kc3-lang/freetype/src/autofit/afcjk.c

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• Hash : a20de84e
  Author :
  Date : 2023-08-12T11:47:41
  

  Fix warnings in tracing messages for 32bit compilation. Since we now require C99, use `%td` for `ptrdiff_t` and `%zu` for `size_t`.

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• src/autofit/afcjk.c

• /****************************************************************************
   *
   * afcjk.c
   *
   *   Auto-fitter hinting routines for CJK writing system (body).
   *
   * Copyright (C) 2006-2023 by
   * David Turner, Robert Wilhelm, and Werner Lemberg.
   *
   * This file is part of the FreeType project, and may only be used,
   * modified, and distributed under the terms of the FreeType project
   * license, LICENSE.TXT.  By continuing to use, modify, or distribute
   * this file you indicate that you have read the license and
   * understand and accept it fully.
   *
   */
  
    /*
     * The algorithm is based on akito's autohint patch, archived at
     *
     * https://web.archive.org/web/20051219160454/http://www.kde.gr.jp:80/~akito/patch/freetype2/2.1.7/
     *
     */
  
  #include <freetype/ftadvanc.h>
  #include <freetype/internal/ftdebug.h>
  
  #include "afglobal.h"
  #include "aflatin.h"
  #include "afcjk.h"
  
  
  #ifdef AF_CONFIG_OPTION_CJK
  
  #undef AF_CONFIG_OPTION_CJK_BLUE_HANI_VERT
  
  #include "aferrors.h"
  
  
    /**************************************************************************
     *
     * The macro FT_COMPONENT is used in trace mode.  It is an implicit
     * parameter of the FT_TRACE() and FT_ERROR() macros, used to print/log
     * messages during execution.
     */
  #undef  FT_COMPONENT
  #define FT_COMPONENT  afcjk
  
  
    /*************************************************************************/
    /*************************************************************************/
    /*****                                                               *****/
    /*****              C J K   G L O B A L   M E T R I C S              *****/
    /*****                                                               *****/
    /*************************************************************************/
    /*************************************************************************/
  
  
    /* Basically the Latin version with AF_CJKMetrics */
    /* to replace AF_LatinMetrics.                    */
  
    FT_LOCAL_DEF( void )
    af_cjk_metrics_init_widths( AF_CJKMetrics  metrics,
                                FT_Face        face )
    {
      /* scan the array of segments in each direction */
      AF_GlyphHintsRec  hints[1];
  
  
      FT_TRACE5(( "\n" ));
      FT_TRACE5(( "cjk standard widths computation (style `%s')\n",
                  af_style_names[metrics->root.style_class->style] ));
      FT_TRACE5(( "===================================================\n" ));
      FT_TRACE5(( "\n" ));
  
      af_glyph_hints_init( hints, face->memory );
  
      metrics->axis[AF_DIMENSION_HORZ].width_count = 0;
      metrics->axis[AF_DIMENSION_VERT].width_count = 0;
  
      {
        FT_Error          error;
        FT_ULong          glyph_index;
        int               dim;
        AF_CJKMetricsRec  dummy[1];
        AF_Scaler         scaler = &dummy->root.scaler;
  
        AF_StyleClass   style_class  = metrics->root.style_class;
        AF_ScriptClass  script_class = af_script_classes[style_class->script];
  
        /* If HarfBuzz is not available, we need a pointer to a single */
        /* unsigned long value.                                        */
  #ifdef FT_CONFIG_OPTION_USE_HARFBUZZ
        void*     shaper_buf;
  #else
        FT_ULong  shaper_buf_;
        void*     shaper_buf = &shaper_buf_;
  #endif
  
        const char*  p;
  
  #ifdef FT_DEBUG_LEVEL_TRACE
        FT_ULong  ch = 0;
  #endif
  
        p = script_class->standard_charstring;
  
  #ifdef FT_CONFIG_OPTION_USE_HARFBUZZ
        shaper_buf = af_shaper_buf_create( face );
  #endif
  
        /* We check a list of standard characters.  The first match wins. */
  
        glyph_index = 0;
        while ( *p )
        {
          unsigned int  num_idx;
  
  #ifdef FT_DEBUG_LEVEL_TRACE
          const char*  p_old;
  #endif
  
  
          while ( *p == ' ' )
            p++;
  
  #ifdef FT_DEBUG_LEVEL_TRACE
          p_old = p;
          GET_UTF8_CHAR( ch, p_old );
  #endif
  
          /* reject input that maps to more than a single glyph */
          p = af_shaper_get_cluster( p, &metrics->root, shaper_buf, &num_idx );
          if ( num_idx > 1 )
            continue;
  
          /* otherwise exit loop if we have a result */
          glyph_index = af_shaper_get_elem( &metrics->root,
                                            shaper_buf,
                                            0,
                                            NULL,
                                            NULL );
          if ( glyph_index )
            break;
        }
  
        af_shaper_buf_destroy( face, shaper_buf );
  
        if ( !glyph_index )
          goto Exit;
  
        if ( !glyph_index )
          goto Exit;
  
        FT_TRACE5(( "standard character: U+%04lX (glyph index %ld)\n",
                    ch, glyph_index ));
  
        error = FT_Load_Glyph( face, glyph_index, FT_LOAD_NO_SCALE );
        if ( error || face->glyph->outline.n_points <= 0 )
          goto Exit;
  
        FT_ZERO( dummy );
  
        dummy->units_per_em = metrics->units_per_em;
  
        scaler->x_scale = 0x10000L;
        scaler->y_scale = 0x10000L;
        scaler->x_delta = 0;
        scaler->y_delta = 0;
  
        scaler->face        = face;
        scaler->render_mode = FT_RENDER_MODE_NORMAL;
        scaler->flags       = 0;
  
        af_glyph_hints_rescale( hints, (AF_StyleMetrics)dummy );
  
        error = af_glyph_hints_reload( hints, &face->glyph->outline );
        if ( error )
          goto Exit;
  
        for ( dim = 0; dim < AF_DIMENSION_MAX; dim++ )
        {
          AF_CJKAxis    axis    = &metrics->axis[dim];
          AF_AxisHints  axhints = &hints->axis[dim];
          AF_Segment    seg, limit, link;
          FT_UInt       num_widths = 0;
  
  
          error = af_latin_hints_compute_segments( hints,
                                                   (AF_Dimension)dim );
          if ( error )
            goto Exit;
  
          /*
           * We assume that the glyphs selected for the stem width
           * computation are `featureless' enough so that the linking
           * algorithm works fine without adjustments of its scoring
           * function.
           */
          af_latin_hints_link_segments( hints,
                                        0,
                                        NULL,
                                        (AF_Dimension)dim );
  
          seg   = axhints->segments;
          limit = seg + axhints->num_segments;
  
          for ( ; seg < limit; seg++ )
          {
            link = seg->link;
  
            /* we only consider stem segments there! */
            if ( link && link->link == seg && link > seg )
            {
              FT_Pos  dist;
  
  
              dist = seg->pos - link->pos;
              if ( dist < 0 )
                dist = -dist;
  
              if ( num_widths < AF_CJK_MAX_WIDTHS )
                axis->widths[num_widths++].org = dist;
            }
          }
  
