afcjk.c

奇趣公司比较新的qt/emd版本

        {
          FT_Bool  is_serif;


          /* check for roundness of segment */
          if ( seg->flags & AF_EDGE_ROUND )
            is_round++;
          else
            is_straight++;

          /* check for links -- if seg->serif is set, then seg->link must */
          /* be ignored                                                   */
          is_serif = (FT_Bool)( seg->serif && seg->serif->edge != edge );

          if ( seg->link || is_serif )
          {
            AF_Edge     edge2;
            AF_Segment  seg2;


            edge2 = edge->link;
            seg2  = seg->link;

            if ( is_serif )
            {
              seg2  = seg->serif;
              edge2 = edge->serif;
            }

            if ( edge2 )
            {
              FT_Pos  edge_delta;
              FT_Pos  seg_delta;


              edge_delta = edge->fpos - edge2->fpos;
              if ( edge_delta < 0 )
                edge_delta = -edge_delta;

              seg_delta = AF_SEGMENT_DIST( seg, seg2 );

              if ( seg_delta < edge_delta )
                edge2 = seg2->edge;
            }
            else
              edge2 = seg2->edge;

            if ( is_serif )
            {
              edge->serif   = edge2;
              edge2->flags |= AF_EDGE_SERIF;
            }
            else
              edge->link  = edge2;
          }

          seg = seg->edge_next;

        } while ( seg != edge->first );

        /* set the round/straight flags */
        edge->flags = AF_EDGE_NORMAL;

        if ( is_round > 0 && is_round >= is_straight )
          edge->flags |= AF_EDGE_ROUND;

        /* get rid of serifs if link is set                 */
        /* XXX: This gets rid of many unpleasant artefacts! */
        /*      Example: the `c' in cour.pfa at size 13     */

        if ( edge->serif && edge->link )
          edge->serif = 0;
      }
    }

  Exit:
    return error;
  }


  static FT_Error
  af_cjk_hints_detect_features( AF_GlyphHints  hints,
                                AF_Dimension   dim )
  {
    FT_Error  error;


    error = af_cjk_hints_compute_segments( hints, dim );
    if ( !error )
    {
      af_cjk_hints_link_segments( hints, dim );

      error = af_cjk_hints_compute_edges( hints, dim );
    }
    return error;
  }


  static FT_Error
  af_cjk_hints_init( AF_GlyphHints    hints,
                     AF_LatinMetrics  metrics )
  {
    FT_Render_Mode  mode;
    FT_UInt32       scaler_flags, other_flags;


    af_glyph_hints_rescale( hints, (AF_ScriptMetrics)metrics );

    /*
     *  correct x_scale and y_scale when needed, since they may have
     *  been modified af_cjk_scale_dim above
     */
    hints->x_scale = metrics->axis[AF_DIMENSION_HORZ].scale;
    hints->x_delta = metrics->axis[AF_DIMENSION_HORZ].delta;
    hints->y_scale = metrics->axis[AF_DIMENSION_VERT].scale;
    hints->y_delta = metrics->axis[AF_DIMENSION_VERT].delta;

    /* compute flags depending on render mode, etc. */
    mode = metrics->root.scaler.render_mode;

#ifdef AF_USE_WARPER
    if ( mode == FT_RENDER_MODE_LCD || mode == FT_RENDER_MODE_LCD_V )
      metrics->root.scaler.render_mode = mode = FT_RENDER_MODE_NORMAL;
#endif

    scaler_flags = hints->scaler_flags;
    other_flags  = 0;

    /*
     *  We snap the width of vertical stems for the monochrome and
     *  horizontal LCD rendering targets only.
     */
    if ( mode == FT_RENDER_MODE_MONO || mode == FT_RENDER_MODE_LCD )
      other_flags |= AF_LATIN_HINTS_HORZ_SNAP;

    /*
     *  We snap the width of horizontal stems for the monochrome and
     *  vertical LCD rendering targets only.
     */
    if ( mode == FT_RENDER_MODE_MONO || mode == FT_RENDER_MODE_LCD_V )
      other_flags |= AF_LATIN_HINTS_VERT_SNAP;

    /*
     *  We adjust stems to full pixels only if we don't use the `light' mode.
     */
    if ( mode != FT_RENDER_MODE_LIGHT )
      other_flags |= AF_LATIN_HINTS_STEM_ADJUST;

    if ( mode == FT_RENDER_MODE_MONO )
      other_flags |= AF_LATIN_HINTS_MONO;

    scaler_flags |= AF_SCALER_FLAG_NO_ADVANCE;

    hints->scaler_flags = scaler_flags;
    hints->other_flags  = other_flags;

    return 0;
  }


  /*************************************************************************/
  /*************************************************************************/
  /*****                                                               *****/
  /*****          C J K   G L Y P H   G R I D - F I T T I N G          *****/
  /*****                                                               *****/
  /*************************************************************************/
  /*************************************************************************/

