if let NABufferType::None = frm.get_buffer() { return; }
let name = format!("{}out{:02}_{:08}.pgm", pfx, strno, num);
let mut ofile = File::create(name).unwrap();
let buf = frm.get_buffer().get_vbuf().unwrap();
let (w, h) = buf.get_dimensions(0);
let (w2, h2) = buf.get_dimensions(1);
if let NABufferType::None = frm.get_buffer() { return; }
let name = format!("{}out{:02}_{:08}.pgm", pfx, strno, num);
let mut ofile = File::create(name).unwrap();
let buf = frm.get_buffer().get_vbuf().unwrap();
let (w, h) = buf.get_dimensions(0);
let (w2, h2) = buf.get_dimensions(1);