[autofit] Add bluezones for CJK Ideographs.

To remove extremas of vertical strokes of CJK Ideographs at
low resolution and make the top and bottom horizontal stems
aligned, bluezones for CJK Ideographs are calculated from
sample glyphs.  At present, vertical bluezones (bluezones
to align vertical stems) are disabled by default.  For detail, see
http://lists.gnu.org/archive/html/freetype-devel/2011-04/msg00070.html
http://lists.gnu.org/archive/html/freetype-devel/2011-04/msg00092.html
http://lists.gnu.org/archive/html/freetype-devel/2011-05/msg00001.html

* include/freetype/internal/fttrace.h: New trace component `afcjk'.
* src/autofit/afcjk.h (AF_CJK{Blue,Axis,Metric}Rec): Add CJK version
for AF_Latin{Blue,Axis,Metric}Rec.
(af_cjk_metrics_check_digits): Ditto, shared with Indic module.
(af_cjk_metrics_init_widths): Ditto.
(af_cjk_metrics_init): Take AF_CJKMetric instead of AF_LatinMetric.
(af_cjk_metrics_scale): Ditto (declaration).
(af_cjk_hints_init): Ditto (declaration).
(af_cjk_hints_apply): Ditto (declaration).
* src/autofit/afcjk.c (af_cjk_metrics_scale): Ditto (body).
(af_cjk_hints_init): Ditto (body).
(af_cjk_hints_apply): Ditto (body).
(af_cjk_metrics_init_widths): Duplicate af_latin_metrics_init_widths.
(af_cjk_metrics_check_digits): Duplicate af_latin_metrics_check_digits.
(af_cjk_metrics_init): Call CJK bluezone initializer.
(af_cjk_metrics_scale_dim): Add code to scale bluezones.
(af_cjk_hints_compute_blue_edges): New function, CJK version of
af_latin_hints_compute_blue_edges.
(af_cjk_metrics_init_blues): New function, CJK version of
af_latin_metrics_init_blues.
(af_cjk_hints_edges): Add code to align the edge stems to blue zones.

* src/autofit/afindic.c (af_indic_metrics_init): Take AF_CJKMetric
instead of AF_LatinMetric, and initialize as af_cjk_metrics_init.
However bluezones are not initialized.
(af_indic_metrics_scale): Take AF_CJKMetric instead of AF_LatinMetric.
(af_indic_hints_init): Ditto.
(af_indic_hints_apply): Ditto.

* docs/CHANGES: Note about CJK bluezone support.
diff --git a/src/autofit/afcjk.c b/src/autofit/afcjk.c
index c15d343..101e668 100644
--- a/src/autofit/afcjk.c
+++ b/src/autofit/afcjk.c
@@ -22,12 +22,18 @@
    *
    */
 
+#include <ft2build.h>
+#include FT_ADVANCES_H
+#include FT_INTERNAL_DEBUG_H
+
 #include "aftypes.h"
 #include "aflatin.h"
 
 
 #ifdef AF_CONFIG_OPTION_CJK
 
+#undef AF_CONFIG_OPTION_CJK_BLUE_HANI_VERT
+
 #include "afcjk.h"
 #include "aferrors.h"
 
@@ -38,6 +44,16 @@
 
 
   /*************************************************************************/
+  /*                                                                       */
+  /* 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  trace_afcjk
+
+
+  /*************************************************************************/
   /*************************************************************************/
   /*****                                                               *****/
   /*****              C J K   G L O B A L   M E T R I C S              *****/
@@ -45,24 +61,481 @@
   /*************************************************************************/
   /*************************************************************************/
 
