Export QtGui functions required by QtMultimediaKit backend

In order for video rendering to work, the Symbian QtMultimediaKit
backend needs access to QtGui functionality which is not exposed
via public interfaces, namely:
* QSymbianControl::setIgnoreFocusChanged(bool)
* Setting custom painting modes, which control how content is
  blitted from the backing store into the native window surface
* Requesting notification when Qt drawing starts and stops, so
  that the backend can ensure this does not interfere with video
  rendering.

Until now, this has been achieved by the backend including private
QtGui headers.  If these headers are not present in the environment
in which QtMobility is compiled, a warning is printed, telling the
user that video / viewfinder rendering will not work correctly when
the resulting binaries are installed.

This patch adds a Symbian-specific public interface to QtGui, which
exports the functionality above.

Task-number: MOBILITY-747
Reviewed-by: mread

3 files changed, 227 insertions, 2 deletions

diff --git a/src/gui/painting/painting.pri b/src/gui/painting/painting.pri
index 27b1bf2..d4f904b 100644
--- a/src/gui/painting/painting.pri
+++ b/src/gui/painting/painting.pri
@@ -200,10 +200,12 @@ symbian {
         SOURCES += \
 		painting/qpaintengine_raster_symbian.cpp \
                 painting/qregion_s60.cpp \
-                painting/qcolormap_s60.cpp
+                painting/qcolormap_s60.cpp \
+                painting/qgraphicssystemhelper_symbian.cpp
 
         HEADERS += \
-                painting/qpaintengine_raster_symbian_p.h
+                painting/qpaintengine_raster_symbian_p.h \
+                painting/qgraphicssystemhelper_symbian.h
 }
 