          /* this also replaces multiple almost identical stem widths */
          /* with a single one (the value 100 is heuristic)           */
          af_sort_and_quantize_widths( &num_widths, axis->widths,
                                       dummy->units_per_em / 100 );
          axis->width_count = num_widths;
        }
  
      Exit:
        for ( dim = 0; dim < AF_DIMENSION_MAX; dim++ )
        {
          AF_CJKAxis  axis = &metrics->axis[dim];
          FT_Pos      stdw;
  
  
          stdw = ( axis->width_count > 0 ) ? axis->widths[0].org
                                           : AF_LATIN_CONSTANT( metrics, 50 );
  
          /* let's try 20% of the smallest width */
          axis->edge_distance_threshold = stdw / 5;
          axis->standard_width          = stdw;
          axis->extra_light             = 0;
  
  #ifdef FT_DEBUG_LEVEL_TRACE
          {
            FT_UInt  i;
  
  
            FT_TRACE5(( "%s widths:\n",
                        dim == AF_DIMENSION_VERT ? "horizontal"
                                                 : "vertical" ));
  
            FT_TRACE5(( "  %ld (standard)", axis->standard_width ));
            for ( i = 1; i < axis->width_count; i++ )
              FT_TRACE5(( " %ld", axis->widths[i].org ));
  
            FT_TRACE5(( "\n" ));
          }
  #endif
        }
      }
  
      FT_TRACE5(( "\n" ));
  
      af_glyph_hints_done( hints );
    }
  
  
    /* Find all blue zones. */
  
    static void
    af_cjk_metrics_init_blues( AF_CJKMetrics  metrics,
                               FT_Face        face )
    {
      FT_Pos      fills[AF_BLUE_STRING_MAX_LEN];
      FT_Pos      flats[AF_BLUE_STRING_MAX_LEN];
  
      FT_UInt     num_fills;
      FT_UInt     num_flats;
  
      FT_Bool     fill;
  
      AF_CJKBlue  blue;
      FT_Error    error;
      AF_CJKAxis  axis;
      FT_Outline  outline;
  
      AF_StyleClass  sc = metrics->root.style_class;
  
      AF_Blue_Stringset         bss = sc->blue_stringset;
      const AF_Blue_StringRec*  bs  = &af_blue_stringsets[bss];
  
      /* If HarfBuzz is not available, we need a pointer to a single */
      /* unsigned long value.                                        */
  #ifdef FT_CONFIG_OPTION_USE_HARFBUZZ
      void*     shaper_buf;
  #else
      FT_ULong  shaper_buf_;
      void*     shaper_buf = &shaper_buf_;
  #endif
  
  
      /* we walk over the blue character strings as specified in the   */
      /* style's entry in the `af_blue_stringset' array, computing its */
      /* extremum points (depending on the string properties)          */
  
      FT_TRACE5(( "cjk blue zones computation\n" ));
      FT_TRACE5(( "==========================\n" ));
      FT_TRACE5(( "\n" ));
  
  #ifdef FT_CONFIG_OPTION_USE_HARFBUZZ
      shaper_buf = af_shaper_buf_create( face );
  #endif
  
      for ( ; bs->string != AF_BLUE_STRING_MAX; bs++ )
      {
        const char*  p = &af_blue_strings[bs->string];
        FT_Pos*      blue_ref;
        FT_Pos*      blue_shoot;
  
  
        if ( AF_CJK_IS_HORIZ_BLUE( bs ) )
          axis = &metrics->axis[AF_DIMENSION_HORZ];
        else
          axis = &metrics->axis[AF_DIMENSION_VERT];
  
  #ifdef FT_DEBUG_LEVEL_TRACE
        {
          FT_String*  cjk_blue_name[4] =
          {
            (FT_String*)"bottom",    /* --   , --  */
            (FT_String*)"top",       /* --   , TOP */
            (FT_String*)"left",      /* HORIZ, --  */
            (FT_String*)"right"      /* HORIZ, TOP */
          };
  
  
          FT_TRACE5(( "blue zone %d (%s):\n",
                      axis->blue_count,
                      cjk_blue_name[AF_CJK_IS_HORIZ_BLUE( bs ) |
                                    AF_CJK_IS_TOP_BLUE( bs )   ] ));
        }
  #endif /* FT_DEBUG_LEVEL_TRACE */
  
        num_fills = 0;
        num_flats = 0;
  
        fill = 1;  /* start with characters that define fill values */
        FT_TRACE5(( "  [overshoot values]\n" ));
  
        while ( *p )
        {
          FT_ULong    glyph_index;
          FT_Pos      best_pos;       /* same as points.y or points.x, resp. */
          FT_Int      best_point;
          FT_Vector*  points;
  
          unsigned int  num_idx;
  
  #ifdef FT_DEBUG_LEVEL_TRACE
          const char*  p_old;
          FT_ULong     ch;
  #endif
  
  
          while ( *p == ' ' )
            p++;
  
  #ifdef FT_DEBUG_LEVEL_TRACE
          p_old = p;
          GET_UTF8_CHAR( ch, p_old );
  #endif
  
          /* switch to characters that define flat values */
          if ( *p == '|' )
          {
            fill = 0;
            FT_TRACE5(( "  [reference values]\n" ));
            p++;
            continue;
          }
  
          /* reject input that maps to more than a single glyph */
          p = af_shaper_get_cluster( p, &metrics->root, shaper_buf, &num_idx );
          if ( num_idx > 1 )
            continue;
  
          /* load the character in the face -- skip unknown or empty ones */
          glyph_index = af_shaper_get_elem( &metrics->root,
                                            shaper_buf,
                                            0,
                                            NULL,
                                            NULL );
          if ( glyph_index == 0 )
          {
            FT_TRACE5(( "  U+%04lX unavailable\n", ch ));
            continue;
          }
  
          error   = FT_Load_Glyph( face, glyph_index, FT_LOAD_NO_SCALE );
          outline = face->glyph->outline;
          if ( error || outline.n_points <= 2 )
          {
            FT_TRACE5(( "  U+%04lX contains no (usable) outlines\n", ch ));
            continue;
          }
  
          /* now compute min or max point indices and coordinates */
          points     = outline.points;
          best_point = -1;
          best_pos   = 0;  /* make compiler happy */
  
          {
            FT_Int  nn;
            FT_Int  pp, first, last;
  
  
            last = -1;
            for ( nn = 0; nn < outline.n_contours; nn++ )
            {
              first = last + 1;
              last  = outline.contours[nn];
  
