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+/****************************************************************************
+**
+** Copyright (C) 2013 Digia Plc and/or its subsidiary(-ies).
+** Contact: http://www.qt-project.org/legal
+**
+** This file is part of the plugins 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.
+**
+**
+** $QT_END_LICENSE$
+**
+****************************************************************************/
+
+#ifndef QWINDOWSDIRECT2DDEVICECONTEXT_H
+#define QWINDOWSDIRECT2DDEVICECONTEXT_H
+
+#include "qwindowsdirect2dhelpers.h"
+
+#include <QtCore/QScopedPointer>
+
+QT_BEGIN_NAMESPACE
+
+/*
+ * Convenience class for handling device contexts. We have to call BeginDraw
+ * before anything can happen, and EndDraw once we're done, for every frame and
+ * pretty much any kind of operation.
+ *
+ * Unfortunately, these calls cannot be interleaved, and there is no way to check
+ * what state a device context is in.
+ *
+ * The end result is that the following throws an error if we don't track it:
+ * QPixmap pmap;
+ * QPainter painter(&pmap);
+ * pmap.clear();
+ *
+ * Here BeginDraw would first be called through the paint device, then when we clear
+ * the pixmap we would have to call it again. There is no way to know what state
+ * the device context is in when performing the clear, and activating the dc is an
+ * error. Bummer.
+ *
+ * Hence we keep a reference count here and only activate/deactivate the device
+ * if the refcount is zero.
+ *
+ * In a nutshell: Do not call BeginDraw/EndDraw yourself on the device pointer, do
+ * so through the begin/end members below.
+ */
+
+class QWindowsDirect2DDeviceContextPrivate;
+class QWindowsDirect2DDeviceContext
+{
+ Q_DECLARE_PRIVATE(QWindowsDirect2DDeviceContext)
+public:
+ QWindowsDirect2DDeviceContext(ID2D1DeviceContext *dc);
+ ~QWindowsDirect2DDeviceContext();
+
+ ID2D1DeviceContext *get() const;
+
+ void begin();
+ bool end();
+
+private:
+ QScopedPointer<QWindowsDirect2DDeviceContextPrivate> d_ptr;
+};
+
+QT_END_NAMESPACE
+
+#endif // QWINDOWSDIRECT2DDEVICECONTEXT_H