1 /***************************************************************************/

     2 /*                                                                         */

     3 /*  afcjk.c                                                                */

     4 /*                                                                         */

     5 /*    Auto-fitter hinting routines for CJK script (body).                  */

     6 /*                                                                         */

     7 /*  Copyright 2006-2011 by                                                 */

     8 /*  David Turner, Robert Wilhelm, and Werner Lemberg.                      */

     9 /*                                                                         */

    10 /*  This file is part of the FreeType project, and may only be used,       */

    11 /*  modified, and distributed under the terms of the FreeType project      */

    12 /*  license, LICENSE.TXT.  By continuing to use, modify, or distribute     */

    13 /*  this file you indicate that you have read the license and              */

    14 /*  understand and accept it fully.                                        */

    15 /*                                                                         */

    16 /***************************************************************************/

    17 

    18   /*

    19    *  The algorithm is based on akito's autohint patch, available here:

    20    *

    21    *  http://www.kde.gr.jp/~akito/patch/freetype2/

    22    *

    23    */

    24 

    25 #include "aftypes.h"

    26 #include "aflatin.h"

    27 

    28 

    29 #ifdef AF_CONFIG_OPTION_CJK

    30 

    31 #include "afcjk.h"

    32 #include "aferrors.h"

    33 

    34 

    35 #ifdef AF_CONFIG_OPTION_USE_WARPER

    36 #include "afwarp.h"

    37 #endif

    38 

    39 

    40   /*************************************************************************/

    41   /*************************************************************************/

    42   /*****                                                               *****/

    43   /*****              C J K   G L O B A L   M E T R I C S              *****/

    44   /*****                                                               *****/

    45   /*************************************************************************/

    46   /*************************************************************************/

    47 

    48   FT_LOCAL_DEF( FT_Error )

    49   af_cjk_metrics_init( AF_LatinMetrics  metrics,

    50                        FT_Face          face )

    51   {

    52     FT_CharMap  oldmap = face->charmap;

    53 

    54 

    55     metrics->units_per_em = face->units_per_EM;

    56 

    57     /* TODO are there blues? */

    58 

    59     if ( FT_Select_Charmap( face, FT_ENCODING_UNICODE ) )

    60       face->charmap = NULL;

    61     else

    62     {

    63       /* latin's version would suffice */

    64       af_latin_metrics_init_widths( metrics, face, 0x7530 );

    65       af_latin_metrics_check_digits( metrics, face );

    66     }

    67 

    68     FT_Set_Charmap( face, oldmap );

    69 

    70     return AF_Err_Ok;

    71   }

    72 

    73 

    74   static void

    75   af_cjk_metrics_scale_dim( AF_LatinMetrics  metrics,

    76                             AF_Scaler        scaler,

    77                             AF_Dimension     dim )

    78   {

    79     AF_LatinAxis  axis;

    80 

    81 

    82     axis = &metrics->axis[dim];

    83 

    84     if ( dim == AF_DIMENSION_HORZ )

    85     {

    86       axis->scale = scaler->x_scale;

    87       axis->delta = scaler->x_delta;

    88     }

    89     else

    90     {

    91       axis->scale = scaler->y_scale;

    92       axis->delta = scaler->y_delta;

    93     }

    94   }

    95 

    96 

    97   FT_LOCAL_DEF( void )

    98   af_cjk_metrics_scale( AF_LatinMetrics  metrics,

    99                         AF_Scaler        scaler )

   100   {

   101     metrics->root.scaler = *scaler;

   102 

   103     af_cjk_metrics_scale_dim( metrics, scaler, AF_DIMENSION_HORZ );

   104     af_cjk_metrics_scale_dim( metrics, scaler, AF_DIMENSION_VERT );

   105   }

   106 

   107 

   108   /*************************************************************************/

   109   /*************************************************************************/

   110   /*****                                                               *****/

   111   /*****              C J K   G L Y P H   A N A L Y S I S              *****/

   112   /*****                                                               *****/

   113   /*************************************************************************/

   114   /*************************************************************************/

   115 

   116   static FT_Error

   117   af_cjk_hints_compute_segments( AF_GlyphHints  hints,

   118                                  AF_Dimension   dim )

   119   {

   120     AF_AxisHints  axis          = &hints->axis[dim];

   121     AF_Segment    segments      = axis->segments;

   122     AF_Segment    segment_limit = segments + axis->num_segments;

   123     FT_Error      error;

   124     AF_Segment    seg;

   125 

   126 

   127     error = af_latin_hints_compute_segments( hints, dim );

   128     if ( error )