              /* Avoid single-point contours since they are never rasterized. */
              /* In some fonts, they correspond to mark attachment points     */
              /* which are way outside of the glyph's real outline.           */
              if ( last <= first )
                continue;
  
              if ( AF_CJK_IS_HORIZ_BLUE( bs ) )
              {
                if ( AF_CJK_IS_RIGHT_BLUE( bs ) )
                {
                  for ( pp = first; pp <= last; pp++ )
                    if ( best_point < 0 || points[pp].x > best_pos )
                    {
                      best_point = pp;
                      best_pos   = points[pp].x;
                    }
                }
                else
                {
                  for ( pp = first; pp <= last; pp++ )
                    if ( best_point < 0 || points[pp].x < best_pos )
                    {
                      best_point = pp;
                      best_pos   = points[pp].x;
                    }
                }
              }
              else
              {
                if ( AF_CJK_IS_TOP_BLUE( bs ) )
                {
                  for ( pp = first; pp <= last; pp++ )
                    if ( best_point < 0 || points[pp].y > best_pos )
                    {
                      best_point = pp;
                      best_pos   = points[pp].y;
                    }
                }
                else
                {
                  for ( pp = first; pp <= last; pp++ )
                    if ( best_point < 0 || points[pp].y < best_pos )
                    {
                      best_point = pp;
                      best_pos   = points[pp].y;
                    }
                }
              }
            }
  
            FT_TRACE5(( "  U+%04lX: best_pos = %5ld\n", ch, best_pos ));
          }
  
          if ( fill )
            fills[num_fills++] = best_pos;
          else
            flats[num_flats++] = best_pos;
  
        } /* end while loop */
  
        if ( num_flats == 0 && num_fills == 0 )
        {
          /*
           * we couldn't find a single glyph to compute this blue zone,
           * we will simply ignore it then
           */
          FT_TRACE5(( "  empty\n" ));
          continue;
        }
  
        /* we have computed the contents of the `fill' and `flats' tables,   */
        /* now determine the reference and overshoot position of the blue -- */
        /* we simply take the median value after a simple sort               */
        af_sort_pos( num_fills, fills );
        af_sort_pos( num_flats, flats );
  
        blue       = &axis->blues[axis->blue_count];
        blue_ref   = &blue->ref.org;
        blue_shoot = &blue->shoot.org;
  
        axis->blue_count++;
  
        if ( num_flats == 0 )
        {
          *blue_ref   =
          *blue_shoot = fills[num_fills / 2];
        }
        else if ( num_fills == 0 )
        {
          *blue_ref   =
          *blue_shoot = flats[num_flats / 2];
        }
        else
        {
          *blue_ref   = fills[num_fills / 2];
          *blue_shoot = flats[num_flats / 2];
        }
  
        /* make sure blue_ref >= blue_shoot for top/right or */
        /* vice versa for bottom/left                        */
        if ( *blue_shoot != *blue_ref )
        {
          FT_Pos   ref       = *blue_ref;
          FT_Pos   shoot     = *blue_shoot;
          FT_Bool  under_ref = FT_BOOL( shoot < ref );
  
  
          /* AF_CJK_IS_TOP_BLUE covers `right' and `top' */
          if ( AF_CJK_IS_TOP_BLUE( bs ) ^ under_ref )
          {
            *blue_ref   =
            *blue_shoot = ( shoot + ref ) / 2;
  
            FT_TRACE5(( "  [reference smaller than overshoot,"
                        " taking mean value]\n" ));
          }
        }
  
        blue->flags = 0;
        if ( AF_CJK_IS_TOP_BLUE( bs ) )
          blue->flags |= AF_CJK_BLUE_TOP;
  
        FT_TRACE5(( "    -> reference = %ld\n", *blue_ref ));
        FT_TRACE5(( "       overshoot = %ld\n", *blue_shoot ));
  
      } /* end for loop */
  
      af_shaper_buf_destroy( face, shaper_buf );
  
      FT_TRACE5(( "\n" ));
  
      return;
    }
  
  
    /* Basically the Latin version with type AF_CJKMetrics for metrics. */
  
    FT_LOCAL_DEF( void )
    af_cjk_metrics_check_digits( AF_CJKMetrics  metrics,
                                 FT_Face        face )
    {
      FT_Bool  started = 0, same_width = 1;
      FT_Long  advance = 0, old_advance = 0;
  
      /* If HarfBuzz is not available, we need a pointer to a single */
      /* unsigned long value.                                        */
  #ifdef FT_CONFIG_OPTION_USE_HARFBUZZ
      void*     shaper_buf;
  #else
      FT_ULong  shaper_buf_;
      void*     shaper_buf = &shaper_buf_;
  #endif
  
      /* in all supported charmaps, digits have character codes 0x30-0x39 */
      const char   digits[] = "0 1 2 3 4 5 6 7 8 9";
      const char*  p;
  
  
      p = digits;
  
  #ifdef FT_CONFIG_OPTION_USE_HARFBUZZ
      shaper_buf = af_shaper_buf_create( face );
  #endif
  
      while ( *p )
      {
        FT_ULong      glyph_index;
        unsigned int  num_idx;
  
  
        /* reject input that maps to more than a single glyph */
        p = af_shaper_get_cluster( p, &metrics->root, shaper_buf, &num_idx );
        if ( num_idx > 1 )
          continue;
  
        glyph_index = af_shaper_get_elem( &metrics->root,
                                          shaper_buf,
                                          0,
                                          &advance,
                                          NULL );
        if ( !glyph_index )
          continue;
  
        if ( started )
        {
          if ( advance != old_advance )
          {
            same_width = 0;
            break;
          }
        }
        else
        {
          old_advance = advance;
          started     = 1;
        }
      }
  
      af_shaper_buf_destroy( face, shaper_buf );
  
      metrics->root.digits_have_same_width = same_width;
    }
  
  
    /* Initialize global metrics. */
  
    FT_LOCAL_DEF( FT_Error )
    af_cjk_metrics_init( AF_StyleMetrics  metrics_,  /* AF_CJKMetrics */
                         FT_Face          face )
    {
      AF_CJKMetrics  metrics = (AF_CJKMetrics)metrics_;
      FT_CharMap     oldmap  = face->charmap;
  
  
      metrics->units_per_em = face->units_per_EM;
  
      if ( !FT_Select_Charmap( face, FT_ENCODING_UNICODE ) )
      {
        af_cjk_metrics_init_widths( metrics, face );
        af_cjk_metrics_init_blues( metrics, face );
        af_cjk_metrics_check_digits( metrics, face );
      }
  
      face->charmap = oldmap;
      return FT_Err_Ok;
    }
  
  
    /* Adjust scaling value, then scale and shift widths   */
    /* and blue zones (if applicable) for given dimension. */
  
    static void
    af_cjk_metrics_scale_dim( AF_CJKMetrics  metrics,
                              AF_Scaler      scaler,
                              AF_Dimension   dim )
    {
      FT_Fixed    scale;
      FT_Pos      delta;
      AF_CJKAxis  axis;
      FT_UInt     nn;
  
  
      if ( dim == AF_DIMENSION_HORZ )
      {
        scale = scaler->x_scale;
        delta = scaler->x_delta;
      }
      else
      {
        scale = scaler->y_scale;
        delta = scaler->y_delta;
      }
  
      axis = &metrics->axis[dim];
  
      if ( axis->org_scale == scale && axis->org_delta == delta )
        return;
  
      axis->org_scale = scale;
      axis->org_delta = delta;
  
      axis->scale = scale;
      axis->delta = delta;
  
