ttdriver.c

a very goog book

  /*************************************************************************/
  /*                                                                       */
  /* <Function>                                                            */
  /*    Load_Glyph                                                         */
  /*                                                                       */
  /* <Description>                                                         */
  /*    A driver method used to load a glyph within a given glyph slot.    */
  /*                                                                       */
  /* <Input>                                                               */
  /*    slot        :: A handle to the target slot object where the glyph  */
  /*                   will be loaded.                                     */
  /*                                                                       */
  /*    size        :: A handle to the source face size at which the glyph */
  /*                   must be scaled, loaded, etc.                        */
  /*                                                                       */
  /*    glyph_index :: The index of the glyph in the font file.            */
  /*                                                                       */
  /*    load_flags  :: A flag indicating what to load for this glyph.  The */
  /*                   FTLOAD_??? constants can be used to control the     */
  /*                   glyph loading process (e.g., whether the outline    */
  /*                   should be scaled, whether to load bitmaps or not,   */
  /*                   whether to hint the outline, etc).                  */
  /*                                                                       */
  /* <Return>                                                              */
  /*    FreeType error code.  0 means success.                             */
  /*                                                                       */
  static FT_Error
  Load_Glyph( TT_GlyphSlot  slot,
              TT_Size       size,
              FT_UShort     glyph_index,
              FT_UInt       load_flags )
  {
    FT_Error  error;


    if ( !slot )
      return TT_Err_Invalid_Slot_Handle;

    /* check whether we want a scaled outline or bitmap */
    if ( !size )
      load_flags |= FT_LOAD_NO_SCALE | FT_LOAD_NO_HINTING;

    if ( load_flags & FT_LOAD_NO_SCALE )
      size = NULL;

    /* reset the size object if necessary */
    if ( size )
    {
      /* these two object must have the same parent */
      if ( size->root.face != slot->face )
        return TT_Err_Invalid_Face_Handle;

      if ( !size->ttmetrics.valid )
      {
        if ( FT_SET_ERROR( TT_Size_Reset( size ) ) )
          return error;
      }
    }

    /* now load the glyph outline if necessary */
    error = TT_Load_Glyph( size, slot, glyph_index, load_flags );

    /* force drop-out mode to 2 - irrelevant now */
    /* slot->outline.dropout_mode = 2; */

    return error;
  }


  /*************************************************************************/
  /*************************************************************************/
  /*************************************************************************/
  /****                                                                 ****/
  /****                                                                 ****/
  /****             C H A R A C T E R   M A P P I N G S                 ****/
  /****                                                                 ****/
  /****                                                                 ****/
  /*************************************************************************/
  /*************************************************************************/
  /*************************************************************************/

  /*************************************************************************/
  /*                                                                       */
  /* <Function>                                                            */
  /*    Get_Char_Index                                                     */
  /*                                                                       */
  /* <Description>                                                         */
  /*    Uses a charmap to return a given character code's glyph index.     */
  /*                                                                       */
  /* <Input>                                                               */
  /*    charmap  :: A handle to the source charmap object.                 */
  /*    charcode :: The character code.                                    */
  /*                                                                       */
  /* <Return>                                                              */
  /*    Glyph index.  0 means `undefined character code'.                  */
  /*                                                                       */
  static FT_UInt
  Get_Char_Index( TT_CharMap  charmap,
                  FT_Long     charcode )
  {
    FT_Error      error;
    TT_Face       face;
    TT_CMapTable  cmap;


    cmap = &charmap->cmap;
    face = (TT_Face)charmap->root.face;

    /* Load table if needed */
    if ( !cmap->loaded )
    {
      SFNT_Service  sfnt = (SFNT_Service)face->sfnt;


      error = sfnt->load_charmap( face, cmap, face->root.stream );
      if ( error )
        return 0;

      cmap->loaded = TRUE;
    }

    if ( cmap->get_index )
      return cmap->get_index( cmap, charcode );
    else
      return 0;
  }


