godot/thirdparty/freetype/src/sfnt/pngshim.c

/****************************************************************************
 *
 * pngshim.c
 *
 *   PNG Bitmap glyph support.
 *
 * Copyright (C) 2013-2023 by
 * Google, Inc.
 * Written by Stuart Gill and Behdad Esfahbod.
 *
 * This file is part of the FreeType project, and may only be used,
 * modified, and distributed under the terms of the FreeType project
 * license, LICENSE.TXT.  By continuing to use, modify, or distribute
 * this file you indicate that you have read the license and
 * understand and accept it fully.
 *
 */


#include <freetype/internal/ftdebug.h>
#include <freetype/internal/ftstream.h>
#include <freetype/tttags.h>
#include FT_CONFIG_STANDARD_LIBRARY_H


#if defined( TT_CONFIG_OPTION_EMBEDDED_BITMAPS ) && \
    defined( FT_CONFIG_OPTION_USE_PNG )

  /* We always include <setjmp.h>, so make libpng shut up! */
#define PNG_SKIP_SETJMP_CHECK …
#include <png.h>
#include "pngshim.h"

#include "sferrors.h"


  /* This code is freely based on cairo-png.c.  There's so many ways */
  /* to call libpng, and the way cairo does it is defacto standard.  */

  static unsigned int
  multiply_alpha( unsigned int  alpha,
                  unsigned int  color )
  { … }


  /* Premultiplies data and converts RGBA bytes => BGRA. */
  static void
  premultiply_data( png_structp    png,
                    png_row_infop  row_info,
                    png_bytep      data )
  { … }


  /* Converts RGBx bytes to BGRA. */
  static void
  convert_bytes_to_data( png_structp    png,
                         png_row_infop  row_info,
                         png_bytep      data )
  { … }


  /* Use error callback to avoid png writing to stderr. */
  static void
  error_callback( png_structp      png,
                  png_const_charp  error_msg )
  { … }


  /* Use warning callback to avoid png writing to stderr. */
  static void
  warning_callback( png_structp      png,
                    png_const_charp  error_msg )
  { … }


  static void
  read_data_from_FT_Stream( png_structp  png,
                            png_bytep    data,
                            png_size_t   length )
  { … }


  FT_LOCAL_DEF( FT_Error )
  Load_SBit_Png( FT_GlyphSlot     slot,
                 FT_Int           x_offset,
                 FT_Int           y_offset,
                 FT_Int           pix_bits,
                 TT_SBit_Metrics  metrics,
                 FT_Memory        memory,
                 FT_Byte*         data,
                 FT_UInt          png_len,
                 FT_Bool          populate_map_and_metrics,
                 FT_Bool          metrics_only )
  { … }

#else /* !(TT_CONFIG_OPTION_EMBEDDED_BITMAPS && FT_CONFIG_OPTION_USE_PNG) */

  /* ANSI C doesn't like empty source files */
  typedef int  pngshim_dummy_;

#endif /* !(TT_CONFIG_OPTION_EMBEDDED_BITMAPS && FT_CONFIG_OPTION_USE_PNG) */


/* END */