      /* scale the blue zones */
      for ( nn = 0; nn < axis->blue_count; nn++ )
      {
        AF_CJKBlue  blue = &axis->blues[nn];
        FT_Pos      dist;
  
  
        blue->ref.cur   = FT_MulFix( blue->ref.org, scale ) + delta;
        blue->ref.fit   = blue->ref.cur;
        blue->shoot.cur = FT_MulFix( blue->shoot.org, scale ) + delta;
        blue->shoot.fit = blue->shoot.cur;
        blue->flags    &= ~AF_CJK_BLUE_ACTIVE;
  
        /* a blue zone is only active if it is less than 3/4 pixels tall */
        dist = FT_MulFix( blue->ref.org - blue->shoot.org, scale );
        if ( dist <= 48 && dist >= -48 )
        {
          FT_Pos  delta1, delta2;
  
  
          blue->ref.fit  = FT_PIX_ROUND( blue->ref.cur );
  
          /* shoot is under shoot for cjk */
          delta1 = FT_DivFix( blue->ref.fit, scale ) - blue->shoot.org;
          delta2 = delta1;
          if ( delta1 < 0 )
            delta2 = -delta2;
  
          delta2 = FT_MulFix( delta2, scale );
  
          FT_TRACE5(( "delta: %ld", delta1 ));
          if ( delta2 < 32 )
            delta2 = 0;
  #if 0
          else if ( delta2 < 64 )
            delta2 = 32 + ( ( ( delta2 - 32 ) + 16 ) & ~31 );
  #endif
          else
            delta2 = FT_PIX_ROUND( delta2 );
          FT_TRACE5(( "/%ld\n", delta2 ));
  
          if ( delta1 < 0 )
            delta2 = -delta2;
  
          blue->shoot.fit = blue->ref.fit - delta2;
  
          FT_TRACE5(( ">> active cjk blue zone %c%d[%ld/%ld]:\n",
                      ( dim == AF_DIMENSION_HORZ ) ? 'H' : 'V',
                      nn, blue->ref.org, blue->shoot.org ));
          FT_TRACE5(( "     ref:   cur=%.2f fit=%.2f\n",
                      (double)blue->ref.cur / 64,
                      (double)blue->ref.fit / 64 ));
          FT_TRACE5(( "     shoot: cur=%.2f fit=%.2f\n",
                      (double)blue->shoot.cur / 64,
                      (double)blue->shoot.fit / 64 ));
  
          blue->flags |= AF_CJK_BLUE_ACTIVE;
        }
      }
    }
  
  
    /* Scale global values in both directions. */
  
    FT_LOCAL_DEF( void )
    af_cjk_metrics_scale( AF_StyleMetrics  metrics_,   /* AF_CJKMetrics */
                          AF_Scaler        scaler )
    {
      AF_CJKMetrics  metrics = (AF_CJKMetrics)metrics_;
  
  
      /* we copy the whole structure since the x and y scaling values */
      /* are not modified, contrary to e.g. the `latin' auto-hinter   */
      metrics->root.scaler = *scaler;
  
      af_cjk_metrics_scale_dim( metrics, scaler, AF_DIMENSION_HORZ );
      af_cjk_metrics_scale_dim( metrics, scaler, AF_DIMENSION_VERT );
    }
  
  
    /* Extract standard_width from writing system/script specific */
    /* metrics class.                                             */
  
    FT_CALLBACK_DEF( void )
    af_cjk_get_standard_widths( AF_StyleMetrics  metrics_,  /* AF_CJKMetrics */
                                FT_Pos*          stdHW,
                                FT_Pos*          stdVW )
    {
      AF_CJKMetrics  metrics = (AF_CJKMetrics)metrics_;
  
  
      if ( stdHW )
        *stdHW = metrics->axis[AF_DIMENSION_VERT].standard_width;
  
      if ( stdVW )
        *stdVW = metrics->axis[AF_DIMENSION_HORZ].standard_width;
    }
  
  
    /*************************************************************************/
    /*************************************************************************/
    /*****                                                               *****/
    /*****              C J K   G L Y P H   A N A L Y S I S              *****/
    /*****                                                               *****/
    /*************************************************************************/
    /*************************************************************************/
  
  
    /* Walk over all contours and compute its segments. */
  
    static FT_Error
    af_cjk_hints_compute_segments( AF_GlyphHints  hints,
                                   AF_Dimension   dim )
    {
      AF_AxisHints  axis          = &hints->axis[dim];
      AF_Segment    segments      = axis->segments;
      AF_Segment    segment_limit = FT_OFFSET( segments, axis->num_segments );
      FT_Error      error;
      AF_Segment    seg;
  
  
      error = af_latin_hints_compute_segments( hints, dim );
      if ( error )
        return error;
  
      /* a segment is round if it doesn't have successive */
      /* on-curve points.                                 */
      for ( seg = segments; seg < segment_limit; seg++ )
      {
        AF_Point  pt   = seg->first;
        AF_Point  last = seg->last;
        FT_UInt   f0   = pt->flags & AF_FLAG_CONTROL;
        FT_UInt   f1;
  
  
        seg->flags &= ~AF_EDGE_ROUND;
  
        for ( ; pt != last; f0 = f1 )
        {
          pt = pt->next;
          f1 = pt->flags & AF_FLAG_CONTROL;
  
          if ( !f0 && !f1 )
            break;
  
          if ( pt == last )
            seg->flags |= AF_EDGE_ROUND;
        }
      }
  
      return FT_Err_Ok;
    }
  
  
    static void
    af_cjk_hints_link_segments( AF_GlyphHints  hints,
                                AF_Dimension   dim )
    {
      AF_AxisHints  axis          = &hints->axis[dim];
      AF_Segment    segments      = axis->segments;
      AF_Segment    segment_limit = FT_OFFSET( segments, axis->num_segments );
      AF_Direction  major_dir     = axis->major_dir;
      AF_Segment    seg1, seg2;
      FT_Pos        len_threshold;
      FT_Pos        dist_threshold;
  
  
      len_threshold = AF_LATIN_CONSTANT( hints->metrics, 8 );
  
      dist_threshold = ( dim == AF_DIMENSION_HORZ ) ? hints->x_scale
                                                    : hints->y_scale;
      dist_threshold = FT_DivFix( 64 * 3, dist_threshold );
  
      /* now compare each segment to the others */
      for ( seg1 = segments; seg1 < segment_limit; seg1++ )
      {
        if ( seg1->dir != major_dir )
          continue;
  
        for ( seg2 = segments; seg2 < segment_limit; seg2++ )
          if ( seg2 != seg1 && seg1->dir + seg2->dir == 0 )
          {
            FT_Pos  dist = seg2->pos - seg1->pos;
  
  
            if ( dist < 0 )
              continue;
  
