Added workable QScreen API on top of QPlatformScreen.

QPlatformIntegration::screens() no longer has to be implemented,
implementations should call QPlatformIntegration::screenAdded() for each
screen instead. This is for being able to support adding screens at
run-time later on, by connecting it to a signal in QGuiApplication.

The QGuiGLContext API has changed a bit, by not sending in all the
parameters in the constructor but instead having a create() function.
The createPlatformGLContext() factory in QPlatformIntegration takes a
QGuiGLContext * instead of a QSurfaceFormat and a share context, similar
to how the window and backing store factory functions work.

The XCB plugin has experimental support for connecting to multiple X
displays simultaneously, creating one or more QScreen for each.

Change-Id: I248a22a4fd3481280710110272c04a30a8021e8f
Reviewed-on: http://codereview.qt.nokia.com/2103
Reviewed-by: Qt Sanity Bot <qt_sanity_bot@ovi.com>
Reviewed-by: Jørgen Lind <jorgen.lind@nokia.com>

15 files changed, 379 insertions, 69 deletions

diff --git a/src/gui/kernel/kernel.pri b/src/gui/kernel/kernel.pri
index 7f9434e9b4..58291f5237 100644
--- a/src/gui/kernel/kernel.pri
+++ b/src/gui/kernel/kernel.pri
@@ -20,6 +20,7 @@ HEADERS += \
         kernel/qpalette.h \
         kernel/qsessionmanager.h \
         kernel/qwindowdefs.h \
+        kernel/qscreen.h
 
 SOURCES += \
         kernel/qclipboard.cpp \
@@ -33,6 +34,7 @@ SOURCES += \
         kernel/qmime.cpp \
         kernel/qpalette.cpp \
         kernel/qguivariant.cpp \
+        kernel/qscreen.cpp
 
 qpa {
 	HEADERS += \
diff --git a/src/gui/kernel/qdnd_p.h b/src/gui/kernel/qdnd_p.h
index 2eebcf6158..7159acf594 100644
--- a/src/gui/kernel/qdnd_p.h
+++ b/src/gui/kernel/qdnd_p.h
@@ -113,7 +113,7 @@ class QShapedPixmapWindow : public QWindow {
     QPixmap pixmap;
 public:
     QShapedPixmapWindow() :
-        QWindow(0)
+        QWindow()
     {
         setWindowFlags(Qt::Tool | Qt::FramelessWindowHint | Qt::X11BypassWindowManagerHint);
         // ### Should we set the surface type to raster?
diff --git a/src/gui/kernel/qguiapplication.cpp b/src/gui/kernel/qguiapplication.cpp
index ad01a72a45..a54dab6398 100644
--- a/src/gui/kernel/qguiapplication.cpp
+++ b/src/gui/kernel/qguiapplication.cpp
@@ -52,6 +52,7 @@
 #include <QtCore/qmutex.h>
 #include <QtDebug>
 #include <qpalette.h>
+#include <qscreen.h>
 
 #include <QtGui/QPlatformIntegration>
 #include <QtGui/QGenericPluginFactory>
@@ -103,6 +104,8 @@ QGuiApplicationPrivate *QGuiApplicationPrivate::self = 0;
 QClipboard *QGuiApplicationPrivate::qt_clipboard = 0;
 #endif
 
+QList<QScreen *> QGuiApplicationPrivate::screen_list;
+
 QWindowList QGuiApplicationPrivate::window_list;
 QWindow *QGuiApplicationPrivate::active_window = 0;
 
@@ -179,21 +182,27 @@ QWindowList QGuiApplication::topLevelWindows()
     return QGuiApplicationPrivate::window_list;
 }
 
-QWindow *QGuiApplication::topLevelAt(const QPoint &pos)
+QScreen *QGuiApplication::primaryScreen()
 {
-    QPlatformIntegration *pi = QGuiApplicationPrivate::platformIntegration();
+    if (QGuiApplicationPrivate::screen_list.isEmpty())
+        return 0;
+    return QGuiApplicationPrivate::screen_list.at(0);
+}
 