  /*************************************************************************/
  /*                                                                       */
  /* <Function>                                                            */
  /*    Get_Next_Char                                                      */
  /*                                                                       */
  /* <Description>                                                         */
  /*    Uses a charmap to return the next encoded char.                    */
  /*                                                                       */
  /* <Input>                                                               */
  /*    charmap  :: A handle to the source charmap object.                 */
  /*    charcode :: The character code.                                    */
  /*                                                                       */
  /* <Return>                                                              */
  /*    Next char code.  0 means `no more encoded characters'.             */
  /*                                                                       */
  static FT_UInt
  Get_Next_Char( TT_CharMap  charmap,
                 FT_Long     charcode )
  {
    FT_Error      error;
    TT_Face       face;
    TT_CMapTable  cmap;


    cmap = &charmap->cmap;
    face = (TT_Face)charmap->root.face;

    /* Load table if needed */
    if ( !cmap->loaded )
    {
      SFNT_Service  sfnt = (SFNT_Service)face->sfnt;


      error = sfnt->load_charmap( face, cmap, face->root.stream );
      if ( error )
        return 0;

      cmap->loaded = TRUE;
    }

    if ( cmap->get_next_char )
      return cmap->get_next_char ( cmap, charcode );
    else
      return 0;
  }


  /*************************************************************************/
  /*************************************************************************/
  /*************************************************************************/
  /****                                                                 ****/
  /****                                                                 ****/
  /****                D R I V E R  I N T E R F A C E                   ****/
  /****                                                                 ****/
  /****                                                                 ****/
  /*************************************************************************/
  /*************************************************************************/
  /*************************************************************************/


  static FT_Module_Interface
  tt_get_interface( TT_Driver    driver,
                    const char*  tt_interface )
  {
    FT_Module     sfntd = FT_Get_Module( driver->root.root.library,
                                         "sfnt" );
    SFNT_Service  sfnt;


    /* only return the default interface from the SFNT module */
    if ( sfntd )
    {
      sfnt = (SFNT_Service)( sfntd->clazz->module_interface );
      if ( sfnt )
        return sfnt->get_interface( FT_MODULE( driver ), tt_interface );
    }

    return 0;
  }


  /* The FT_DriverInterface structure is defined in ftdriver.h. */

  FT_CALLBACK_TABLE_DEF
  const FT_Driver_ClassRec  tt_driver_class =
  {
    {
      ft_module_font_driver     |
      ft_module_driver_scalable |
#ifdef TT_CONFIG_OPTION_BYTECODE_INTERPRETER
      ft_module_driver_has_hinter,
#else
      0,
#endif

      sizeof ( TT_DriverRec ),

      "truetype",      /* driver name                           */
      0x10000L,        /* driver version == 1.0                 */
      0x20000L,        /* driver requires FreeType 2.0 or above */

      (void*)0,        /* driver specific interface */

      (FT_Module_Constructor)TT_Driver_Init,
      (FT_Module_Destructor) TT_Driver_Done,
      (FT_Module_Requester)  tt_get_interface,
    },

    sizeof ( TT_FaceRec ),
    sizeof ( TT_SizeRec ),
    sizeof ( FT_GlyphSlotRec ),


    (FT_Face_InitFunc)        TT_Face_Init,
    (FT_Face_DoneFunc)        TT_Face_Done,
    (FT_Size_InitFunc)        TT_Size_Init,
    (FT_Size_DoneFunc)        TT_Size_Done,
    (FT_Slot_InitFunc)        0,
    (FT_Slot_DoneFunc)        0,

    (FT_Size_ResetPointsFunc) Set_Char_Sizes,
    (FT_Size_ResetPixelsFunc) Set_Pixel_Sizes,
    (FT_Slot_LoadFunc)        Load_Glyph,
    (FT_CharMap_CharIndexFunc)Get_Char_Index,

    (FT_Face_GetKerningFunc)  Get_Kerning,
    (FT_Face_AttachFunc)      0,
    (FT_Face_GetAdvancesFunc) 0,
    
    (FT_CharMap_CharNextFunc) Get_Next_Char
  };


/* END */