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Imported from libpng-0.98.tar

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This commit is contained in:
Glenn Randers-Pehrson
1998-01-16 22:06:18 -06:00
parent 2687fcc7b5
commit c4a2ae6cac
26 changed files with 687 additions and 240 deletions
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84
pngwtran.c
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@@ -1,12 +1,12 @@
/* pngwtran.c - transforms the data in a row for PNG writers
*
* libpng 0.97
* libpng 0.98
* For conditions of distribution and use, see copyright notice in png.h
* Copyright (c) 1995, 1996 Guy Eric Schalnat, Group 42, Inc.
* Copyright (c) 1996, 1997 Andreas Dilger
* Copyright (c) 1998, Glenn Randers-Pehrson
* January 7, 1998
* January 16, 1998
*/
#define PNG_INTERNAL
@@ -42,6 +42,10 @@ png_do_write_transformations(png_structp png_ptr)
if (png_ptr->transformations & PNG_SWAP_ALPHA)
png_do_write_swap_alpha(&(png_ptr->row_info), png_ptr->row_buf + 1);
#endif
#if defined(PNG_WRITE_INVERT_ALPHA_SUPPORTED)
if (png_ptr->transformations & PNG_INVERT_ALPHA)
png_do_write_invert_alpha(&(png_ptr->row_info), png_ptr->row_buf + 1);
#endif
#if defined(PNG_WRITE_BGR_SUPPORTED)
if (png_ptr->transformations & PNG_BGR)
png_do_bgr(&(png_ptr->row_info), png_ptr->row_buf + 1);
@@ -394,3 +398,79 @@ png_do_write_swap_alpha(png_row_infop row_info, png_bytep row)
}
#endif
#if defined(PNG_WRITE_INVERT_ALPHA_SUPPORTED)
void
png_do_write_invert_alpha(png_row_infop row_info, png_bytep row)
{
png_debug(1, "in png_do_write_invert_alpha\n");
#if defined(PNG_USELESS_TESTS_SUPPORTED)
if (row != NULL && row_info != NULL)
#endif
{
if (row_info->color_type == PNG_COLOR_TYPE_RGB_ALPHA)
{
/* This inverts the alpha channel in RGBA */
if (row_info->bit_depth == 8)
{
png_bytep sp, dp;
png_uint_32 i;
for (i = 0, sp = dp = row; i < row_info->width; i++)
{
*(dp++) = *(sp++);
*(dp++) = *(sp++);
*(dp++) = *(sp++);
*(dp++) = 255 - *(sp++);
}
}
/* This inverts the alpha channel in RRGGBBAA */
else
{
png_bytep sp, dp;
png_uint_32 i;
for (i = 0, sp = dp = row; i < row_info->width; i++)
{
*(dp++) = *(sp++);
*(dp++) = *(sp++);
*(dp++) = *(sp++);
*(dp++) = *(sp++);
*(dp++) = *(sp++);
*(dp++) = *(sp++);
*(dp++) = 255 - *(sp++);
*(dp++) = 255 - *(sp++);
}
}
}
else if (row_info->color_type == PNG_COLOR_TYPE_GRAY_ALPHA)
{
/* This inverts the alpha channel in GA */
if (row_info->bit_depth == 8)
{
png_bytep sp, dp;
png_uint_32 i;
for (i = 0, sp = dp = row; i < row_info->width; i++)
{
*(dp++) = *(sp++);
*(dp++) = 255 - *(sp++);
}
}
/* This inverts the alpha channel in GGAA */
else
{
png_bytep sp, dp;
png_uint_32 i;
for (i = 0, sp = dp = row; i < row_info->width; i++)
{
*(dp++) = *(sp++);
*(dp++) = *(sp++);
*(dp++) = 255 - *(sp++);
*(dp++) = 255 - *(sp++);
}
}
}
}
}
#endif