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    41 

    42 #include <QtGui>

    43 

    44 #include "bubble.h"

    45 

    46 Bubble::Bubble(const QPointF &position, qreal radius, const QPointF &velocity)

    47     : position(position), vel(velocity), radius(radius)

    48 {

    49     innerColor = randomColor();

    50     outerColor = randomColor();

    51     updateBrush();

    52 }

    53 

    54 void Bubble::updateBrush()

    55 {

    56     QRadialGradient gradient(QPointF(radius, radius), radius,

    57                              QPointF(radius*0.5, radius*0.5));

    58 

    59     gradient.setColorAt(0, QColor(255, 255, 255, 255));

    60     gradient.setColorAt(0.25, innerColor);

    61     gradient.setColorAt(1, outerColor);

    62     brush = QBrush(gradient);

    63 }

    64 

    65 void Bubble::drawBubble(QPainter *painter)

    66 {

    67     painter->save();

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

    69     painter->setBrush(brush);

    70     painter->drawEllipse(0, 0, int(2*radius), int(2*radius));

    71     painter->restore();

    72 }

    73 

    74 QColor Bubble::randomColor()

    75 {

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

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

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

    79     int alpha = int(91 + 100.0*qrand()/(RAND_MAX+1.0));

    80 

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

    82 }

    83 

    84 void Bubble::move(const QRect &bbox)

    85 {

    86     position += vel;

    87     qreal leftOverflow = position.x() - radius - bbox.left();

    88     qreal rightOverflow = position.x() + radius - bbox.right();

    89     qreal topOverflow = position.y() - radius - bbox.top();

    90     qreal bottomOverflow = position.y() + radius - bbox.bottom();

    91     

    92     if (leftOverflow < 0.0) {

    93         position.setX(position.x() - 2 * leftOverflow);

    94         vel.setX(-vel.x());

    95     } else if (rightOverflow > 0.0) {

    96         position.setX(position.x() - 2 * rightOverflow);

    97         vel.setX(-vel.x());

    98     }

    99 

   100     if (topOverflow < 0.0) {

   101         position.setY(position.y() - 2 * topOverflow);

   102         vel.setY(-vel.y());

   103     } else if (bottomOverflow > 0.0) {

   104         position.setY(position.y() - 2 * bottomOverflow);

   105         vel.setY(-vel.y());

   106     }

   107 }

   108 

   109 QRectF Bubble::rect()

   110 {

   111     return QRectF(position.x() - radius, position.y() - radius,

   112                   2 * radius, 2 * radius);

   113 }