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// Copyright (C) 2016 The Qt Company Ltd.
// SPDX-License-Identifier: LicenseRef-Qt-Commercial OR BSD-3-Clause
#include "circlewidget.h"
#include <QPainter>
#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]
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