Introduce QRasterWindow

A simple convenience class providing a QWindow that has a
paintEvent and supports opening a painter on itself. It
behaves exactly like QOpenGLWindow in this respect, which is not
surprising since they share the same base class (QPaintDeviceWindow).

QRasterWindow does not however have any OpenGL dependencies and will
be present in -no-opengl builds too.

[ChangeLog] Added QRasterWindow, a thin convenience wrapper for a
QWindow on which a QPainter can be opened.

Done-with: Jorgen Lind <jorgen.lind@digia.com>
Change-Id: I37e82720492945d7b85d5f713eea8d5f7556e511
Reviewed-by: Allan Sandfeld Jensen <allan.jensen@digia.com>

1 files changed, 136 insertions, 0 deletions

diff --git a/src/gui/kernel/qrasterwindow.cpp b/src/gui/kernel/qrasterwindow.cpp
new file mode 100644
index 0000000000..5f4d707f86
--- /dev/null
+++ b/src/gui/kernel/qrasterwindow.cpp
@@ -0,0 +1,136 @@
+/****************************************************************************
+ **
+ ** Copyright (C) 2014 Digia Plc and/or its subsidiary(-ies).
+ ** Contact: http://www.qt-project.org/legal
+ **
+ ** This file is part of the QtGui module of the Qt Toolkit.
+ **
+ ** $QT_BEGIN_LICENSE:LGPL$
+ ** Commercial License Usage
+ ** Licensees holding valid commercial Qt licenses may use this file in
+ ** accordance with the commercial license agreement provided with the
+ ** Software or, alternatively, in accordance with the terms contained in
+ ** a written agreement between you and Digia.  For licensing terms and
+ ** conditions see http://qt.digia.com/licensing.  For further information
+ ** use the contact form at http://qt.digia.com/contact-us.
+ **
+ ** 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, Digia gives you certain additional
+ ** rights.  These rights are described in the Digia 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.
+ **
+ **
+ ** $QT_END_LICENSE$
+ **
+ ****************************************************************************/
+
+#include "qrasterwindow.h"
+
+#include <QtGui/private/qpaintdevicewindow_p.h>
+
+#include <QtGui/QBackingStore>
+#include <QtGui/QPainter>
+
+QT_BEGIN_NAMESPACE
+
+/*!
+  \class QRasterWindow
+  \inmodule QtGui
+  \since 5.4
+  \brief QRasterWindow is a convenience class for using QPainter on a QWindow
+
+  QRasterWindow is a QWindow with a raster-based, non-OpenGL surface. On top of
+  the functionality offered by QWindow, QRasterWindow adds a virtual
+  paintEvent() function and the possibility to open a QPainter on itself. The
+  underlying paint engine will be the raster one, meaning that all drawing will
+  happen on the CPU. For performing accelerated, OpenGL-based drawing, use
+  QOpenGLWindow instead.
+
+  Internally the class is thin wrapper for QWindow and QBackingStore
+  and is very similar to the \l{Raster Window Example}{Raster Window
+  Example} that uses these classes directly.
+
+  \sa QPaintDeviceWindow::paintEvent(), QPaintDeviceWindow::update()
+*/
+
+class QRasterWindowPrivate : public QPaintDeviceWindowPrivate
+{
+    Q_DECLARE_PUBLIC(QRasterWindow)
+public:
+    void beginPaint(const QRegion &region) Q_DECL_OVERRIDE
+    {
+        Q_Q(QRasterWindow);
+        if (backingstore->size() != q->size()) {
+            backingstore->resize(q->size());
+            markWindowAsDirty();
+        }
+        backingstore->beginPaint(region);
+    }
+
+    void endPaint() Q_DECL_OVERRIDE
+    {
+        backingstore->endPaint();
+    }
+
+    void flush(const QRegion &region) Q_DECL_OVERRIDE
+    {
+        Q_Q(QRasterWindow);
+        backingstore->flush(region, q);
+    }
+
+    QScopedPointer<QBackingStore> backingstore;
+};
+
+/*!
+  Constructs a new QRasterWindow with \a parent.
+*/
+QRasterWindow::QRasterWindow(QWindow *parent)
+    : QPaintDeviceWindow(*(new QRasterWindowPrivate), parent)
+{
+    setSurfaceType(QSurface::RasterSurface);
+    d_func()->backingstore.reset(new QBackingStore(this));
+}
+
+/*!
+  \internal
+*/
+int QRasterWindow::metric(PaintDeviceMetric metric) const
+{
+    Q_D(const QRasterWindow);
+
+    switch (metric) {
+    case PdmDepth:
+        return d->backingstore->paintDevice()->depth();
+    case PdmDevicePixelRatio:
+        return d->backingstore->paintDevice()->devicePixelRatio();
+    default:
+        break;
+    }
+    return QPaintDeviceWindow::metric(metric);
+}
+
+/*!
+  \internal
+*/
+QPaintDevice *QRasterWindow::redirected(QPoint *) const
+{
+    Q_D(const QRasterWindow);
+    return d->backingstore->paintDevice();
+}
+
+QT_END_NAMESPACE