ttgload.c

神龙卡开发原代码

      if ( n_ins > exec->face->maxProfile.maxSizeOfInstructions )
      {
        PTRACE0(( "ERROR: Too many instructions in composite glyph %ld\n",
                  subg->index ));
        return TT_Err_Too_Many_Ins;
      }

      if ( FILE_Read( exec->glyphIns, n_ins ) )
        return error;

      error = Set_CodeRange( exec,
                             TT_CodeRange_Glyph,
                             exec->glyphIns,
                             n_ins );

      if ( error )
        return error;
    }
    else
      n_ins = 0;


    /* prepare the execution context */
    n_points += 2;
    exec->pts = subg->zone;
    pts       = &exec->pts;

    pts->n_points   = n_points;
    pts->n_contours = n_contours;

    /* add phantom points */
    pts->cur[n_points - 2] = subg->pp1;
    pts->cur[n_points - 1] = subg->pp2;

    pts->touch[n_points - 1] = 0;
    pts->touch[n_points - 2] = 0;

    /* if hinting, round the phantom points */
    if ( subg->is_hinted )
    {
      pts->cur[n_points - 2].x = (subg->pp1.x + 32) & -64;
      pts->cur[n_points - 1].x = (subg->pp2.x + 32) & -64;
    }

    for ( k = 0; k < n_points; k++ )
      pts->touch[k] &= TT_Flag_On_Curve;

    cur_to_org( n_points, pts );

    /* now consider hinting */
    if ( subg->is_hinted && n_ins > 0 )
    {
      exec->is_composite     = TRUE;
      exec->pedantic_hinting = load_flags & TTLOAD_PEDANTIC;

      error = Context_Run( exec, FALSE );
      if (error && exec->pedantic_hinting)
        return error;
    }

    /* save glyph origin and advance points */
    subg->pp1 = pts->cur[n_points - 2];
    subg->pp2 = pts->cur[n_points - 1];

    return TT_Err_Ok;
  }


/*******************************************************************
 *
 *  Function    :  Init_Glyph_Component
 *
 ******************************************************************/

  static
  void  Init_Glyph_Component( PSubglyph_Record    element,
                              PSubglyph_Record    original,
                              PExecution_Context  exec )
  {
    element->index     = -1;
    element->is_scaled = FALSE;
    element->is_hinted = FALSE;

    if ( original )
      mount_zone( &original->zone, &element->zone );
    else
      element->zone = exec->pts;

    element->zone.n_contours = 0;
    element->zone.n_points   = 0;

    element->arg1 = 0;
    element->arg2 = 0;

    element->element_flag = 0;
    element->preserve_pps = FALSE;

    element->transform.xx = 1L << 16;
    element->transform.xy = 0;
    element->transform.yx = 0;
    element->transform.yy = 1L << 16;

    element->transform.ox = 0;
    element->transform.oy = 0;

    element->metrics.horiBearingX = 0;
    element->metrics.horiAdvance  = 0;
  }



  LOCAL_FUNC
  TT_Error  Load_TrueType_Glyph(  PInstance   instance,
                                  PGlyph      glyph,
                                  UShort      glyph_index,
                                  UShort      load_flags )
  {
    enum TPhases_
    {
      Load_Exit,
      Load_Glyph,
      Load_Header,
      Load_Simple,
      Load_Composite,
      Load_End
    };

    typedef enum TPhases_  TPhases;

    DEFINE_ALL_LOCALS;

    PFace   face;

    UShort  num_points;
    Short   num_contours;
    UShort  left_points;
    Short   left_contours;
    UShort  num_elem_points;

    Long    table;
    UShort  load_top;
    Long    k, l;
    UShort  new_flags;
    Long    index;
    UShort  u, v;

    Long  glyph_offset, offset;

    TT_F26Dot6  x, y, nx, ny;

    Fixed  xx, xy, yx, yy;

    PExecution_Context  exec;

    PSubglyph_Record  subglyph, subglyph2;

    TGlyph_Zone base_pts;

    TPhases     phase;
    PByte       widths;

/*  TT_Glyph_Loader_Callback  cacheCb;        */
/*  TT_Outline                cached_outline; */


