if (sx - pre < 0) || ((sx >> 1) - pre < 0) || (sx + (bw as isize) + post > (w as isize)) ||
(sy - pre < 0) || ((sy >> 1) - pre < 0) || (sy + (bh as isize) + post > (h as isize)) {
let ebuf_stride: usize = 32;
if (sx - pre < 0) || ((sx >> 1) - pre < 0) || (sx + (bw as isize) + post > (w as isize)) ||
(sy - pre < 0) || ((sy >> 1) - pre < 0) || (sy + (bh as isize) + post > (h as isize)) {
let ebuf_stride: usize = 32;