-    QList<QPlatformScreen *> screens = pi->screens();
-    QList<QPlatformScreen *>::const_iterator screen = screens.constBegin();
-    QList<QPlatformScreen *>::const_iterator end = screens.constEnd();
+QList<QScreen *> QGuiApplication::screens()
+{
+    return QGuiApplicationPrivate::screen_list;
+}
 
-    // The first screen in a virtual environment should know about all top levels
-    if (pi->isVirtualDesktop())
-        return (*screen)->topLevelAt(pos);
+QWindow *QGuiApplication::topLevelAt(const QPoint &pos)
+{
+    QList<QScreen *> screens = QGuiApplication::screens();
+    QList<QScreen *>::const_iterator screen = screens.constBegin();
+    QList<QScreen *>::const_iterator end = screens.constEnd();
 
     while (screen != end) {
         if ((*screen)->geometry().contains(pos))
-            return (*screen)->topLevelAt(pos);
+            return (*screen)->handle()->topLevelAt(pos);
         ++screen;
     }
     return 0;
diff --git a/src/gui/kernel/qguiapplication.h b/src/gui/kernel/qguiapplication.h
index 4557b946a8..8338fa1f9a 100644
--- a/src/gui/kernel/qguiapplication.h
+++ b/src/gui/kernel/qguiapplication.h
@@ -57,6 +57,7 @@ QT_MODULE(Gui)
 class QGuiApplicationPrivate;
 class QPlatformNativeInterface;
 class QPalette;
+class QScreen;
 
 #if defined(qApp)
 #undef qApp
@@ -83,6 +84,8 @@ public:
     static QWindow *topLevelAt(const QPoint &pos);
 
     static QWindow *activeWindow();
+    static QScreen *primaryScreen();
+    static QList<QScreen *> screens();
 
 #ifndef QT_NO_CURSOR
     static QCursor *overrideCursor();
@@ -125,6 +128,7 @@ public:
 
 Q_SIGNALS:
     void fontDatabaseChanged();
+    void screenAdded(QScreen *screen);
 
 protected:
     bool event(QEvent *);
@@ -140,6 +144,7 @@ private:
     friend class QGestureManager;
 #endif
     friend class QFontDatabasePrivate;
+    friend class QPlatformIntegration;
 };
 
 QT_END_NAMESPACE
diff --git a/src/gui/kernel/qguiapplication_p.h b/src/gui/kernel/qguiapplication_p.h
index 6d44caa35a..8391662a4a 100644
--- a/src/gui/kernel/qguiapplication_p.h
+++ b/src/gui/kernel/qguiapplication_p.h
@@ -162,6 +162,7 @@ public:
 #ifndef QT_NO_CURSOR
     QList<QCursor> cursor_list;
 #endif
+    static QList<QScreen *> screen_list;
 
     static QFont *app_font;
 private:
diff --git a/src/gui/kernel/qguiglcontext_qpa.cpp b/src/gui/kernel/qguiglcontext_qpa.cpp
index fd827966c4..61a0479bd3 100644
--- a/src/gui/kernel/qguiglcontext_qpa.cpp
+++ b/src/gui/kernel/qguiglcontext_qpa.cpp
@@ -47,6 +47,7 @@
 #include <QtCore/QThread>
 
 #include <QtGui/private/qguiapplication_p.h>
+#include <QtGui/QScreen>
 
 #include <QDebug>
 
@@ -69,6 +70,7 @@ public:
         : qGLContextHandle(0)
         , platformGLContext(0)
         , shareContext(0)
+        , screen(0)
     {
     }
 
@@ -79,8 +81,11 @@ public:
     }
     void *qGLContextHandle;
     void (*qGLContextDeleteFunction)(void *handle);
+
+    QSurfaceFormat requestedFormat;
     QPlatformGLContext *platformGLContext;
     QGuiGLContext *shareContext;
+    QScreen *screen;
 
     static void setCurrentContext(QGuiGLContext *context);
 };
@@ -117,29 +122,87 @@ QPlatformGLContext *QGuiGLContext::handle() const
     return d->platformGLContext;
 }
 
