ttobjs.c

下载来的一个看图软件的源代码

    /* Compute root ascender, descender, text height, and max_advance */
    metrics->ascender    = ( FT_MulFix( face->root.ascender,
                                        metrics->y_scale ) + 32 ) & -64;
    metrics->descender   = ( FT_MulFix( face->root.descender,
                                        metrics->y_scale ) + 32 ) & -64;
    metrics->height      = ( FT_MulFix( face->root.height,
                                        metrics->y_scale ) + 32 ) & -64;
    metrics->max_advance = ( FT_MulFix( face->root.max_advance_width,
                                        metrics->x_scale ) + 32 ) & -64;


#ifdef TT_CONFIG_OPTION_EMBEDDED_BITMAPS
    /* set to `invalid' by default */
    size->strike_index = 0xFFFFU;
#endif

#ifdef TT_CONFIG_OPTION_BYTECODE_INTERPRETER

    {
      TT_ExecContext  exec;
      FT_UInt         i, j;


      /* Scale the cvt values to the new ppem.          */
      /* We use by default the y ppem to scale the CVT. */
      for ( i = 0; i < size->cvt_size; i++ )
        size->cvt[i] = FT_MulFix( face->cvt[i], size->ttmetrics.scale );

      /* All twilight points are originally zero */
      for ( j = 0; j < (FT_UInt)size->twilight.n_points; j++ )
      {
        size->twilight.org[j].x = 0;
        size->twilight.org[j].y = 0;
        size->twilight.cur[j].x = 0;
        size->twilight.cur[j].y = 0;
      }

      /* clear storage area */
      for ( i = 0; i < (FT_UInt)size->storage_size; i++ )
        size->storage[i] = 0;

      size->GS = tt_default_graphics_state;

      /* get execution context and run prep program */
      if ( size->debug )
        exec = size->context;
      else
        exec = TT_New_Context( face );
      /* debugging instances have their own context */

      if ( !exec )
        return TT_Err_Could_Not_Find_Context;

      TT_Load_Context( exec, face, size );

      TT_Set_CodeRange( exec,
                        tt_coderange_cvt,
                        face->cvt_program,
                        face->cvt_program_size );

      TT_Clear_CodeRange( exec, tt_coderange_glyph );

      exec->instruction_trap = FALSE;

      exec->top     = 0;
      exec->callTop = 0;

      if ( face->cvt_program_size > 0 )
      {
        error = TT_Goto_CodeRange( exec, tt_coderange_cvt, 0 );
        if ( error )
          goto End;

        if ( !size->debug )
          error = face->interpreter( exec );
      }
      else
        error = TT_Err_Ok;

      size->GS = exec->GS;
      /* save default graphics state */

    End:
      TT_Save_Context( exec, size );

      if ( !size->debug )
        TT_Done_Context( exec );
      /* debugging instances keep their context */
    }

#endif /* TT_CONFIG_OPTION_BYTECODE_INTERPRETER */

    if ( !error )
      size->ttmetrics.valid = TRUE;

    return error;
  }


#ifdef TT_CONFIG_OPTION_EMBEDDED_BITMAPS

  /*************************************************************************/
  /*                                                                       */
  /* <Function>                                                            */
  /*    Reset_SBit_Size                                                    */
  /*                                                                       */
  /* <Description>                                                         */
  /*    Resets a TrueType sbit size when resolutions and character         */
  /*    dimensions have been changed.                                      */
  /*                                                                       */
  /* <Input>                                                               */
  /*    size :: A handle to the target size object.                        */
  /*                                                                       */
  static FT_Error
  Reset_SBit_Size( TT_Size  size )
  {
    TT_Face           face;
    FT_Error          error = TT_Err_Ok;

    FT_ULong          strike_index;
    FT_Size_Metrics*  metrics;
    FT_Size_Metrics*  sbit_metrics;
    SFNT_Service      sfnt;


    metrics = &size->metrics;

    if ( size->strike_index != 0xFFFFU )
      return TT_Err_Ok;

    face = (TT_Face)size->root.face;
    sfnt = (SFNT_Service)face->sfnt;

    sbit_metrics = &size->strike_metrics;

    error = sfnt->set_sbit_strike( face,
                                   metrics->x_ppem, metrics->y_ppem,
                                   &strike_index );

    if ( !error )
    {
      TT_SBit_Strike  strike = face->sbit_strikes + strike_index;


      sbit_metrics->x_ppem = metrics->x_ppem;
      sbit_metrics->y_ppem = metrics->y_ppem;
#if 0
      /*
       * sbit_metrics->?_scale
       * are not used now.
       */
      sbit_metrics->x_scale = 1 << 16;
      sbit_metrics->y_scale = 1 << 16;
#endif

      sbit_metrics->ascender  = strike->hori.ascender << 6;
      sbit_metrics->descender = strike->hori.descender << 6;