    /* first of all, check arguments */
    if ( !glyph )
      return TT_Err_Invalid_Glyph_Handle;

    face = glyph->face;
    if ( !face )
      return TT_Err_Invalid_Glyph_Handle;

    if ( glyph_index >= face->numGlyphs )
      return TT_Err_Invalid_Glyph_Index;

    if ( instance && (load_flags & TTLOAD_SCALE_GLYPH) == 0 )
    {
      instance    = 0;
      load_flags &= ~( TTLOAD_SCALE_GLYPH | TTLOAD_HINT_GLYPH );
    }

    table = TT_LookUp_Table( face, TTAG_glyf );
    if ( table < 0 )
    {
      PTRACE0(( "ERROR: There is no glyph table in this font file!\n" ));
      return TT_Err_Glyf_Table_Missing;
    }

    glyph_offset = face->dirTables[table].Offset;

    /* query new execution context */

    if ( instance && instance->debug )
      exec = instance->context;
    else
      exec = New_Context( face );

    if ( !exec )
      return TT_Err_Could_Not_Find_Context;

    Context_Load( exec, face, instance );

    if ( instance )
    {
      if ( instance->GS.instruct_control & 2 )
        exec->GS = Default_GraphicsState;
      else
        exec->GS = instance->GS;
      /* load default graphics state */

      glyph->outline.high_precision = ( instance->metrics.y_ppem < 24 );
    }

    /* save its critical pointers, as they'll be modified during load */
    base_pts = exec->pts;

    /* init variables */
    left_points   = face->maxPoints;
    left_contours = face->maxContours;

    num_points   = 0;
    num_contours = 0;

    load_top = 0;
    subglyph = exec->loadStack;

    Init_Glyph_Component( subglyph, NULL, exec );

    subglyph->index     = glyph_index;
    subglyph->is_hinted = load_flags & TTLOAD_HINT_GLYPH;

    /* when the cvt program has disabled hinting, the argument */
    /* is ignored.                                             */
    if ( instance && instance->GS.instruct_control & 1 )
      subglyph->is_hinted = FALSE;


    /* now access stream */

    if ( USE_Stream( face->stream, stream ) )
      goto Fin;

    /* Main loading loop */

    phase = Load_Glyph;
    index = 0;

    while ( phase != Load_Exit )
    {
      subglyph = exec->loadStack + load_top;

      switch ( phase )
      {
        /************************************************************/
        /*                                                          */
        /* Load_Glyph state                                         */
        /*                                                          */
        /*   reading a glyph's generic header to determine          */
        /*   whether it's simple or composite                       */
        /*                                                          */
        /* exit states: Load_Header and Load_End                    */

      case Load_Glyph:
        /* check glyph index and table */

        index = subglyph->index;
        if ( index < 0 || index >= face->numGlyphs )
        {
          error = TT_Err_Invalid_Glyph_Index;
          goto Fail;
        }

        /* get horizontal metrics */

        {
          Short   left_bearing;
          UShort  advance_width;


          Get_HMetrics( face, (UShort)index,
                        !(load_flags & TTLOAD_IGNORE_GLOBAL_ADVANCE_WIDTH),
                        &left_bearing,
                        &advance_width );

          subglyph->metrics.horiBearingX = left_bearing;
          subglyph->metrics.horiAdvance  = advance_width;
        }

        phase = Load_Header;


        /* The cache callback isn't part of the FreeType release yet */
        /* It is discarded for the moment..                          */
        /*                                                           */
#if 0
        if ( instance )
        {
          /* is the glyph in an outline cache ? */
          cacheCb = instance->owner->engine->glCallback;
          if ( cacheCb && 0 )   /* disabled */
          {
            /* we have a callback */
            error = cacheCb( instance->generic,
                             index, &cached_outline, &x, &y );
            if ( !error )
            {
              /* no error, then append the outline to the current subglyph */
              /* error = Append_Outline( subglyph,
                                         &left_points,
                                         &left_contours,
                                         &cached_outline ); */
              phase = Load_End;
            }
          }
        }
#endif
        break;


