aflatin2.c

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    serif->pos = base->pos + (serif->opos - base->opos);
  }


  /*************************************************************************/
  /*************************************************************************/
  /*************************************************************************/
  /****                                                                 ****/
  /****                    E D G E   H I N T I N G                      ****/
  /****                                                                 ****/
  /*************************************************************************/
  /*************************************************************************/
  /*************************************************************************/


  FT_LOCAL_DEF( void )
  af_latin2_hint_edges( AF_GlyphHints  hints,
                       AF_Dimension   dim )
  {
    AF_AxisHints  axis       = &hints->axis[dim];
    AF_Edge       edges      = axis->edges;
    AF_Edge       edge_limit = edges + axis->num_edges;
    FT_Int        n_edges;
    AF_Edge       edge;
    AF_Edge       anchor     = 0;
    FT_Int        has_serifs = 0;
    FT_Pos        anchor_drift = 0;



    AF_LOG(( "==== hinting %s edges =====\n", dim == AF_DIMENSION_HORZ ? "vertical" : "horizontal" ));

    /* we begin by aligning all stems relative to the blue zone */
    /* if needed -- that's only for horizontal edges            */

    if ( dim == AF_DIMENSION_VERT && AF_HINTS_DO_BLUES( hints ) )
    {
      for ( edge = edges; edge < edge_limit; edge++ )
      {
        AF_Width  blue;
        AF_Edge   edge1, edge2;


        if ( edge->flags & AF_EDGE_DONE )
          continue;

        blue  = edge->blue_edge;
        edge1 = NULL;
        edge2 = edge->link;

        if ( blue )
        {
          edge1 = edge;
        }
        else if ( edge2 && edge2->blue_edge )
        {
          blue  = edge2->blue_edge;
          edge1 = edge2;
          edge2 = edge;
        }

        if ( !edge1 )
          continue;

        AF_LOG(( "BLUE: edge %d (opos=%.2f) snapped to (%.2f), "
                 "was (%.2f)\n",
                 edge1-edges, edge1->opos / 64.0, blue->fit / 64.0,
                 edge1->pos / 64.0 ));

        edge1->pos    = blue->fit;
        edge1->flags |= AF_EDGE_DONE;

        if ( edge2 && !edge2->blue_edge )
        {
          af_latin2_align_linked_edge( hints, dim, edge1, edge2 );
          edge2->flags |= AF_EDGE_DONE;
        }

        if ( !anchor )
        {
          anchor = edge;

          anchor_drift = (anchor->pos - anchor->opos);
          if (edge2)
            anchor_drift = (anchor_drift + (edge2->pos - edge2->opos)) >> 1;
        }
      }
    }

    /* now we will align all stem edges, trying to maintain the */
    /* relative order of stems in the glyph                     */
    for ( edge = edges; edge < edge_limit; edge++ )
    {
      AF_Edge  edge2;


      if ( edge->flags & AF_EDGE_DONE )
        continue;

      /* skip all non-stem edges */
      edge2 = edge->link;
      if ( !edge2 )
      {
        has_serifs++;
        continue;
      }

      /* now align the stem */

      /* this should not happen, but it's better to be safe */
      if ( edge2->blue_edge )
      {
        AF_LOG(( "ASSERTION FAILED for edge %d\n", edge2-edges ));

        af_latin2_align_linked_edge( hints, dim, edge2, edge );
        edge->flags |= AF_EDGE_DONE;
        continue;
      }

      if ( !anchor )
      {
        FT_Pos  org_len, org_center, cur_len;
        FT_Pos  cur_pos1, error1, error2, u_off, d_off;


        org_len = edge2->opos - edge->opos;
        cur_len = af_latin2_compute_stem_width(
                    hints, dim, org_len,
                    (AF_Edge_Flags)edge->flags,
                    (AF_Edge_Flags)edge2->flags );
        if ( cur_len <= 64 )
          u_off = d_off = 32;
        else
        {
          u_off = 38;
          d_off = 26;
        }

        if ( cur_len < 96 )
        {
          org_center = edge->opos + ( org_len >> 1 );

          cur_pos1   = FT_PIX_ROUND( org_center );

          error1 = org_center - ( cur_pos1 - u_off );
          if ( error1 < 0 )
            error1 = -error1;

          error2 = org_center - ( cur_pos1 + d_off );
          if ( error2 < 0 )
            error2 = -error2;

          if ( error1 < error2 )
            cur_pos1 -= u_off;
          else
            cur_pos1 += d_off;

          edge->pos  = cur_pos1 - cur_len / 2;
          edge2->pos = edge->pos + cur_len;
        }
        else
          edge->pos = FT_PIX_ROUND( edge->opos );