   129       return error;

   130 

   131     /* a segment is round if it doesn't have successive */

   132     /* on-curve points.                                 */

   133     for ( seg = segments; seg < segment_limit; seg++ )

   134     {

   135       AF_Point  pt   = seg->first;

   136       AF_Point  last = seg->last;

   137       AF_Flags  f0   = (AF_Flags)(pt->flags & AF_FLAG_CONTROL);

   138       AF_Flags  f1;

   139 

   140 

   141       seg->flags &= ~AF_EDGE_ROUND;

   142 

   143       for ( ; pt != last; f0 = f1 )

   144       {

   145         pt = pt->next;

   146         f1 = (AF_Flags)(pt->flags & AF_FLAG_CONTROL);

   147 

   148         if ( !f0 && !f1 )

   149           break;

   150 

   151         if ( pt == last )

   152           seg->flags |= AF_EDGE_ROUND;

   153       }

   154     }

   155 

   156     return AF_Err_Ok;

   157   }

   158 

   159 

   160   static void

   161   af_cjk_hints_link_segments( AF_GlyphHints  hints,

   162                               AF_Dimension   dim )

   163   {

   164     AF_AxisHints  axis          = &hints->axis[dim];

   165     AF_Segment    segments      = axis->segments;

   166     AF_Segment    segment_limit = segments + axis->num_segments;

   167     AF_Direction  major_dir     = axis->major_dir;

   168     AF_Segment    seg1, seg2;

   169     FT_Pos        len_threshold;

   170     FT_Pos        dist_threshold;

   171 

   172 

   173     len_threshold = AF_LATIN_CONSTANT( hints->metrics, 8 );

   174 

   175     dist_threshold = ( dim == AF_DIMENSION_HORZ ) ? hints->x_scale

   176                                                   : hints->y_scale;

   177     dist_threshold = FT_DivFix( 64 * 3, dist_threshold );

   178 

   179     /* now compare each segment to the others */

   180     for ( seg1 = segments; seg1 < segment_limit; seg1++ )

   181     {

   182       /* the fake segments are for metrics hinting only */

   183       if ( seg1->first == seg1->last )

   184         continue;

   185 

   186       if ( seg1->dir != major_dir )

   187         continue;

   188 

   189       for ( seg2 = segments; seg2 < segment_limit; seg2++ )

   190         if ( seg2 != seg1 && seg1->dir + seg2->dir == 0 )

   191         {

   192           FT_Pos  dist = seg2->pos - seg1->pos;

   193 

   194 

   195           if ( dist < 0 )

   196             continue;

   197 

   198           {

   199             FT_Pos  min = seg1->min_coord;

   200             FT_Pos  max = seg1->max_coord;

   201             FT_Pos  len;

   202 

   203 

   204             if ( min < seg2->min_coord )

   205               min = seg2->min_coord;

   206 

   207             if ( max > seg2->max_coord )

   208               max = seg2->max_coord;

   209 

   210             len = max - min;

   211             if ( len >= len_threshold )

   212             {

   213               if ( dist * 8 < seg1->score * 9                        &&

   214                    ( dist * 8 < seg1->score * 7 || seg1->len < len ) )

   215               {

   216                 seg1->score = dist;

   217                 seg1->len   = len;

   218                 seg1->link  = seg2;

   219               }

   220 

   221               if ( dist * 8 < seg2->score * 9                        &&

   222                    ( dist * 8 < seg2->score * 7 || seg2->len < len ) )

   223               {

   224                 seg2->score = dist;

   225                 seg2->len   = len;

   226                 seg2->link  = seg1;

   227               }

   228             }

   229           }

   230         }

   231     }

   232 

   233     /*

   234      *  now compute the `serif' segments

   235      *

   236      *  In Hanzi, some strokes are wider on one or both of the ends.

   237      *  We either identify the stems on the ends as serifs or remove

   238      *  the linkage, depending on the length of the stems.

