ttgload.c

下载来的一个看图软件的源代码

      if ( loader->exec )
        loader->exec->glyphSize = 0;

#endif

      error = TT_Err_Ok;
      goto Exit;
    }

    loader->byte_len = (FT_Int)count;

    offset = loader->glyf_offset + offset;

    /* access glyph frame */
    error = face->access_glyph_frame( loader, glyph_index, offset, count );
    if ( error )
      goto Exit;

    opened_frame = 1;

    /* read first glyph header */
    error = face->read_glyph_header( loader );
    if ( error )
      goto Fail;

    contours_count = loader->n_contours;

    count -= 10;

    loader->pp1.x = loader->bbox.xMin - loader->left_bearing;
    loader->pp1.y = 0;
    loader->pp2.x = loader->pp1.x + loader->advance;
    loader->pp2.y = 0;

    if ( ( loader->load_flags & FT_LOAD_NO_SCALE ) == 0 )
    {
      loader->pp1.x = FT_MulFix( loader->pp1.x, x_scale );
      loader->pp2.x = FT_MulFix( loader->pp2.x, x_scale );
    }

    /***********************************************************************/
    /***********************************************************************/
    /***********************************************************************/

    /* if it is a simple glyph, load it */

    if ( contours_count >= 0 )
    {
      /* check that we can add the contours to the glyph */
      error = FT_GlyphLoader_CheckPoints( gloader, 0, contours_count );
      if ( error )
        goto Fail;

      error = face->read_simple_glyph( loader );
      if ( error )
        goto Fail;

#ifdef TT_CONFIG_OPTION_BYTECODE_INTERPRETER

      {
        TT_Size  size = (TT_Size)loader->size;


        error = TT_Process_Simple_Glyph( loader,
                                         (FT_Bool)( size && size->debug ) );
      }

#else

      error = TT_Process_Simple_Glyph( loader, 0 );

#endif

      if ( error )
        goto Fail;

      FT_GlyphLoader_Add( gloader );

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

    /***********************************************************************/
    /***********************************************************************/
    /***********************************************************************/

    /* otherwise, load a composite! */
    else if ( contours_count == -1 )
    {
      TT_GlyphSlot  glyph = (TT_GlyphSlot)loader->glyph;
      FT_UInt       start_point;
#ifdef TT_CONFIG_OPTION_BYTECODE_INTERPRETER
      FT_UInt       start_contour;
      FT_ULong      ins_pos;  /* position of composite instructions, if any */
#endif


      /* for each subglyph, read composite header */
      start_point   = gloader->base.outline.n_points;
#ifdef TT_CONFIG_OPTION_BYTECODE_INTERPRETER
      start_contour = gloader->base.outline.n_contours;
#endif

      error = face->read_composite_glyph( loader );
      if ( error )
        goto Fail;

#ifdef TT_CONFIG_OPTION_BYTECODE_INTERPRETER
      ins_pos = loader->ins_pos;
#endif
      face->forget_glyph_frame( loader );
      opened_frame = 0;

      /* if the flag FT_LOAD_NO_RECURSE is set, we return the subglyph */
      /* `as is' in the glyph slot (the client application will be     */
      /* responsible for interpreting these data)...                   */
      /*                                                               */
      if ( loader->load_flags & FT_LOAD_NO_RECURSE )
      {
        /* set up remaining glyph fields */
        FT_GlyphLoader_Add( gloader );

        glyph->num_subglyphs = gloader->base.num_subglyphs;
        glyph->format        = FT_GLYPH_FORMAT_COMPOSITE;
        glyph->subglyphs     = gloader->base.subglyphs;

        goto Exit;
      }

      /*********************************************************************/
      /*********************************************************************/
      /*********************************************************************/

      /* Now, read each subglyph independently. */
      {
        FT_Int       n, num_base_points, num_new_points;
        FT_SubGlyph  subglyph       = 0;

        FT_UInt      num_subglyphs  = gloader->current.num_subglyphs;
        FT_UInt      num_base_subgs = gloader->base.num_subglyphs;


        FT_GlyphLoader_Add( gloader );

        for ( n = 0; n < (FT_Int)num_subglyphs; n++ )
        {
          FT_Vector  pp1, pp2;
          FT_Pos     x, y;


          /* Each time we call load_truetype_glyph in this loop, the   */
          /* value of `gloader.base.subglyphs' can change due to table */
          /* reallocations.  We thus need to recompute the subglyph    */
          /* pointer on each iteration.                                */
          subglyph = gloader->base.subglyphs + num_base_subgs + n;

          pp1 = loader->pp1;
          pp2 = loader->pp2;

          num_base_points = gloader->base.outline.n_points;

          error = load_truetype_glyph( loader, subglyph->index,
                                       recurse_count + 1 );
          if ( error )
            goto Fail;

