1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
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
|