+QPlatformGLContext *QGuiGLContext::shareHandle() const
+{
+    Q_D(const QGuiGLContext);
+    if (d->shareContext)
+        return d->shareContext->handle();
+    return 0;
+}
+
 /*!
-  Creates a new GL context with the given format and shared context.
+  Creates a new GL context instance, you need to call create() before it can be used.
 */
-QGuiGLContext::QGuiGLContext(const QSurfaceFormat &format, QGuiGLContext *shareContext)
+QGuiGLContext::QGuiGLContext()
     : d_ptr(new QGuiGLContextPrivate())
 {
     Q_D(QGuiGLContext);
-    QPlatformGLContext *share = shareContext ? shareContext->handle() : 0;
+    d->screen = QGuiApplication::primaryScreen();
+}
+
+/*!
+  Sets the format the GL context should be compatible with. You need to call create() before it takes effect.
+*/
+void QGuiGLContext::setFormat(const QSurfaceFormat &format)
+{
+    Q_D(QGuiGLContext);
+    d->requestedFormat = format;
+}
+
+/*!
+  Sets the context to share textures, shaders, and other GL resources with. You need to call create() before it takes effect.
+*/
+void QGuiGLContext::setShareContext(QGuiGLContext *shareContext)
+{
+    Q_D(QGuiGLContext);
     d->shareContext = shareContext;
-    d->platformGLContext = QGuiApplicationPrivate::platformIntegration()->createPlatformGLContext(format, share);
 }
 
 /*!
-  If this is the current context for the thread, doneCurrent is called
+  Sets the screen the GL context should be valid for. You need to call create() before it takes effect.
 */
-QGuiGLContext::~QGuiGLContext()
+void QGuiGLContext::setScreen(QScreen *screen)
+{
+    Q_D(QGuiGLContext);
+    d->screen = screen;
+    if (!d->screen)
+        d->screen = QGuiApplication::primaryScreen();
+}
+
+/*!
+  Attempts to create the GL context with the desired parameters.
+
+  Returns true if the native context was successfully created and is ready to be used.d
+*/
+bool QGuiGLContext::create()
+{
+    destroy();
+
+    Q_D(QGuiGLContext);
+    d->platformGLContext = QGuiApplicationPrivate::platformIntegration()->createPlatformGLContext(this);
+    return d->platformGLContext;
+}
+
+void QGuiGLContext::destroy()
 {
     Q_D(QGuiGLContext);
     if (QGuiGLContext::currentContext() == this)
         doneCurrent();
     delete d->platformGLContext;
+    d->platformGLContext = 0;
+}
+
+/*!
+  If this is the current context for the thread, doneCurrent is called
+*/
+QGuiGLContext::~QGuiGLContext()
+{
+    destroy();
 }
 
+/*!
+  Returns if this context is valid, i.e. has been successfully created.
+*/
 bool QGuiGLContext::isValid() const
 {
     Q_D(const QGuiGLContext);
@@ -210,18 +273,22 @@ QSurfaceFormat QGuiGLContext::format() const
 {
     Q_D(const QGuiGLContext);
     if (!d->platformGLContext)
-        return QSurfaceFormat();
+        return d->requestedFormat;
     return d->platformGLContext->format();
 }
 
 QGuiGLContext *QGuiGLContext::shareContext() const
 {
     Q_D(const QGuiGLContext);
-    if (!d->platformGLContext)
-        return 0;
     return d->shareContext;
 }
 
