pshalgo.c

winNT技术操作系统,国外开放的原代码和LIUX一样

    /* first of all, compute all local extrema */
    for ( n = 0; n < glyph->num_contours; n++ )
    {
      PSH_Point  first = glyph->contours[n].start;
      PSH_Point  point, before, after;


      if ( glyph->contours[n].count == 0 )
        continue;

      point  = first;
      before = point;
      after  = point;

      do
      {
        before = before->prev;
        if ( before == first )
          goto Skip;

      } while ( before->org_u == point->org_u );

      first = point = before->next;

      for (;;)
      {
        after = point;
        do
        {
          after = after->next;
          if ( after == first )
            goto Next;

        } while ( after->org_u == point->org_u );

        if ( before->org_u < point->org_u )
        {
          if ( after->org_u < point->org_u )
          {
            /* local maximum */
            goto Extremum;
          }
        }
        else /* before->org_u > point->org_u */
        {
          if ( after->org_u > point->org_u )
          {
            /* local minimum */
          Extremum:
            do
            {
              psh_point_set_extremum( point );
              point = point->next;

            } while ( point != after );
          }
        }

        before = after->prev;
        point  = after;

      } /* for  */

    Next:
      ;
    }

    /* for each extremum, determine its direction along the */
    /* orthogonal axis                                      */
    for ( n = 0; n < glyph->num_points; n++ )
    {
      PSH_Point  point, before, after;


      point  = &glyph->points[n];
      before = point;
      after  = point;

      if ( psh_point_is_extremum( point ) )
      {
        do
        {
          before = before->prev;
          if ( before == point )
            goto Skip;

        } while ( before->org_v == point->org_v );

        do
        {
          after = after->next;
          if ( after == point )
            goto Skip;

        } while ( after->org_v == point->org_v );
      }

      if ( before->org_v < point->org_v &&
           after->org_v  > point->org_v )
      {
        psh_point_set_positive( point );
      }
      else if ( before->org_v > point->org_v &&
                after->org_v  < point->org_v )
      {
        psh_point_set_negative( point );
      }

    Skip:
      ;
    }
  }


  /* major_dir is the direction for points on the bottom/left of the stem; */
  /* Points on the top/right of the stem will have a direction of          */
  /* -major_dir.                                                           */

  static void
  psh_hint_table_find_strong_points( PSH_Hint_Table  table,
                                     PSH_Point       point,
                                     FT_UInt         count,
                                     FT_Int          threshold,
                                     FT_Int          major_dir )
  {
    PSH_Hint*  sort      = table->sort;
    FT_UInt    num_hints = table->num_hints;


    for ( ; count > 0; count--, point++ )
    {
      FT_Int  point_dir = 0;
      FT_Pos  org_u     = point->org_u;


      if ( psh_point_is_strong( point ) )
        continue;

      if ( PSH_DIR_COMPARE( point->dir_in, major_dir ) )
        point_dir = point->dir_in;

      else if ( PSH_DIR_COMPARE( point->dir_out, major_dir ) )
        point_dir = point->dir_out;

      if ( point_dir )
      {
        if ( point_dir == major_dir )
        {
          FT_UInt  nn;


          for ( nn = 0; nn < num_hints; nn++ )
          {
            PSH_Hint  hint = sort[nn];
            FT_Pos    d    = org_u - hint->org_pos;


            if ( d < threshold && -d < threshold )
            {
              psh_point_set_strong( point );
              point->flags2 |= PSH_POINT_EDGE_MIN;
              point->hint    = hint;
              break;
            }
          }
        }
        else if ( point_dir == -major_dir )
        {
          FT_UInt  nn;


          for ( nn = 0; nn < num_hints; nn++ )
          {
            PSH_Hint  hint = sort[nn];
            FT_Pos    d    = org_u - hint->org_pos - hint->org_len;


            if ( d < threshold && -d < threshold )
            {
              psh_point_set_strong( point );
              point->flags2 |= PSH_POINT_EDGE_MAX;
              point->hint    = hint;
              break;
            }
          }
        }
      }

#if 1
      else if ( psh_point_is_extremum( point ) )
      {
        /* treat extrema as special cases for stem edge alignment */
        FT_UInt  nn, min_flag, max_flag;


        if ( major_dir == PSH_DIR_HORIZONTAL )
        {
          min_flag = PSH_POINT_POSITIVE;
          max_flag = PSH_POINT_NEGATIVE;
        }
        else
        {
          min_flag = PSH_POINT_NEGATIVE;
          max_flag = PSH_POINT_POSITIVE;
        }

        if ( point->flags2 & min_flag )
        {
          for ( nn = 0; nn < num_hints; nn++ )
          {
            PSH_Hint  hint = sort[nn];
            FT_Pos    d    = org_u - hint->org_pos;


            if ( d < threshold && -d < threshold )
            {
              point->flags2 |= PSH_POINT_EDGE_MIN;
              point->hint    = hint;
              psh_point_set_strong( point );
              break;
            }
          }
        }
        else if ( point->flags2 & max_flag )
        {
          for ( nn = 0; nn < num_hints; nn++ )
          {
            PSH_Hint  hint = sort[nn];
            FT_Pos    d    = org_u - hint->org_pos - hint->org_len;


            if ( d < threshold && -d < threshold )
            {
              point->flags2 |= PSH_POINT_EDGE_MAX;
              point->hint    = hint;
              psh_point_set_strong( point );
              break;
            }
          }
        }

        if ( point->hint == NULL )
        {
          for ( nn = 0; nn < num_hints; nn++ )
          {
            PSH_Hint  hint = sort[nn];


            if ( org_u >= hint->org_pos                 &&
                org_u <= hint->org_pos + hint->org_len )
            {
              point->hint = hint;
              break;
            }
          }
        }
      }