          /* restore subglyph pointer */
          subglyph = gloader->base.subglyphs + num_base_subgs + n;

          if ( subglyph->flags & USE_MY_METRICS )
          {
            pp1 = loader->pp1;
            pp2 = loader->pp2;
          }
          else
          {
            loader->pp1 = pp1;
            loader->pp2 = pp2;
          }

          num_points = gloader->base.outline.n_points;

          num_new_points = num_points - num_base_points;

          /* now perform the transform required for this subglyph */

          if ( subglyph->flags & ( WE_HAVE_A_SCALE     |
                                   WE_HAVE_AN_XY_SCALE |
                                   WE_HAVE_A_2X2       ) )
          {
            FT_Vector*  cur   = gloader->base.outline.points +
                                  num_base_points;
            FT_Vector*  org   = gloader->base.extra_points +
                                  num_base_points;
            FT_Vector*  limit = cur + num_new_points;


            for ( ; cur < limit; cur++, org++ )
            {
              FT_Vector_Transform( cur, &subglyph->transform );
              FT_Vector_Transform( org, &subglyph->transform );
            }
          }

          /* apply offset */

          if ( !( subglyph->flags & ARGS_ARE_XY_VALUES ) )
          {
            FT_UInt     k = subglyph->arg1;
            FT_UInt     l = subglyph->arg2;
            FT_Vector*  p1;
            FT_Vector*  p2;


            if ( start_point + k >= (FT_UInt)num_base_points ||
                               l >= (FT_UInt)num_new_points  )
            {
              error = TT_Err_Invalid_Composite;
              goto Fail;
            }

            l += num_base_points;

            p1 = gloader->base.outline.points + start_point + k;
            p2 = gloader->base.outline.points + start_point + l;

            x = p1->x - p2->x;
            y = p1->y - p2->y;
          }
          else
          {
            x = subglyph->arg1;
            y = subglyph->arg2;

  /* Use a default value dependent on                                     */
  /* TT_CONFIG_OPTION_COMPONENT_OFFSET_SCALED.  This is useful for old TT */
  /* fonts which don't set the xxx_COMPONENT_OFFSET bit.                  */

#ifdef TT_CONFIG_OPTION_COMPONENT_OFFSET_SCALED
            if ( !( subglyph->flags & UNSCALED_COMPONENT_OFFSET ) &&
#else
            if (  ( subglyph->flags & SCALED_COMPONENT_OFFSET ) &&
#endif
                  ( subglyph->flags & ( WE_HAVE_A_SCALE     |
                                        WE_HAVE_AN_XY_SCALE |
                                        WE_HAVE_A_2X2       )) )
            {
#if 0

  /*************************************************************************/
  /*                                                                       */
  /* This algorithm is what Apple documents.  But it doesn't work.         */
  /*                                                                       */
              int  a = subglyph->transform.xx > 0 ?  subglyph->transform.xx
                                                  : -subglyph->transform.xx;
              int  b = subglyph->transform.yx > 0 ?  subglyph->transform.yx
                                                  : -subglyph->transform.yx;
              int  c = subglyph->transform.xy > 0 ?  subglyph->transform.xy
                                                  : -subglyph->transform.xy;
              int  d = subglyph->transform.yy > 0 ? subglyph->transform.yy
                                                  : -subglyph->transform.yy;
              int  m = a > b ? a : b;
              int  n = c > d ? c : d;


              if ( a - b <= 33 && a - b >= -33 )
                m *= 2;
              if ( c - d <= 33 && c - d >= -33 )
                n *= 2;
              x = FT_MulFix( x, m );
              y = FT_MulFix( y, n );

#else /* 0 */

  /*************************************************************************/
  /*                                                                       */
  /* This algorithm is a guess and works much better than the above.       */
  /*                                                                       */
              FT_Fixed  mac_xscale = FT_SqrtFixed(
                                       FT_MulFix( subglyph->transform.xx,
                                                  subglyph->transform.xx ) +
                                       FT_MulFix( subglyph->transform.xy,
                                                  subglyph->transform.xy) );
              FT_Fixed  mac_yscale = FT_SqrtFixed(
                                       FT_MulFix( subglyph->transform.yy,
                                                  subglyph->transform.yy ) +
                                       FT_MulFix( subglyph->transform.yx,
                                                  subglyph->transform.yx ) );


              x = FT_MulFix( x, mac_xscale );
              y = FT_MulFix( y, mac_yscale );
#endif /* 0 */