            {
              FT_Pos  min = seg1->min_coord;
              FT_Pos  max = seg1->max_coord;
              FT_Pos  len;
  
  
              if ( min < seg2->min_coord )
                min = seg2->min_coord;
  
              if ( max > seg2->max_coord )
                max = seg2->max_coord;
  
              len = max - min;
              if ( len >= len_threshold )
              {
                if ( dist * 8 < seg1->score * 9                        &&
                     ( dist * 8 < seg1->score * 7 || seg1->len < len ) )
                {
                  seg1->score = dist;
                  seg1->len   = len;
                  seg1->link  = seg2;
                }
  
                if ( dist * 8 < seg2->score * 9                        &&
                     ( dist * 8 < seg2->score * 7 || seg2->len < len ) )
                {
                  seg2->score = dist;
                  seg2->len   = len;
                  seg2->link  = seg1;
                }
              }
            }
          }
      }
  
      /*
       * now compute the `serif' segments
       *
       * In Hanzi, some strokes are wider on one or both of the ends.
       * We either identify the stems on the ends as serifs or remove
       * the linkage, depending on the length of the stems.
       *
       */
  
      {
        AF_Segment  link1, link2;
  
  
        for ( seg1 = segments; seg1 < segment_limit; seg1++ )
        {
          link1 = seg1->link;
          if ( !link1 || link1->link != seg1 || link1->pos <= seg1->pos )
            continue;
  
          if ( seg1->score >= dist_threshold )
            continue;
  
          for ( seg2 = segments; seg2 < segment_limit; seg2++ )
          {
            if ( seg2->pos > seg1->pos || seg1 == seg2 )
              continue;
  
            link2 = seg2->link;
            if ( !link2 || link2->link != seg2 || link2->pos < link1->pos )
              continue;
  
            if ( seg1->pos == seg2->pos && link1->pos == link2->pos )
              continue;
  
            if ( seg2->score <= seg1->score || seg1->score * 4 <= seg2->score )
              continue;
  
            /* seg2 < seg1 < link1 < link2 */
  
            if ( seg1->len >= seg2->len * 3 )
            {
              AF_Segment  seg;
  
  
              for ( seg = segments; seg < segment_limit; seg++ )
              {
                AF_Segment  link = seg->link;
  
  
                if ( link == seg2 )
                {
                  seg->link  = NULL;
                  seg->serif = link1;
                }
                else if ( link == link2 )
                {
                  seg->link  = NULL;
                  seg->serif = seg1;
                }
              }
            }
            else
            {
              seg1->link = link1->link = NULL;
  
              break;
            }
          }
        }
      }
  
      for ( seg1 = segments; seg1 < segment_limit; seg1++ )
      {
        seg2 = seg1->link;
  
        if ( seg2 )
        {
          if ( seg2->link != seg1 )
          {
            seg1->link = NULL;
  
            if ( seg2->score < dist_threshold || seg1->score < seg2->score * 4 )
              seg1->serif = seg2->link;
          }
        }
      }
    }
  
  
    static FT_Error
    af_cjk_hints_compute_edges( AF_GlyphHints  hints,
                                AF_Dimension   dim )
    {
      AF_AxisHints  axis   = &hints->axis[dim];
      FT_Error      error  = FT_Err_Ok;
      FT_Memory     memory = hints->memory;
      AF_CJKAxis    laxis  = &((AF_CJKMetrics)hints->metrics)->axis[dim];
  
      AF_Segment    segments      = axis->segments;
      AF_Segment    segment_limit = FT_OFFSET( segments, axis->num_segments );
      AF_Segment    seg;
  
      FT_Fixed      scale;
      FT_Pos        edge_distance_threshold;
  
  
      axis->num_edges = 0;
  
      scale = ( dim == AF_DIMENSION_HORZ ) ? hints->x_scale
                                           : hints->y_scale;
  
      /**********************************************************************
       *
       * We begin by generating a sorted table of edges for the current
       * direction.  To do so, we simply scan each segment and try to find
       * an edge in our table that corresponds to its position.
       *
       * If no edge is found, we create and insert a new edge in the
       * sorted table.  Otherwise, we simply add the segment to the edge's
       * list which is then processed in the second step to compute the
       * edge's properties.
       *
       * Note that the edges table is sorted along the segment/edge
       * position.
       *
       */
  
      edge_distance_threshold = FT_MulFix( laxis->edge_distance_threshold,
                                           scale );
      if ( edge_distance_threshold > 64 / 4 )
        edge_distance_threshold = FT_DivFix( 64 / 4, scale );
      else
        edge_distance_threshold = laxis->edge_distance_threshold;
  
      for ( seg = segments; seg < segment_limit; seg++ )
      {
        AF_Edge  found = NULL;
        FT_Pos   best  = 0xFFFFU;
        FT_UInt  ee;
  
  
        /* look for an edge corresponding to the segment */
        for ( ee = 0; ee < axis->num_edges; ee++ )
        {
          AF_Edge  edge = axis->edges + ee;
          FT_Pos   dist;
  
  
          if ( edge->dir != seg->dir )
            continue;
  
          dist = seg->pos - edge->fpos;
          if ( dist < 0 )
            dist = -dist;
  
          if ( dist < edge_distance_threshold && dist < best )
          {
            AF_Segment  link = seg->link;
  
  
            /* check whether all linked segments of the candidate edge */
            /* can make a single edge.                                 */
            if ( link )
            {
              AF_Segment  seg1  = edge->first;
              FT_Pos      dist2 = 0;
  
  
              do
              {
                AF_Segment  link1 = seg1->link;
  
  
                if ( link1 )
                {
                  dist2 = AF_SEGMENT_DIST( link, link1 );
                  if ( dist2 >= edge_distance_threshold )
                    break;
                }
  
              } while ( ( seg1 = seg1->edge_next ) != edge->first );
  
              if ( dist2 >= edge_distance_threshold )
                continue;
            }
  
            best  = dist;
            found = edge;
          }
        }
  
        if ( !found )
        {
          AF_Edge  edge;
  
  
          /* insert a new edge in the list and */
          /* sort according to the position    */
          error = af_axis_hints_new_edge( axis, seg->pos,
                                          (AF_Direction)seg->dir, 0,
                                          memory, &edge );
          if ( error )
            goto Exit;
  
          /* add the segment to the new edge's list */
          FT_ZERO( edge );
  
          edge->first    = seg;
          edge->last     = seg;
          edge->dir      = seg->dir;
          edge->fpos     = seg->pos;
          edge->opos     = FT_MulFix( seg->pos, scale );
          edge->pos      = edge->opos;
          seg->edge_next = seg;
        }
        else
        {
          /* if an edge was found, simply add the segment to the edge's */
          /* list                                                       */
          seg->edge_next         = found->first;
          found->last->edge_next = seg;
          found->last            = seg;
        }
      }
  
      /*******************************************************************
       *
       * Good, we now compute each edge's properties according to the
       * segments found on its position.  Basically, these are
       *
       * - the edge's main direction
       * - stem edge, serif edge or both (which defaults to stem then)
       * - rounded edge, straight or both (which defaults to straight)
       * - link for edge
       *
       */
  
      /* first of all, set the `edge' field in each segment -- this is */
      /* required in order to compute edge links                       */
  
