The brush style() defines the fill pattern using the Qt::BrushStyle enum.
A brush has a style, a color, a gradient and a texture. The QBrush class defines the fill pattern of shapes drawn by QPainter. The 0.4 gradient norm is only a suggestion. However, it is frequently not practical to reduce the gradient norm further, and to date no-one has determined just how slack the gradient criterion can be before unacceptable errors appear in the thermodynamic quantities. In particular, the gradient norm should be very small.