            }

            if ( !( loader->load_flags & FT_LOAD_NO_SCALE ) )
            {
              x = FT_MulFix( x, x_scale );
              y = FT_MulFix( y, y_scale );

              if ( subglyph->flags & ROUND_XY_TO_GRID )
              {
                x = ( x + 32 ) & -64;
                y = ( y + 32 ) & -64;
              }
            }
          }

          if ( x || y )
          {
            translate_array( num_new_points,
                             gloader->base.outline.points + num_base_points,
                             x, y );

            translate_array( num_new_points,
                             gloader->base.extra_points + num_base_points,
                             x, y );
          }
        }

        /*******************************************************************/
        /*******************************************************************/
        /*******************************************************************/

        /* we have finished loading all sub-glyphs; now, look for */
        /* instructions for this composite!                       */

#ifdef TT_CONFIG_OPTION_BYTECODE_INTERPRETER

        if ( num_subglyphs > 0               &&
             loader->exec                    &&
             ins_pos > 0                     &&
             subglyph->flags & WE_HAVE_INSTR )
        {
          FT_UShort       n_ins;
          TT_ExecContext  exec = loader->exec;
          TT_GlyphZone    pts;
          FT_Vector*      pp1;


          /* read size of instructions */
          if ( FT_STREAM_SEEK( ins_pos ) ||
               FT_READ_USHORT( n_ins ) )
            goto Fail;
          FT_TRACE5(( "  Instructions size = %d\n", n_ins ));

          /* in some fonts? */
          if ( n_ins == 0xFFFFU )
            n_ins = 0;

          /* check it */
          if ( n_ins > face->max_profile.maxSizeOfInstructions )
          {
            FT_TRACE0(( "Too many instructions (%d) in composite glyph %ld\n",
                        n_ins, subglyph->index ));
            error = TT_Err_Too_Many_Hints;
            goto Fail;
          }

          /* read the instructions */
          if ( FT_STREAM_READ( exec->glyphIns, n_ins ) )
            goto Fail;

          glyph->control_data = exec->glyphIns;
          glyph->control_len  = n_ins;

          error = TT_Set_CodeRange( exec,
                                    tt_coderange_glyph,
                                    exec->glyphIns,
                                    n_ins );
          if ( error )
            goto Fail;

          error = FT_GlyphLoader_CheckPoints( gloader, num_points + 2, 0 );
          if ( error )
            goto Fail;

          /* prepare the execution context */
          tt_prepare_zone( &exec->pts, &gloader->base,
                           start_point, start_contour );
          pts = &exec->pts;

          pts->n_points   = (short)(num_points + 2);
          pts->n_contours = gloader->base.outline.n_contours;

          /* add phantom points */
          pp1    = pts->cur + num_points;
          pp1[0] = loader->pp1;
          pp1[1] = loader->pp2;

          pts->tags[num_points    ] = 0;
          pts->tags[num_points + 1] = 0;

          /* if hinting, round the phantom points */
          if ( IS_HINTED( loader->load_flags ) )
          {
            pp1[0].x = ( ( loader->pp1.x + 32 ) & -64 );
            pp1[1].x = ( ( loader->pp2.x + 32 ) & -64 );
          }

          {
            FT_UInt  k;


            for ( k = 0; k < num_points; k++ )
              pts->tags[k] &= FT_CURVE_TAG_ON;
          }

          cur_to_org( num_points + 2, pts );

          /* now consider hinting */
          if ( IS_HINTED( loader->load_flags ) && n_ins > 0 )
          {
            exec->is_composite     = TRUE;
            exec->pedantic_hinting =
              (FT_Bool)( loader->load_flags & FT_LOAD_PEDANTIC );
            error = TT_Run_Context( exec, ((TT_Size)loader->size)->debug );
            if ( error && exec->pedantic_hinting )
              goto Fail;
          }

          /* save glyph origin and advance points */
          loader->pp1 = pp1[0];
          loader->pp2 = pp1[1];
        }

#endif /* TT_CONFIG_OPTION_BYTECODE_INTERPRETER */

      }
      /* end of composite loading */
    }
    else
    {
      /* invalid composite count ( negative but not -1 ) */
      error = TT_Err_Invalid_Outline;
      goto Fail;
    }

    /***********************************************************************/
    /***********************************************************************/
    /***********************************************************************/

  Fail:
    if ( opened_frame )
      face->forget_glyph_frame( loader );

  Exit: