How can I draw arcs with psychtoolbox with controlled curvature?

Hi everybody! I would like to design an experiment to test curvature perception on curved screen. For that purpose I would like to draws arcs, with constant chord, but varying curvature (probably with staircase function), using psychtoolbox. Does anyone have an idea on how to do it? Circle drawing does not work since the center would be outside of the screen (large radius, small curvature). Thank you very much for your help!