      /*
       * Note that removing this loop and setting the `edge' field of each
       * segment directly in the code above slows down execution speed for
       * some reasons on platforms like the Sun.
       */
      {
        AF_Edge  edges      = axis->edges;
        AF_Edge  edge_limit = FT_OFFSET( edges, axis->num_edges );
        AF_Edge  edge;
  
  
        for ( edge = edges; edge < edge_limit; edge++ )
        {
          seg = edge->first;
          if ( seg )
            do
            {
              seg->edge = edge;
              seg       = seg->edge_next;
  
            } while ( seg != edge->first );
        }
  
        /* now compute each edge properties */
        for ( edge = edges; edge < edge_limit; edge++ )
        {
          FT_Int  is_round    = 0;  /* does it contain round segments?    */
          FT_Int  is_straight = 0;  /* does it contain straight segments? */
  
  
          seg = edge->first;
          if ( !seg )
            goto Skip_Loop;
  
          do
          {
            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 );
  
        Skip_Loop:
          /* 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 = NULL;
        }
      }
  
    Exit:
      return error;
    }
  
  
    /* Detect segments and edges for given dimension. */
  
    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;
    }
  
  
    /* Compute all edges which lie within blue zones. */
  
    static void
    af_cjk_hints_compute_blue_edges( AF_GlyphHints  hints,
                                     AF_CJKMetrics  metrics,
                                     AF_Dimension   dim )
    {
      AF_AxisHints  axis       = &hints->axis[dim];
      AF_Edge       edge       = axis->edges;
      AF_Edge       edge_limit = FT_OFFSET( edge, axis->num_edges );
      AF_CJKAxis    cjk        = &metrics->axis[dim];
      FT_Fixed      scale      = cjk->scale;
      FT_Pos        best_dist0;  /* initial threshold */
  
  
      /* compute the initial threshold as a fraction of the EM size */
      best_dist0 = FT_MulFix( metrics->units_per_em / 40, scale );
  
      if ( best_dist0 > 64 / 2 ) /* maximum 1/2 pixel */
        best_dist0 = 64 / 2;
  
      /* compute which blue zones are active, i.e. have their scaled */
      /* size < 3/4 pixels                                           */
  
      /* If the distant between an edge and a blue zone is shorter than */
      /* best_dist0, set the blue zone for the edge.  Then search for   */
      /* the blue zone with the smallest best_dist to the edge.         */
  
      for ( ; edge < edge_limit; edge++ )
      {
        FT_UInt   bb;
        AF_Width  best_blue = NULL;
        FT_Pos    best_dist = best_dist0;
  
  
        for ( bb = 0; bb < cjk->blue_count; bb++ )
        {
          AF_CJKBlue  blue = cjk->blues + bb;
          FT_Bool     is_top_right_blue, is_major_dir;
  
  
          /* skip inactive blue zones (i.e., those that are too small) */
          if ( !( blue->flags & AF_CJK_BLUE_ACTIVE ) )
            continue;
  
          /* if it is a top zone, check for right edges -- if it is a bottom */
          /* zone, check for left edges                                      */
          /*                                                                 */
          /* of course, that's for TrueType                                  */
          is_top_right_blue =
            (FT_Byte)( ( blue->flags & AF_CJK_BLUE_TOP ) != 0 );
          is_major_dir =
            FT_BOOL( edge->dir == axis->major_dir );
  
          /* if it is a top zone, the edge must be against the major    */
          /* direction; if it is a bottom zone, it must be in the major */
          /* direction                                                  */
          if ( is_top_right_blue ^ is_major_dir )
          {
            FT_Pos    dist;
            AF_Width  compare;
  
  
            /* Compare the edge to the closest blue zone type */
            if ( FT_ABS( edge->fpos - blue->ref.org ) >
                 FT_ABS( edge->fpos - blue->shoot.org ) )
              compare = &blue->shoot;
            else
              compare = &blue->ref;
  
            dist = edge->fpos - compare->org;
            if ( dist < 0 )
              dist = -dist;
  
            dist = FT_MulFix( dist, scale );
            if ( dist < best_dist )
            {
              best_dist = dist;
              best_blue = compare;
            }
          }
        }
  
        if ( best_blue )
          edge->blue_edge = best_blue;
      }
    }
  
  
    /* Initalize hinting engine. */
  
    FT_LOCAL_DEF( FT_Error )
    af_cjk_hints_init( AF_GlyphHints    hints,
                       AF_StyleMetrics  metrics_ )   /* AF_CJKMetrics */
    {
      AF_CJKMetrics   metrics = (AF_CJKMetrics)metrics_;
      FT_Render_Mode  mode;
      FT_UInt32       scaler_flags, other_flags;
  
  
      af_glyph_hints_rescale( hints, (AF_StyleMetrics)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;
  
      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 unless in `light' or `lcd' mode.
       */
      if ( mode != FT_RENDER_MODE_LIGHT && mode != FT_RENDER_MODE_LCD )
        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 FT_Err_Ok;
    }
  
  
    /*************************************************************************/
    /*************************************************************************/
    /*****                                                               *****/
    /*****          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_UInt   count,
                       FT_Pos    width )
    {
      FT_UInt  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.                          */
    /* There is a lot of voodoo in this function; changing the hard-coded  */
    /* parameters influence the whole hinting process.                     */
  
    static FT_Pos
    af_cjk_compute_stem_width( AF_GlyphHints  hints,
                               AF_Dimension   dim,
                               FT_Pos         width,
                               FT_UInt        base_flags,
                               FT_UInt        stem_flags )
    {
      AF_CJKMetrics  metrics  = (AF_CJKMetrics)hints->metrics;
      AF_CJKAxis     axis     = &metrics->axis[dim];
      FT_Pos         dist     = width;
      FT_Int         sign     = 0;
      FT_Bool        vertical = FT_BOOL( 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,
                                                        base_edge->flags,
                                                        stem_edge->flags );
  
  
      stem_edge->pos = base_edge->pos + fitted_width;
  
      FT_TRACE5(( "  CJKLINK: edge %td @%d (opos=%.2f) linked to %.2f,"
                  " dist was %.2f, now %.2f\n",
                  stem_edge - hints->axis[dim].edges, stem_edge->fpos,
                  (double)stem_edge->opos / 64,
                  (double)stem_edge->pos / 64,
                  (double)dist / 64,
                  (double)fitted_width / 64 ));
    }
  
  
    /* Shift the coordinates of the `serif' edge by the same amount */
    /* as the corresponding `base' edge has been moved already.     */
  
    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,
                                              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 & 63;
  
      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;
      }
  
      return delta;
    }
  
  
    /* The main grid-fitting routine. */
  
    static void
    af_cjk_hint_edges( AF_GlyphHints  hints,
                       AF_Dimension   dim )
    {
      AF_AxisHints  axis       = &hints->axis[dim];
      AF_Edge       edges      = axis->edges;
      AF_Edge       edge_limit = FT_OFFSET( edges, axis->num_edges );
      FT_PtrDist    n_edges;
      AF_Edge       edge;
      AF_Edge       anchor   = NULL;
      FT_Pos        delta    = 0;
      FT_Int        skipped  = 0;
      FT_Bool       has_last_stem = FALSE;
      FT_Pos        last_stem_pos = 0;
  