#endif /* 1 */
    }
  }


  /* the accepted shift for strong points in fractional pixels */
#define PSH_STRONG_THRESHOLD  32

  /* the maximum shift value in font units */
#define PSH_STRONG_THRESHOLD_MAXIMUM  30


  /* find strong points in a glyph */
  static void
  psh_glyph_find_strong_points( PSH_Glyph  glyph,
                                FT_Int     dimension )
  {
    /* a point is `strong' if it is located on a stem edge and       */
    /* has an `in' or `out' tangent parallel to the hint's direction */

    PSH_Hint_Table  table     = &glyph->hint_tables[dimension];
    PS_Mask         mask      = table->hint_masks->masks;
    FT_UInt         num_masks = table->hint_masks->num_masks;
    FT_UInt         first     = 0;
    FT_Int          major_dir = dimension == 0 ? PSH_DIR_VERTICAL
                                               : PSH_DIR_HORIZONTAL;
    PSH_Dimension   dim       = &glyph->globals->dimension[dimension];
    FT_Fixed        scale     = dim->scale_mult;
    FT_Int          threshold;


    threshold = (FT_Int)FT_DivFix( PSH_STRONG_THRESHOLD, scale );
    if ( threshold > PSH_STRONG_THRESHOLD_MAXIMUM )
      threshold = PSH_STRONG_THRESHOLD_MAXIMUM;

    /* process secondary hints to `selected' points */
    if ( num_masks > 1 && glyph->num_points > 0 )
    {
      first = mask->end_point;
      mask++;
      for ( ; num_masks > 1; num_masks--, mask++ )
      {
        FT_UInt  next;
        FT_Int   count;


        next  = mask->end_point;
        count = next - first;
        if ( count > 0 )
        {
          PSH_Point  point = glyph->points + first;


          psh_hint_table_activate_mask( table, mask );

          psh_hint_table_find_strong_points( table, point, count,
                                             threshold, major_dir );
        }
        first = next;
      }
    }

    /* process primary hints for all points */
    if ( num_masks == 1 )
    {
      FT_UInt    count = glyph->num_points;
      PSH_Point  point = glyph->points;


      psh_hint_table_activate_mask( table, table->hint_masks->masks );

      psh_hint_table_find_strong_points( table, point, count,
                                         threshold, major_dir );
    }

    /* now, certain points may have been attached to a hint and */
    /* not marked as strong; update their flags then            */
    {
      FT_UInt    count = glyph->num_points;
      PSH_Point  point = glyph->points;


      for ( ; count > 0; count--, point++ )
        if ( point->hint && !psh_point_is_strong( point ) )
          psh_point_set_strong( point );
    }
  }


  /* find points in a glyph which are in a blue zone and have `in' or */
  /* `out' tangents parallel to the horizontal axis                   */
  static void
  psh_glyph_find_blue_points( PSH_Blues  blues,
                              PSH_Glyph  glyph )
  {
    PSH_Blue_Table  table;
    PSH_Blue_Zone   zone;
    FT_UInt         glyph_count = glyph->num_points;
    FT_UInt         blue_count;
    PSH_Point       point = glyph->points;


    for ( ; glyph_count > 0; glyph_count--, point++ )
    {
      FT_Pos  y;


      /* check tangents */
      if ( !PSH_DIR_COMPARE( point->dir_in,  PSH_DIR_HORIZONTAL ) &&
           !PSH_DIR_COMPARE( point->dir_out, PSH_DIR_HORIZONTAL ) )
        continue;

      /* skip strong points */
      if ( psh_point_is_strong( point ) )
        continue;

      y = point->org_u;

      /* look up top zones */
      table      = &blues->normal_top;
      blue_count = table->count;
      zone       = table->zones;

      for ( ; blue_count > 0; blue_count--, zone++ )
      {
        FT_Pos  delta = y - zone->org_bottom;


        if ( delta < -blues->blue_fuzz )
          break;

        if ( y <= zone->org_top + blues->blue_fuzz )
          if ( blues->no_overshoots || delta <= blues->blue_threshold )
          {
            point->cur_u = zone->cur_bottom;
            psh_point_set_strong( point );
            psh_point_set_fitted( point );
          }
      }

      /* look up bottom zones */
      table      = &blues->normal_bottom;
      blue_count = table->count;
      zone       = table->zones + blue_count - 1;

      for ( ; blue_count > 0; blue_count--, zone-- )
      {
        FT_Pos  delta = zone->org_top - y;


        if ( delta < -blues->blue_fuzz )
          break;

        if ( y >= zone->org_bottom - blues->blue_fuzz )
          if ( blues->no_overshoots || delta < blues->blue_threshold )
          {
            point->cur_u = zone->cur_top;
            psh_point_set_strong( point );
            psh_point_set_fitted( point );
          }
      }
    }
  }


  /* interpolate strong points with the help of hinted coordinates */
  static void
  psh_glyph_interpolate_strong_points( PSH_Glyph  glyph,
                                       FT_Int     dimension )
  {
    PSH_Dimension  dim   = &glyph->globals->dimension[dimension];
    FT_Fixed       scale = dim->scale_mult;

    FT_UInt        count = glyph->num_points;
    PSH_Point      point = glyph->points;


    for ( ; count > 0; count--, point++ )
    {
      PSH_Hint  hint = point->hint;


      if ( hint )
      {
        FT_Pos  delta;


        if ( psh_point_is_edge_min( point ) )
          point->cur_u = hint->cur_pos;

        else if ( psh_point_is_edge_max( point ) )