+
+  /* 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,
+                              FT_ULong       charcode )
+  {
+    /* scan the array of segments in each direction */
+    AF_GlyphHintsRec  hints[1];
+
+
+    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_UInt              glyph_index;
+      int                  dim;
+      AF_CJKMetricsRec     dummy[1];
+      AF_Scaler            scaler = &dummy->root.scaler;
+
+
+      glyph_index = FT_Get_Char_Index( face, charcode );
+      if ( glyph_index == 0 )
+        goto Exit;
+
+      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_ScriptMetrics)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;
+
+        af_latin_hints_link_segments( hints,
+                                      (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;
+          }
+        }
+
+        af_sort_widths( num_widths, axis->widths );
+        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;
+      }
+    }
+
+    af_glyph_hints_done( hints );
+  }
+
+
+
+#define AF_CJK_MAX_TEST_CHARACTERS  32
+
+
+  /* Every blue zone has 2 types of fill and unfill,
+   * Which means fill the entire square or not.
+   * */
+  enum
+  {
+    AF_CJK_BLUE_TYPE_FILL,
+    AF_CJK_BLUE_TYPE_UNFILL,
+    AF_CJK_BLUE_TYPE_MAX
+  };
+
+  /* Put some common and representative Han Ideographs characters here. */
+  static const FT_ULong af_cjk_hani_blue_chars[AF_CJK_BLUE_MAX]
+                                              [AF_CJK_BLUE_TYPE_MAX]
+                                              [AF_CJK_MAX_TEST_CHARACTERS] =
+  {
+    {
+      {
+        0x4ED6, 0x4EEC, 0x4F60, 0x4F86, 0x5011, 0x5230, 0x548C, 0x5730,
+        0x5BF9, 0x5C0D, 0x5C31, 0x5E2D, 0x6211, 0x65F6, 0x6642, 0x6703,
+        0x6765, 0x70BA, 0x80FD, 0x8230, 0x8AAA, 0x8BF4, 0x8FD9, 0x9019,
+        0x9F4A /* top fill */
+      },
+      {
+        0x519B, 0x540C, 0x5DF2, 0x613F, 0x65E2, 0x661F, 0x662F, 0x666F,
+        0x6C11, 0x7167, 0x73B0, 0x73FE, 0x7406, 0x7528, 0x7F6E, 0x8981,
+        0x8ECD, 0x90A3, 0x914D, 0x91CC, 0x958B, 0x96F7, 0x9732, 0x9762,
+        0x987E /* top unfill */
+      }
+    },
+    {
+      {
+        0x4E2A, 0x4E3A, 0x4EBA, 0x4ED6, 0x4EE5, 0x4EEC, 0x4F60, 0x4F86,
+        0x500B, 0x5011, 0x5230, 0x548C, 0x5927, 0x5BF9, 0x5C0D, 0x5C31,
+        0x6211, 0x65F6, 0x6642, 0x6709, 0x6765, 0x70BA, 0x8981, 0x8AAA,
+        0x8BF4 /* bottom fill */
+      },
+      {
+        0x4E3B, 0x4E9B, 0x56E0, 0x5B83, 0x60F3, 0x610F, 0x7406, 0x751F,
+        0x7576, 0x770B, 0x7740, 0x7F6E, 0x8005, 0x81EA, 0x8457, 0x88E1,
+        0x8FC7, 0x8FD8, 0x8FDB, 0x9032, 0x904E, 0x9053, 0x9084, 0x91CC,
+        0x9762 /* bottom unfill */
+      }
+    },
+#ifndef AF_CONFIG_OPTION_CJK_BLUE_HANI_VERT
+      { {0x0000}, {0x0000} },
+      { {0x0000}, {0x0000} }
+#else
+    {
+      {
+        0x4E9B, 0x4EEC, 0x4F60, 0x4F86, 0x5011, 0x5230, 0x548C, 0x5730,
+        0x5979, 0x5C06, 0x5C07, 0x5C31, 0x5E74, 0x5F97, 0x60C5, 0x6700,
+        0x6837, 0x6A23, 0x7406, 0x80FD, 0x8AAA, 0x8BF4, 0x8FD9, 0x9019,
+        0x901A /* left fill */
+      },
+      {
+        0x5373, 0x5417, 0x5427, 0x542C, 0x5462, 0x54C1, 0x54CD, 0x55CE,
+        0x5E08, 0x5E2B, 0x6536, 0x65AD, 0x65B7, 0x660E, 0x773C, 0x9593,
+        0x95F4, 0x9645, 0x9648, 0x9650, 0x9664, 0x9673, 0x968F, 0x969B,
+        0x96A8 /* left unfill */
+      }
+    },
+    {
+      {
+        0x4E8B, 0x524D, 0x5B78, 0x5C06, 0x5C07, 0x60C5, 0x60F3, 0x6216,
+        0x653F, 0x65AF, 0x65B0, 0x6837, 0x6A23, 0x6C11, 0x6C92, 0x6CA1,
+        0x7136, 0x7279, 0x73B0, 0x73FE, 0x7403, 0x7B2C, 0x7D93, 0x8C01,
+        0x8D77 /* right fill */
+      },
+      {
+        0x4F8B, 0x5225, 0x522B, 0x5236, 0x52A8, 0x52D5, 0x5417, 0x55CE,
