Function vips_sys::im_draw_line_user

pub unsafe extern "C" fn im_draw_line_user(
    image: *mut VipsImage, 
    x1: c_int, 
    y1: c_int, 
    x2: c_int, 
    y2: c_int, 
    plot: VipsPlotFn, 
    a: *mut c_void, 
    b: *mut c_void, 
    c: *mut c_void
) -> c_int