  /* snap a given width in scaled coordinates to one of the */
  /* current standard widths                                */

  static FT_Pos
  af_cjk_snap_width( AF_Width  widths,
                     FT_Int    count,
                     FT_Pos    width )
  {
    int     n;
    FT_Pos  best      = 64 + 32 + 2;
    FT_Pos  reference = width;
    FT_Pos  scaled;


    for ( n = 0; n < count; n++ )
    {
      FT_Pos  w;
      FT_Pos  dist;


      w = widths[n].cur;
      dist = width - w;
      if ( dist < 0 )
        dist = -dist;
      if ( dist < best )
      {
        best      = dist;
        reference = w;
      }
    }

    scaled = FT_PIX_ROUND( reference );

    if ( width >= reference )
    {
      if ( width < scaled + 48 )
        width = reference;
    }
    else
    {
      if ( width > scaled - 48 )
        width = reference;
    }

    return width;
  }


  /* compute the snapped width of a given stem */

  static FT_Pos
  af_cjk_compute_stem_width( AF_GlyphHints  hints,
                             AF_Dimension   dim,
                             FT_Pos         width,
                             AF_Edge_Flags  base_flags,
                             AF_Edge_Flags  stem_flags )
  {
    AF_LatinMetrics  metrics  = (AF_LatinMetrics) hints->metrics;
    AF_LatinAxis     axis     = & metrics->axis[dim];
    FT_Pos           dist     = width;
    FT_Int           sign     = 0;
    FT_Int           vertical = ( dim == AF_DIMENSION_VERT );

    FT_UNUSED( base_flags );
    FT_UNUSED( stem_flags );


    if ( !AF_LATIN_HINTS_DO_STEM_ADJUST( hints ) )
      return width;

    if ( dist < 0 )
    {
      dist = -width;
      sign = 1;
    }

    if ( (  vertical && !AF_LATIN_HINTS_DO_VERT_SNAP( hints ) ) ||
         ( !vertical && !AF_LATIN_HINTS_DO_HORZ_SNAP( hints ) ) )
    {
      /* smooth hinting process: very lightly quantize the stem width */

      if ( axis->width_count > 0 )
      {
        if ( FT_ABS( dist - axis->widths[0].cur ) < 40 )
        {
          dist = axis->widths[0].cur;
          if ( dist < 48 )
            dist = 48;

          goto Done_Width;
        }
      }

      if ( dist < 54 )
        dist += ( 54 - dist ) / 2 ;
      else if ( dist < 3 * 64 )
      {
        FT_Pos  delta;


        delta  = dist & 63;
        dist  &= -64;

        if ( delta < 10 )
          dist += delta;
        else if ( delta < 22 )
          dist += 10;
        else if ( delta < 42 )
          dist += delta;
        else if ( delta < 54 )
          dist += 54;
        else
          dist += delta;
      }
    }
    else
    {
      /* strong hinting process: snap the stem width to integer pixels */

      dist = af_cjk_snap_width( axis->widths, axis->width_count, dist );

      if ( vertical )
      {
        /* in the case of vertical hinting, always round */
        /* the stem heights to integer pixels            */

        if ( dist >= 64 )
          dist = ( dist + 16 ) & ~63;
        else
          dist = 64;
      }
      else
      {
        if ( AF_LATIN_HINTS_DO_MONO( hints ) )
        {
          /* monochrome horizontal hinting: snap widths to integer pixels */
          /* with a different threshold                                   */

          if ( dist < 64 )
            dist = 64;
          else
            dist = ( dist + 32 ) & ~63;
        }
        else
        {
          /* for horizontal anti-aliased hinting, we adopt a more subtle */
          /* approach: we strengthen small stems, round stems whose size */
          /* is between 1 and 2 pixels to an integer, otherwise nothing  */

          if ( dist < 48 )
            dist = ( dist + 64 ) >> 1;

          else if ( dist < 128 )
            dist = ( dist + 22 ) & ~63;
          else
            /* round otherwise to prevent color fringes in LCD mode */
            dist = ( dist + 32 ) & ~63;
        }
      }
    }

  Done_Width:
    if ( sign )
      dist = -dist;

    return dist;
  }


  /* align one stem edge relative to the previous stem edge */

  static void
  af_cjk_align_linked_edge( AF_GlyphHints  hints,
                            AF_Dimension   dim,
                            AF_Edge        base_edge,
                            AF_Edge        stem_edge )
  {
    FT_Pos  dist = stem_edge->opos - base_edge->opos;

