ttload.c

下载来的一个看图软件的源代码

    FT_TRACE2(( "loaded\n" ));

  Exit:
    return error;
  }


  /*************************************************************************/
  /*                                                                       */
  /* <Function>                                                            */
  /*    tt_face_load_postscript                                            */
  /*                                                                       */
  /* <Description>                                                         */
  /*    Loads the Postscript table.                                        */
  /*                                                                       */
  /* <Input>                                                               */
  /*    face   :: A handle to the target face object.                      */
  /*                                                                       */
  /*    stream :: A handle to the input stream.                            */
  /*                                                                       */
  /* <Return>                                                              */
  /*    FreeType error code.  0 means success.                             */
  /*                                                                       */
  FT_LOCAL_DEF( FT_Error )
  tt_face_load_postscript( TT_Face    face,
                           FT_Stream  stream )
  {
    FT_Error        error;
    TT_Postscript*  post = &face->postscript;

    static const FT_Frame_Field  post_fields[] =
    {
#undef  FT_STRUCTURE
#define FT_STRUCTURE  TT_Postscript

      FT_FRAME_START( 32 ),
        FT_FRAME_ULONG( FormatType ),
        FT_FRAME_ULONG( italicAngle ),
        FT_FRAME_SHORT( underlinePosition ),
        FT_FRAME_SHORT( underlineThickness ),
        FT_FRAME_ULONG( isFixedPitch ),
        FT_FRAME_ULONG( minMemType42 ),
        FT_FRAME_ULONG( maxMemType42 ),
        FT_FRAME_ULONG( minMemType1 ),
        FT_FRAME_ULONG( maxMemType1 ),
      FT_FRAME_END
    };


    FT_TRACE2(( "PostScript " ));

    error = face->goto_table( face, TTAG_post, stream, 0 );
    if ( error )
      return SFNT_Err_Post_Table_Missing;

    if ( FT_STREAM_READ_FIELDS( post_fields, post ) )
      return error;

    /* we don't load the glyph names, we do that in another */
    /* module (ttpost).                                     */
    FT_TRACE2(( "loaded\n" ));

    return SFNT_Err_Ok;
  }


  /*************************************************************************/
  /*                                                                       */
  /* <Function>                                                            */
  /*    tt_face_load_pclt                                                  */
  /*                                                                       */
  /* <Description>                                                         */
  /*    Loads the PCL 5 Table.                                             */
  /*                                                                       */
  /* <Input>                                                               */
  /*    face   :: A handle to the target face object.                      */
  /*                                                                       */
  /*    stream :: A handle to the input stream.                            */
  /*                                                                       */
  /* <Return>                                                              */
  /*    FreeType error code.  0 means success.                             */
  /*                                                                       */
  FT_LOCAL_DEF( FT_Error )
  tt_face_load_pclt( TT_Face    face,
                     FT_Stream  stream )
  {
    static const FT_Frame_Field  pclt_fields[] =
    {
#undef  FT_STRUCTURE
#define FT_STRUCTURE  TT_PCLT

      FT_FRAME_START( 54 ),
        FT_FRAME_ULONG ( Version ),
        FT_FRAME_ULONG ( FontNumber ),
        FT_FRAME_USHORT( Pitch ),
        FT_FRAME_USHORT( xHeight ),
        FT_FRAME_USHORT( Style ),
        FT_FRAME_USHORT( TypeFamily ),
        FT_FRAME_USHORT( CapHeight ),
        FT_FRAME_BYTES ( TypeFace, 16 ),
        FT_FRAME_BYTES ( CharacterComplement, 8 ),
        FT_FRAME_BYTES ( FileName, 6 ),
        FT_FRAME_CHAR  ( StrokeWeight ),
        FT_FRAME_CHAR  ( WidthType ),
        FT_FRAME_BYTE  ( SerifStyle ),
        FT_FRAME_BYTE  ( Reserved ),
      FT_FRAME_END
    };

    FT_Error  error;
    TT_PCLT*  pclt = &face->pclt;


    FT_TRACE2(( "PCLT " ));

    /* optional table */
    error = face->goto_table( face, TTAG_PCLT, stream, 0 );
    if ( error )
    {
      FT_TRACE2(( "missing (optional)\n" ));
      pclt->Version = 0;
      return SFNT_Err_Ok;
    }

    if ( FT_STREAM_READ_FIELDS( pclt_fields, pclt ) )
      goto Exit;

    FT_TRACE2(( "loaded\n" ));

  Exit:
    return error;
  }


  /*************************************************************************/
  /*                                                                       */
  /* <Function>                                                            */
  /*    tt_face_load_gasp                                                  */
  /*                                                                       */
  /* <Description>                                                         */
  /*    Loads the `gasp' table into a face object.                         */
  /*                                                                       */
  /* <Input>                                                               */
  /*    face   :: A handle to the target face object.                      */
  /*                                                                       */
  /*    stream :: The input stream.                                        */
  /*                                                                       */
  /* <Return>                                                              */
  /*    FreeType error code.  0 means success.                             */
  /*                                                                       */
  FT_LOCAL_DEF( FT_Error )
  tt_face_load_gasp( TT_Face    face,
                     FT_Stream  stream )
  {
    FT_Error   error;
    FT_Memory  memory = stream->memory;

    FT_UInt        j,num_ranges;
    TT_GaspRange   gaspranges;


    FT_TRACE2(( "tt_face_load_gasp: %08p\n", face ));