+        0x589E, 0x6307, 0x660E, 0x671D, 0x671F, 0x6784, 0x7269, 0x786E,
+        0x79CD, 0x8ABF, 0x8C03, 0x8CBB, 0x8D39, 0x90A3, 0x90FD, 0x9593,
+        0x95F4 /* right unfill */
+      }
+    }
+#endif /* AF_CONFIG_OPTION_CJK_BLUE_HANI_VERT */
+  };
+
+
+  /* Calculate blue zones for all the CJK_BLUE_XXX's */
+
+  static void
+  af_cjk_metrics_init_blues( AF_CJKMetrics   metrics,
+                             FT_Face         face,
+                             const FT_ULong  blue_chars[AF_CJK_BLUE_MAX]
+                                                       [AF_CJK_BLUE_TYPE_MAX]
+                                                       [AF_CJK_MAX_TEST_CHARACTERS] )
+  {
+    FT_Pos        fills[AF_CJK_MAX_TEST_CHARACTERS];
+    FT_Pos        flats[AF_CJK_MAX_TEST_CHARACTERS];
+    FT_Int        num_fills;
+    FT_Int        num_flats;
+    FT_Int        bb;
+    AF_CJKBlue    blue;
+    FT_Error      error;
+    AF_CJKAxis    axis;
+    FT_GlyphSlot  glyph = face->glyph;
+
+    /* we compute the blues simply by loading each character from the    */
+    /* 'blue_chars[blues]' string, then compute its extreme  */
+    /* points (depending blue zone type etc.)                */
+
+    FT_TRACE5(( "cjk blue zones computation\n" ));
+    FT_TRACE5(( "------------------------------------------------\n" ));
+
+    for ( bb = 0; bb < AF_CJK_BLUE_MAX; bb++ )
+    {
+      FT_Int   fill_type;
+      FT_Pos*  blue_ref;
+      FT_Pos*  blue_shoot;
+
+
+      num_fills  = 0;
+      num_flats  = 0;
+      for ( fill_type = 0 ; fill_type < AF_CJK_BLUE_TYPE_MAX; fill_type++)
+      {
+        const FT_ULong*  p     = blue_chars[bb][fill_type];
+        const FT_ULong*  limit = p + AF_CJK_MAX_TEST_CHARACTERS;
+        FT_Bool          fill  = FT_BOOL( fill_type == AF_CJK_BLUE_TYPE_FILL );
+
+
+        FT_TRACE5(( "cjk blue %3d/%d: ", bb, fill_type ));
+
+
+        for ( ; p < limit && *p; p++ )
+        {
+          FT_UInt     glyph_index;
+          FT_Pos      best_pos; /* same as points.y */
+          FT_Int      best_point, best_first, best_last;
+          FT_Vector*  points;
+
+          FT_TRACE5(( "0x%lX", *p ));
+
+          /* load the character in the face -- skip unknown or empty ones */
+          glyph_index = FT_Get_Char_Index( face, *p );
+          if ( glyph_index == 0 )
+            continue;
+
+          error = FT_Load_Glyph( face, glyph_index, FT_LOAD_NO_SCALE );
+          if ( error || glyph->outline.n_points <= 0 )
+            continue;
+
+          /* now compute min or max point indices and coordinates */
+          points     = glyph->outline.points;
+          best_point = -1;
+          best_pos   = 0;  /* make compiler happy */
+          best_first = 0;  /* ditto */
+          best_last  = 0;  /* ditto */
+
+          {
+            FT_Int  nn;
+            FT_Int  first = 0;
+            FT_Int  last  = -1;
+
+
+            for ( nn = 0; nn < glyph->outline.n_contours; first = last+1, nn++ )
+            {
+              FT_Int  old_best_point = best_point;
+              FT_Int  pp;
+
+
+              last = glyph->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;
+
+              switch (bb)
+              {
+                case AF_CJK_BLUE_TOP:
+                  for ( pp = first; pp <= last; pp++ )
+                    if ( best_point < 0 || points[pp].y > best_pos )
+                    {
+                      best_point = pp;
+                      best_pos   = points[pp].y;
+                    }
+                  break;
+                case AF_CJK_BLUE_BOTTOM:
+                  for ( pp = first; pp <= last; pp++ )
+                    if ( best_point < 0 || points[pp].y < best_pos )
+                    {
+                      best_point = pp;
+                      best_pos   = points[pp].y;
