1  /****************************************************************************
       2   *
       3   * ftlzw.h
       4   *
       5   *   LZW-compressed stream support.
       6   *
       7   * Copyright (C) 2004-2023 by
       8   * David Turner, Robert Wilhelm, and Werner Lemberg.
       9   *
      10   * This file is part of the FreeType project, and may only be used,
      11   * modified, and distributed under the terms of the FreeType project
      12   * license, LICENSE.TXT.  By continuing to use, modify, or distribute
      13   * this file you indicate that you have read the license and
      14   * understand and accept it fully.
      15   *
      16   */
      17  
      18  
      19  #ifndef FTLZW_H_
      20  #define FTLZW_H_
      21  
      22  #include <freetype/freetype.h>
      23  
      24  #ifdef FREETYPE_H
      25  #error "freetype.h of FreeType 1 has been loaded!"
      26  #error "Please fix the directory search order for header files"
      27  #error "so that freetype.h of FreeType 2 is found first."
      28  #endif
      29  
      30  
      31  FT_BEGIN_HEADER
      32  
      33    /**************************************************************************
      34     *
      35     * @section:
      36     *   lzw
      37     *
      38     * @title:
      39     *   LZW Streams
      40     *
      41     * @abstract:
      42     *   Using LZW-compressed font files.
      43     *
      44     * @description:
      45     *   In certain builds of the library, LZW compression recognition is
      46     *   automatically handled when calling @FT_New_Face or @FT_Open_Face.
      47     *   This means that if no font driver is capable of handling the raw
      48     *   compressed file, the library will try to open a LZW stream from it and
      49     *   re-open the face with it.
      50     *
      51     *   The stream implementation is very basic and resets the decompression
      52     *   process each time seeking backwards is needed within the stream,
      53     *   which significantly undermines the performance.
      54     *
      55     *   This section contains the declaration of LZW-specific functions.
      56     *
      57     */
      58  
      59    /**************************************************************************
      60     *
      61     * @function:
      62     *   FT_Stream_OpenLZW
      63     *
      64     * @description:
      65     *   Open a new stream to parse LZW-compressed font files.  This is mainly
      66     *   used to support the compressed `*.pcf.Z` fonts that come with XFree86.
      67     *
      68     * @input:
      69     *   stream ::
      70     *     The target embedding stream.
      71     *
      72     *   source ::
      73     *     The source stream.
      74     *
      75     * @return:
      76     *   FreeType error code.  0~means success.
      77     *
      78     * @note:
      79     *   The source stream must be opened _before_ calling this function.
      80     *
      81     *   Calling the internal function `FT_Stream_Close` on the new stream will
      82     *   **not** call `FT_Stream_Close` on the source stream.  None of the
      83     *   stream objects will be released to the heap.
      84     *
      85     *   This function may return `FT_Err_Unimplemented_Feature` if your build
      86     *   of FreeType was not compiled with LZW support.
      87     */
      88    FT_EXPORT( FT_Error )
      89    FT_Stream_OpenLZW( FT_Stream  stream,
      90                       FT_Stream  source );
      91  
      92    /* */
      93  
      94  
      95  FT_END_HEADER
      96  
      97  #endif /* FTLZW_H_ */
      98  
      99  
     100  /* END */