ttpload.c

QT 开发环境里面一个很重要的文件

    FT_TRACE2(( "loaded\n" ));

#ifdef TT_CONFIG_OPTION_GX_VAR_SUPPORT
    if ( face->doblend )
      error = tt_face_vary_cvt( face, stream );
#endif

  Exit:
    return error;

#else /* !TT_CONFIG_OPTION_BYTECODE_INTERPRETER */

    FT_UNUSED( face   );
    FT_UNUSED( stream );

    return TT_Err_Ok;

#endif
  }


  /*************************************************************************/
  /*                                                                       */
  /* <Function>                                                            */
  /*    tt_face_load_fpgm                                                  */
  /*                                                                       */
  /* <Description>                                                         */
  /*    Load the font program.                                             */
  /*                                                                       */
  /* <InOut>                                                               */
  /*    face   :: A handle to the target face object.                      */
  /*                                                                       */
  /* <Input>                                                               */
  /*    stream :: A handle to the input stream.                            */
  /*                                                                       */
  /* <Return>                                                              */
  /*    FreeType error code.  0 means success.                             */
  /*                                                                       */
  FT_LOCAL_DEF( FT_Error )
  tt_face_load_fpgm( TT_Face    face,
                     FT_Stream  stream )
  {
#ifdef TT_CONFIG_OPTION_BYTECODE_INTERPRETER

    FT_Error  error;
    FT_ULong  table_len;


    FT_TRACE2(( "Font program " ));

    /* The font program is optional */
    error = face->goto_table( face, TTAG_fpgm, stream, &table_len );
    if ( error )
    {
      face->font_program      = NULL;
      face->font_program_size = 0;
      error                   = TT_Err_Ok;

      FT_TRACE2(( "is missing!\n" ));
    }
    else
    {
      face->font_program_size = table_len;
      if ( FT_FRAME_EXTRACT( table_len, face->font_program ) )
        goto Exit;

      FT_TRACE2(( "loaded, %12d bytes\n", face->font_program_size ));
    }

  Exit:
    return error;

#else /* !TT_CONFIG_OPTION_BYTECODE_INTERPRETER */

    FT_UNUSED( face   );
    FT_UNUSED( stream );

    return TT_Err_Ok;

#endif
  }


  /*************************************************************************/
  /*                                                                       */
  /* <Function>                                                            */
  /*    tt_face_load_prep                                                  */
  /*                                                                       */
  /* <Description>                                                         */
  /*    Load the cvt program.                                              */
  /*                                                                       */
  /* <InOut>                                                               */
  /*    face   :: A handle to the target face object.                      */
  /*                                                                       */
  /* <Input>                                                               */
  /*    stream :: A handle to the input stream.                            */
  /*                                                                       */
  /* <Return>                                                              */
  /*    FreeType error code.  0 means success.                             */
  /*                                                                       */
  FT_LOCAL_DEF( FT_Error )
  tt_face_load_prep( TT_Face    face,
                     FT_Stream  stream )
  {
#ifdef TT_CONFIG_OPTION_BYTECODE_INTERPRETER

    FT_Error  error;
    FT_ULong  table_len;


    FT_TRACE2(( "Prep program " ));

    error = face->goto_table( face, TTAG_prep, stream, &table_len );
    if ( error )
    {
      face->cvt_program      = NULL;
      face->cvt_program_size = 0;
      error                  = TT_Err_Ok;

      FT_TRACE2(( "is missing!\n" ));
    }
    else
    {
      face->cvt_program_size = table_len;
      if ( FT_FRAME_EXTRACT( table_len, face->cvt_program ) )
        goto Exit;

      FT_TRACE2(( "loaded, %12d bytes\n", face->cvt_program_size ));
    }

  Exit:
    return error;

#else /* !TT_CONFIG_OPTION_BYTECODE_INTERPRETER */

    FT_UNUSED( face   );
    FT_UNUSED( stream );

    return TT_Err_Ok;

#endif
  }


  /*************************************************************************/
  /*                                                                       */
  /* <Function>                                                            */
  /*    tt_face_load_hdmx                                                  */
  /*                                                                       */
  /* <Description>                                                         */
  /*    Load the `hdmx' table into the face object.                        */
  /*                                                                       */
  /* <Input>                                                               */
  /*    face   :: A handle to the target face object.                      */
  /*                                                                       */
  /*    stream :: A handle to the input stream.                            */
  /*                                                                       */
  /* <Return>                                                              */
  /*    FreeType error code.  0 means success.                             */
  /*                                                                       */
#ifdef FT_OPTIMIZE_MEMORY

  FT_LOCAL_DEF( FT_Error )
  tt_face_load_hdmx( TT_Face    face,
                     FT_Stream  stream )
  {
    FT_Error   error;
    FT_Memory  memory = stream->memory;
    FT_UInt    version, nn, num_records;
    FT_ULong   table_size, record_size;
    FT_Byte*   p;
    FT_Byte*   limit;


