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# chasewidget.cpp Example File
demos/browser/chasewidget.cpp

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     #include "chasewidget.h"

     #include <QtCore/QPoint>

     #include <QtGui/QApplication>
     #include <QtGui/QPainter>
     #include <QtGui/QPaintEvent>
     #include <QtGui/QHideEvent>
     #include <QtGui/QShowEvent>

     ChaseWidget::ChaseWidget(QWidget *parent, QPixmap pixmap, bool pixmapEnabled)
         : QWidget(parent)
         , m_segment(0)
         , m_delay(100)
         , m_step(40)
         , m_timerId(-1)
         , m_animated(false)
         , m_pixmap(pixmap)
         , m_pixmapEnabled(pixmapEnabled)
     {
     }

     ChaseWidget::~ChaseWidget()
     {
     }

     void ChaseWidget::setAnimated(bool val)
     {
         if (m_animated == val)
             return;
         m_animated = val;
         if (m_timerId != -1) {
             killTimer(m_timerId);
             m_timerId = -1;
         }
         if (m_animated) {
             m_segment = 0;
             m_timerId = startTimer(m_delay);
         }
         update();
     }

     void ChaseWidget::showEvent(QShowEvent *e)
     {
         Q_UNUSED(e);
     }

     void ChaseWidget::hideEvent(QHideEvent *e)
     {
         Q_UNUSED(e);
     }

     void ChaseWidget::paintEvent(QPaintEvent *)
     {
         QPainter p(this);

         if (m_pixmapEnabled && !m_pixmap.isNull()) {
             p.drawPixmap(0, 0, m_pixmap);
             return;
         }

         const int extent = qMin(width() - 8, height() - 8);
         const int displ = extent / 4;
         const int ext = extent / 4 - 1;

         p.setRenderHint(QPainter::Antialiasing, true);

         if(m_animated)
             p.setPen(Qt::gray);
         else
             p.setPen(QPen(palette().dark().color()));

         p.translate(width() / 2, height() / 2); // center

         for (int segment = 0; segment < segmentCount(); segment++) {
             p.rotate(QApplication::isRightToLeft() ? m_step : -m_step);
             if(m_animated)
                 p.setBrush(colorForSegment(segment));
             else
                 p.setBrush(palette().background());
             p.drawEllipse(QRect(displ, -ext / 2, ext, ext));
         }
     }

     QSize ChaseWidget::sizeHint() const
     {
         return QSize(32, 32);
     }

     void ChaseWidget::timerEvent(QTimerEvent *e)
     {
         if (e->timerId() == m_timerId) {
             m_segment++;
             update();
         }
     }

     QColor ChaseWidget::colorForSegment(int seg) const
     {
         int index = ((seg + m_segment) % segmentCount());
         int comp = qMax(0, 255 - (index * (255 / segmentCount())));
         return QColor(comp, comp, comp, 255);
     }

     int ChaseWidget::segmentCount() const
     {
         return 360 / m_step;
     }

     void ChaseWidget::setPixmapEnabled(bool enable)
     {
         m_pixmapEnabled = enable;
     }