+                    }
+                  break;
+                case AF_CJK_BLUE_LEFT:
+                  for ( pp = first; pp <= last; pp++ )
+                    if ( best_point < 0 || points[pp].x < best_pos )
+                    {
+                      best_point = pp;
+                      best_pos   = points[pp].x;
+                    }
+                  break;
+                case AF_CJK_BLUE_RIGHT:
+                  for ( pp = first; pp <= last; pp++ )
+                    if ( best_point < 0 || points[pp].x > best_pos )
+                    {
+                      best_point = pp;
+                      best_pos   = points[pp].x;
+                    }
+                  break;
+                default:
+                  ;
+            }
+
+              if ( best_point != old_best_point )
+              {
+                best_first = first;
+                best_last  = last;
+              }
+            }
+            FT_TRACE5(( "%5ld, ", best_pos ));
+          }
+
+          if (fill)
+            fills[num_fills++] = best_pos;
+          else
+            flats[num_flats++] = best_pos;
+        }
+
+        FT_TRACE5(( "\n" ));
+      }
+
+      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 position of the blue --  */
+      /* we simply take the median value after a simple sort  */
+      af_sort_pos( num_flats, flats );
+      af_sort_pos( num_fills, fills );
+
+      if ( AF_CJK_BLUE_TOP == bb || AF_CJK_BLUE_BOTTOM == bb )
+        axis = &metrics->axis[AF_DIMENSION_VERT];
+      else
+        axis = &metrics->axis[AF_DIMENSION_HORZ];
+
+      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   = fills[num_fills / 2];
+        *blue_shoot = fills[num_fills / 2];
+      }
+      else if ( num_fills == 0 )
+      {
+        *blue_ref   = flats[num_flats / 2];
+        *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
+       * vis vesa 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 );
+
+
+        if ( (AF_CJK_BLUE_TOP == bb || AF_CJK_BLUE_RIGHT == bb) ^ under_ref )
+          *blue_shoot = *blue_ref = ( shoot + ref ) / 2;
+      }
+
+      blue->flags = 0;
+      if ( AF_CJK_BLUE_TOP == bb )
+        blue->flags |= AF_CJK_BLUE_IS_TOP;
+      else if ( AF_CJK_BLUE_RIGHT == bb )
+        blue->flags |= AF_CJK_BLUE_IS_RIGHT;
+
+      FT_TRACE5(( "-- cjk ref = %ld shoot = %ld\n", *blue_ref, *blue_shoot ));
+    }
+    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_UInt   i;
+    FT_Bool   started = 0, same_width = 1;
+    FT_Fixed  advance, old_advance = 0;
+
+
+    /* check whether all ASCII digits have the same advance width; */
+    /* digit `0' is 0x30 in all supported charmaps                 */
+    for ( i = 0x30; i <= 0x39; i++ )
+    {
+      FT_UInt  glyph_index;
+
+
+      glyph_index = FT_Get_Char_Index( face, i );
+      if ( glyph_index == 0 )
+        continue;
+
+      if ( FT_Get_Advance( face, glyph_index,
+                           FT_LOAD_NO_SCALE         |
+                           FT_LOAD_NO_HINTING       |
+                           FT_LOAD_IGNORE_TRANSFORM,
+                           &advance ) )
+        continue;
+
+      if ( started )
+      {
+        if ( advance != old_advance )
+        {
+          same_width = 0;
+          break;
+        }
+      }
+      else
+      {
+        old_advance = advance;
+        started     = 1;
+      }
+    }
+
+    metrics->root.digits_have_same_width = same_width;
+  }
+
+
   FT_LOCAL_DEF( FT_Error )
-  af_cjk_metrics_init( AF_LatinMetrics  metrics,
-                       FT_Face          face )
+  af_cjk_metrics_init( AF_CJKMetrics  metrics,
+                       FT_Face        face )
   {
     FT_CharMap  oldmap = face->charmap;
 