      /* XXX: Is this correct? */
      sbit_metrics->height = sbit_metrics->ascender - sbit_metrics->descender;

      /* XXX: Is this correct? */
      sbit_metrics->max_advance = ( strike->hori.min_origin_SB  +
                                    strike->hori.max_width      +
                                    strike->hori.min_advance_SB ) << 6;

      size->strike_index = (FT_UInt)strike_index;
    }
    else
    {
      size->strike_index = 0xFFFFU;

      sbit_metrics->x_ppem      = 0;
      sbit_metrics->y_ppem      = 0;
      sbit_metrics->ascender    = 0;
      sbit_metrics->descender   = 0;
      sbit_metrics->height      = 0;
      sbit_metrics->max_advance = 0;
    }

    return error;
  }

#endif /* TT_CONFIG_OPTION_EMBEDDED_BITMAPS */


  /*************************************************************************/
  /*                                                                       */
  /* <Function>                                                            */
  /*    tt_size_reset                                                      */
  /*                                                                       */
  /* <Description>                                                         */
  /*    Resets a TrueType size when resolutions and character dimensions   */
  /*    have been changed.                                                 */
  /*                                                                       */
  /* <Input>                                                               */
  /*    size :: A handle to the target size object.                        */
  /*                                                                       */
  FT_LOCAL_DEF( FT_Error )
  tt_size_reset( TT_Size  size )
  {
    FT_Face   face;
    FT_Error  error = TT_Err_Ok;


    face = size->root.face;

    if ( face->face_flags & FT_FACE_FLAG_SCALABLE )
    {
      if ( !size->ttmetrics.valid )
        error = Reset_Outline_Size( size );

      if ( error )
        return error;
    }

#ifdef TT_CONFIG_OPTION_EMBEDDED_BITMAPS

    if ( face->face_flags & FT_FACE_FLAG_FIXED_SIZES )
    {
      if ( size->strike_index == 0xFFFFU )
        error = Reset_SBit_Size( size );

      if ( !error && !( face->face_flags & FT_FACE_FLAG_SCALABLE ) )
        size->root.metrics = size->strike_metrics;
    }

#endif /* TT_CONFIG_OPTION_EMBEDDED_BITMAPS */

    if ( face->face_flags & FT_FACE_FLAG_SCALABLE )
      return TT_Err_Ok;
    else
      return error;
  }


  /*************************************************************************/
  /*                                                                       */
  /* <Function>                                                            */
  /*    tt_driver_init                                                     */
  /*                                                                       */
  /* <Description>                                                         */
  /*    Initializes a given TrueType driver object.                        */
  /*                                                                       */
  /* <Input>                                                               */
  /*    driver :: A handle to the target driver object.                    */
  /*                                                                       */
  /* <Return>                                                              */
  /*    FreeType error code.  0 means success.                             */
  /*                                                                       */
  FT_LOCAL_DEF( FT_Error )
  tt_driver_init( TT_Driver  driver )
  {
    FT_Error  error;


    /* set `extra' in glyph loader */
    error = FT_GlyphLoader_CreateExtra( FT_DRIVER( driver )->glyph_loader );

    return error;
  }


  /*************************************************************************/
  /*                                                                       */
  /* <Function>                                                            */
  /*    tt_driver_done                                                     */
  /*                                                                       */
  /* <Description>                                                         */
  /*    Finalizes a given TrueType driver.                                 */
  /*                                                                       */
  /* <Input>                                                               */
  /*    driver :: A handle to the target TrueType driver.                  */
  /*                                                                       */
  FT_LOCAL_DEF( void )
  tt_driver_done( TT_Driver  driver )
  {
#ifdef TT_CONFIG_OPTION_BYTECODE_INTERPRETER

    /* destroy the execution context */
    if ( driver->context )
    {
      TT_Destroy_Context( driver->context, driver->root.root.memory );
      driver->context = NULL;
    }
#else
    FT_UNUSED( driver );
#endif

  }


/* END */