ttgload.c

下载来的一个看图软件的源代码

        if ( ( *flag & 32 ) == 0 )
          y = -y;
      }
      else if ( ( *flag & 32 ) == 0 )
        y = (FT_Pos)FT_GET_SHORT();

      x     += y;
      vec->y = x;
    }

    /* clear the touch tags */
    for ( n = 0; n < n_points; n++ )
      outline->tags[n] &= FT_CURVE_TAG_ON;

    outline->n_points   = (FT_UShort)n_points;
    outline->n_contours = (FT_Short) n_contours;

    load->byte_len = byte_len;

  Fail:
    return error;

  Invalid_Outline:
    error = TT_Err_Invalid_Outline;
    goto Fail;
  }


  FT_CALLBACK_DEF( FT_Error )
  TT_Load_Composite_Glyph( TT_Loader  loader )
  {
    FT_Error        error;
    FT_Stream       stream  = loader->stream;
    FT_GlyphLoader  gloader = loader->gloader;
    FT_SubGlyph     subglyph;
    FT_UInt         num_subglyphs;
    FT_Int          byte_len = loader->byte_len;


    num_subglyphs = 0;

    do
    {
      FT_Fixed  xx, xy, yy, yx;


      /* check that we can load a new subglyph */
      error = FT_GlyphLoader_CheckSubGlyphs( gloader, num_subglyphs + 1 );
      if ( error )
        goto Fail;

      /* check space */
      byte_len -= 4;
      if ( byte_len < 0 )
        goto Invalid_Composite;

      subglyph = gloader->current.subglyphs + num_subglyphs;

      subglyph->arg1 = subglyph->arg2 = 0;

      subglyph->flags = FT_GET_USHORT();
      subglyph->index = FT_GET_USHORT();

      /* check space */
      byte_len -= 2;
      if ( subglyph->flags & ARGS_ARE_WORDS )
        byte_len -= 2;
      if ( subglyph->flags & WE_HAVE_A_SCALE )
        byte_len -= 2;
      else if ( subglyph->flags & WE_HAVE_AN_XY_SCALE )
        byte_len -= 4;
      else if ( subglyph->flags & WE_HAVE_A_2X2 )
        byte_len -= 8;

      if ( byte_len < 0 )
        goto Invalid_Composite;

      /* read arguments */
      if ( subglyph->flags & ARGS_ARE_WORDS )
      {
        subglyph->arg1 = FT_GET_SHORT();
        subglyph->arg2 = FT_GET_SHORT();
      }
      else
      {
        subglyph->arg1 = FT_GET_CHAR();
        subglyph->arg2 = FT_GET_CHAR();
      }

      /* read transform */
      xx = yy = 0x10000L;
      xy = yx = 0;

      if ( subglyph->flags & WE_HAVE_A_SCALE )
      {
        xx = (FT_Fixed)FT_GET_SHORT() << 2;
        yy = xx;
      }
      else if ( subglyph->flags & WE_HAVE_AN_XY_SCALE )
      {
        xx = (FT_Fixed)FT_GET_SHORT() << 2;
        yy = (FT_Fixed)FT_GET_SHORT() << 2;
      }
      else if ( subglyph->flags & WE_HAVE_A_2X2 )
      {
        xx = (FT_Fixed)FT_GET_SHORT() << 2;
        yx = (FT_Fixed)FT_GET_SHORT() << 2;
        xy = (FT_Fixed)FT_GET_SHORT() << 2;
        yy = (FT_Fixed)FT_GET_SHORT() << 2;
      }

      subglyph->transform.xx = xx;
      subglyph->transform.xy = xy;
      subglyph->transform.yx = yx;
      subglyph->transform.yy = yy;

      num_subglyphs++;

    } while ( subglyph->flags & MORE_COMPONENTS );

    gloader->current.num_subglyphs = num_subglyphs;

#ifdef TT_CONFIG_OPTION_BYTECODE_INTERPRETER
    {
      /* we must undo the FT_FRAME_ENTER in order to point to the */
      /* composite instructions, if we find some.               */
      /* we will process them later...                          */
      /*                                                        */
      loader->ins_pos = (FT_ULong)( FT_STREAM_POS() +
                                    stream->cursor - stream->limit );
    }
#endif

    loader->byte_len = byte_len;

  Fail:
    return error;

  Invalid_Composite:
    error = TT_Err_Invalid_Composite;
    goto Fail;
  }


  FT_LOCAL_DEF( void )
  TT_Init_Glyph_Loading( TT_Face  face )
  {
    face->access_glyph_frame   = TT_Access_Glyph_Frame;
    face->read_glyph_header    = TT_Load_Glyph_Header;
    face->read_simple_glyph    = TT_Load_Simple_Glyph;
    face->read_composite_glyph = TT_Load_Composite_Glyph;
    face->forget_glyph_frame   = TT_Forget_Glyph_Frame;
  }


