Method paint_trace

DSView/pv/view/dsosignal.cpp:967–1015

}

void DsoSignal::paint_trace(QPainter &p,
    const pv::data::DsoSnapshot *snapshot,
    int zeroY, int left, const int64_t start, const int64_t end, int hw_offset,
    const double pixels_offset, const double samples_per_pixel, uint64_t num_channels)
{
    (void)num_channels;

    const int64_t sample_count = end - start + 1;

    if (sample_count > 0) {
        pv::data::DsoSnapshot *pshot = const_cast<pv::data::DsoSnapshot*>(snapshot);
        const uint8_t *const samples_buffer = pshot->get_samples(start, end, get_index());;
        assert(samples_buffer);

        QColor trace_colour = _colour;
        trace_colour.setAlpha(View::ForeAlpha);
        p.setPen(trace_colour);

        QPointF *points = new QPointF[sample_count];
        QPointF *point = points;

        float top = get_view_rect().top();
        float bottom = get_view_rect().bottom();
        float right =  (float)get_view_rect().right();
        double  pixels_per_sample = 1.0/samples_per_pixel;

        uint8_t value; 
        float x = (start / samples_per_pixel - pixels_offset) + left + _view->trig_hoff()*pixels_per_sample;
        float y;
 
        for (int64_t sample = 0; sample < sample_count; sample++) {
            value = samples_buffer[sample];
            y = min(max(top, zeroY + (value - hw_offset) * _scale), bottom);
            if (x > right) {
                point--;
                const float lastY = point->y() + (y - point->y()) / (x - point->x()) * (right - point->x());
                point++;
                *point++ = QPointF(right, lastY);
                break;
            }
            *point++ = QPointF(x, y);
            x += pixels_per_sample;
        }

        p.drawPolyline(points, point - points);

        delete[] points;
    }
}

void DsoSignal::paint_envelope(QPainter &p,
    const pv::data::DsoSnapshot *snapshot,