 
     metrics->units_per_em = face->units_per_EM;
 
-    /* TODO are there blues? */
-
     if ( FT_Select_Charmap( face, FT_ENCODING_UNICODE ) )
       face->charmap = NULL;
     else
     {
-      /* latin's version would suffice */
-      af_latin_metrics_init_widths( metrics, face, 0x7530 );
-      af_latin_metrics_check_digits( metrics, face );
+      af_cjk_metrics_init_widths( metrics, face, 0x7530 );
+      af_cjk_metrics_init_blues( metrics, face, af_cjk_hani_blue_chars );
+      af_cjk_metrics_check_digits( metrics, face );
     }
 
     FT_Set_Charmap( face, oldmap );
@@ -72,31 +545,99 @@
 
 
   static void
-  af_cjk_metrics_scale_dim( AF_LatinMetrics  metrics,
-                            AF_Scaler        scaler,
-                            AF_Dimension     dim )
+  af_cjk_metrics_scale_dim( AF_CJKMetrics  metrics,
+                            AF_Scaler      scaler,
+                            AF_Dimension   dim )
   {
-    AF_LatinAxis  axis;
+    FT_Fixed    scale;
+    FT_Pos      delta;
+    AF_CJKAxis  axis;
+    FT_UInt     nn;
 
 
     axis = &metrics->axis[dim];
 
     if ( dim == AF_DIMENSION_HORZ )
     {
-      axis->scale = scaler->x_scale;
-      axis->delta = scaler->x_delta;
+      scale = scaler->x_scale;
+      delta = scaler->x_delta;
     }
     else
     {
-      axis->scale = scaler->y_scale;
-      axis->delta = scaler->y_delta;
+      scale = scaler->y_scale;
+      delta = scaler->y_delta;
+    }
+
+    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: %d", delta1 ));
+        if ( delta2 < 32 )
+          delta2 = 0;
+        /*
+        else if ( delta2 < 64 )
+          delta2 = 32 + ( ( ( delta2 - 32 ) + 16 ) & ~31 );
+        */
+        else
+          delta2 = FT_PIX_ROUND( delta2 );
+        FT_TRACE5(( "/%d\n", delta2 ));
+
+        if ( delta1 < 0 )
+          delta2 = -delta2;
+
+        blue->shoot.fit = blue->ref.fit - delta2;
+
+        FT_TRACE5(( ">> active cjk blue zone %c%d[%ld/%ld]: "
+                     "ref: cur=%.2f fit=%.2f shoot: cur=%.2f fit=%.2f\n",
+                       ( dim == AF_DIMENSION_HORZ ) ? 'H':'V',
+                       nn, blue->ref.org, blue->shoot.org,
+                       blue->ref.cur/64.0, blue->ref.fit/64.0,
+                       blue->shoot.cur/64.0, blue->shoot.fit/64.0 ));
+
+        blue->flags |= AF_CJK_BLUE_ACTIVE;
+      }
     }
   }
 
 
   FT_LOCAL_DEF( void )
-  af_cjk_metrics_scale( AF_LatinMetrics  metrics,
-                        AF_Scaler        scaler )
+  af_cjk_metrics_scale( AF_CJKMetrics  metrics,
+                        AF_Scaler      scaler )
   {
     metrics->root.scaler = *scaler;
 
@@ -329,7 +870,7 @@
     AF_AxisHints  axis   = &hints->axis[dim];
     FT_Error      error  = AF_Err_Ok;
     FT_Memory     memory = hints->memory;
-    AF_LatinAxis  laxis  = &((AF_LatinMetrics)hints->metrics)->axis[dim];
+    AF_CJKAxis    laxis  = &((AF_CJKMetrics)hints->metrics)->axis[dim];
 