+QScreen *QGuiGLContext::screen() const
+{
+    Q_D(const QGuiGLContext);
+    return d->screen;
+}
+
 /*
   internal: Needs to have a pointer to qGLContext. But since this is in QtGui we cant
   have any type information.
diff --git a/src/gui/kernel/qguiglcontext_qpa.h b/src/gui/kernel/qguiglcontext_qpa.h
index 9e62905b68..db3d6f29e6 100644
--- a/src/gui/kernel/qguiglcontext_qpa.h
+++ b/src/gui/kernel/qguiglcontext_qpa.h
@@ -61,24 +61,30 @@ class Q_GUI_EXPORT QGuiGLContext
 {
 Q_DECLARE_PRIVATE(QGuiGLContext);
 public:
-    QGuiGLContext(const QSurfaceFormat &format = QSurfaceFormat(), QGuiGLContext *shareContext = 0);
+    QGuiGLContext();
     ~QGuiGLContext();
 
+    void setFormat(const QSurfaceFormat &format);
+    void setShareContext(QGuiGLContext *shareContext);
+    void setScreen(QScreen *screen);
+
+    bool create();
     bool isValid() const;
 
+    QSurfaceFormat format() const;
+    QGuiGLContext *shareContext() const;
+    QScreen *screen() const;
+
     bool makeCurrent(QSurface *surface);
     void doneCurrent();
 
     void swapBuffers(QSurface *surface);
     void (*getProcAddress(const QByteArray &procName)) ();
 
-    QSurfaceFormat format() const;
-
-    QGuiGLContext *shareContext() const;
-
     static QGuiGLContext *currentContext();
 
     QPlatformGLContext *handle() const;
+    QPlatformGLContext *shareHandle() const;
 
 private:
     QScopedPointer<QGuiGLContextPrivate> d_ptr;
@@ -91,6 +97,8 @@ private:
     void setQGLContextHandle(void *handle,void (*qGLContextDeleteFunction)(void *));
     void deleteQGLContext();
 
+    void destroy();
+
     Q_DISABLE_COPY(QGuiGLContext);
 };
 
diff --git a/src/gui/kernel/qplatformintegration_qpa.cpp b/src/gui/kernel/qplatformintegration_qpa.cpp
index ab0d5100c3..c190c4f481 100644
--- a/src/gui/kernel/qplatformintegration_qpa.cpp
+++ b/src/gui/kernel/qplatformintegration_qpa.cpp
@@ -44,21 +44,12 @@
 #include <QtGui/QPlatformFontDatabase>
 #include <QtGui/QPlatformClipboard>
 #include <QtGui/QPlatformPrinterSupport>
+#include <QtGui/private/qguiapplication_p.h>
+#include <QtGui/private/qpixmap_raster_p.h>
 #include <private/qdnd_p.h>
 
 QT_BEGIN_NAMESPACE
 
-QPixmap QPlatformIntegration::grabWindow(WId window, int x, int y, int width, int height) const
-{
-    Q_UNUSED(window);
-    Q_UNUSED(x);
-    Q_UNUSED(y);
-    Q_UNUSED(width);
-    Q_UNUSED(height);
-    return QPixmap();
-}
-
-
 /*!
     Accessor for the platform integrations fontdatabase.
 
@@ -177,12 +168,6 @@ QPlatformNativeInterface * QPlatformIntegration::nativeInterface() const
 */
 
 
-QPlatformGLContext *QPlatformIntegration::createPlatformGLContext(const QSurfaceFormat &, QPlatformGLContext *) const
-{
-    qWarning("This plugin does not support createPlatformGLContext!");
-    return 0;
-}
-
 /*!
     \fn void QPlatformIntegration::moveToScreen(QWindow *window, int screen)
 
@@ -212,15 +197,6 @@ QPlatformGLContext *QPlatformIntegration::createPlatformGLContext(const QSurface
 */
 
 /*!
-    \fn QPixmap QPlatformIntegration::grabWindow(WId window, int x, int y, int width, int height) const
-
-    This function is called when Qt needs to be able to grab the content of a window.
-
-    Returnes the content of the window specified with the WId handle within the boundaries of
-    QRect(x,y,width,height).
-*/
-
-/*!
     \fn QAbstractEventDispatcher *createEventDispatcher() const
 
     Factory function for the event dispatcher. The platform plugin
@@ -234,6 +210,17 @@ bool QPlatformIntegration::hasCapability(Capability cap) const
     return false;
 }
 
+QPlatformPixmap *QPlatformIntegration::createPlatformPixmap(QPlatformPixmap::PixelType type) const
+{
+    return new QRasterPlatformPixmap(type);
+}
+
+QPlatformGLContext *QPlatformIntegration::createPlatformGLContext(QGuiGLContext *context) const
+{
+    qWarning("This plugin does not support createPlatformGLContext!");
+    return 0;
+}
+
 /*!
 