    /* this table is optional */
    error = face->goto_table( face, TTAG_hdmx, stream, &table_size );
    if ( error || table_size < 8 )
      return TT_Err_Ok;

    if ( FT_FRAME_EXTRACT( table_size, face->hdmx_table ) )
      goto Exit;

    p     = face->hdmx_table;
    limit = p + table_size;

    version     = FT_NEXT_USHORT( p );
    num_records = FT_NEXT_USHORT( p );
    record_size = FT_NEXT_ULONG( p );

    if ( version != 0 || num_records > 255 || record_size > 0x40000 )
    {
      error = TT_Err_Invalid_File_Format;
      goto Fail;
    }

    if ( FT_NEW_ARRAY( face->hdmx_record_sizes, num_records ) )
      goto Fail;

    for ( nn = 0; nn < num_records; nn++ )
    {
      if ( p + record_size > limit )
        break;

      face->hdmx_record_sizes[nn] = p[0];
      p                          += record_size;
    }

    face->hdmx_record_count = nn;
    face->hdmx_table_size   = table_size;
    face->hdmx_record_size  = record_size;

  Exit:
    return error;

  Fail:
    FT_FRAME_RELEASE( face->hdmx_table );
    face->hdmx_table_size = 0;
    goto Exit;
  }


  FT_LOCAL_DEF( void )
  tt_face_free_hdmx( TT_Face  face )
  {
    FT_Stream  stream = face->root.stream;
    FT_Memory  memory = stream->memory;


    FT_FREE( face->hdmx_record_sizes );
    FT_FRAME_RELEASE( face->hdmx_table );
  }

#else /* !FT_OPTIMIZE_MEMORY */

  FT_LOCAL_DEF( FT_Error )
  tt_face_load_hdmx( TT_Face    face,
                     FT_Stream  stream )
  {
    FT_Error   error;
    FT_Memory  memory = stream->memory;

    TT_Hdmx    hdmx = &face->hdmx;
    FT_Short   num_records;
    FT_Long    num_glyphs;
    FT_Long    record_size;


    hdmx->version     = 0;
    hdmx->num_records = 0;
    hdmx->records     = 0;

    /* this table is optional */
    error = face->goto_table( face, TTAG_hdmx, stream, 0 );
    if ( error )
      return TT_Err_Ok;

    if ( FT_FRAME_ENTER( 8L ) )
      goto Exit;

    hdmx->version = FT_GET_USHORT();
    num_records   = FT_GET_SHORT();
    record_size   = FT_GET_LONG();

    FT_FRAME_EXIT();

    if ( record_size < 0 || num_records < 0 )
      return TT_Err_Invalid_File_Format;

    /* Only recognize format 0 */
    if ( hdmx->version != 0 )
      goto Exit;

    /* we can't use FT_QNEW_ARRAY here; otherwise tt_face_free_hdmx */
    /* could fail during deallocation                               */
    if ( FT_NEW_ARRAY( hdmx->records, num_records ) )
      goto Exit;

    hdmx->num_records = num_records;
    num_glyphs        = face->root.num_glyphs;
    record_size      -= num_glyphs + 2;

    {
      TT_HdmxEntry  cur   = hdmx->records;
      TT_HdmxEntry  limit = cur + hdmx->num_records;


      for ( ; cur < limit; cur++ )
      {
        /* read record */
        if ( FT_READ_BYTE( cur->ppem      ) ||
             FT_READ_BYTE( cur->max_width ) )
          goto Exit;

        if ( FT_QALLOC( cur->widths, num_glyphs )      ||
             FT_STREAM_READ( cur->widths, num_glyphs ) )
          goto Exit;

        /* skip padding bytes */
        if ( record_size > 0 && FT_STREAM_SKIP( record_size ) )
          goto Exit;
      }
    }

  Exit:
    return error;
  }


  FT_LOCAL_DEF( void )
  tt_face_free_hdmx( TT_Face  face )
  {
    if ( face )
    {
      FT_Int     n;
      FT_Memory  memory = face->root.driver->root.memory;


      for ( n = 0; n < face->hdmx.num_records; n++ )
        FT_FREE( face->hdmx.records[n].widths );

      FT_FREE( face->hdmx.records );
      face->hdmx.num_records = 0;
    }
  }

#endif /* !OPTIMIZE_MEMORY */


  /*************************************************************************/
  /*                                                                       */
  /* Return the advance width table for a given pixel size if it is found  */
  /* in the font's `hdmx' table (if any).                                  */
  /*                                                                       */
  FT_LOCAL_DEF( FT_Byte* )
  tt_face_get_device_metrics( TT_Face  face,
                              FT_UInt  ppem,
                              FT_UInt  gindex )
  {
#ifdef FT_OPTIMIZE_MEMORY

    FT_UInt   nn;
    FT_Byte*  result      = NULL;
    FT_ULong  record_size = face->hdmx_record_size;
    FT_Byte*  record      = face->hdmx_table + 8;


    for ( nn = 0; nn < face->hdmx_record_count; nn++ )
      if ( face->hdmx_record_sizes[nn] == ppem )
      {
        gindex += 2;
        if ( gindex < record_size )
          result = record + nn * record_size + gindex;
        break;
      }

    return result;

#else

    FT_UShort  n;


    for ( n = 0; n < face->hdmx.num_records; n++ )
      if ( face->hdmx.records[n].ppem == ppem )
        return &face->hdmx.records[n].widths[gindex];

    return NULL;

#endif
  }


/* END */