  #ifdef FT_DEBUG_LEVEL_TRACE
      FT_UInt       num_actions = 0;
  #endif
  
  
      FT_TRACE5(( "cjk %s edge hinting (style `%s')\n",
                  dim == AF_DIMENSION_VERT ? "horizontal" : "vertical",
                  af_style_names[hints->metrics->style_class->style] ));
  
      /* we begin by aligning all stems relative to the blue zone */
  
      if ( 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;
  
  #ifdef FT_DEBUG_LEVEL_TRACE
          FT_TRACE5(( "  CJKBLUE: edge %td @%d (opos=%.2f) snapped to %.2f,"
                      " was %.2f\n",
                      edge1 - edges, edge1->fpos, (double)edge1->opos / 64,
                      (double)blue->fit / 64, (double)edge1->pos / 64 ));
  
          num_actions++;
  #endif
  
          edge1->pos    = blue->fit;
          edge1->flags |= AF_EDGE_DONE;
  
          if ( edge2 && !edge2->blue_edge )
          {
            af_cjk_align_linked_edge( hints, dim, edge1, edge2 );
            edge2->flags |= AF_EDGE_DONE;
  
  #ifdef FT_DEBUG_LEVEL_TRACE
            num_actions++;
  #endif
          }
  
          if ( !anchor )
            anchor = edge;
        }
      }
  
      /* now we align all stem edges. */
      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 )
        {
          skipped++;
          continue;
        }
  
        /* Some CJK characters have so many stems that
         * the hinter is likely to merge two adjacent ones.
         * To solve this problem, if either edge of a stem
         * is too close to the previous one, we avoid
         * aligning the two edges, but rather interpolate
         * their locations at the end of this function in
         * order to preserve the space between the stems.
         */
        if ( has_last_stem                       &&
             ( edge->pos  < last_stem_pos + 64 ||
               edge2->pos < last_stem_pos + 64 ) )
        {
          skipped++;
          continue;
        }
  
        /* now align the stem */
  
        /* this should not happen, but it's better to be safe */
        if ( edge2->blue_edge )
        {
          FT_TRACE5(( "ASSERTION FAILED for edge %td\n", edge2 - edges ));
  
          af_cjk_align_linked_edge( hints, dim, edge2, edge );
          edge->flags |= AF_EDGE_DONE;
  
  #ifdef FT_DEBUG_LEVEL_TRACE
          num_actions++;
  #endif
  
          continue;
        }
  
        if ( edge2 < edge )
        {
          af_cjk_align_linked_edge( hints, dim, edge2, edge );
          edge->flags |= AF_EDGE_DONE;
  
  #ifdef FT_DEBUG_LEVEL_TRACE
          num_actions++;
  #endif
  
          /* We rarely reaches here it seems;
           * usually the two edges belonging
           * to one stem are marked as DONE together
           */
          has_last_stem = TRUE;
          last_stem_pos = edge->pos;
          continue;
        }
  
        if ( dim != AF_DIMENSION_VERT && !anchor )
        {
  
  #if 0
          if ( fixedpitch )
          {
            AF_Edge     left  = edge;
            AF_Edge     right = edge_limit - 1;
            AF_EdgeRec  left1, left2, right1, right2;
            FT_Pos      target, center1, center2;
            FT_Pos      delta1, delta2, d1, d2;
  
  
            while ( right > left && !right->link )
              right--;
  
            left1  = *left;
            left2  = *left->link;
            right1 = *right->link;
            right2 = *right;
  
            delta  = ( ( ( hinter->pp2.x + 32 ) & -64 ) - hinter->pp2.x ) / 2;
            target = left->opos + ( right->opos - left->opos ) / 2 + delta - 16;
  
            delta1  = delta;
            delta1 += af_hint_normal_stem( hints, left, left->link,
                                           delta1, 0 );
  
            if ( left->link != right )
              af_hint_normal_stem( hints, right->link, right, delta1, 0 );
  
            center1 = left->pos + ( right->pos - left->pos ) / 2;
  
            if ( center1 >= target )
              delta2 = delta - 32;
            else
              delta2 = delta + 32;
  
            delta2 += af_hint_normal_stem( hints, &left1, &left2, delta2, 0 );
  
            if ( delta1 != delta2 )
            {
              if ( left->link != right )
                af_hint_normal_stem( hints, &right1, &right2, delta2, 0 );
  
              center2 = left1.pos + ( right2.pos - left1.pos ) / 2;
  
              d1 = center1 - target;
              d2 = center2 - target;
  
              if ( FT_ABS( d2 ) < FT_ABS( d1 ) )
              {
                left->pos       = left1.pos;
                left->link->pos = left2.pos;
  
                if ( left->link != right )
                {
                  right->link->pos = right1.pos;
                  right->pos       = right2.pos;
                }
  
                delta1 = delta2;
              }
            }
  
            delta               = delta1;
            right->link->flags |= AF_EDGE_DONE;
            right->flags       |= AF_EDGE_DONE;
          }
          else
  
  #endif /* 0 */
  
            delta = af_hint_normal_stem( hints, edge, edge2, 0,
                                         AF_DIMENSION_HORZ );
        }
        else
          af_hint_normal_stem( hints, edge, edge2, delta, dim );
  
  #if 0
        printf( "stem (%d,%d) adjusted (%.1f,%.1f)\n",
                 edge - edges, edge2 - edges,
                 (double)( edge->pos - edge->opos ) / 64,
                 (double)( edge2->pos - edge2->opos ) / 64 );
  #endif
  
        anchor = edge;
        edge->flags  |= AF_EDGE_DONE;
        edge2->flags |= AF_EDGE_DONE;
        has_last_stem = TRUE;
        last_stem_pos = edge2->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.                                         */
  
      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;
  
  
        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 ( edge1->link == edge1 + 1 &&
             edge2->link == edge2 + 1 &&
             edge3->link == edge3 + 1 && 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;
        }
      }
  
      if ( !skipped )
        goto Exit;
  
      /*
       * now hint the remaining edges (serifs and single) in order
       * to complete our processing
       */
      for ( edge = edges; edge < edge_limit; edge++ )
      {
        if ( edge->flags & AF_EDGE_DONE )
          continue;
  
        if ( edge->serif )
        {
          af_cjk_align_serif_edge( hints, edge->serif, edge );
          edge->flags |= AF_EDGE_DONE;
          skipped--;
        }
      }
  
      if ( !skipped )
        goto Exit;
  
      for ( edge = edges; edge < edge_limit; edge++ )
      {
        AF_Edge  before, after;
  
  
        if ( edge->flags & AF_EDGE_DONE )
          continue;
  
        before = after = edge;
  
        while ( --before >= edges )
          if ( before->flags & AF_EDGE_DONE )
            break;
  
        while ( ++after < edge_limit )
          if ( after->flags & AF_EDGE_DONE )
            break;
  
        if ( before >= edges || after < edge_limit )
        {
          if ( before < edges )
            af_cjk_align_serif_edge( hints, after, edge );
          else if ( after >= edge_limit )
            af_cjk_align_serif_edge( hints, before, edge );
          else
          {
            if ( after->fpos == before->fpos )
              edge->pos = before->pos;
            else
              edge->pos = before->pos +
                          FT_MulDiv( edge->fpos - before->fpos,
                                     after->pos - before->pos,
                                     after->fpos - before->fpos );
          }
        }
      }
  