    /* the gasp table is optional */
    error = face->goto_table( face, TTAG_gasp, stream, 0 );
    if ( error )
      return SFNT_Err_Ok;

    if ( FT_FRAME_ENTER( 4L ) )
      goto Exit;

    face->gasp.version   = FT_GET_USHORT();
    face->gasp.numRanges = FT_GET_USHORT();

    FT_FRAME_EXIT();

    num_ranges = face->gasp.numRanges;
    FT_TRACE3(( "number of ranges = %d\n", num_ranges ));

    if ( FT_NEW_ARRAY( gaspranges, num_ranges ) ||
         FT_FRAME_ENTER( num_ranges * 4L )      )
      goto Exit;

    face->gasp.gaspRanges = gaspranges;

    for ( j = 0; j < num_ranges; j++ )
    {
      gaspranges[j].maxPPEM  = FT_GET_USHORT();
      gaspranges[j].gaspFlag = FT_GET_USHORT();

      FT_TRACE3(( " [max:%d flag:%d]",
                    gaspranges[j].maxPPEM,
                    gaspranges[j].gaspFlag ));
    }
    FT_TRACE3(( "\n" ));

    FT_FRAME_EXIT();
    FT_TRACE2(( "GASP loaded\n" ));

  Exit:
    return error;
  }


  FT_CALLBACK_DEF( int )
  tt_kern_pair_compare( const void*  a,
                        const void*  b );


  /*************************************************************************/
  /*                                                                       */
  /* <Function>                                                            */
  /*    tt_face_load_kern                                                  */
  /*                                                                       */
  /* <Description>                                                         */
  /*    Loads the first kerning table with format 0 in the font.  Only     */
  /*    accepts the first horizontal kerning table.  Developers should use */
  /*    the `ftxkern' extension to access other kerning tables in the font */
  /*    file, if they really want to.                                      */
  /*                                                                       */
  /* <Input>                                                               */
  /*    face   :: A handle to the target face object.                      */
  /*                                                                       */
  /*    stream :: The input stream.                                        */
  /*                                                                       */
  /* <Return>                                                              */
  /*    FreeType error code.  0 means success.                             */
  /*                                                                       */
  FT_LOCAL_DEF( FT_Error )
  tt_face_load_kern( TT_Face    face,
                     FT_Stream  stream )
  {
    FT_Error   error;
    FT_Memory  memory = stream->memory;

    FT_UInt    n, num_tables;


    /* the kern table is optional; exit silently if it is missing */
    error = face->goto_table( face, TTAG_kern, stream, 0 );
    if ( error )
      return SFNT_Err_Ok;

    if ( FT_FRAME_ENTER( 4L ) )
      goto Exit;

    (void)FT_GET_USHORT();         /* version */
    num_tables = FT_GET_USHORT();

    FT_FRAME_EXIT();

    for ( n = 0; n < num_tables; n++ )
    {
      FT_UInt  coverage;
      FT_UInt  length;


      if ( FT_FRAME_ENTER( 6L ) )
        goto Exit;

      (void)FT_GET_USHORT();           /* version                 */
      length   = FT_GET_USHORT() - 6;  /* substract header length */
      coverage = FT_GET_USHORT();

      FT_FRAME_EXIT();

      if ( coverage == 0x0001 )
      {
        FT_UInt        num_pairs;
        TT_Kern0_Pair  pair;
        TT_Kern0_Pair  limit;


        /* found a horizontal format 0 kerning table! */
        if ( FT_FRAME_ENTER( 8L ) )
          goto Exit;

        num_pairs = FT_GET_USHORT();

        /* skip the rest */

        FT_FRAME_EXIT();

        /* allocate array of kerning pairs */
        if ( FT_NEW_ARRAY( face->kern_pairs, num_pairs ) ||
             FT_FRAME_ENTER( 6L * num_pairs )            )
          goto Exit;

        pair  = face->kern_pairs;
        limit = pair + num_pairs;
        for ( ; pair < limit; pair++ )
        {
          pair->left  = FT_GET_USHORT();
          pair->right = FT_GET_USHORT();
          pair->value = FT_GET_USHORT();
        }

        FT_FRAME_EXIT();

        face->num_kern_pairs   = num_pairs;
        face->kern_table_index = n;

        /* ensure that the kerning pair table is sorted (yes, some */
        /* fonts have unsorted tables!)                            */
        {
          FT_UInt        i;
          TT_Kern0_Pair  pair0;


          pair0 = face->kern_pairs;

          for ( i = 1; i < num_pairs; i++, pair0++ )
          {
            if ( tt_kern_pair_compare( pair0, pair0 + 1 ) != -1 )
            {
              ft_qsort( (void*)face->kern_pairs, (int)num_pairs,
                        sizeof ( TT_Kern0_PairRec ), tt_kern_pair_compare );
              break;
            }
          }
        }

        goto Exit;
      }

      if ( FT_STREAM_SKIP( length ) )
        goto Exit;
    }

    /* no kern table found -- doesn't matter */
    face->kern_table_index = -1;
    face->num_kern_pairs   = 0;
    face->kern_pairs       = NULL;

  Exit:
    return error;
  }


#undef  TT_KERN_INDEX
#define TT_KERN_INDEX( g1, g2 )  ( ( (FT_ULong)g1 << 16 ) | g2 )


  FT_CALLBACK_DEF( int )
  tt_kern_pair_compare( co