     Returns the platform's printing support.
@@ -261,4 +248,24 @@ QPlatformInputContext *QPlatformIntegration::inputContext() const
     return 0;
 }
 
+/*!
+  Should be called by the implementation whenever a new screen is added.
+
+  The first screen added will be the primary screen, used for default-created
+  windows, GL contexts, and other resources unless otherwise specified.
+
+  This adds the screen to QGuiApplication::screens(), and emits the
+  QGuiApplication::screenAdded() signal.
+
+  The screen is automatically removed when the QPlatformScreen is destroyed.
+*/
+void QPlatformIntegration::screenAdded(QPlatformScreen *ps)
+{
+    QScreen *screen = ps ? ps->screen() : 0;
+    if (screen && !QGuiApplicationPrivate::screen_list.contains(screen)) {
+        QGuiApplicationPrivate::screen_list << screen;
+        emit qGuiApp->screenAdded(screen);
+    }
+}
+
 QT_END_NAMESPACE
diff --git a/src/gui/kernel/qplatformintegration_qpa.h b/src/gui/kernel/qplatformintegration_qpa.h
index 092186c160..35dfe07140 100644
--- a/src/gui/kernel/qplatformintegration_qpa.h
+++ b/src/gui/kernel/qplatformintegration_qpa.h
@@ -43,7 +43,6 @@
 #define QPLATFORMINTEGRATION_H
 
 #include <QtGui/qwindowdefs.h>
-#include <QtGui/qplatformpixmap_qpa.h>
 #include <QtGui/qplatformscreen_qpa.h>
 #include <QtGui/qsurfaceformat.h>
 
@@ -78,17 +77,10 @@ public:
 
     virtual bool hasCapability(Capability cap) const;
 
-// GraphicsSystem functions
-    virtual QPlatformPixmap *createPlatformPixmap(QPlatformPixmap::PixelType type) const = 0;
+    virtual QPlatformPixmap *createPlatformPixmap(QPlatformPixmap::PixelType type) const;
     virtual QPlatformWindow *createPlatformWindow(QWindow *window) const = 0;
     virtual QPlatformBackingStore *createPlatformBackingStore(QWindow *window) const = 0;
-    virtual QPlatformGLContext *createPlatformGLContext(const QSurfaceFormat &format, QPlatformGLContext *share) const;
-
-// Window System functions
-    virtual QList<QPlatformScreen *> screens() const = 0;
-    virtual void moveToScreen(QWindow *window, int screen) {Q_UNUSED(window); Q_UNUSED(screen);}
-    virtual bool isVirtualDesktop() { return false; }
-    virtual QPixmap grabWindow(WId window, int x, int y, int width, int height) const;
+    virtual QPlatformGLContext *createPlatformGLContext(QGuiGLContext *context) const;
 
 // Event dispatcher:
     virtual QAbstractEventDispatcher *createEventDispatcher() const = 0;
@@ -107,6 +99,9 @@ public:
     virtual QPlatformNativeInterface *nativeInterface() const;
 
     virtual QPlatformPrinterSupport *printerSupport() const;
+
+protected:
+    void screenAdded(QPlatformScreen *screen);
 };
 
