Method paintEvent

src/qt/trafficgraphwidget.cpp:79–136

void TrafficGraphWidget::paintEvent(QPaintEvent*)
{
    QPainter painter(this);
    painter.fillRect(rect(), Qt::black);

    if (fMax <= 0.0f) return;

    QColor axisCol(Qt::gray);
    int h = height() - YMARGIN * 2;
    painter.setPen(axisCol);
    painter.drawLine(XMARGIN, YMARGIN + h, width() - XMARGIN, YMARGIN + h);

    // decide what order of magnitude we are
    int base = floor(log10(fMax));
    float val = pow(10.0f, base);

    const QString units = tr("KB/s");
    const float yMarginText = 2.0;

    // draw lines
    painter.setPen(axisCol);
    painter.drawText(XMARGIN, YMARGIN + h - h * val / fMax - yMarginText, QString("%1 %2").arg(val).arg(units));
    for (float y = val; y < fMax; y += val) {
        int yy = YMARGIN + h - h * y / fMax;
        painter.drawLine(XMARGIN, yy, width() - XMARGIN, yy);
    }
    // if we drew 3 or fewer lines, break them up at the next lower order of magnitude
    if (fMax / val <= 3.0f) {
        axisCol = axisCol.darker();
        val = pow(10.0f, base - 1);
        painter.setPen(axisCol);
        painter.drawText(XMARGIN, YMARGIN + h - h * val / fMax - yMarginText, QString("%1 %2").arg(val).arg(units));
        int count = 1;
        for (float y = val; y < fMax; y += val, count++) {
            // don't overwrite lines drawn above
            if (count % 10 == 0)
                continue;
            int yy = YMARGIN + h - h * y / fMax;
            painter.drawLine(XMARGIN, yy, width() - XMARGIN, yy);
        }
    }

    const TrafficGraphData::SampleQueue& queue = trafficGraphData.getCurrentRangeQueue();

    if(!queue.empty()) {
        QPainterPath pIn;
        paintPath(pIn, queue, boost::bind(chooseIn,_1));
        painter.fillPath(pIn, QColor(0, 255, 0, 128));
        painter.setPen(Qt::green);
        painter.drawPath(pIn);

        QPainterPath pOut;
        paintPath(pOut, queue, boost::bind(chooseOut,_1));
        painter.fillPath(pOut, QColor(255, 0, 0, 128));
        painter.setPen(Qt::red);
        painter.drawPath(pOut);
    }
}