libswscale/hscale_fast_bilinear.c

   1 /*
   2  * Copyright (C) 2001-2011 Michael Niedermayer <michaelni@gmx.at>
   3  *
   4  * This file is part of FFmpeg.
   5  *
   6  * FFmpeg is free software; you can redistribute it and/or
   7  * modify it under the terms of the GNU Lesser General Public
   8  * License as published by the Free Software Foundation; either
   9  * version 2.1 of the License, or (at your option) any later version.
  10  *
  11  * FFmpeg is distributed in the hope that it will be useful,
  12  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  13  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  14  * Lesser General Public License for more details.
  15  *
  16  * You should have received a copy of the GNU Lesser General Public
  17  * License along with FFmpeg; if not, write to the Free Software
  18  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
  19  */
  20
  21 #include "swscale_internal.h"
  22
  23 void ff_hyscale_fast_c(SwsInternal *c, int16_t *dst, int dstWidth,
  24                            const uint8_t *src, int srcW, int xInc)
  25 {
  26     int i;
  27     unsigned int xpos = 0;
  28     for (i = 0; i < dstWidth; i++) {
  29         register unsigned int xx     = xpos >> 16;
  30         register unsigned int xalpha = (xpos & 0xFFFF) >> 9;
  31         dst[i] = (src[xx] << 7) + (src[xx + 1] - src[xx]) * xalpha;
  32         xpos  += xInc;
  33     }
  34     for (i=dstWidth-1; (i*xInc)>>16 >=srcW-1; i--)
  35         dst[i] = src[srcW-1]*128;
  36 }
  37
  38 void ff_hcscale_fast_c(SwsInternal *c, int16_t *dst1, int16_t *dst2,
  39                            int dstWidth, const uint8_t *src1,
  40                            const uint8_t *src2, int srcW, int xInc)
  41 {
  42     int i;
  43     unsigned int xpos = 0;
  44     for (i = 0; i < dstWidth; i++) {
  45         register unsigned int xx     = xpos >> 16;
  46         register unsigned int xalpha = (xpos & 0xFFFF) >> 9;
  47         dst1[i] = (src1[xx] * (xalpha ^ 127) + src1[xx + 1] * xalpha);
  48         dst2[i] = (src2[xx] * (xalpha ^ 127) + src2[xx + 1] * xalpha);
  49         xpos   += xInc;
  50     }
  51     for (i=dstWidth-1; (i*xInc)>>16 >=srcW-1; i--) {
  52         dst1[i] = src1[srcW-1]*128;
  53         dst2[i] = src2[srcW-1]*128;
  54     }
  55 }