File indexing completed on 2024-05-12 15:54:18

0001 /*
0002  * Copyright (C) 2001-2015 Klaralvdalens Datakonsult AB.  All rights reserved.
0003  *
0004  * This file is part of the KD Chart library.
0005  *
0006  * This program is free software; you can redistribute it and/or
0007  * modify it under the terms of the GNU General Public License as
0008  * published by the Free Software Foundation; either version 2 of
0009  * the License, or (at your option) any later version.
0010  *
0011  * This program is distributed in the hope that it will be useful,
0012  * but WITHOUT ANY WARRANTY; without even the implied warranty of
0013  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
0014  * GNU General Public License for more details.
0015  *
0016  * You should have received a copy of the GNU General Public License
0017  * along with this program.  If not, see <https://www.gnu.org/licenses/>.
0018  */
0019 
0020 #ifndef KCHARTPAINTERSAVER_P_H
0021 #define KCHARTPAINTERSAVER_P_H
0022 
0023 //
0024 //  W A R N I N G
0025 //  -------------
0026 //
0027 // This file is not part of the KD Chart API.  It exists purely as an
0028 // implementation detail.  This header file may change from version to
0029 // version without notice, or even be removed.
0030 //
0031 // We mean it.
0032 //
0033 
0034 #include "KChartMath_p.h"
0035 
0036 #include <qpainter.h>
0037 
0038 
0039 namespace KChart {
0040 
0041 /**
0042    \internal
0043 
0044    @short Resource Allocation Is Initialization for QPainter::save and
0045    restore
0046 
0047    Usage:
0048 
0049    Instead of
0050    \code
0051    painter.save();
0052    // ...
0053    painter.restore();
0054    \endcode
0055 
0056    Use this:
0057 
0058    \code
0059    const KChart::PainterSaver saver( &painter );
0060    // ...
0061    \endcode
0062 
0063    which makes sure that restore() is called when exiting from guard
0064    clauses, or when exceptions are thrown.
0065 */
0066 class PainterSaver {
0067     Q_DISABLE_COPY( PainterSaver )
0068 public:
0069     explicit PainterSaver( QPainter* p )
0070         : painter( p ) 
0071     {
0072 #if defined Q_OS_WIN
0073         static bool initialized = false;
0074         static bool isQt4_3_0;
0075         if ( !initialized )
0076         {
0077             isQt4_3_0 = ( QString::fromLatin1( qVersion() ) == QString::fromLatin1( "4.3.0" ) );
0078         }
0079         initialized = true;
0080         m_isQt4_3_0 = isQt4_3_0;
0081 #endif
0082         p->save();
0083     }
0084 
0085     ~PainterSaver()
0086     {
0087 #if defined Q_OS_WIN
0088         // the use of setClipRect is a workaround for a bug in Qt 4.3.0 which could
0089         // lead to an assert on Windows
0090         if ( m_isQt4_3_0 )
0091         {
0092             painter->setClipRect( 0, 0, 2, 2 );
0093         }
0094 #endif
0095         painter->restore(); 
0096     }
0097 
0098 private:
0099 #if defined Q_OS_WIN
0100     bool m_isQt4_3_0;
0101 #endif
0102     QPainter* const painter;
0103 };
0104 
0105 }
0106 
0107 #endif /* KCHARTPAINTERSAVER_P_H */
0108