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/* pngtrans.c - transforms the data in a row
routines used by both readers and writers
libpng 1.0 beta 3 - version 0.89
For conditions of distribution and use, see copyright notice in png.h
Copyright (c) 1995, 1996 Guy Eric Schalnat, Group 42, Inc.
May 25, 1996
*/
#define PNG_INTERNAL
#include "png.h"
#if defined(PNG_READ_BGR_SUPPORTED) || defined(PNG_WRITE_BGR_SUPPORTED)
/* turn on bgr to rgb mapping */
void
png_set_bgr(png_structp png_ptr)
{
png_ptr->transformations |= PNG_BGR;
}
#endif
#if defined(PNG_READ_SWAP_SUPPORTED) || defined(PNG_WRITE_SWAP_SUPPORTED)
/* turn on 16 bit byte swapping */
void
png_set_swap(png_structp png_ptr)
{
if (png_ptr->bit_depth == 16)
png_ptr->transformations |= PNG_SWAP_BYTES;
}
#endif
#if defined(PNG_READ_PACK_SUPPORTED) || defined(PNG_WRITE_PACK_SUPPORTED)
/* turn on pixel packing */
void
png_set_packing(png_structp png_ptr)
{
if (png_ptr->bit_depth < 8)
{
png_ptr->transformations |= PNG_PACK;
png_ptr->usr_bit_depth = 8;
}
}
#endif
#if defined(PNG_READ_SHIFT_SUPPORTED) || defined(PNG_WRITE_SHIFT_SUPPORTED)
void
png_set_shift(png_structp png_ptr, png_color_8p true_bits)
{
png_ptr->transformations |= PNG_SHIFT;
png_ptr->shift = *true_bits;
}
#endif
#if defined(PNG_READ_INTERLACING_SUPPORTED) || defined(PNG_WRITE_INTERLACING_SUPPORTED)
int
png_set_interlace_handling(png_structp png_ptr)
{
if (png_ptr->interlaced)
{
png_ptr->transformations |= PNG_INTERLACE;
return 7;
}
return 1;
}
#endif
#if defined(PNG_READ_FILLER_SUPPORTED) || defined(PNG_WRITE_FILLER_SUPPORTED)
void
png_set_filler(png_structp png_ptr, int filler, int filler_loc)
{
png_ptr->transformations |= PNG_FILLER;
png_ptr->filler = (png_byte)filler;
if (filler_loc == PNG_FILLER_AFTER)
png_ptr->flags |= PNG_FLAG_FILLER_AFTER;
else
png_ptr->flags &= ~PNG_FLAG_FILLER_AFTER;
if (png_ptr->color_type == PNG_COLOR_TYPE_RGB &&
png_ptr->bit_depth == 8)
png_ptr->usr_channels = 4;
}
/* old functions kept around for compatability purposes */
void
png_set_rgbx(png_structp png_ptr)
{
png_set_filler(png_ptr, 0xff, PNG_FILLER_AFTER);
}
void
png_set_xrgb(png_structp png_ptr)
{
png_set_filler(png_ptr, 0xff, PNG_FILLER_BEFORE);
}
#endif
#if defined(PNG_READ_INVERT_SUPPORTED) || defined(PNG_WRITE_INVERT_SUPPORTED)
void
png_set_invert_mono(png_structp png_ptr)
{
png_ptr->transformations |= PNG_INVERT_MONO;
}
/* invert monocrome grayscale data */
void
png_do_invert(png_row_infop row_info, png_bytep row)
{
if (row && row_info && row_info->bit_depth == 1 &&
row_info->color_type == PNG_COLOR_TYPE_GRAY)
{
png_bytep rp;
png_uint_32 i;
for (i = 0, rp = row;
i < row_info->rowbytes;
i++, rp++)
{
*rp = (png_byte)(~(*rp));
}
}
}
#endif
#if defined(PNG_READ_SWAP_SUPPORTED) || defined(PNG_WRITE_SWAP_SUPPORTED)
/* swaps byte order on 16 bit depth images */
void
png_do_swap(png_row_infop row_info, png_bytep row)
{
if (row && row_info && row_info->bit_depth == 16)
{
png_bytep rp;
png_byte t;
png_uint_32 i;
for (i = 0, rp = row;
i < row_info->width * row_info->channels;
i++, rp += 2)
{
t = *rp;
*rp = *(rp + 1);
*(rp + 1) = t;
}
}
}
#endif
#if defined(PNG_READ_BGR_SUPPORTED) || defined(PNG_WRITE_BGR_SUPPORTED)
/* swaps red and blue */
void
png_do_bgr(png_row_infop row_info, png_bytep row)
{
if (row && row_info && (row_info->color_type & 2))
{
if (row_info->color_type == 2 && row_info->bit_depth == 8)
{
png_bytep rp;
png_byte t;
png_uint_32 i;
for (i = 0, rp = row;
i < row_info->width;
i++, rp += 3)
{
t = *rp;
*rp = *(rp + 2);
*(rp + 2) = t;
}
}
else if (row_info->color_type == 6 && row_info->bit_depth == 8)
{
png_bytep rp;
png_byte t;
png_uint_32 i;
for (i = 0, rp = row;
i < row_info->width;
i++, rp += 4)
{
t = *rp;
*rp = *(rp + 2);
*(rp + 2) = t;
}
}
else if (row_info->color_type == 2 && row_info->bit_depth == 16)
{
png_bytep rp;
png_byte t[2];
png_uint_32 i;
for (i = 0, rp = row;
i < row_info->width;
i++, rp += 6)
{
t[0] = *rp;
t[1] = *(rp + 1);
*rp = *(rp + 4);
*(rp + 1) = *(rp + 5);
*(rp + 4) = t[0];
*(rp + 5) = t[1];
}
}
else if (row_info->color_type == 6 && row_info->bit_depth == 16)
{
png_bytep rp;
png_byte t[2];
png_uint_32 i;
for (i = 0, rp = row;
i < row_info->width;
i++, rp += 8)
{
t[0] = *rp;
t[1] = *(rp + 1);
*rp = *(rp + 4);
*(rp + 1) = *(rp + 5);
*(rp + 4) = t[0];
*(rp + 5) = t[1];
}
}
}
}
#endif
These are the contents of the former NiCE NeXT User Group NeXTSTEP/OpenStep software archive, currently hosted by Netfuture.ch.