bubble.cpp

qt-x11-opensource-src-4.1.4.tar.gz源码

/****************************************************************************
**
** Copyright (C) 2006-2006 Trolltech ASA. All rights reserved.
**
** This file is part of the example classes of the Qt Toolkit.
**
** This file may be used under the terms of the GNU General Public
** License version 2.0 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 GNU
** General Public Licensing requirements will be met:
** http://www.trolltech.com/products/qt/opensource.html
**
** If you are unsure which license is appropriate for your use, please
** review the following information:
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** sales department at [e-mail].
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** This file is provided AS IS with NO WARRANTY OF ANY KIND, INCLUDING THE
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****************************************************************************/

#include <QtGui>

#include "bubble.h"

Bubble::Bubble(const QPointF &position, qreal radius, const QPointF &velocity)
    : position(position), vel(velocity), radius(radius)
{
    innerColor = randomColor();
    outerColor = randomColor();
    updateBrush();
}

void Bubble::updateBrush()
{
    QRadialGradient gradient(QPointF(radius, radius), radius,
                             QPointF(radius*0.5, radius*0.5));

    gradient.setColorAt(0, QColor(255, 255, 255, 255));
    gradient.setColorAt(0.25, innerColor);
    gradient.setColorAt(1, outerColor);
    brush = QBrush(gradient);
}

void Bubble::drawBubble(QPainter *painter)
{
    painter->save();
    painter->translate(position.x() - radius, position.y() - radius);
    painter->setBrush(brush);
    painter->drawEllipse(0, 0, int(2*radius), int(2*radius));
    painter->restore();
}

QColor Bubble::randomColor()
{
    int red = int(205 + 50.0*rand()/(RAND_MAX+1.0));
    int green = int(205 + 50.0*rand()/(RAND_MAX+1.0));
    int blue = int(205 + 50.0*rand()/(RAND_MAX+1.0));
    int alpha = int(91 + 100.0*rand()/(RAND_MAX+1.0));

    return QColor(red, green, blue, alpha);
}

void Bubble::move(const QRect &bbox)
{
    position += vel;
    qreal leftOverflow = position.x() - radius - bbox.left();
    qreal rightOverflow = position.x() + radius - bbox.right();
    qreal topOverflow = position.y() - radius - bbox.top();
    qreal bottomOverflow = position.y() + radius - bbox.bottom();
    
    if (leftOverflow < 0.0) {
        position.setX(position.x() - 2 * leftOverflow);
        vel.setX(-vel.x());
    } else if (rightOverflow > 0.0) {
        position.setX(position.x() - 2 * rightOverflow);
        vel.setX(-vel.x());
    }

    if (topOverflow < 0.0) {
        position.setY(position.y() - 2 * topOverflow);
        vel.setY(-vel.y());
    } else if (bottomOverflow > 0.0) {
        position.setY(position.y() - 2 * bottomOverflow);
        vel.setY(-vel.y());
    }
}

QRectF Bubble::rect()
{
    return QRectF(position.x() - radius, position.y() - radius,
                  2 * radius, 2 * radius);
}