QSlideText电子滚动屏[附源码] - QTCN开发网

void update(bool repaint)
{
  Q_Q(QSlideText);

  // mode check
  if (m_text.isEmpty()) {
    m_mode = QSlideText::Still;
  }

  // draw backgroud
  if (repaint) {
    // prepare background
    m_bckLayer = m_bckLayer.scaled(q->size());
    m_bckLayer.fill(m_backgroundColor);
    QPainter painter(&m_bckLayer);

    // draw boder
    painter.setPen(m_boderColor);
    painter.drawRect(0, 0, q->width() - 1, q->height() - 1);
  }

  // draw grid
  if (repaint) {
    // prepare background
    m_gridLayer = m_gridLayer.scaled(q->size());
    m_gridLayer.fill(QColor(0, 0, 0, 0));
    QPainter painter(&m_gridLayer);

    // draw grid
    m_gridColor.setAlpha(127);
    painter.setPen(m_gridColor);
    for (int i = 0; i < q->width(); i += m_gridStep) {
      painter.drawLine(i, 0, i, q->height());
    }
    for (int j = 0; j < q->height(); j += m_gridStep) {
      painter.drawLine(0, j, q->width(), j);
    }
  }

  // draw text
  if (repaint) {
    // fetch font
    QFont font = q->font();
    font.setPixelSize(q->height() * 0.8);

    // test size
    m_textRect = QFontMetrics(font).boundingRect(m_text);
    m_drawRect = m_textRect;
    if (q->width() > m_drawRect.width()) {
      m_drawRect.setWidth(q->width());
    }
    m_drawPosY = (q->height() - m_textRect.height()) / 2;

    // prepare text layer
    if (m_drawRect.width() && m_drawRect.height()) {
      m_txtLayer = m_txtLayer.scaled(m_drawRect.size());
    }
    m_txtLayer.fill(QColor(0, 0, 0, 0));
    QPainter painter(&m_txtLayer);

    // draw text
    painter.setFont(font);
    painter.setPen(m_textColor);
    painter.drawText(m_txtLayer.rect(), 0, m_text);
  }

  // setup timer
  {
    int interval = 0;
    switch (m_speed) {
      case QSlideText::VerySlow:
        interval = 500;
        break;
      case QSlideText::Slow:
        interval = 250;
        break;
      case QSlideText::Fast:
        interval = 25;
        break;
      case QSlideText::VeryFast:
        interval = 5;
        break;
      case QSlideText::Normal:
      default:
        interval = 50;
        break;
    }

    // start timer
    if (m_mode == QSlideText::Slide || m_mode == QSlideText::Intermittent) {
      m_timer.start(interval);
    } else {
      if (m_timer.isActive()) {
        m_timer.stop();
      }
    }
  }

  // update draw position
  {
    if (m_mode == QSlideText::Still) {
      if (m_algin == QSlideText::AlignCenter) {
        m_drawPosX = (q->width() - m_textRect.width()) / 2;
      }
      if (m_algin == QSlideText::AlignLeft) {
        m_drawPosX = 0;
      }
      if (m_algin == QSlideText::AlignRight) {
        m_drawPosX = q->width() - m_textRect.width();
      }
    }
  }

  // request update
  q->update();
}