   239      *

   240      */

   241 

   242     {

   243       AF_Segment  link1, link2;

   244 

   245 

   246       for ( seg1 = segments; seg1 < segment_limit; seg1++ )

   247       {

   248         link1 = seg1->link;

   249         if ( !link1 || link1->link != seg1 || link1->pos <= seg1->pos )

   250           continue;

   251 

   252         if ( seg1->score >= dist_threshold )

   253           continue;

   254 

   255         for ( seg2 = segments; seg2 < segment_limit; seg2++ )

   256         {

   257           if ( seg2->pos > seg1->pos || seg1 == seg2 )

   258             continue;

   259 

   260           link2 = seg2->link;

   261           if ( !link2 || link2->link != seg2 || link2->pos < link1->pos )

   262             continue;

   263 

   264           if ( seg1->pos == seg2->pos && link1->pos == link2->pos )

   265             continue;

   266 

   267           if ( seg2->score <= seg1->score || seg1->score * 4 <= seg2->score )

   268             continue;

   269 

   270           /* seg2 < seg1 < link1 < link2 */

   271 

   272           if ( seg1->len >= seg2->len * 3 )

   273           {

   274             AF_Segment  seg;

   275 

   276 

   277             for ( seg = segments; seg < segment_limit; seg++ )

   278             {

   279               AF_Segment  link = seg->link;

   280 

   281 

   282               if ( link == seg2 )

   283               {

   284                 seg->link  = 0;

   285                 seg->serif = link1;

   286               }

   287               else if ( link == link2 )

   288               {

   289                 seg->link  = 0;

   290                 seg->serif = seg1;

   291               }

   292             }

   293           }

   294           else

   295           {

   296             seg1->link = link1->link = 0;

   297 

   298             break;

   299           }

   300         }

   301       }

   302     }

   303 

   304     for ( seg1 = segments; seg1 < segment_limit; seg1++ )

   305     {

   306       seg2 = seg1->link;

   307 

   308       if ( seg2 )

   309       {

   310         seg2->num_linked++;

   311         if ( seg2->link != seg1 )

   312         {

   313           seg1->link = 0;

   314 

   315           if ( seg2->score < dist_threshold || seg1->score < seg2->score * 4 )

   316             seg1->serif = seg2->link;

   317           else

   318             seg2->num_linked--;

   319         }

   320       }

   321     }

   322   }

   323 

   324 

   325   static FT_Error

   326   af_cjk_hints_compute_edges( AF_GlyphHints  hints,

   327                               AF_Dimension   dim )

   328   {

   329     AF_AxisHints  axis   = &hints->axis[dim];

   330     FT_Error      error  = AF_Err_Ok;

   331     FT_Memory     memory = hints->memory;

   332     AF_LatinAxis  laxis  = &((AF_LatinMetrics)hints->metrics)->axis[dim];

   333 

   334     AF_Segment    segments      = axis->segments;

   335     AF_Segment    segment_limit = segments + axis->num_segments;

   336     AF_Segment    seg;

   337 

   338     FT_Fixed      scale;

   339     FT_Pos        edge_distance_threshold;

   340 

   341 

   342     axis->num_edges = 0;

   343 

   344     scale = ( dim == AF_DIMENSION_HORZ ) ? hints->x_scale

   345                                          : hints->y_scale;

   346 

   347     /*********************************************************************/

   348     /*                                                                   */

   349     /* We begin by generating a sorted table of edges for the current    */

   350     /* direction.  To do so, we simply scan each segment and try to find */

   351     /* an edge in our table that corresponds to its position.            */

   352     /*                                                                   */

   353     /* If no edge is found, we create and insert a new edge in the       */

   354     /* sorted table.  Otherwise, we simply add the segment to the edge's */

   355     /* list which is then processed in the second step to compute the    */

   356     /* edge's properties.                                                */

   357     /*                                                                   */

   358     /* Note that the edges table is sorted along the segment/edge        */

   359     /* position.                                                         */

   360     /*                                                                   */

   361     /*********************************************************************/

   362 

   363     edge_distance_threshold = FT_MulFix( laxis->edge_distance_threshold,

   364                                          scale );

   365     if ( edge_distance_threshold > 64 / 4 )

   366       edge_distance_threshold = FT_DivFix( 64 / 4, scale );

   367     else

   368       edge_distance_threshold = laxis->edge_distance_threshold;

   369 

   370     for ( seg = segments; seg < segment_limit; seg++ )

   371     {

   372       AF_Edge  found = 0;

   373       FT_Pos   best  = 0xFFFFU;

   374       FT_Int   ee;

   375 

   376 

   377       /* look for an edge corresponding to the segment */

   378       for ( ee = 0; ee < axis->num_edges; ee++ )

   379       {

   380         AF_Edge  edge = axis->edges + ee;

   381         FT_Pos   dist;

   382 

   383 

   384         if ( edge->dir != seg->dir )

   385           continue;

   386 

   387         dist = seg->pos - edge->fpos;

   388         if ( dist < 0 )

   389           dist = -dist;

   390 

   391         if ( dist < edge_distance_threshold && dist < best )

