C++/Qt/QRadialGradient

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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.
    • $QT_END_LICENSE$
                                                                                                                                                        • /
  1. 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.
*
*/
  1. include <QApplication>
  2. include <QPainter>
  3. include <QBrush>
  4. 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.
    • $QT_END_LICENSE$
                                                                                                                                                        • /
  1. 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">

  1. 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>
Источник — «http://cppe.ru/index.php?title=C%2B%2B/Qt/QRadialGradient&oldid=1129»