 x11|embedded|qpa {
diff --git a/src/gui/painting/qgraphicssystemhelper_symbian.cpp b/src/gui/painting/qgraphicssystemhelper_symbian.cpp
new file mode 100644
index 0000000..eb70247
--- /dev/null
+++ b/src/gui/painting/qgraphicssystemhelper_symbian.cpp
@@ -0,0 +1,141 @@
+/****************************************************************************
+**
+** Copyright (C) 2011 Nokia Corporation and/or its subsidiary(-ies).
+** All rights reserved.
+** Contact: Nokia Corporation (qt-info@nokia.com)
+**
+** This file is part of the QtGui module of the Qt Toolkit.
+**
+** $QT_BEGIN_LICENSE:LGPL$
+** GNU Lesser General Public License Usage
+** This file may be used under the terms of the GNU Lesser General Public
+** License version 2.1 as published by the Free Software Foundation and
+** appearing in the file LICENSE.LGPL included in the packaging of this
+** file. Please review the following information to ensure the GNU Lesser
+** General Public License version 2.1 requirements will be met:
+** http://www.gnu.org/licenses/old-licenses/lgpl-2.1.html.
+**
+** In addition, as a special exception, Nokia gives you certain additional
+** rights. These rights are described in the Nokia Qt LGPL Exception
+** version 1.1, included in the file LGPL_EXCEPTION.txt in this package.
+**
+** GNU General Public License Usage
+** Alternatively, this file may be used under the terms of the GNU General
+** Public License version 3.0 as published by the Free Software Foundation
+** and appearing in the file LICENSE.GPL included in the packaging of this
+** file. Please review the following information to ensure the GNU General
+** Public License version 3.0 requirements will be met:
+** http://www.gnu.org/copyleft/gpl.html.
+**
+** Other Usage
+** Alternatively, this file may be used in accordance with the terms and
+** conditions contained in a signed written agreement between you and Nokia.
+**
+**
+**
+**
+**
+** $QT_END_LICENSE$
+**
+****************************************************************************/
+
+#include "qgraphicssystemhelper_symbian.h"
+#include "qt_s60_p.h"
+#include "qwidget_p.h"
+
+QT_BEGIN_NAMESPACE
+
+/*!
+    \enum QSymbianGraphicsSystemHelper::NativePaintMode
+
+    This enum controls the way in which QWidget paints content from the Qt
+    backing store into the corresponding native window surface.
+
+    \value NativePaintModeDefault Default painting behaviour.
+    \value NativePaintModeZeroFill Ignore contents of backing store, and
+        fill the window surface region with zeroes.
+    \value NativePaintModeWriteAlpha By default, alpha values are only copied
+        from the backing store into the window surface if the top-level widget
+        has the Qt::WA_TranslucentBackground attribute.  If this mode is set,
+        alpha values are copied regardless of the value of that attribute.
+    \value NativePaintModeDisable Do not paint anything into the native window
+        surface.
+ */
+
+/*!
+    \class QSymbianGraphicsSystemHelper
+    \ingroup painting
+
+    \brief QSymbianGraphicsSystemHelper defines functions required by
+    QtMultimediaKit in order to enable video rendering.
+
+    This class is not intended for use by applications.
+*/
+
+/*!
+    Specify whether native focus change events should be ignored by the widget.
+*/
+
+void QSymbianGraphicsSystemHelper::setIgnoreFocusChanged(QWidget *widget, bool value)
+{
+    static_cast<QSymbianControl *>(widget->winId())->setIgnoreFocusChanged(value);
+}
+
+/*!
+    Set the native paint mode to the specified \a mode.
+*/
+
+void QSymbianGraphicsSystemHelper::setNativePaintMode(QWidget *widget, NativePaintMode mode)
+{
+    QWidgetPrivate *widgetPrivate = qt_widget_private(widget->window());
+    widgetPrivate->createExtra();
+    QWExtra::NativePaintMode widgetMode = QWExtra::Default;
+    switch (mode) {
+    case NativePaintModeDefault:
+        break;
+    case NativePaintModeZeroFill:
+        widgetMode = QWExtra::ZeroFill;
+        break;
+    case NativePaintModeWriteAlpha:
+        widgetMode = QWExtra::BlitWriteAlpha;
+        break;
+    case NativePaintModeDisable:
+        widgetMode = QWExtra::Disable;
+        break;
+    }
+    widgetPrivate->extraData()->nativePaintMode = widgetMode;
+}
+
+/*!
+    Set the native paint mode to the specified \a mode.
+*/
+
+void QSymbianGraphicsSystemHelper::setNativePaintMode(WId wid, NativePaintMode mode)
+{
+    QWidget *window = static_cast<QSymbianControl *>(wid)->widget()->window();
+    setNativePaintMode(window, mode);
+}
+
+/*!
+    Specify whether the widget should receive receive native paint events.
+
+    If enabled, the QWidget::beginNativePaintEvent slot is called before
+    content from the backing store is written into the native window
+    surface, and QWidget::endNativePaintEvent is called once writing to
+    the native window surface is complete.
+
+    This function is intended for use by QWidget clients such as video
+    widgets, which wish to use Direct Screen Access to write into the
+    native window surface.  Such clients should stop their DSA session on
+    receipt of QWidget::beginNativePaintEvent, and re-start it on receipt of
+    QWidget::endNativePaintEvent.
+*/
+
+void QSymbianGraphicsSystemHelper::setReceiveNativePaintEvents(QWidget *widget, bool value)
+{
+    QWidgetPrivate *widgetPrivate = qt_widget_private(widget);
+    widgetPrivate->createExtra();
+    widgetPrivate->extraData()->receiveNativePaintEvents = value;
+}
+
+QT_END_NAMESPACE
diff --git a/src/gui/painting/qgraphicssystemhelper_symbian.h b/src/gui/painting/qgraphicssystemhelper_symbian.h
new file mode 100644
index 0000000..b74144e
--- /dev/null
+++ b/src/gui/painting/qgraphicssystemhelper_symbian.h
@@ -0,0 +1,82 @@
+/****************************************************************************
+**
+** Copyright (C) 2011 Nokia Corporation and/or its subsidiary(-ies).
+** All rights reserved.
+** Contact: Nokia Corporation (qt-info@nokia.com)
+**
+** This file is part of the QtGui module of the Qt Toolkit.
+**
+** $QT_BEGIN_LICENSE:LGPL$
+** GNU Lesser General Public License Usage
+** This file may be used under the terms of the GNU Lesser General Public
+** License version 2.1 as published by the Free Software Foundation and
+** appearing in the file LICENSE.LGPL included in the packaging of this
+** file. Please review the following information to ensure the GNU Lesser
+** General Public License version 2.1 requirements will be met:
+** http://www.gnu.org/licenses/old-licenses/lgpl-2.1.html.
+**
+** In addition, as a special exception, Nokia gives you certain additional
+** rights. These rights are described in the Nokia Qt LGPL Exception
+** version 1.1, included in the file LGPL_EXCEPTION.txt in this package.
+**
+** GNU General Public License Usage
+** Alternatively, this file may be used under the terms of the GNU General
+** Public License version 3.0 as published by the Free Software Foundation
+** and appearing in the file LICENSE.GPL included in the packaging of this
+** file. Please review the following information to ensure the GNU General
+** Public License version 3.0 requirements will be met:
+** http://www.gnu.org/copyleft/gpl.html.
+**
+** Other Usage
+** Alternatively, this file may be used in accordance with the terms and
+** conditions contained in a signed written agreement between you and Nokia.
+**
+**
+**
+**
+**
+** $QT_END_LICENSE$
+**
+****************************************************************************/
+
+#ifndef QSYMBIANGRAPHICSSYSTEMHELPER_H
+#define QSYMBIANGRAPHICSSYSTEMHELPER_H
+
+#include <QtCore/qglobal.h>
+
+#ifndef Q_OS_SYMBIAN
+#error "This header file can only be included when building for Symbian"
+#endif
+
+#include <QtGui/qwindowdefs.h>
+
+QT_BEGIN_HEADER
+
+QT_BEGIN_NAMESPACE
+
+QT_MODULE(Gui)
+
+class QWidget;
+
+class Q_GUI_EXPORT QSymbianGraphicsSystemHelper
+{
+public:
+    enum NativePaintMode {
+        NativePaintModeDefault,
+        NativePaintModeZeroFill,
+        NativePaintModeWriteAlpha,
+        NativePaintModeDisable
+    };
+
+    static void setIgnoreFocusChanged(QWidget *widget, bool value);
+    static void setNativePaintMode(QWidget *widget, NativePaintMode mode);
+    static void setNativePaintMode(WId wid, NativePaintMode mode);
+    static void setReceiveNativePaintEvents(QWidget *widget, bool value);
+};
+
+QT_END_NAMESPACE
+
+QT_END_HEADER
+
+#endif // QSYMBIANGRAPHICSSYSTEMHELPER_H
+