     AF_Segment    segments      = axis->segments;
     AF_Segment    segment_limit = segments + axis->num_segments;
@@ -601,9 +1142,93 @@
   }
 
 
+  FT_LOCAL_DEF( 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 = 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_BOOL( ( ( blue->flags & AF_CJK_BLUE_IS_TOP )   != 0 ) ||
+                                      ( ( blue->flags & AF_CJK_BLUE_IS_RIGHT ) != 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;
+    }
+  }
+
+
   FT_LOCAL_DEF( FT_Error )
   af_cjk_hints_init( AF_GlyphHints    hints,
-                     AF_LatinMetrics  metrics )
+                     AF_CJKMetrics    metrics )
   {
     FT_Render_Mode  mode;
     FT_UInt32       scaler_flags, other_flags;
@@ -728,11 +1353,11 @@
                              AF_Edge_Flags  base_flags,
                              AF_Edge_Flags  stem_flags )
   {
-    AF_LatinMetrics  metrics  = (AF_LatinMetrics) hints->metrics;
-    AF_LatinAxis     axis     = & metrics->axis[dim];
+    AF_CJKMetrics    metrics  = (AF_CJKMetrics) hints->metrics;
+    AF_CJKAxis       axis     = & metrics->axis[dim];
     FT_Pos           dist     = width;
     FT_Int           sign     = 0;
-    FT_Int           vertical = ( dim == AF_DIMENSION_VERT );
+    FT_Bool          vertical = FT_BOOL( dim == AF_DIMENSION_VERT );
 
     FT_UNUSED( base_flags );
     FT_UNUSED( stem_flags );
@@ -1029,6 +1654,58 @@
     FT_Pos        last_stem_pos = 0;
 
 
+    /* we begin by aligning all stems relative to the blue zone */
+    FT_TRACE5(( "==== cjk hinting %s edges =====\n",
+          dim == AF_DIMENSION_HORZ ? "vertical" : "horizontal" ));
+
+    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;
+
+        FT_TRACE5(( "CJKBLUE: edge %d @%d (opos=%.2f) snapped to (%.2f), "
+                 "was (%.2f)\n",
+                 edge1-edges, edge1->fpos, 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_cjk_align_linked_edge( hints, dim, edge1, edge2 );
+          edge2->flags |= AF_EDGE_DONE;
+        }
+
+        if ( !anchor )
+          anchor = edge;
+      }
+    }
+
     /* now we align all stem edges. */
     for ( edge = edges; edge < edge_limit; edge++ )
     {
@@ -1063,6 +1740,15 @@
       }
 
       /* 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 %d\n", edge2-edges ));
+
+        af_cjk_align_linked_edge( hints, dim, edge2, edge );
+        edge->flags |= AF_EDGE_DONE;
+        continue;
+      }
 
       if ( edge2 < edge )
       {
@@ -1389,7 +2075,7 @@
   FT_LOCAL_DEF( FT_Error )
   af_cjk_hints_apply( AF_GlyphHints    hints,
                       FT_Outline*      outline,
-                      AF_LatinMetrics  metrics )
+                      AF_CJKMetrics    metrics )
   {
     FT_Error  error;
     int       dim;
@@ -1407,6 +2093,8 @@
       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 ) )
@@ -1414,6 +2102,8 @@
       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 */
@@ -1512,7 +2202,7 @@
     AF_SCRIPT_CJK,
     af_cjk_uniranges,
 
-    sizeof( AF_LatinMetricsRec ),
+    sizeof( AF_CJKMetricsRec ),
 
     (AF_Script_InitMetricsFunc) af_cjk_metrics_init,
     (AF_Script_ScaleMetricsFunc)af_cjk_metrics_scale,
@@ -1534,7 +2224,7 @@
     AF_SCRIPT_CJK,
     af_cjk_uniranges,
 
-    sizeof( AF_LatinMetricsRec ),
+    sizeof( AF_CJKMetricsRec ),
 
     (AF_Script_InitMetricsFunc) NULL,
     (AF_Script_ScaleMetricsFunc)NULL,