        /************************************************************/
        /*                                                          */
        /* Load_Header state                                        */
        /*                                                          */
        /*   reading a glyph's generic header to determine          */
        /*   wether it's simple or composite                        */
        /*                                                          */
        /* exit states: Load_Simple and Load_Composite              */
        /*                                                          */

      case Load_Header: /* load glyph */

        if ( index + 1 < face->numLocations &&
             face->glyphLocations[index] == face->glyphLocations[index + 1] )
        {
          /* as described by Frederic Loyer, these are spaces, and */
          /* not the unknown glyph.                                */

          num_contours = 0;
          num_points   = 0;

          subglyph->metrics.bbox.xMin = 0;
          subglyph->metrics.bbox.xMax = 0;
          subglyph->metrics.bbox.yMin = 0;
          subglyph->metrics.bbox.yMax = 0;

          subglyph->pp1.x = 0;
          subglyph->pp2.x = subglyph->metrics.horiAdvance;
          if (load_flags & TTLOAD_SCALE_GLYPH)
            subglyph->pp2.x = Scale_X( &exec->metrics, subglyph->pp2.x );

          exec->glyphSize = 0;
          phase = Load_End;
          break;
        }

        offset = glyph_offset + face->glyphLocations[index];

        /* read first glyph header */
        if ( FILE_Seek( offset ) ||
             ACCESS_Frame( 10L ) )
          goto Fail_File;

        num_contours = GET_Short();

        subglyph->metrics.bbox.xMin = GET_Short();
        subglyph->metrics.bbox.yMin = GET_Short();
        subglyph->metrics.bbox.xMax = GET_Short();
        subglyph->metrics.bbox.yMax = GET_Short();

        FORGET_Frame();

        PTRACE6(( "Glyph %ld:\n", index ));
        PTRACE6(( " # of contours: %d\n", num_contours ));
        PTRACE6(( " xMin: %4d  xMax: %4d\n",
                     subglyph->metrics.bbox.xMin,
                     subglyph->metrics.bbox.xMax ));
        PTRACE6(( " yMin: %4d  yMax: %4d\n",
                     subglyph->metrics.bbox.yMin,
                     subglyph->metrics.bbox.yMax ));

        if ( num_contours > left_contours )
        {
          PTRACE0(( "ERROR: Too many contours for glyph %ld\n", index ));
          error = TT_Err_Too_Many_Contours;
          goto Fail;
        }

        subglyph->pp1.x = subglyph->metrics.bbox.xMin -
                          subglyph->metrics.horiBearingX;
        subglyph->pp1.y = 0;
        subglyph->pp2.x = subglyph->pp1.x + subglyph->metrics.horiAdvance;
        if (load_flags & TTLOAD_SCALE_GLYPH)
        {
          subglyph->pp1.x = Scale_X( &exec->metrics, subglyph->pp1.x );
          subglyph->pp2.x = Scale_X( &exec->metrics, subglyph->pp2.x );
        }

        /* is it a simple glyph ? */
        if ( num_contours > 0 )
          phase = Load_Simple;
        else
          phase = Load_Composite;

        break;


        /************************************************************/
        /*                                                          */
        /* Load_Simple state                                        */
        /*                                                          */
        /*   reading a simple glyph (num_contours must be set to    */
        /*   the glyph's number of contours.)                       */
        /*                                                          */
        /* exit states : Load_End                                   */
        /*                                                          */

      case Load_Simple:
        new_flags = load_flags;

        /* disable hinting when scaling */
        if ( !subglyph->is_hinted )
          new_flags &= ~TTLOAD_HINT_GLYPH;

        error = Load_Simple_Glyph( exec,
                                   stream,
                                   num_contours,
                                   left_contours,
                                   left_points,
                                   new_flags,
                                   subglyph );
        if ( error )
          goto Fail;

        /* Note: We could have put the simple loader source there */
        /*       but the code is fat enough already :-)           */

        num_points = exec->pts.n_points - 2;

        phase = Load_End;

        break;


        /************************************************************/
        /*                                                          */
        /* Load_Composite state                                     */
        /*                                                          */
        /*   reading a composite glyph header a pushing a new       */
        /*   load element on the stack.                             */
        /*                                                          */