        AF_LOG(( "ANCHOR: edge %d (opos=%.2f) and %d (opos=%.2f) "
                 "snapped to (%.2f) (%.2f)\n",
                 edge-edges, edge->opos / 64.0,
                 edge2-edges, edge2->opos / 64.0,
                 edge->pos / 64.0, edge2->pos / 64.0 ));
        anchor = edge;

        edge->flags |= AF_EDGE_DONE;

        af_latin2_align_linked_edge( hints, dim, edge, edge2 );

        edge2->flags |= AF_EDGE_DONE;

        anchor_drift = ( (anchor->pos - anchor->opos) +
                         (edge2->pos - edge2->opos)) >> 1;

        AF_LOG(( "DRIFT: %.2f\n", anchor_drift/64.0 ));
      }
      else
      {
        FT_Pos   org_pos, org_len, org_center, cur_center, cur_len;
        FT_Pos   org_left, org_right;


        org_pos    = edge->opos + anchor_drift;
        org_len    = edge2->opos - edge->opos;
        org_center = org_pos + ( org_len >> 1 );

        cur_len = af_latin2_compute_stem_width(
                   hints, dim, org_len,
                   (AF_Edge_Flags)edge->flags,
                   (AF_Edge_Flags)edge2->flags );

        org_left  = org_pos + ((org_len - cur_len) >> 1);
        org_right = org_pos + ((org_len + cur_len) >> 1);

        AF_LOG(( "ALIGN: left=%.2f right=%.2f ", org_left/64.0, org_right/64.0 ));
        cur_center = org_center;

        if ( edge2->flags & AF_EDGE_DONE )
        {
          AF_LOG(( "\n" ));
          edge->pos = edge2->pos - cur_len;
        }
        else
        {
         /* we want to compare several displacement, and choose
          * the one that increases fitness while minimizing
          * distortion as well
          */
          FT_Pos   displacements[6], scores[6], org, fit, delta;
          FT_UInt  count = 0;

          /* note: don't even try to fit tiny stems */
          if ( cur_len < 32 )
          {
            AF_LOG(( "tiny stem\n" ));
            goto AlignStem;
          }

          /* if the span is within a single pixel, don't touch it */
          if ( FT_PIX_FLOOR(org_left) == FT_PIX_CEIL(org_right) )
          {
            AF_LOG(( "single pixel stem\n" ));
            goto AlignStem;
          }

          if (cur_len <= 96)
          {
           /* we want to avoid the absolute worst case which is
            * when the left and right edges of the span each represent
            * about 50% of the gray. we'd better want to change this
            * to 25/75%, since this is much more pleasant to the eye with
            * very acceptable distortion
            */
            FT_Pos  frac_left  = (org_left) & 63;
            FT_Pos  frac_right = (org_right) & 63;

            if ( frac_left  >= 22 && frac_left  <= 42 &&
                 frac_right >= 22 && frac_right <= 42 )
            {
              org = frac_left;
              fit = (org <= 32) ? 16 : 48;
              delta = FT_ABS(fit - org);
              displacements[count] = fit - org;
              scores[count++]      = delta;
              AF_LOG(( "dispA=%.2f (%d) ", (fit - org)/64.0, delta ));

              org = frac_right;
              fit = (org <= 32) ? 16 : 48;
              delta = FT_ABS(fit - org);
              displacements[count] = fit - org;
              scores[count++]     = delta;
              AF_LOG(( "dispB=%.2f (%d) ", (fit - org)/64.0, delta ));
            }
          }

          /* snapping the left edge to the grid */
          org   = org_left;
          fit   = FT_PIX_ROUND(org);
          delta = FT_ABS(fit - org);
          displacements[count] = fit - org;
          scores[count++]      = delta;
          AF_LOG(( "dispC=%.2f (%d) ", (fit - org)/64.0, delta ));

          /* snapping the right edge to the grid */
          org   = org_right;
          fit   = FT_PIX_ROUND(org);
          delta = FT_ABS(fit - org);
          displacements[count] = fit - org;
          scores[count++]      = delta;
          AF_LOG(( "dispD=%.2f (%d) ", (fit - org)/64.0, delta ));

          /* now find the best displacement */
          {
            FT_Pos  best_score = scores[0];
            FT_Pos  best_disp  = displacements[0];
            FT_UInt nn;

            for (nn = 1; nn < count; nn++)
            {
              if (scores[nn] < best_score)
              {
                best_score = scores[nn];
                best_disp  = displacements[nn];
              }
            }

            cur_center = org_center + best_disp;
          }
          AF_LOG(( "\n" ));
        }

