6 files changed, 14 insertions, 9 deletions
diff --git a/src/widgets/kernel/qgridlayout.cpp b/src/widgets/kernel/qgridlayout.cpp
index 0e0c1588a1..85898ae86c 100644
--- a/src/widgets/kernel/qgridlayout.cpp
+++ b/src/widgets/kernel/qgridlayout.cpp
@@ -1275,7 +1275,7 @@ QSize QGridLayout::maximumSize() const
 */
 bool QGridLayout::hasHeightForWidth() const
 {
-    return ((QGridLayout*)this)->d_func()->hasHeightForWidth(horizontalSpacing(), verticalSpacing());
+    return const_cast<QGridLayout*>(this)->d_func()->hasHeightForWidth(horizontalSpacing(), verticalSpacing());
 }
 
 /*!
diff --git a/src/widgets/kernel/qlayoutengine.cpp b/src/widgets/kernel/qlayoutengine.cpp
index ae10b84e81..f071ca567e 100644
--- a/src/widgets/kernel/qlayoutengine.cpp
+++ b/src/widgets/kernel/qlayoutengine.cpp
@@ -370,7 +370,7 @@ Q_WIDGETS_EXPORT QSize qSmartMinSize(const QSize &sizeHint, const QSize &minSize
 
 Q_WIDGETS_EXPORT QSize qSmartMinSize(const QWidgetItem *i)
 {
-    QWidget *w = ((QWidgetItem *)i)->widget();
+    QWidget *w = const_cast<QWidgetItem *>(i)->widget();
     return qSmartMinSize(w->sizeHint(), w->minimumSizeHint(),
                             w->minimumSize(), w->maximumSize(),
                             w->sizePolicy());
@@ -408,7 +408,7 @@ Q_WIDGETS_EXPORT QSize qSmartMaxSize(const QSize &sizeHint,
 
 Q_WIDGETS_EXPORT QSize qSmartMaxSize(const QWidgetItem *i, Qt::Alignment align)
 {
-    QWidget *w = ((QWidgetItem*)i)->widget();
+    QWidget *w = const_cast<QWidgetItem*>(i)->widget();
 
     return qSmartMaxSize(w->sizeHint().expandedTo(w->minimumSizeHint()), w->minimumSize(), w->maximumSize(),
                             w->sizePolicy(), align);
diff --git a/src/widgets/kernel/qlayoutitem.cpp b/src/widgets/kernel/qlayoutitem.cpp
index a79d9bb2c6..0e69bbc8ae 100644
--- a/src/widgets/kernel/qlayoutitem.cpp
+++ b/src/widgets/kernel/qlayoutitem.cpp
@@ -341,6 +341,8 @@ QSpacerItem * QSpacerItem::spacerItem()
 }
 
 /*!
+    \since 5.5
+
     Returns the size policy of this item.
 */
 QSizePolicy QSpacerItem::sizePolicy() const
diff --git a/src/widgets/kernel/qopenglwidget.cpp b/src/widgets/kernel/qopenglwidget.cpp
index 3b33894627..8faa9f8681 100644
--- a/src/widgets/kernel/qopenglwidget.cpp
+++ b/src/widgets/kernel/qopenglwidget.cpp
@@ -691,7 +691,7 @@ void QOpenGLWidgetPrivate::beginCompose()
     if (flushPending) {
         flushPending = false;
         q->makeCurrent();
-        context->functions()->glFlush();
+        static_cast<QOpenGLExtensions *>(context->functions())->flushShared();
     }
     hasBeenComposed = true;
     emit q->aboutToCompose();
@@ -768,7 +768,7 @@ void QOpenGLWidgetPrivate::resolveSamples()
         q->makeCurrent();
         QRect rect(QPoint(0, 0), fbo->size());
         QOpenGLFramebufferObject::blitFramebuffer(resolvedFbo, rect, fbo, rect);
-        QOpenGLContext::currentContext()->functions()->glFlush();
+        flushPending = true;
     }
 }
 
@@ -779,7 +779,7 @@ void QOpenGLWidgetPrivate::invokeUserPaint()
 
     f->glViewport(0, 0, q->width() * q->devicePixelRatio(), q->height() * q->devicePixelRatio());
     q->paintGL();
-    f->glFlush();
+    flushPending = true;
 }
 
 void QOpenGLWidgetPrivate::render()
diff --git a/src/widgets/kernel/qwhatsthis.cpp b/src/widgets/kernel/qwhatsthis.cpp
index db9e09c8c2..5fb4695687 100644
--- a/src/widgets/kernel/qwhatsthis.cpp
+++ b/src/widgets/kernel/qwhatsthis.cpp
@@ -495,7 +495,7 @@ private slots:
 QWhatsThisAction::QWhatsThisAction(QObject *parent) : QAction(tr("What's This?"), parent)
 {
 #ifndef QT_NO_IMAGEFORMAT_XPM
-    QPixmap p((const char**)button_image);
+    QPixmap p(button_image);
     setIcon(p);
 #endif
     setCheckable(true);
diff --git a/src/widgets/kernel/qwidget.cpp b/src/widgets/kernel/qwidget.cpp
index 850490ff6b..ad0142c5df 100644
--- a/src/widgets/kernel/qwidget.cpp
+++ b/src/widgets/kernel/qwidget.cpp
@@ -4285,7 +4285,7 @@ QPoint QWidget::mapFromParent(const QPoint &pos) const
 
 QWidget *QWidget::window() const
 {
-    QWidget *w = (QWidget *)this;
+    QWidget *w = const_cast<QWidget *>(this);
     QWidget *p = w->parentWidget();
     while (!w->isWindow() && p) {
         w = p;
@@ -5353,7 +5353,10 @@ void QWidgetPrivate::render_helper(QPainter *painter, const QPoint &targetOffset
         if (size.isNull())
             return;
 
-        QPixmap pixmap(size);
+        const qreal pixmapDevicePixelRatio = qreal(painter->device()->devicePixelRatio());
+        QPixmap pixmap(size * pixmapDevicePixelRatio);
+        pixmap.setDevicePixelRatio(pixmapDevicePixelRatio);
+
         if (!(renderFlags & QWidget::DrawWindowBackground) || !isOpaque)
             pixmap.fill(Qt::transparent);
         q->render(&pixmap, QPoint(), toBePainted, renderFlags);