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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();

    cache = 0;

    updateBrush();

}

//! [0]

void Bubble::updateCache()

{

    if (cache)

        delete cache;

    cache = new QImage(qRound(radius * 2 + 2), qRound(radius * 2 + 2), QImage::Format_ARGB32);

    cache->fill(0x00000000);

    QPainter p(cache);

    p.setRenderHint(QPainter::HighQualityAntialiasing);

    QPen pen(Qt::white);

    pen.setWidth(2);

    p.setPen(pen);

    p.setBrush(brush);

    p.drawEllipse(0, 0, int(2*radius), int(2*radius));

}

//! [0]

Bubble::~Bubble()

{

    if (cache)

        delete cache;

}

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);

    updateCache();

}

//! [1]

void Bubble::drawBubble(QPainter *painter)

{

    painter->save();

    painter->translate(position.x() - radius, position.y() - radius);

    painter->setOpacity(0.8);

    painter->drawImage(0, 0, *cache);

    painter->restore();

}

//! [1]

QColor Bubble::randomColor()

{

    int red = int(185 + 70.0*qrand()/(RAND_MAX+1.0));

    int green = int(185 + 70.0*qrand()/(RAND_MAX+1.0));

    int blue = int(205 + 50.0*qrand()/(RAND_MAX+1.0));

    int alpha = int(91 + 100.0*qrand()/(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);

}