 QT_END_NAMESPACE
diff --git a/src/gui/kernel/qplatformscreen_qpa.cpp b/src/gui/kernel/qplatformscreen_qpa.cpp
index 16b2557a15..ae1c6dcf06 100644
--- a/src/gui/kernel/qplatformscreen_qpa.cpp
+++ b/src/gui/kernel/qplatformscreen_qpa.cpp
@@ -43,8 +43,47 @@
 #include <QtGui/qguiapplication.h>
 #include <QtGui/private/qguiapplication_p.h>
 #include <QtGui/qplatformintegration_qpa.h>
+#include <QtGui/qscreen.h>
 #include <QtGui/qwindow.h>
 
+struct QPlatformScreenPrivate
+{
+    QScreen *screen;
+};
+
+QPlatformScreen::QPlatformScreen()
+    : d_ptr(new QPlatformScreenPrivate)
+{
+    Q_D(QPlatformScreen);
+    d->screen = new QScreen(this);
+}
+
+QPlatformScreen::~QPlatformScreen()
+{
+    Q_D(QPlatformScreen);
+
+    QGuiApplicationPrivate::screen_list.removeOne(d->screen);
+    delete d->screen;
+}
+
+/*!
+    \fn QPixmap QPlatformScreen::grabWindow(WId window, int x, int y, int width, int height) const
+
+    This function is called when Qt needs to be able to grab the content of a window.
+
+    Returnes the content of the window specified with the WId handle within the boundaries of
+    QRect(x,y,width,height).
+*/
+QPixmap QPlatformScreen::grabWindow(WId window, int x, int y, int width, int height) const
+{
+    Q_UNUSED(window);
+    Q_UNUSED(x);
+    Q_UNUSED(y);
+    Q_UNUSED(width);
+    Q_UNUSED(height);
+    return QPixmap();
+}
+
 /*!
     Return the given top level window for a given position.
 
@@ -64,6 +103,26 @@ QWindow *QPlatformScreen::topLevelAt(const QPoint & pos) const
 }
 
 /*!
+    Returns a list of all the platform screens that are part of the same
+    virtual desktop.
+
+    Screens part of the same virtual desktop share a common coordinate system,
+    and windows can be freely moved between them.
+*/
+QList<QPlatformScreen *> QPlatformScreen::virtualSiblings() const
+{
+    QList<QPlatformScreen *> list;
+    list << const_cast<QPlatformScreen *>(this);
+    return list;
+}
+
+QScreen *QPlatformScreen::screen() const
+{
+    Q_D(const QPlatformScreen);
+    return d->screen;
+}
+
+/*!
     Reimplement this function in subclass to return the physical size of the
     screen. This function is used by QFont to convert point sizes to pixel
     sizes.
@@ -81,9 +140,9 @@ QSize QPlatformScreen::physicalSize() const
     return QSize(width,height);
 }
 
-QPlatformScreen * QPlatformScreen::platformScreenForWindow(const QWindow *)
+QPlatformScreen * QPlatformScreen::platformScreenForWindow(const QWindow *window)
 {
-    return QGuiApplicationPrivate::platformIntegration()->screens().at(0);
+    return window->screen()->handle();
 }
 
 /*!
diff --git a/src/gui/kernel/qplatformscreen_qpa.h b/src/gui/kernel/qplatformscreen_qpa.h
index 16e62dd6c6..8d3dd4cc71 100644
--- a/src/gui/kernel/qplatformscreen_qpa.h
+++ b/src/gui/kernel/qplatformscreen_qpa.h
@@ -52,6 +52,7 @@
 #include <QtGui/qcursor.h>
 #include <QtGui/qimage.h>
 #include <QtGui/qwindowdefs.h>
+#include <QtGui/qplatformpixmap_qpa.h>
 
 QT_BEGIN_HEADER
 
@@ -59,24 +60,46 @@ QT_BEGIN_NAMESPACE
 
 QT_MODULE(Gui)
 