  /*************************************************************************/
  /*                                                                       */
  /* <Function>                                                            */
  /*    TT_Process_Simple_Glyph                                            */
  /*                                                                       */
  /* <Description>                                                         */
  /*    Once a simple glyph has been loaded, it needs to be processed.     */
  /*    Usually, this means scaling and hinting through bytecode           */
  /*    interpretation.                                                    */
  /*                                                                       */
  static FT_Error
  TT_Process_Simple_Glyph( TT_Loader  load,
                           FT_Bool    debug )
  {
    FT_GlyphLoader  gloader  = load->gloader;
    FT_Outline*     outline  = &gloader->current.outline;
    FT_UInt         n_points = outline->n_points;
#ifdef TT_CONFIG_OPTION_BYTECODE_INTERPRETER
    FT_UInt         n_ins;
#endif
    TT_GlyphZone    zone     = &load->zone;
    FT_Error        error    = TT_Err_Ok;

    FT_UNUSED( debug );  /* used by truetype interpreter only */


#ifdef TT_CONFIG_OPTION_BYTECODE_INTERPRETER
    n_ins = load->glyph->control_len;
#endif

    /* add shadow points */

    /* Now add the two shadow points at n and n + 1.    */
    /* We need the left side bearing and advance width. */

    {
      FT_Vector*  pp1;
      FT_Vector*  pp2;


      /* pp1 = xMin - lsb */
      pp1    = outline->points + n_points;
      pp1->x = load->bbox.xMin - load->left_bearing;
      pp1->y = 0;

      /* pp2 = pp1 + aw */
      pp2    = pp1 + 1;
      pp2->x = pp1->x + load->advance;
      pp2->y = 0;

      outline->tags[n_points    ] = 0;
      outline->tags[n_points + 1] = 0;
    }

    /* Note that we return two more points that are not */
    /* part of the glyph outline.                       */

    n_points += 2;

    /* set up zone for hinting */
    tt_prepare_zone( zone, &gloader->current, 0, 0 );

    /* eventually scale the glyph */
    if ( !( load->load_flags & FT_LOAD_NO_SCALE ) )
    {
      FT_Vector*  vec     = zone->cur;
      FT_Vector*  limit   = vec + n_points;
      FT_Fixed    x_scale = load->size->metrics.x_scale;
      FT_Fixed    y_scale = load->size->metrics.y_scale;


      /* first scale the glyph points */
      for ( ; vec < limit; vec++ )
      {
        vec->x = FT_MulFix( vec->x, x_scale );
        vec->y = FT_MulFix( vec->y, y_scale );
      }
    }

    cur_to_org( n_points, zone );

    /* eventually hint the glyph */
    if ( IS_HINTED( load->load_flags ) )
    {
      FT_Pos  x = zone->org[n_points-2].x;


      x = ( ( x + 32 ) & -64 ) - x;
      translate_array( n_points, zone->org, x, 0 );

      org_to_cur( n_points, zone );

      zone->cur[n_points - 1].x = ( zone->cur[n_points - 1].x + 32 ) & -64;

#ifdef TT_CONFIG_OPTION_BYTECODE_INTERPRETER

      /* now consider hinting */
      if ( n_ins > 0 )
      {
        error = TT_Set_CodeRange( load->exec, tt_coderange_glyph,
                                  load->exec->glyphIns, n_ins );
        if ( error )
          goto Exit;

        load->exec->is_composite     = FALSE;
        load->exec->pedantic_hinting = (FT_Bool)( load->load_flags &
                                                  FT_LOAD_PEDANTIC );
        load->exec->pts              = *zone;
        load->exec->pts.n_points    += 2;

        error = TT_Run_Context( load->exec, debug );
        if ( error && load->exec->pedantic_hinting )
          goto Exit;

        error = TT_Err_Ok;  /* ignore bytecode errors in non-pedantic mode */
      }

#endif /* TT_CONFIG_OPTION_BYTECODE_INTERPRETER */

    }

    /* save glyph phantom points */
    if ( !load->preserve_pps )
    {
      load->pp1 = zone->cur[n_points - 2];
      load->pp2 = zone->cur[n_points - 1];
    }

#ifdef TT_CONFIG_OPTION_BYTECODE_INTERPRETER
  Exit:
#endif
    return error;
  }


  /*************************************************************************/
  /*                                                                       */
  /* <Function>                                                            */
  /*    load_truetype_glyph                                                */
  /*                                                                       */
  /* <Description>                                                         */
  /*    Loads a given truetype glyph.  Handles composites and uses a       */
  /*    TT_Loader object.                                                  */
  /*                                                                       */
  static FT_Error
  load_truetype_glyph( TT_Loader  loader,
                       FT_UInt    glyph_index,
                       FT_UInt    recurse_count )
  {

