godot/thirdparty/libpng/pngwtran.c

/* pngwtran.c - transforms the data in a row for PNG writers
 *
 * Copyright (c) 2018 Cosmin Truta
 * Copyright (c) 1998-2002,2004,2006-2016,2018 Glenn Randers-Pehrson
 * Copyright (c) 1996-1997 Andreas Dilger
 * Copyright (c) 1995-1996 Guy Eric Schalnat, Group 42, Inc.
 *
 * This code is released under the libpng license.
 * For conditions of distribution and use, see the disclaimer
 * and license in png.h
 */

#include "pngpriv.h"

#ifdef PNG_WRITE_SUPPORTED
#ifdef PNG_WRITE_TRANSFORMS_SUPPORTED

#ifdef PNG_WRITE_PACK_SUPPORTED
/* Pack pixels into bytes.  Pass the true bit depth in bit_depth.  The
 * row_info bit depth should be 8 (one pixel per byte).  The channels
 * should be 1 (this only happens on grayscale and paletted images).
 */
static void
png_do_pack(png_row_infop row_info, png_bytep row, png_uint_32 bit_depth)
{ … }
#endif

#ifdef PNG_WRITE_SHIFT_SUPPORTED
/* Shift pixel values to take advantage of whole range.  Pass the
 * true number of bits in bit_depth.  The row should be packed
 * according to row_info->bit_depth.  Thus, if you had a row of
 * bit depth 4, but the pixels only had values from 0 to 7, you
 * would pass 3 as bit_depth, and this routine would translate the
 * data to 0 to 15.
 */
static void
png_do_shift(png_row_infop row_info, png_bytep row,
    png_const_color_8p bit_depth)
{ … }
#endif

#ifdef PNG_WRITE_SWAP_ALPHA_SUPPORTED
static void
png_do_write_swap_alpha(png_row_infop row_info, png_bytep row)
{ … }
#endif

#ifdef PNG_WRITE_INVERT_ALPHA_SUPPORTED
static void
png_do_write_invert_alpha(png_row_infop row_info, png_bytep row)
{ … }
#endif

/* Transform the data according to the user's wishes.  The order of
 * transformations is significant.
 */
void /* PRIVATE */
png_do_write_transformations(png_structrp png_ptr, png_row_infop row_info)
{ … }
#endif /* WRITE_TRANSFORMS */
#endif /* WRITE */