-class Q_GUI_EXPORT QPlatformScreen : public QObject
+class QPlatformBackingStore;
+class QPlatformGLContext;
+class QPlatformScreenPrivate;
+class QPlatformWindow;
+class QScreen;
+class QSurfaceFormat;
+
+class Q_GUI_EXPORT QPlatformScreen
 {
-    Q_OBJECT
+    Q_DECLARE_PRIVATE(QPlatformScreen)
+
 public:
-    virtual ~QPlatformScreen() { }
+    QPlatformScreen();
+    virtual ~QPlatformScreen();
+
+    virtual QPixmap grabWindow(WId window, int x, int y, int width, int height) const;
 
     virtual QRect geometry() const = 0;
     virtual QRect availableGeometry() const {return geometry();}
+
     virtual int depth() const = 0;
     virtual QImage::Format format() const = 0;
     virtual QSize physicalSize() const;
-    //jl: should setDirty be removed.
-    virtual void setDirty(const QRect &) {}
+
     virtual QWindow *topLevelAt(const QPoint &point) const;
+    virtual QList<QPlatformScreen *> virtualSiblings() const;
+
+    QScreen *screen() const;
 
     //jl: should this function be in QPlatformIntegration
     //jl: maybe screenForWindow is a better name?
     static QPlatformScreen *platformScreenForWindow(const QWindow *window);
+
+    virtual QString name() const { return QString(); }
+
+protected:
+    QScopedPointer<QPlatformScreenPrivate> d_ptr;
+
+private:
+    Q_DISABLE_COPY(QPlatformScreen)
 };
 
 QT_END_NAMESPACE
diff --git a/src/gui/kernel/qscreen.h b/src/gui/kernel/qscreen.h
new file mode 100644
index 0000000000..f96056e45a
--- /dev/null
+++ b/src/gui/kernel/qscreen.h
@@ -0,0 +1,95 @@
+/****************************************************************************
+**
+** 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.
+**
+** $QT_BEGIN_LICENSE:LGPL$
+** No Commercial Usage
+** This file contains pre-release code and may not be distributed.
+** You may use this file in accordance with the terms and conditions
+** contained in the Technology Preview License Agreement accompanying
+** this package.
+**
+** GNU Lesser General Public License Usage
+** Alternatively, 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.
+**
+** If you have questions regarding the use of this file, please contact
+** Nokia at qt-info@nokia.com.
+**
+**
+**
+**
+**
+**
+**
+**
+** $QT_END_LICENSE$
+**
+****************************************************************************/
+
+#ifndef QSCREEN_H
+#define QSCREEN_H
+
+QT_BEGIN_HEADER
+
+QT_BEGIN_NAMESPACE
+
+QT_MODULE(Gui)
+
+#include <QList>
+
+class QPlatformScreen;
+class QScreenPrivate;
+class QWindow;
+
+class Q_GUI_EXPORT QScreen : public QObject
+{
+    Q_OBJECT
+    Q_DECLARE_PRIVATE(QScreen)
+
+public:
+    QPlatformScreen *handle() const;
+
+    QString name() const;
+
+    int depth() const;
+
+    QSize size() const;
+    QRect geometry() const;
+
+    QSize availableSize() const;
+    QRect availableGeometry() const;
+
+    QList<QScreen *> virtualSiblings() const;
+
+    QSize virtualSize() const;
+    QRect virtualGeometry() const;
+
+    QSize availableVirtualSize() const;
+    QRect availableVirtualGeometry() const;
+
+private:
+    QScreen(QPlatformScreen *screen);
+
+    Q_DISABLE_COPY(QScreen)
+    friend class QPlatformScreen;
+};
+
+QT_END_NAMESPACE
+
+QT_END_HEADER
+
+#endif // QSCREEN_H
+
diff --git a/src/gui/kernel/qwindow.cpp b/src/gui/kernel/qwindow.cpp
index 7fa9316878..018474aba7 100644
--- a/src/gui/kernel/qwindow.cpp
+++ b/src/gui/kernel/qwindow.cpp
@@ -45,6 +45,7 @@
 #include "qsurfaceformat.h"
 #include "qplatformglcontext_qpa.h"
 #include "qguiglcontext_qpa.h"
+#include "qscreen.h"
 