    Exit:
  
  #ifdef FT_DEBUG_LEVEL_TRACE
      if ( !num_actions )
        FT_TRACE5(( "  (none)\n" ));
      FT_TRACE5(( "\n" ));
  #endif
  
      return;
    }
  
  
    static void
    af_cjk_align_edge_points( AF_GlyphHints  hints,
                              AF_Dimension   dim )
    {
      AF_AxisHints  axis       = & hints->axis[dim];
      AF_Edge       edges      = axis->edges;
      AF_Edge       edge_limit = FT_OFFSET( edges, axis->num_edges );
      AF_Edge       edge;
      FT_Bool       snapping;
  
  
      snapping = FT_BOOL( ( dim == AF_DIMENSION_HORZ             &&
                            AF_LATIN_HINTS_DO_HORZ_SNAP( hints ) )  ||
                          ( dim == AF_DIMENSION_VERT             &&
                            AF_LATIN_HINTS_DO_VERT_SNAP( hints ) )  );
  
      for ( edge = edges; edge < edge_limit; edge++ )
      {
        /* move the points of each segment     */
        /* in each edge to the edge's position */
        AF_Segment  seg = edge->first;
  
  
        if ( snapping )
        {
          do
          {
            AF_Point  point = seg->first;
  
  
            for (;;)
            {
              if ( dim == AF_DIMENSION_HORZ )
              {
                point->x      = edge->pos;
                point->flags |= AF_FLAG_TOUCH_X;
              }
              else
              {
                point->y      = edge->pos;
                point->flags |= AF_FLAG_TOUCH_Y;
              }
  
              if ( point == seg->last )
                break;
  
              point = point->next;
            }
  
            seg = seg->edge_next;
  
          } while ( seg != edge->first );
        }
        else
        {
          FT_Pos  delta = edge->pos - edge->opos;
  
  
          do
          {
            AF_Point  point = seg->first;
  
  
            for (;;)
            {
              if ( dim == AF_DIMENSION_HORZ )
              {
                point->x     += delta;
                point->flags |= AF_FLAG_TOUCH_X;
              }
              else
              {
                point->y     += delta;
                point->flags |= AF_FLAG_TOUCH_Y;
              }
  
              if ( point == seg->last )
                break;
  
              point = point->next;
            }
  
            seg = seg->edge_next;
  
          } while ( seg != edge->first );
        }
      }
    }
  
  
    /* Apply the complete hinting algorithm to a CJK glyph. */
  
    FT_LOCAL_DEF( FT_Error )
    af_cjk_hints_apply( FT_UInt          glyph_index,
                        AF_GlyphHints    hints,
                        FT_Outline*      outline,
                        AF_StyleMetrics  metrics_ )   /* AF_CJKMetrics */
    {
      AF_CJKMetrics  metrics = (AF_CJKMetrics)metrics_;
  
      FT_Error  error;
      int       dim;
  
      FT_UNUSED( metrics );
      FT_UNUSED( glyph_index );
  
  
      error = af_glyph_hints_reload( hints, outline );
      if ( error )
        goto Exit;
  
      /* analyze glyph outline */
      if ( AF_HINTS_DO_HORIZONTAL( hints ) )
      {
        error = af_cjk_hints_detect_features( hints, AF_DIMENSION_HORZ );
        if ( error )
          goto Exit;
  
        af_cjk_hints_compute_blue_edges( hints, metrics, AF_DIMENSION_HORZ );
      }
  
      if ( AF_HINTS_DO_VERTICAL( hints ) )
      {
        error = af_cjk_hints_detect_features( hints, AF_DIMENSION_VERT );
        if ( error )
          goto Exit;
  
        af_cjk_hints_compute_blue_edges( hints, metrics, AF_DIMENSION_VERT );
      }
  
      /* grid-fit the outline */
      for ( dim = 0; dim < AF_DIMENSION_MAX; dim++ )
      {
        if ( ( dim == AF_DIMENSION_HORZ && AF_HINTS_DO_HORIZONTAL( hints ) ) ||
             ( dim == AF_DIMENSION_VERT && AF_HINTS_DO_VERTICAL( hints ) )   )
        {
          af_cjk_hint_edges( hints, (AF_Dimension)dim );
          af_cjk_align_edge_points( hints, (AF_Dimension)dim );
          af_glyph_hints_align_strong_points( hints, (AF_Dimension)dim );
          af_glyph_hints_align_weak_points( hints, (AF_Dimension)dim );
        }
      }
  
      af_glyph_hints_save( hints, outline );
  
    Exit:
      return error;
    }
  
  
    /*************************************************************************/
    /*************************************************************************/
    /*****                                                               *****/
    /*****                C J K   S C R I P T   C L A S S                *****/
    /*****                                                               *****/
    /*************************************************************************/
    /*************************************************************************/
  
  
    AF_DEFINE_WRITING_SYSTEM_CLASS(
      af_cjk_writing_system_class,
  
      AF_WRITING_SYSTEM_CJK,
  
      sizeof ( AF_CJKMetricsRec ),
  
      (AF_WritingSystem_InitMetricsFunc) af_cjk_metrics_init,        /* style_metrics_init    */
      (AF_WritingSystem_ScaleMetricsFunc)af_cjk_metrics_scale,       /* style_metrics_scale   */
      (AF_WritingSystem_DoneMetricsFunc) NULL,                       /* style_metrics_done    */
      (AF_WritingSystem_GetStdWidthsFunc)af_cjk_get_standard_widths, /* style_metrics_getstdw */
  
      (AF_WritingSystem_InitHintsFunc)   af_cjk_hints_init,          /* style_hints_init      */
      (AF_WritingSystem_ApplyHintsFunc)  af_cjk_hints_apply          /* style_hints_apply     */
    )
  
  
  #else /* !AF_CONFIG_OPTION_CJK */
  
  
    AF_DEFINE_WRITING_SYSTEM_CLASS(
      af_cjk_writing_system_class,
  
      AF_WRITING_SYSTEM_CJK,
  
      sizeof ( AF_CJKMetricsRec ),
  
      (AF_WritingSystem_InitMetricsFunc) NULL, /* style_metrics_init    */
      (AF_WritingSystem_ScaleMetricsFunc)NULL, /* style_metrics_scale   */
      (AF_WritingSystem_DoneMetricsFunc) NULL, /* style_metrics_done    */
      (AF_WritingSystem_GetStdWidthsFunc)NULL, /* style_metrics_getstdw */
  
      (AF_WritingSystem_InitHintsFunc)   NULL, /* style_hints_init      */
      (AF_WritingSystem_ApplyHintsFunc)  NULL  /* style_hints_apply     */
    )
  
  
  #endif /* !AF_CONFIG_OPTION_CJK */
  
  
  /* END */
  

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