pshalgo2.c

a very goog book

      if ( dimension == 0 )
        vec[n].x = point->cur_u;
      else
        vec[n].y = point->cur_u;

      if ( psh2_point_is_strong( point ) )
        tags[n] |= (char)( ( dimension == 0 ) ? 32 : 64 );

#ifdef DEBUG_HINTER
      if ( dimension == 0 )
      {
        point->cur_x   = point->cur_u;
        point->flags_x = point->flags;
      }
      else
      {
        point->cur_y   = point->cur_u;
        point->flags_y = point->flags;
      }
#endif
      point++;
    }
  }


#define PSH2_STRONG_THRESHOLD  10


  static void
  psh2_hint_table_find_strong_point( PSH2_Hint_Table  table,
                                     PSH2_Point       point,
                                     FT_Int           major_dir )
  {
    PSH2_Hint*   sort      = table->sort;
    FT_UInt      num_hints = table->num_hints;


    for ( ; num_hints > 0; num_hints--, sort++ )
    {
      PSH2_Hint  hint = sort[0];


      if ( ABS( point->dir_in )  == major_dir ||
           ABS( point->dir_out ) == major_dir )
      {
        FT_Pos  d;


        d = point->org_u - hint->org_pos;
        if ( ABS( d ) < PSH2_STRONG_THRESHOLD )
        {
        Is_Strong:
          psh2_point_set_strong( point );
          point->hint = hint;
          break;
        }

        d -= hint->org_len;
        if ( ABS( d ) < PSH2_STRONG_THRESHOLD )
          goto Is_Strong;
      }

#if 1
      if ( point->org_u >= hint->org_pos &&
           point->org_u <= hint->org_pos + hint->org_len &&
           psh2_point_is_extremum( point ) )
      {
        /* attach to hint, but don't mark as strong */
        point->hint = hint;
        break;
      }
#endif
    }
  }


  /* find strong points in a glyph */
  static void
  psh2_glyph_find_strong_points( PSH2_Glyph  glyph,
                                 FT_Int      dimension )
  {
    /* a point is strong if it is located on a stem                   */
    /* edge and has an "in" or "out" tangent to the hint's direction  */
    {
      PSH2_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 ? PSH2_DIR_UP : PSH2_DIR_RIGHT;


      /* process secondary hints to "selected" points */
      if ( num_masks > 1 )
      {
        mask++;
        for ( ; num_masks > 1; num_masks--, mask++ )
        {
          FT_UInt  next;
          FT_Int   count;


          next  = mask->end_point;
          count = next - first;
          if ( count > 0 )
          {
            PSH2_Point  point = glyph->points + first;


            psh2_hint_table_activate_mask( table, mask );

            for ( ; count > 0; count--, point++ )
              psh2_hint_table_find_strong_point( table, point, major_dir );
          }
          first = next;
        }
      }

      /* process primary hints for all points */
      if ( num_masks == 1 )
      {
        FT_UInt     count = glyph->num_points;
        PSH2_Point  point = glyph->points;


        psh2_hint_table_activate_mask( table, table->hint_masks->masks );
        for ( ; count > 0; count--, point++ )
        {
          if ( !psh2_point_is_strong( point ) )
            psh2_hint_table_find_strong_point( table, point, major_dir );
        }
      }

      /* now, certain points may have been attached to hint and */
      /* not marked as strong; update their flags then          */
      {
        FT_UInt     count = glyph->num_points;
        PSH2_Point  point = glyph->points;


        for ( ; count > 0; count--, point++ )
          if ( point->hint && !psh2_point_is_strong( point ) )
            psh2_point_set_strong( point );
      }
    }
  }


  /* interpolate strong points with the help of hinted coordinates */
  static void
  psh2_glyph_interpolate_strong_points( PSH2_Glyph  glyph,
                                        FT_Int      dimension )
  {
    PSH_Dimension    dim   = &glyph->globals->dimension[dimension];
    FT_Fixed         scale = dim->scale_mult;


