Function interp_grid_circle 

fn interp_grid_circle(
    args: &[RValue],
    named: &[(String, RValue)],
    context: &BuiltinContext<'_>,
) -> Result<RValue, RError>

Draw a circle on the grid graphics device.

@param x x-coordinate of center @param y y-coordinate of center @param r radius @param default.units default unit type @param gp graphical parameters @param vp viewport to use @param name grob name @param draw whether to draw immediately (default TRUE) @return a circle grob (invisibly)