Method drawBackground

QtNodeEditor/src/FlowView.cpp:343–395

void
FlowView::
drawBackground(QPainter* painter, const QRectF& r)
{
  QGraphicsView::drawBackground(painter, r);

  auto drawGrid =
    [&](double gridStep)
    {
      gridStep = 1;
      QRect   windowRect = rect();
      QPointF tl = mapToScene(windowRect.topLeft());
      QPointF br = mapToScene(windowRect.bottomRight());

      double left   = std::floor(tl.x() / gridStep - 0.5);
      double right  = std::floor(br.x() / gridStep + 1.0);
      double bottom = std::floor(tl.y() / gridStep - 0.5);
      double top    = std::floor (br.y() / gridStep + 1.0);

      // vertical lines
   //   for (int xi = int(left); xi <= int(right); ++xi)
      {
        int xi = 0;
        QLineF line(xi * gridStep, bottom  * gridStep,
                    xi * gridStep, top  * gridStep);

        painter->drawLine(line);
      }

      // horizontal lines
      //for (int yi = int(bottom); yi <= int(top); ++yi)
      {
        int yi = 0;
        QLineF line(left  * gridStep, yi * gridStep,
                    right * gridStep, yi * gridStep );
        painter->drawLine(line);
      }
    };

  auto const &flowViewStyle = StyleCollection::flowViewStyle();

  QBrush bBrush = backgroundBrush();

  QPen pfine(flowViewStyle.FineGridColor, 1.0);

  painter->setPen(pfine);
  drawGrid(20);

  QPen p(Qt::white, 2.0);

  painter->setPen(p);
  //drawGrid(150);
}


void