QCustomPlot Discussion and Comments

I have QCPItemText boxes on my plot. I want to have a QLinearGradient brush. Each text box should have the same dark to light gardient. I have not found a way to get consistent appearance. I have played with the coordinates and modes but I just don't undestand.

  // Set the background color for both regular and selected.
  QColor color = m_format.GetColor();
  QColor dark = color.darker();
  QColor light = color.lighter();

  setBrush(color);

  auto tl = topLeft->pixelPosition();
  auto br = bottomRight->pixelPosition();
  QLinearGradient gradient(tl.x(), tl.y(), br.x(), br.y());
//  gradient.setCoordinateMode(QGradient::ObjectBoundingMode);
  gradient.setColorAt(0, dark);
  gradient.setColorAt(1, light);
  setSelectedBrush(QBrush(gradient));