diff options
Diffstat (limited to 'src/plugins/platforms/direct2d/qwindowsdirect2ddevicecontext.h')
-rw-r--r-- | src/plugins/platforms/direct2d/qwindowsdirect2ddevicecontext.h | 95 |
1 files changed, 95 insertions, 0 deletions
diff --git a/src/plugins/platforms/direct2d/qwindowsdirect2ddevicecontext.h b/src/plugins/platforms/direct2d/qwindowsdirect2ddevicecontext.h new file mode 100644 index 0000000000..4986efb967 --- /dev/null +++ b/src/plugins/platforms/direct2d/qwindowsdirect2ddevicecontext.h @@ -0,0 +1,95 @@ +/**************************************************************************** +** +** 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 |