      AlignStem:
        edge->pos  = cur_center - (cur_len >> 1);
        edge2->pos = edge->pos + cur_len;

        AF_LOG(( "STEM1: %d (opos=%.2f) to %d (opos=%.2f) "
                 "snapped to (%.2f) and (%.2f), org_len = %.2f cur_len=%.2f\n",
                 edge-edges, edge->opos / 64.0,
                 edge2-edges, edge2->opos / 64.0,
                 edge->pos / 64.0, edge2->pos / 64.0,
                 org_len / 64.0, cur_len / 64.0 ));

        edge->flags  |= AF_EDGE_DONE;
        edge2->flags |= AF_EDGE_DONE;

        if ( edge > edges && edge->pos < edge[-1].pos )
        {
          AF_LOG(( "BOUND: %d (pos=%.2f) to (%.2f)\n",
                   edge-edges, edge->pos / 64.0, edge[-1].pos / 64.0 ));
          edge->pos = edge[-1].pos;
        }
      }
    }

    /* make sure that lowercase m's maintain their symmetry */

    /* In general, lowercase m's have six vertical edges if they are sans */
    /* serif, or twelve if they are with serifs.  This implementation is  */
    /* based on that assumption, and seems to work very well with most    */
    /* faces.  However, if for a certain face this assumption is not      */
    /* true, the m is just rendered like before.  In addition, any stem   */
    /* correction will only be applied to symmetrical glyphs (even if the */
    /* glyph is not an m), so the potential for unwanted distortion is    */
    /* relatively low.                                                    */

    /* We don't handle horizontal edges since we can't easily assure that */
    /* the third (lowest) stem aligns with the base line; it might end up */
    /* one pixel higher or lower.                                         */
#if 0
    n_edges = edge_limit - edges;
    if ( dim == AF_DIMENSION_HORZ && ( n_edges == 6 || n_edges == 12 ) )
    {
      AF_Edge  edge1, edge2, edge3;
      FT_Pos   dist1, dist2, span, delta;


      if ( n_edges == 6 )
      {
        edge1 = edges;
        edge2 = edges + 2;
        edge3 = edges + 4;
      }
      else
      {
        edge1 = edges + 1;
        edge2 = edges + 5;
        edge3 = edges + 9;
      }

      dist1 = edge2->opos - edge1->opos;
      dist2 = edge3->opos - edge2->opos;

      span = dist1 - dist2;
      if ( span < 0 )
        span = -span;

      if ( span < 8 )
      {
        delta = edge3->pos - ( 2 * edge2->pos - edge1->pos );
        edge3->pos -= delta;
        if ( edge3->link )
          edge3->link->pos -= delta;

        /* move the serifs along with the stem */
        if ( n_edges == 12 )
        {
          ( edges + 8 )->pos -= delta;
          ( edges + 11 )->pos -= delta;
        }

        edge3->flags |= AF_EDGE_DONE;
        if ( edge3->link )
          edge3->link->flags |= AF_EDGE_DONE;
      }
    }
#endif
    if ( has_serifs || !anchor )
    {
      /*
       *  now hint the remaining edges (serifs and single) in order
       *  to complete our processing
       */
      for ( edge = edges; edge < edge_limit; edge++ )
      {
        FT_Pos  delta;


        if ( edge->flags & AF_EDGE_DONE )
          continue;

        delta = 1000;

        if ( edge->serif )
        {
          delta = edge->serif->opos - edge->opos;
          if ( delta < 0 )
            delta = -delta;
        }

        if ( delta < 64 + 16 )
        {
          af_latin2_align_serif_edge( hints, edge->serif, edge );
          AF_LOG(( "SERIF: edge %d (opos=%.2f) serif to %d (opos=%.2f) "
                   "aligned to (%.2f)\n",
                   edge-edges, edge->opos / 64.0,
                   edge->serif - edges, edge->serif->opos / 64.0,
                   edge->pos / 64.0 ));
        }
        else if ( !anchor )
        {
          AF_LOG(( "SERIF_ANCHOR: edge %d (opos=%.2f) snapped to (%.2f)\n",
                   edge-edges, edge->opos / 64.0, edge->pos / 64.0 ));
          edge->pos = FT_PIX_ROUND( edge->opos );
          anchor    = edge;
        }
        else
        {
          AF_Edge  before, after;


          for ( before = edge