    FT_Pos  fitted_width = af_cjk_compute_stem_width(
                             hints, dim, dist,
                             (AF_Edge_Flags)base_edge->flags,
                             (AF_Edge_Flags)stem_edge->flags );


    stem_edge->pos = base_edge->pos + fitted_width;
  }


  static void
  af_cjk_align_serif_edge( AF_GlyphHints  hints,
                           AF_Edge        base,
                           AF_Edge        serif )
  {
    FT_UNUSED( hints );

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


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


#define AF_LIGHT_MODE_MAX_HORZ_GAP    9
#define AF_LIGHT_MODE_MAX_VERT_GAP   15
#define AF_LIGHT_MODE_MAX_DELTA_ABS  14


  static FT_Pos
  af_hint_normal_stem( AF_GlyphHints  hints,
                       AF_Edge        edge,
                       AF_Edge        edge2,
                       FT_Pos         anchor,
                       AF_Dimension   dim )
  {
    FT_Pos  org_len, cur_len, org_center;
    FT_Pos  cur_pos1, cur_pos2;
    FT_Pos  d_off1, u_off1, d_off2, u_off2, delta;
    FT_Pos  offset;
    FT_Pos  threshold = 64;


    if ( !AF_LATIN_HINTS_DO_STEM_ADJUST( hints ) )
    {
      if ( ( edge->flags  & AF_EDGE_ROUND ) &&
           ( edge2->flags & AF_EDGE_ROUND ) )
      {
        if ( dim == AF_DIMENSION_VERT )
          threshold = 64 - AF_LIGHT_MODE_MAX_HORZ_GAP;
        else
          threshold = 64 - AF_LIGHT_MODE_MAX_VERT_GAP;
      }
      else
      {
        if ( dim == AF_DIMENSION_VERT )
          threshold = 64 - AF_LIGHT_MODE_MAX_HORZ_GAP / 3;
        else
          threshold = 64 - AF_LIGHT_MODE_MAX_VERT_GAP / 3;
      }
    }

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

    org_center = ( edge->opos + edge2->opos ) / 2 + anchor;
    cur_pos1   = org_center - cur_len / 2;
    cur_pos2   = cur_pos1 + cur_len;
    d_off1     = cur_pos1 - FT_PIX_FLOOR( cur_pos1 );
    d_off2     = cur_pos2 - FT_PIX_FLOOR( cur_pos2 );
    u_off1     = 64 - d_off1;
    u_off2     = 64 - d_off2;
    delta      = 0;


    if ( d_off1 == 0 || d_off2 == 0 )
      goto Exit;

    if ( cur_len <= threshold )
    {
      if ( d_off2 < cur_len )
      {
        if ( u_off1 <= d_off2 )
          delta =  u_off1;
        else
          delta = -d_off2;
      }

      goto Exit;
    }

    if ( threshold < 64 )
    {
      if ( d_off1 >= threshold || u_off1 >= threshold ||
           d_off2 >= threshold || u_off2 >= threshold )
        goto Exit;
    }

    offset = cur_len % 64;

    if ( offset < 32 )
    {
      if ( u_off1 <= offset || d_off2 <= offset )
        goto Exit;
    }
    else
      offset = 64 - threshold;

    d_off1 = threshold - u_off1;
    u_off1 = u_off1    - offset;
    u_off2 = threshold - d_off2;
    d_off2 = d_off2    - offset;

    if ( d_off1 <= u_off1 )
      u_off1 = -d_off1;

    if ( d_off2 <= u_off2 )
      u_off2 = -d_off2;

    if ( FT_ABS( u_off1 ) <= FT_ABS( u_off2 ) )
      delta = u_off1;
    else
      delta = u_off2;

  Exit:

#if 1
    if ( !AF_LATIN_HINTS_DO_STEM_ADJUST( hints ) )
    {
      if ( delta > AF_LIGHT_MODE_MAX_DELTA_ABS )
        delta = AF_LIGHT_MODE_MAX_DELTA_ABS;
      else if ( delta < -AF_LIGHT_MODE_MAX_DELTA_ABS )
        delta = -AF_LIGHT_MODE_MAX_DELTA_ABS;
    }
#endif

    cur_pos1 += delta;

    if ( edge->opos < edge2->opos )
    {
      edge->pos  = cur_pos1;
      edge2->pos = cur_pos1 + cur_len;
    }
    else
    {
      edge->pos  = cur_pos1 + cur_len;
      edge2->pos = cur_pos1;