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#include <QtGui>

#include "circlewidget.h"

#include <stdlib.h>

//! [0]

CircleWidget::CircleWidget(QWidget *parent)

    : QWidget(parent)

{

    floatBased = false;

    antialiased = false;

    frameNo = 0;

    setBackgroundRole(QPalette::Base);

    setSizePolicy(QSizePolicy::Expanding, QSizePolicy::Expanding);

}

//! [0]

//! [1]

void CircleWidget::setFloatBased(bool floatBased)

{

    this->floatBased = floatBased;

    update();

}

//! [1]

//! [2]

void CircleWidget::setAntialiased(bool antialiased)

{

    this->antialiased = antialiased;

    update();

}

//! [2]

//! [3]

QSize CircleWidget::minimumSizeHint() const

{

    return QSize(50, 50);

}

//! [3]

//! [4]

QSize CircleWidget::sizeHint() const

{

    return QSize(180, 180);

}

//! [4]

//! [5]

void CircleWidget::nextAnimationFrame()

{

    ++frameNo;

    update();

}

//! [5]

//! [6]

void CircleWidget::paintEvent(QPaintEvent *)

{

    QPainter painter(this);

    painter.setRenderHint(QPainter::Antialiasing, antialiased);

    painter.translate(width() / 2, height() / 2);

//! [6]

//! [7]

    for (int diameter = 0; diameter < 256; diameter += 9) {

        int delta = abs((frameNo % 128) - diameter / 2);

        int alpha = 255 - (delta * delta) / 4 - diameter;

//! [7] //! [8]

        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));

            }

        }

    }

}

//! [8]