- let a = buf[off - 2 * stride + x] as i16;
- let b = buf[off - 1 * stride + x] as i16;
- let c = buf[off + 0 * stride + x] as i16;
- let d = buf[off + 1 * stride + x] as i16;
+ let a = i16::from(buf[off - 2 * stride + x]);
+ let b = i16::from(buf[off - 1 * stride + x]);
+ let c = i16::from(buf[off + 0 * stride + x]);
+ let d = i16::from(buf[off + 1 * stride + x]);