Qt 5.7 | Qt WebEngine | WebEngine Demo Browser Example | chasewidget.cpp Example File

Qt 5.7.1 Reference Documentation

# chasewidget.cpp Example File

webenginewidgets/demobrowser/chasewidget.cpp

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      #include "chasewidget.h"

      #include <QtCore/QPoint>

      #include <QtWidgets/QApplication>
      #include <QtGui/QHideEvent>
      #include <QtGui/QPainter>
      #include <QtGui/QPaintEvent>
      #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)
      {
      }

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

      void ChaseWidget::paintEvent(QPaintEvent *event)
      {
          Q_UNUSED(event);
          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 *event)
      {
          if (event->timerId() == m_timerId) {
              ++m_segment;
              update();
          }
          QWidget::timerEvent(event);
      }

      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;
      }