_SourceOver))
-        {
-            glyphType = QFontEngineGlyphCache::Raster_A8;
+    QPainterState *s = state();
+    float det = s->matrix.determinant();
+
+    // don't try to cache huge fonts or vastly transformed fonts
+    QFontEngine *fontEngine = textItem->fontEngine();
+    const qreal pixelSize = fontEngine->fontDef.pixelSize;
+    if (pixelSize * pixelSize * qAbs(det) < QT_MAX_CACHED_GLYPH_SIZE * QT_MAX_CACHED_GLYPH_SIZE ||
+        det < 0.25f || det > 4.f) {
+        QFontEngineGlyphCache::Type glyphType = fontEngine->glyphFormat >= 0
+                                                ? QFontEngineGlyphCache::Type(textItem->fontEngine()->glyphFormat)
+                                                : d->glyphCacheType;
+        if (glyphType == QFontEngineGlyphCache::Raster_RGBMask) {
+            if (d->device->alphaRequested() || s->matrix.type() > QTransform::TxTranslate
+                || (s->composition_mode != QPainter::CompositionMode_Source
+                && s->composition_mode != QPainter::CompositionMode_SourceOver))
+            {
+                glyphType = QFontEngineGlyphCache::Raster_A8;
+            }
         }
-    }
 
-    d->drawCachedGlyphs(glyphType, textItem);
+        d->drawCachedGlyphs(glyphType, textItem);
+    } else {
+        QPaintEngineEx::drawStaticTextItem(textItem);
+    }
 }
 
 bool QGL2PaintEngineEx::drawTexture(const QRectF &dest, GLuint textureId, const QSize &size, const QRectF &src)
diff --git a/src/opengl/gl2paintengineex/qpaintengineex_opengl2_p.h b/src/opengl/gl2paintengineex/qpaintengineex_opengl2_p.h
index 7ba92e4..2895d5a 100644
--- a/src/opengl/gl2paintengineex/qpaintengineex_opengl2_p.h
+++ b/src/opengl/gl2paintengineex/qpaintengineex_opengl2_p.h
@@ -158,6 +158,7 @@ public:
     void setRenderTextActive(bool);
 
     bool isNativePaintingActive() const;
+    bool supportsTransformations(qreal, const QTransform &) const { return true; }
 private:
     Q_DISABLE_COPY(QGL2PaintEngineEx)
 };
diff --git a/src/opengl/qgl_qpa.cpp b/src/opengl/qgl_qpa.cpp
index e7fc560..f8f3974 100644
--- a/src/opengl/qgl_qpa.cpp
+++ b/src/opengl/qgl_qpa.cpp
@@ -150,6 +150,8 @@ bool QGLContext::chooseContext(const QGLContext* shareContext)
             if (shareContext) {
                 winFormat.setSharedContext(shareContext->d_func()->platformContext);
             }
+            if (widget->testAttribute(Qt::WA_TranslucentBackground))
+                winFormat.setAlpha(true);
             winFormat.setWindowApi(QPlatformWindowFormat::OpenGL);
             winFormat.setWindowSurface(false);
             widget->setPlatformWindowFormat(winFormat);
diff --git a/src/opengl/qpaintengine_opengl_p.h b/src/opengl/qpaintengine_opengl_p.h
index 5d5f5ce..8d0ea83 100644
--- a/src/opengl/qpaintengine_opengl_p.h
+++ b/src/opengl/qpaintengine_opengl_p.h
@@ -143,6 +143,7 @@ public:
     Qt::HANDLE handle() const;
 #endif
     inline Type type() const { return QPaintEngine::OpenGL; }
+    bool supportsTransformations(qreal, const QTransform &) const { return true; }
 
 private:
     void drawPolyInternal(const QPolygonF &pa, bool close = true);
diff --git a/src/opengl/qwindowsurface_gl.cpp b/src/opengl/qwindowsurface_gl.cpp
index 7f63aea..ff55142 100644
--- a/src/opengl/qwindowsurface_gl.cpp
+++ b/src/opengl/qwindowsurface_gl.cpp
@@ -542,19 +542,27 @@ void QGLWindowSurface::beginPaint(const QRegion &)
     d_ptr->did_paint = true;
     updateGeometry();
 
-    if (!context())
-        return;
-
     int clearFlags = 0;
 
-    if (context()->d_func()->workaround_needsFullClearOnEveryFrame)
+    QGLContext *ctx = reinterpret_cast<QGLContext *>(window()->d_func()->extraData()->glContext);
+
+    if (!ctx)
+        return;
+
+    if (ctx->d_func()->workaround_needsFullClearOnEveryFrame)
         clearFlags = GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT | GL_STENCIL_BUFFER_BIT;
-    else if (context()->format().alpha())
+    else if (ctx->format().alpha())
         clearFlags = GL_COLOR_BUFFER_BIT;
 
     if (clearFlags) {
+        if (d_ptr->fbo)
+            d_ptr->fbo->bind();
+
         glClearColor(0.0, 0.0, 0.0, 0.0);
         glClear(clearFlags);
+
+        if (d_ptr->fbo)
+            d_ptr->fbo->release();
     }
 }