Просмотр исходного текста страницы C++/Qt/QRadialGradient

==Create color from RGB value==


   
<source lang="cpp">  
/****************************************************************************
**
** Copyright (C) 2009 Nokia Corporation and/or its subsidiary(-ies).
** All rights reserved.
** Contact: Nokia Corporation (qt-info@nokia.com)
**
** This file is part of the documentation of the Qt Toolkit.
**
** $QT_BEGIN_LICENSE:LGPL$
** Commercial Usage
** Licensees holding valid Qt Commercial licenses may use this file in
** accordance with the Qt Commercial License Agreement provided with the
** Software or, alternatively, in accordance with the terms contained in
** a written agreement between you and Nokia.
**
** 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, Nokia gives you certain additional
** rights.  These rights are described in the Nokia 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.
**
** If you have questions regarding the use of this file, please contact
** Nokia at qt-info@nokia.com.
** $QT_END_LICENSE$
**
****************************************************************************/
#include <QtGui>
int main(int argv, char **args)
{
    QApplication app(argv, args);
    QRadialGradient gradient(50, 50, 50, 50, 50);
    gradient.setColorAt(0, QColor::fromRgbF(0, 1, 0, 1));
    gradient.setColorAt(1, QColor::fromRgbF(0, 0, 0, 0));
    QBrush brush(gradient);
    QWidget widget;
    QPalette palette;
    palette.setBrush(widget.backgroundRole(), brush);
    widget.setPalette(palette);
    widget.show();
    return app.exec();
}
   
    
  </source>


==Draw in QRadialGradient==


   
<source lang="cpp">  
Foundations of Qt Development\Chapter07\brushgradients\main.cpp
/*
 * Copyright (c) 2006-2007, Johan Thelin
 * 
 * All rights reserved.
 * 
 * Redistribution and use in source and binary forms, with or without modification, 
 * are permitted provided that the following conditions are met:
 * 
 *     * Redistributions of source code must retain the above copyright notice, 
 *       this list of conditions and the following disclaimer.
 *     * Redistributions in binary form must reproduce the above copyright notice,  
 *       this list of conditions and the following disclaimer in the documentation 
 *       and/or other materials provided with the distribution.
 *     * Neither the name of APress nor the names of its contributors 
 *       may be used to endorse or promote products derived from this software 
 *       without specific prior written permission.
 * 
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
 * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR
 * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
 * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
 * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
 * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
 * LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
 * NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
 * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 *
 */
#include <QApplication>
#include <QPainter>
#include <QBrush>
#include <QPixmap>
void createBrushShot( QBrush brush, QString name )
{
  QPixmap pixmap( 200, 200 );
  pixmap.fill( Qt::white );
  
  QPainter painter( &pixmap );
  
  painter.setBrush( brush );
  painter.drawRect( pixmap.rect() );
  
  pixmap.save( QString("%1.png").arg( name ) );
}
int main( int argc, char **argv )
{
  QApplication app( argc, argv );
  
  QLinearGradient linGrad( QPointF(80, 80), QPoint( 120, 120 ) );
  linGrad.setColorAt( 0, Qt::black );
  linGrad.setColorAt( 1, Qt::white );
    
  linGrad.setSpread( QGradient::PadSpread );
  createBrushShot( QBrush( linGrad ), "LinearPad" );
  linGrad.setSpread( QGradient::RepeatSpread );
  createBrushShot( QBrush( linGrad ), "LinearRepeat" );
  linGrad.setSpread( QGradient::ReflectSpread );
  createBrushShot( QBrush( linGrad ), "LinearReflect" );  
  QRadialGradient radGrad( QPointF(100, 100), 30 );
  radGrad.setColorAt( 0, Qt::black );
  radGrad.setColorAt( 1, Qt::white );
  
  radGrad.setSpread( QGradient::PadSpread );
  createBrushShot( QBrush( radGrad ), "RadialPad" );
  radGrad.setSpread( QGradient::RepeatSpread );
  createBrushShot( QBrush( radGrad ), "RadialRepeat" );
  radGrad.setSpread( QGradient::ReflectSpread );
  createBrushShot( QBrush( radGrad ), "RadialReflect" );
  
  QConicalGradient conGrad( QPointF(100, 100), -45.0 );
  conGrad.setColorAt( 0, Qt::black );
  conGrad.setColorAt( 1, Qt::white );
  
  conGrad.setSpread( QGradient::PadSpread );
  createBrushShot( QBrush( conGrad ), "ConicalPad" );
  conGrad.setSpread( QGradient::RepeatSpread );
  createBrushShot( QBrush( conGrad ), "ConicalRepeat" );
  conGrad.setSpread( QGradient::ReflectSpread );
  createBrushShot( QBrush( conGrad ), "ConicalReflect" );
  
  QBrush textureBrush( QImage("texture.png") );
  createBrushShot( textureBrush, "TextureBrush" );
  
  return 0;
}
   
    
  </source>


==Radial Gradient==


   
<source lang="cpp">  
/****************************************************************************
**
** Copyright (C) 2009 Nokia Corporation and/or its subsidiary(-ies).
** All rights reserved.
** Contact: Nokia Corporation (qt-info@nokia.com)
**
** This file is part of the documentation of the Qt Toolkit.
**
** $QT_BEGIN_LICENSE:LGPL$
** Commercial Usage
** Licensees holding valid Qt Commercial licenses may use this file in
** accordance with the Qt Commercial License Agreement provided with the
** Software or, alternatively, in accordance with the terms contained in
** a written agreement between you and Nokia.
**
** 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, Nokia gives you certain additional
** rights.  These rights are described in the Nokia 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.
**
** If you have questions regarding the use of this file, please contact
** Nokia at qt-info@nokia.com.
** $QT_END_LICENSE$
**
****************************************************************************/
#include <QtGui>
int main(int argv, char **args)
{
    QApplication app(argv, args);
    QRadialGradient gradient(50, 50, 50, 50, 50);
    gradient.setColorAt(0, QColor::fromRgbF(0, 1, 0, 1));
    gradient.setColorAt(1, QColor::fromRgbF(0, 0, 0, 0));
    QBrush brush(gradient);
    QWidget widget;
    QPalette palette;
    palette.setBrush(widget.backgroundRole(), brush);
    widget.setPalette(palette);
    widget.show();
    return app.exec();
}
   
    
  </source>


==Three color QRadialGradient==


   
<source lang="cpp">  
#include <QtGui>
int main(int argv, char **args)
{
    QApplication app(argv, args);
    QRadialGradient radialGrad(QPointF(100, 100), 100);
    radialGrad.setColorAt(0, Qt::red);
    radialGrad.setColorAt(0.5, Qt::blue);
    radialGrad.setColorAt(1, Qt::green);
    QBrush brush(radialGrad);
    QWidget widget;
    QPalette palette;
    palette.setBrush(widget.backgroundRole(), brush);
    widget.setPalette(palette);
    widget.show();
    return app.exec();
}
   
    
  </source>