Home · All Classes · Main Classes · Grouped Classes · Modules · Functions

circlewidget.cpp Example File
painting/concentriccircles/circlewidget.cpp

 /****************************************************************************
 **
 ** Copyright (C) 2005-2008 Trolltech ASA. All rights reserved.
 **
 ** This file is part of the documentation of the Qt Toolkit.
 **
 ** This file may be used under the terms of the GNU General Public
** License versions 2.0 or 3.0 as published by the Free Software
** Foundation and appearing in the files LICENSE.GPL2 and LICENSE.GPL3
** included in the packaging of this file.  Alternatively you may (at
** your option) use any later version of the GNU General Public
** License if such license has been publicly approved by Trolltech ASA
** (or its successors, if any) and the KDE Free Qt Foundation. In
** addition, as a special exception, Trolltech gives you certain
** additional rights. These rights are described in the Trolltech GPL
** Exception version 1.2, which can be found at
** http://www.trolltech.com/products/qt/gplexception/ and in the file
** GPL_EXCEPTION.txt in this package.
**
** Please review the following information to ensure GNU General
** Public Licensing requirements will be met:
** http://trolltech.com/products/qt/licenses/licensing/opensource/. If
** you are unsure which license is appropriate for your use, please
** review the following information:
** http://trolltech.com/products/qt/licenses/licensing/licensingoverview
** or contact the sales department at sales@trolltech.com.
**
** In addition, as a special exception, Trolltech, as the sole
** copyright holder for Qt Designer, grants users of the Qt/Eclipse
** Integration plug-in the right for the Qt/Eclipse Integration to
** link to functionality provided by Qt Designer and its related
** libraries.
**
** This file is provided "AS IS" with NO WARRANTY OF ANY KIND,
** INCLUDING THE WARRANTIES OF DESIGN, MERCHANTABILITY AND FITNESS FOR
** A PARTICULAR PURPOSE. Trolltech reserves all rights not expressly
** granted herein.
 **
 ** This file is provided AS IS with NO WARRANTY OF ANY KIND, INCLUDING THE
 ** WARRANTY OF DESIGN, MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE.
 **
 ****************************************************************************/

 #include <QtGui>

 #include "circlewidget.h"

 #include <stdlib.h>

 CircleWidget::CircleWidget(QWidget *parent)
     : QWidget(parent)
 {
     floatBased = false;
     antialiased = false;
     frameNo = 0;

     setBackgroundRole(QPalette::Base);
     setSizePolicy(QSizePolicy::Expanding, QSizePolicy::Expanding);
 }

 void CircleWidget::setFloatBased(bool floatBased)
 {
     this->floatBased = floatBased;
     update();
 }

 void CircleWidget::setAntialiased(bool antialiased)
 {
     this->antialiased = antialiased;
     update();
 }

 QSize CircleWidget::minimumSizeHint() const
 {
     return QSize(50, 50);
 }

 QSize CircleWidget::sizeHint() const
 {
     return QSize(180, 180);
 }

 void CircleWidget::nextAnimationFrame()
 {
     ++frameNo;
     update();
 }

 void CircleWidget::paintEvent(QPaintEvent *)
 {
     QPainter painter(this);
     painter.setRenderHint(QPainter::Antialiasing, antialiased);
     painter.translate(width() / 2, height() / 2);

     for (int diameter = 0; diameter < 256; diameter += 9) {
         int delta = abs((frameNo % 128) - diameter / 2);
         int alpha = 255 - (delta * delta) / 4 - diameter;
         if (alpha > 0) {
             painter.setPen(QPen(QColor(0, diameter / 2, 127, alpha), 3));

             if (floatBased) {
                 painter.drawEllipse(QRectF(-diameter / 2.0, -diameter / 2.0,
                                            diameter, diameter));
             } else {
                 painter.drawEllipse(QRect(-diameter / 2, -diameter / 2,
                                           diameter, diameter));
             }
         }
     }
 }


Copyright © 2008 Trolltech Trademarks
Qt 4.3.5