Qt Reference Documentation

# analogclock.cpp Example File

widgets/analogclock/analogclock.cpp

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     #include <QtGui>

     #include "analogclock.h"

     AnalogClock::AnalogClock(QWidget *parent)
         : QWidget(parent)
     {
         QTimer *timer = new QTimer(this);
         connect(timer, SIGNAL(timeout()), this, SLOT(update()));
         timer->start(1000);

         setWindowTitle(tr("Analog Clock"));
         resize(200, 200);
     }

     void AnalogClock::paintEvent(QPaintEvent *)
     {
         static const QPoint hourHand[3] = {
             QPoint(7, 8),
             QPoint(-7, 8),
             QPoint(0, -40)
         };
         static const QPoint minuteHand[3] = {
             QPoint(7, 8),
             QPoint(-7, 8),
             QPoint(0, -70)
         };

         QColor hourColor(127, 0, 127);
         QColor minuteColor(0, 127, 127, 191);

         int side = qMin(width(), height());
         QTime time = QTime::currentTime();

         QPainter painter(this);
         painter.setRenderHint(QPainter::Antialiasing);
         painter.translate(width() / 2, height() / 2);
         painter.scale(side / 200.0, side / 200.0);

         painter.setPen(Qt::NoPen);
         painter.setBrush(hourColor);

         painter.save();
         painter.rotate(30.0 * ((time.hour() + time.minute() / 60.0)));
         painter.drawConvexPolygon(hourHand, 3);
         painter.restore();

         painter.setPen(hourColor);

         for (int i = 0; i < 12; ++i) {
             painter.drawLine(88, 0, 96, 0);
             painter.rotate(30.0);
         }

         painter.setPen(Qt::NoPen);
         painter.setBrush(minuteColor);

         painter.save();
         painter.rotate(6.0 * (time.minute() + time.second() / 60.0));
         painter.drawConvexPolygon(minuteHand, 3);
         painter.restore();

         painter.setPen(minuteColor);

         for (int j = 0; j < 60; ++j) {
             if ((j % 5) != 0)
                 painter.drawLine(92, 0, 96, 0);
             painter.rotate(6.0);
         }
     }