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Imported from libpng-1.0.9beta5.tar

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This commit is contained in:
Glenn Randers-Pehrson
2000-12-15 08:54:42 -06:00
parent f6b4f45c7e
commit 2ad31ae31f
48 changed files with 301 additions and 96 deletions
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63
pngwtran.c
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@@ -1,7 +1,7 @@
/* pngwtran.c - transforms the data in a row for PNG writers
*
* libpng 1.0.9beta4 - December 1, 2000
* libpng 1.0.9beta5 - December 15, 2000
* For conditions of distribution and use, see copyright notice in png.h
* Copyright (c) 1998, 1999, 2000 Glenn Randers-Pehrson
* (Version 0.96 Copyright (c) 1996, 1997 Andreas Dilger)
@@ -498,3 +498,64 @@ png_do_write_invert_alpha(png_row_infop row_info, png_bytep row)
}
}
#endif
#if defined(PNG_MNG_FEATURES_SUPPORTED)
/* undoes intrapixel differencing */
void /* PRIVATE */
png_do_write_intrapixel(png_row_infop row_info, png_bytep row)
{
png_debug(1, "in png_do_write_intrapixel\n");
if (
#if defined(PNG_USELESS_TESTS_SUPPORTED)
row != NULL && row_info != NULL &&
#endif
(row_info->color_type & PNG_COLOR_MASK_COLOR))
{
int bytes_per_pixel;
png_uint_32 row_width = row_info->width;
if (row_info->bit_depth == 8)
{
png_bytep rp;
png_uint_32 i;
if (row_info->color_type == PNG_COLOR_TYPE_RGB)
bytes_per_pixel = 3;
else if (row_info->color_type == PNG_COLOR_TYPE_RGB_ALPHA)
bytes_per_pixel = 4;
else
return;
for (i = 0, rp = row; i < row_width; i++, rp += bytes_per_pixel)
{
*(rp) = (png_byte)((*rp - *(rp+1))&0xff);
*(rp+2) = (png_byte)((*(rp+2) - *(rp+1))&0xff);
}
}
else if (row_info->bit_depth == 16)
{
png_bytep rp;
png_uint_32 i;
if (row_info->color_type == PNG_COLOR_TYPE_RGB)
bytes_per_pixel = 6;
else if (row_info->color_type == PNG_COLOR_TYPE_RGB_ALPHA)
bytes_per_pixel = 8;
else
return;
for (i = 0, rp = row; i < row_width; i++, rp += bytes_per_pixel)
{
png_uint_32 s0=*(rp )<<8 | *(rp+1);
png_uint_32 s1=*(rp+2)<<8 | *(rp+3);
png_uint_32 s2=*(rp+4)<<8 | *(rp+5);
png_uint_32 red=(s0-s1)&0xffff;
png_uint_32 blue=(s2-s1)&0xffff;
*(rp ) = (png_byte)((red>>8)&0xff);
*(rp+1) = (png_byte)(red&0xff);
*(rp+4) = (png_byte)((blue>>8)&0xff);
*(rp+5) = (png_byte)(blue&0xff);
}
}
}
}
#endif /* PNG_MNG_FEATURES_SUPPORTED */