 #include "qwindow_p.h"
 #include "qguiapplication_p.h"
@@ -55,12 +56,27 @@
 
 QT_BEGIN_NAMESPACE
 
+QWindow::QWindow(QScreen *targetScreen)
+    : QObject(*new QWindowPrivate(), 0)
+    , QSurface(QSurface::Window)
+{
+    Q_D(QWindow);
+    d->screen = targetScreen;
+    if (!d->screen)
+        d->screen = QGuiApplication::primaryScreen();
+    QGuiApplicationPrivate::window_list.prepend(this);
+}
+
 QWindow::QWindow(QWindow *parent)
     : QObject(*new QWindowPrivate(), parent)
     , QSurface(QSurface::Window)
 {
     Q_D(QWindow);
     d->parentWindow = parent;
+    if (parent)
+        d->screen = parent->screen();
+    if (!d->screen)
+        d->screen = QGuiApplication::primaryScreen();
     QGuiApplicationPrivate::window_list.prepend(this);
 }
 
@@ -439,6 +455,23 @@ bool QWindow::setMouseGrabEnabled(bool grab)
     return false;
 }
 
+QScreen *QWindow::screen() const
+{
+    Q_D(const QWindow);
+    return d->screen;
+}
+
+void QWindow::setScreen(QScreen *newScreen)
+{
+    Q_D(QWindow);
+    bool wasCreated = d->platformWindow != 0;
+    if (wasCreated)
+        destroy();
+    d->screen = newScreen ? newScreen : QGuiApplication::primaryScreen();
+    if (wasCreated)
+        create();
+}
+
 void QWindow::showMinimized()
 {
     qDebug() << "unimplemented:" << __FILE__ << __LINE__;
@@ -486,7 +519,6 @@ void QWindow::hideEvent(QHideEvent *)
 
 bool QWindow::event(QEvent *event)
 {
-    Q_D(QWindow);
     switch (event->type()) {
     case QEvent::MouseMove:
         mouseMoveEvent(static_cast<QMouseEvent*>(event));
diff --git a/src/gui/kernel/qwindow.h b/src/gui/kernel/qwindow.h
index 67330e5291..adf948b65e 100644
--- a/src/gui/kernel/qwindow.h
+++ b/src/gui/kernel/qwindow.h
@@ -71,6 +71,7 @@ class QWheelEvent;
 class QPlatformSurface;
 class QPlatformWindow;
 class QBackingStore;
+class QScreen;
 
 class Q_GUI_EXPORT QSurface
 {
@@ -102,7 +103,8 @@ class Q_GUI_EXPORT QWindow : public QObject, public QSurface
 public:
     enum SurfaceType { RasterSurface, OpenGLSurface };
 
-    QWindow(QWindow *parent = 0);
+    QWindow(QScreen *screen = 0);
+    QWindow(QWindow *parent);
     virtual ~QWindow();
 
     void setSurfaceType(SurfaceType surfaceType);
@@ -166,6 +168,9 @@ public:
     bool setKeyboardGrabEnabled(bool grab);
     bool setMouseGrabEnabled(bool grab);
 
+    QScreen *screen() const;
+    void setScreen(QScreen *screen);
+
 public Q_SLOTS:
     inline void show() { setVisible(true); }
     inline void hide() { setVisible(false); }
diff --git a/src/gui/kernel/qwindow_p.h b/src/gui/kernel/qwindow_p.h
index cca20bc30a..2016c42d7e 100644
--- a/src/gui/kernel/qwindow_p.h
+++ b/src/gui/kernel/qwindow_p.h
@@ -68,6 +68,7 @@ public:
         , maximumSize(QWINDOWSIZE_MAX, QWINDOWSIZE_MAX)
         , modality(Qt::NonModal)
         , transientParent(0)
+        , screen(0)
     {
         isWindow = true;
     }
@@ -93,6 +94,7 @@ public:
 
     Qt::WindowModality modality;
     QPointer<QWindow> transientParent;
+    QScreen *screen;
 };