#ifdef TT_CONFIG_OPTION_BYTECODE_INTERPRETER
    FT_Stream       stream = loader->stream;
#endif

    FT_Error        error;
    TT_Face         face   = (TT_Face)loader->face;
    FT_ULong        offset;
    FT_Int          contours_count;
    FT_UInt         num_points, count;
    FT_Fixed        x_scale, y_scale;
    FT_GlyphLoader  gloader = loader->gloader;
    FT_Bool         opened_frame = 0;

#ifdef FT_CONFIG_OPTION_INCREMENTAL
    struct FT_StreamRec_  inc_stream;
    FT_Data               glyph_data;
    FT_Bool               glyph_data_loaded = 0;
#endif


    if ( recurse_count >= TT_MAX_COMPOSITE_RECURSE )
    {
      error = TT_Err_Invalid_Composite;
      goto Exit;
    }

    /* check glyph index */
    if ( glyph_index >= (FT_UInt)face->root.num_glyphs )
    {
      error = TT_Err_Invalid_Glyph_Index;
      goto Exit;
    }

    loader->glyph_index = glyph_index;
    num_points          = 0;

    x_scale = 0x10000L;
    y_scale = 0x10000L;
    if ( ( loader->load_flags & FT_LOAD_NO_SCALE ) == 0 )
    {
      x_scale = loader->size->metrics.x_scale;
      y_scale = loader->size->metrics.y_scale;
    }

    /* get horizontal metrics */
    {
      FT_Short   left_bearing = 0;
      FT_UShort  advance_width = 0;

      Get_HMetrics( face, glyph_index,
                    (FT_Bool)!( loader->load_flags &
                                FT_LOAD_IGNORE_GLOBAL_ADVANCE_WIDTH ),
                    &left_bearing,
                    &advance_width );

#ifdef FT_CONFIG_OPTION_INCREMENTAL

      /* If this is an incrementally loaded font see if there are */
      /* overriding metrics for this glyph.                       */
      if ( face->root.internal->incremental_interface &&
           face->root.internal->incremental_interface->funcs->get_glyph_metrics )
      {
        FT_Incremental_MetricsRec  metrics;


        metrics.bearing_x = left_bearing;
        metrics.bearing_y = 0;
        metrics.advance = advance_width;
        error = face->root.internal->incremental_interface->funcs->get_glyph_metrics(
                  face->root.internal->incremental_interface->object,
                  glyph_index, FALSE, &metrics );
        if ( error )
          goto Exit;
        left_bearing  = (FT_Short)metrics.bearing_x;
        advance_width = (FT_UShort)metrics.advance;
      }

#endif /* FT_CONFIG_OPTION_INCREMENTAL */

      loader->left_bearing = left_bearing;
      loader->advance      = advance_width;

      if ( !loader->linear_def )
      {
        loader->linear_def = 1;
        loader->linear     = advance_width;
      }
    }

#ifdef FT_CONFIG_OPTION_INCREMENTAL

    /* Set `offset' to the start of the glyph program relative to the  */
    /* start of the 'glyf' table, and `count' to the length of the     */
    /* glyph program in bytes.                                         */
    /*                                                                 */
    /* If we are loading glyph data via the incremental interface, set */
    /* the loader stream to a memory stream reading the data returned  */
    /* by the interface.                                               */

    if ( face->root.internal->incremental_interface )
    {
      error = face->root.internal->incremental_interface->funcs->get_glyph_data(
                face->root.internal->incremental_interface->object,
                glyph_index, &glyph_data );
      if ( error )
        goto Exit;

      glyph_data_loaded = 1;
      offset            = 0;
      count             = glyph_data.length;

      FT_MEM_ZERO( &inc_stream, sizeof ( inc_stream ) );
      FT_Stream_OpenMemory( &inc_stream,
                            glyph_data.pointer, glyph_data.length );

      loader->stream = &inc_stream;
    }
    else

#endif /* FT_CONFIG_OPTION_INCREMENTAL */

    {
      offset = face->glyph_locations[glyph_index];
      count  = 0;

      if ( glyph_index < (FT_UInt)face->num_locations - 1 )
        count = (FT_UInt)( face->glyph_locations[glyph_index + 1] - offset );
    }

    if ( count == 0 )
    {
      /* as described by Frederic Loyer, these are spaces, and */
      /* not the unknown glyph.                                */
      loader->bbox.xMin = 0;
      loader->bbox.xMax = 0;
      loader->bbox.yMin = 0;
      loader->bbox.yMax = 0;

      loader->pp1.x = 0;
      loader->pp2.x = loader->advance;

      if ( ( loader->load_flags & FT_LOAD_NO_SCALE ) == 0 )
        loader->pp2.x = FT_MulFix( loader->pp2.x, x_scale );

#ifdef TT_CONFIG_OPTION_BYTECODE_INTERPRETER