def mouse_gradient(radius):
        mp = mouse_pos()  # custom function, just wraps fetching mouse coords from sdl2
        mouse_grad = None
        mouse_grad = aggdraw.Draw('RGBA', (radius, radius), (0, 0, 0, 0))
        for n in range(radius):
            n = float(n)
            r = float(radius - n)
            opacity = int(( 0.25 * n / radius) * 100)
            brush = aggdraw.Brush((255, 0, 0), int(opacity))
            tl = (radius - r) // 2
            br = (radius - r) // 2 + r
            mouse_grad.ellipse((tl, tl, br, br), brush)

        return mouse_grad  # where it is subsequently blit to the screen