starrating.cpp Example File

 /****************************************************************************
 **
 ** Copyright (C) 2011 Nokia Corporation and/or its subsidiary(-ies).
 ** All rights reserved.
 ** Contact: Nokia Corporation (qt-info@nokia.com)
 **
 ** This file is part of the examples of the Qt Toolkit.
 **
 ** $QT_BEGIN_LICENSE:BSD$
 ** You may use this file under the terms of the BSD license as follows:
 **
 ** "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 Nokia Corporation and its Subsidiary(-ies) 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."
 ** $QT_END_LICENSE$
 **
 ****************************************************************************/

 #include <QtGui>
 #include <math.h>

 #include "starrating.h"

 const int PaintingScaleFactor = 20;

 StarRating::StarRating(int starCount, int maxStarCount)
 {
     myStarCount = starCount;
     myMaxStarCount = maxStarCount;

     starPolygon << QPointF(1.0, 0.5);
     for (int i = 1; i < 5; ++i)
         starPolygon << QPointF(0.5 + 0.5 * cos(0.8 * i * 3.14),
                                0.5 + 0.5 * sin(0.8 * i * 3.14));

     diamondPolygon << QPointF(0.4, 0.5) << QPointF(0.5, 0.4)
                    << QPointF(0.6, 0.5) << QPointF(0.5, 0.6)
                    << QPointF(0.4, 0.5);
 }

 QSize StarRating::sizeHint() const
 {
     return PaintingScaleFactor * QSize(myMaxStarCount, 1);
 }

 void StarRating::paint(QPainter *painter, const QRect &rect,
                        const QPalette &palette, EditMode mode) const
 {
     painter->save();

     painter->setRenderHint(QPainter::Antialiasing, true);
     painter->setPen(Qt::NoPen);

     if (mode == Editable) {
         painter->setBrush(palette.highlight());
     } else {
         painter->setBrush(palette.foreground());
     }

     int yOffset = (rect.height() - PaintingScaleFactor) / 2;
     painter->translate(rect.x(), rect.y() + yOffset);
     painter->scale(PaintingScaleFactor, PaintingScaleFactor);

     for (int i = 0; i < myMaxStarCount; ++i) {
         if (i < myStarCount) {
             painter->drawPolygon(starPolygon, Qt::WindingFill);
         } else if (mode == Editable) {
             painter->drawPolygon(diamondPolygon, Qt::WindingFill);
         }
         painter->translate(1.0, 0.0);
     }

     painter->restore();
 }