FFmpeg
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hscale_fast_bilinear.c
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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(SwsContext *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(SwsContext *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 }