Mega Code Archive
Circle Widget
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#ifndef CIRCLEWIDGET_H
#define CIRCLEWIDGET_H
#include <QWidget>
class CircleWidget : public QWidget
{
Q_OBJECT
public:
CircleWidget(QWidget *parent = 0);
void setFloatBased(bool floatBased);
void setAntialiased(bool antialiased);
QSize minimumSizeHint() const;
QSize sizeHint() const;
public slots:
void nextAnimationFrame();
protected:
void paintEvent(QPaintEvent *event);
private:
bool floatBased;
bool antialiased;
int frameNo;
};
#endif
#include <QtGui>
#include "circlewidget.h"
#include <stdlib.h>
CircleWidget::CircleWidget(QWidget *parent)
: QWidget(parent)
{
floatBased = false;
antialiased = false;
frameNo = 0;
setBackgroundRole(QPalette::Base);
setSizePolicy(QSizePolicy::Expanding, QSizePolicy::Expanding);
}
void CircleWidget::setFloatBased(bool floatBased)
{
this->floatBased = floatBased;
update();
}
void CircleWidget::setAntialiased(bool antialiased)
{
this->antialiased = antialiased;
update();
}
QSize CircleWidget::minimumSizeHint() const
{
return QSize(50, 50);
}
QSize CircleWidget::sizeHint() const
{
return QSize(180, 180);
}
void CircleWidget::nextAnimationFrame()
{
++frameNo;
update();
}
void CircleWidget::paintEvent(QPaintEvent *)
{
QPainter painter(this);
painter.setRenderHint(QPainter::Antialiasing, antialiased);
painter.translate(width() / 2, height() / 2);
for (int diameter = 0; diameter < 256; diameter += 9) {
int delta = abs((frameNo % 128) - diameter / 2);
int alpha = 255 - (delta * delta) / 4 - diameter;
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));
}
}
}
}
#ifndef WINDOW_H
#define WINDOW_H
#include <QWidget>
QT_BEGIN_NAMESPACE
class QLabel;
QT_END_NAMESPACE
class CircleWidget;
class Window : public QWidget
{
Q_OBJECT
public:
Window();
private:
QLabel *createLabel(const QString &text);
QLabel *aliasedLabel;
QLabel *antialiasedLabel;
QLabel *intLabel;
QLabel *floatLabel;
CircleWidget *circleWidgets[2][2];
};
#endif
#include <QtGui>
#include "circlewidget.h"
#include "window.h"
Window::Window()
{
aliasedLabel = createLabel(tr("Aliased"));
antialiasedLabel = createLabel(tr("Antialiased"));
intLabel = createLabel(tr("Int"));
floatLabel = createLabel(tr("Float"));
QGridLayout *layout = new QGridLayout;
layout->addWidget(aliasedLabel, 0, 1);
layout->addWidget(antialiasedLabel, 0, 2);
layout->addWidget(intLabel, 1, 0);
layout->addWidget(floatLabel, 2, 0);
QTimer *timer = new QTimer(this);
for (int i = 0; i < 2; ++i) {
for (int j = 0; j < 2; ++j) {
circleWidgets[i][j] = new CircleWidget;
circleWidgets[i][j]->setAntialiased(j != 0);
circleWidgets[i][j]->setFloatBased(i != 0);
connect(timer, SIGNAL(timeout()),
circleWidgets[i][j], SLOT(nextAnimationFrame()));
layout->addWidget(circleWidgets[i][j], i + 1, j + 1);
}
}
timer->start(100);
setLayout(layout);
setWindowTitle(tr("Concentric Circles"));
}
QLabel *Window::createLabel(const QString &text)
{
QLabel *label = new QLabel(text);
label->setAlignment(Qt::AlignCenter);
label->setMargin(2);
label->setFrameStyle(QFrame::Box | QFrame::Sunken);
return label;
}
#include <QApplication>
#include "window.h"
int main(int argc, char *argv[])
{
QApplication app(argc, argv);
Window window;
window.show();
return app.exec();
}
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