I have a list of phi, psi angles derived from a number of PDB files based on some criteria. I have plotted a scatter plot using matplotlib with them. But i want to show the favoured, allowed and generously allowed regions in different shades of color at the background. For better understanding, am providing the scatter plot (D_torsionAngle.png) i have already made and an example of the plot (1hmp.png) i wanted to do.