+ int rfirstpix = UNPACK_R16(sptr[0]); \
+ int rlastpix = UNPACK_R16(sptr[pstep * (w - 1)]); \
+ int gfirstpix = UNPACK_G16(sptr[0]); \
+ int glastpix = UNPACK_G16(sptr[pstep * (w - 1)]); \
+ int bfirstpix = UNPACK_B16(sptr[0]); \
+ int blastpix = UNPACK_B16(sptr[pstep * (w - 1)]); \