    {
      FT_UInt     count = glyph->num_points;
      PSH2_Point  point = glyph->points;


      for ( ; count > 0; count--, point++ )
      {
        PSH2_Hint  hint = point->hint;


        if ( hint )
        {
          FT_Pos  delta;


          delta = point->org_u - hint->org_pos;

          if ( delta <= 0 )
            point->cur_u = hint->cur_pos + FT_MulFix( delta, scale );

          else if ( delta >= hint->org_len )
            point->cur_u = hint->cur_pos + hint->cur_len +
                           FT_MulFix( delta - hint->org_len, scale );

          else if ( hint->org_len > 0 )
            point->cur_u = hint->cur_pos +
                           FT_MulDiv( delta, hint->cur_len, hint->org_len );
          else
            point->cur_u = hint->cur_pos;

          psh2_point_set_fitted( point );
        }
      }
    }
  }


  static void
  psh2_glyph_interpolate_normal_points( PSH2_Glyph  glyph,
                                        FT_Int      dimension )
  {
#if 1
    PSH_Dimension    dim   = &glyph->globals->dimension[dimension];
    FT_Fixed         scale = dim->scale_mult;


    /* first technique: a point is strong if it is a local extrema */
    {
      FT_UInt     count = glyph->num_points;
      PSH2_Point  point = glyph->points;


      for ( ; count > 0; count--, point++ )
      {
        if ( psh2_point_is_strong( point ) )
          continue;

        /* sometimes, some local extremas are smooth points */
        if ( psh2_point_is_smooth( point ) )
        {
          if ( point->dir_in == PSH2_DIR_NONE  ||
               point->dir_in != point->dir_out )
            continue;

          if ( !psh2_point_is_extremum( point ) )
            continue;

          point->flags &= ~PSH2_POINT_SMOOTH;
        }

        /* find best enclosing point coordinates */
        {
          PSH2_Point  before = 0;
          PSH2_Point  after  = 0;

          FT_Pos      diff_before = -32000;
          FT_Pos      diff_after  =  32000;
          FT_Pos      u = point->org_u;

          FT_Int      count2 = glyph->num_points;
          PSH2_Point  cur    = glyph->points;


          for ( ; count2 > 0; count2--, cur++ )
          {
            if ( psh2_point_is_strong( cur ) )
            {
              FT_Pos   diff = cur->org_u - u;;


              if ( diff <= 0 )
              {
                if ( diff > diff_before )
                {
                  diff_before = diff;
                  before      = cur;
                }
              }
              else if ( diff >= 0 )
              {
                if ( diff < diff_after )
                {
                  diff_after = diff;
                  after      = cur;
                }
              }
            }
          }

          if ( !before )
          {
            if ( !after )
              continue;

            /* we are before the first strong point coordinate; */
            /* simply translate the point                       */
            point->cur_u = after->cur_u +
                           FT_MulFix( point->org_u - after->org_u, scale );
          }
          else if ( !after )
          {
            /* we are after the last strong point coordinate; */
            /* simply translate the point                     */
            point->cur_u = before->cur_u +
                           FT_MulFix( point->org_u - before->org_u, scale );
          }
          else
          {
            if ( diff_before == 0 )
              point->cur_u = before->cur_u;

            else if ( diff_after == 0 )
              point->cur_u = after->cur_u;

            else
              point->cur_u = before->cur_u +
                             FT_MulDiv( u - before->org_u,
                                        after->cur_u - before->cur_u,
                                        after->org_u - before->org_u );
          }

          psh2_point_set_fitted( point );
        }
      }
    }
#endif
  }


  /* interpolate other points */
  static void
  psh2_glyph_interpolate_other_points( PSH2_Glyph  glyph,
                                       FT_Int      dimension )
  {
    PSH_Dimension dim          = &glyph->globals->dimension[dimension];
    FT_Fixed      scale        = dim->scale_mult;
    FT_Fixed      delta        = dim->scale_delta;
    PSH2_Contour  contour      = glyph->contours;
    FT_UInt       num_contours = glyph->num_contours;


    for ( ; num_contours > 0; num_contours--, contour++ )
    {
      PSH2_Point   start = contour->start;
      PSH2_Point   first, next, point;
      FT_UInt      fit_count;


      /* count the number of strong points in this contour */
      next      = start + contour->count;
      fit_count = 0;
      first     = 0;

      for ( point = start; point < next; point++ )
        if ( psh2_point_is_fitted( point ) )
        {
          if ( !first )
            first = point;

          fit_count++;
        }

      /* if there are less than 2 fitted points in the contour, we */
      /* simply scale and eventually translate the contour points  */
      if ( fit_count < 2 )
      {
        if ( fit_count == 1 )
          delta = first->cur_u - FT_MulFix( first->org_u, scale );

        for ( point = start; point < next; point++ )
          if ( point != first )
            point->cur_u = FT_MulFix( point->org_u, scale ) + delta;

        goto Next_Contour;
      }

      /* there are more than 2 strong points in this contour; we */
      /* need to interpolate weak points between them            */
      start = first;
      do
      {
        point = first;

        /* skip consecutive fitted points */
        for (;;)
        {
          next = first->next;
          if ( next == start )
            goto Next_Contour;

          if ( !psh2_point_is_fitted( next ) )
            break;

          first = next;
        }

        /* find next fitted point after unfitted one */
        for (;;)
        {
          next = next->next;
          if ( psh2_point_is_fitted( next ) )
            break;
        }

        /* now interpolate between them */
        {
          FT_Pos    org_a, org_ab, cur_a, cur_ab;
          FT_Pos    org_c, org_ac, cur_c;
          FT_Fixed  scale_ab;


          if ( first->org_u <= next->org_u )
          {
            org_a  = first->org_u;
            cur_a  = first->cur_u;
            org_ab = next->org_u - org_a;
            cur_ab = next->cur_u - cur_a;
          }
          else
          {
            org_a  = next->org_u;
            cur_a  = next->cur_u;
            org_ab = first->org_u - org_a;
            cur_ab = first->cur_u - cur_a;
          }

          scale_ab = 0x10000L;
          if ( org_ab > 0 )
            scale_ab = FT_DivFix( cur_ab, org_ab );

          point = first->next;
          do
          {
            org_c  = point->org_u;
            org_ac = org_c - org_a;

            if ( org_ac <= 0 )
            {
              /* on the left of the interpolation zone */
              cur_c = cur_a + FT_MulFix( org_ac, scale );
            }
            else if ( org_ac >= org_ab )
            {
              /* on the right on the interpolation zone */
              cur_c = cur_a + cur_ab + FT_MulFix( org_ac - org_ab, scale );
            }
            else
            {
              /* within the interpolation zone */
              cur_c = cur_a + FT_MulFix( org_ac, scale_ab );
            }

            point->cur_u = cur_c;

            point = point->next;

          } while ( point != next );
        }

        /* keep going until all points in the contours have been processed */
        first = next;

      } while ( first != start );

    Next_Contour:
      ;
    }
  }


  /*************************************************************************/
  /*************************************************************************/
  /*****                                                               *****/
  /*****                     HIGH-LEVEL INTERFACE                      *****/
  /*****                                                               *****/
  /*************************************************************************/
  /*************************************************************************/

  FT_Error
  ps2_hints_apply( PS_Hints     ps_hints,
                   FT_Outline*  outline,
                   PSH_Globals  globals )
  {
    PSH2_GlyphRec  glyphrec;
    PSH2_Glyph     glyph = &glyphrec;
    FT_Error       error;
#ifdef DEBUG_HINTER
    FT_Memory      memory;
#endif
    FT_Int         dimension;


#ifdef DEBUG_HINTER
    memory = globals->memory;

    if ( ps2_debug_glyph )
    {
      psh2_glyph_done( ps2_debug_glyph );
      FT_FREE( ps2_debug_glyph );
    }

    if ( FT_NEW( glyph ) )
      return error;

    ps2_debug_glyph = glyph;
#endif

    error = psh2_glyph_init( glyph, outline, ps_hints, globals );
    if ( error )
      goto Exit;

    for ( dimension = 0; dimension < 2; dimension++ )
    {
      /* load outline coordinates into glyph */
      psh2_glyph_load_points( glyph, dimension );

      /* compute aligned stem/hints positions */
      psh2_hint_table_align_hints( &glyph->hint_tables[dimension],
                                   glyph->globals,
                                   dimension );

      /* find strong points, align them, then interpolate others */
      psh2_glyph_find_strong_points( glyph, dimension );
      psh2_glyph_interpolate_strong_points( glyph, dimension );
      psh2_glyph_interpolate_normal_points( glyph, dimension );
      psh2_glyph_interpolate_other_points( glyph, dimension );

      /* save hinted coordinates back to outline */
      psh2_glyph_save_points( glyph, dimension );
    }

  Exit:
#ifndef DEBUG_HINTER
    psh2_glyph_done( glyph );
#endif
    return error;
  }


/* END */