   392         {

   393           AF_Segment  link = seg->link;

   394 

   395 

   396           /* check whether all linked segments of the candidate edge */

   397           /* can make a single edge.                                 */

   398           if ( link )

   399           {

   400             AF_Segment  seg1 = edge->first;

   401             AF_Segment  link1;

   402             FT_Pos      dist2 = 0;

   403 

   404 

   405             do

   406             {

   407               link1 = seg1->link;

   408               if ( link1 )

   409               {

   410                 dist2 = AF_SEGMENT_DIST( link, link1 );

   411                 if ( dist2 >= edge_distance_threshold )

   412                   break;

   413               }

   414 

   415             } while ( ( seg1 = seg1->edge_next ) != edge->first );

   416 

   417             if ( dist2 >= edge_distance_threshold )

   418               continue;

   419           }

   420 

   421           best  = dist;

   422           found = edge;

   423         }

   424       }

   425 

   426       if ( !found )

   427       {

   428         AF_Edge  edge;

   429 

   430 

   431         /* insert a new edge in the list and */

   432         /* sort according to the position    */

   433         error = af_axis_hints_new_edge( axis, seg->pos,

   434                                         (AF_Direction)seg->dir,

   435                                         memory, &edge );

   436         if ( error )

   437           goto Exit;

   438 

   439         /* add the segment to the new edge's list */

   440         FT_ZERO( edge );

   441 

   442         edge->first    = seg;

   443         edge->last     = seg;

   444         edge->fpos     = seg->pos;

   445         edge->opos     = edge->pos = FT_MulFix( seg->pos, scale );

   446         seg->edge_next = seg;

   447         edge->dir      = seg->dir;

   448       }

   449       else

   450       {

   451         /* if an edge was found, simply add the segment to the edge's */

   452         /* list                                                       */

   453         seg->edge_next         = found->first;

   454         found->last->edge_next = seg;

   455         found->last            = seg;

   456       }

   457     }

   458 

   459     /*********************************************************************/

   460     /*                                                                   */

   461     /* Good, we now compute each edge's properties according to segments */

   462     /* found on its position.  Basically, these are as follows.          */

   463     /*                                                                   */

   464     /*  - edge's main direction                                          */

   465     /*  - stem edge, serif edge or both (which defaults to stem then)    */

   466     /*  - rounded edge, straight or both (which defaults to straight)    */

   467     /*  - link for edge                                                  */

   468     /*                                                                   */

   469     /*********************************************************************/

   470 

   471     /* first of all, set the `edge' field in each segment -- this is     */

   472     /* required in order to compute edge links                           */

   473     /*                                                                   */

   474     /* Note that removing this loop and setting the `edge' field of each */

   475     /* segment directly in the code above slows down execution speed for */

   476     /* some reasons on platforms like the Sun.                           */

   477 

   478     {

   479       AF_Edge  edges      = axis->edges;

   480       AF_Edge  edge_limit = edges + axis->num_edges;

   481       AF_Edge  edge;

   482 

   483 

   484       for ( edge = edges; edge < edge_limit; edge++ )

   485       {

   486         seg = edge->first;

   487         if ( seg )

   488           do

   489           {

   490             seg->edge = edge;

   491             seg       = seg->edge_next;

   492 

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

   494       }

   495 

   496       /* now compute each edge properties */

   497       for ( edge = edges; edge < edge_limit; edge++ )

   498       {

   499         FT_Int  is_round    = 0;  /* does it contain round segments?    */

   500         FT_Int  is_straight = 0;  /* does it contain straight segments? */

   501 

   502 

   503         seg = edge->first;

   504 

   505         do

   506         {

   507           FT_Bool  is_serif;

   508 

   509 

   510           /* check for roundness of segment */

   511           if ( seg->flags & AF_EDGE_ROUND )

   512             is_round++;

   513           else

   514             is_straight++;

   515 

   516           /* check for links -- if seg->serif is set, then seg->link must */

   517           /* be ignored                                                   */

   518           is_serif = (FT_Bool)( seg->serif && seg->serif->edge != edge );

   519 

   520           if ( seg->link || is_serif )

   521           {

   522             AF_Edge     edge2;

   523             AF_Segment  seg2;

   524 

   525 

   526             edge2 = edge->link;

   527             seg2  = seg->link;

   528 

   529             if ( is_serif )

   530             {

   531               seg2  = seg->serif;

   532               edge2 = edge->serif;

   533             }

   534 

   535             if ( edge2 )

   536             {

   537               FT_Pos  edge_delta;

   538               FT_Pos  seg_delta;

   539 

   540 

   541               edge_delta = edge->fpos - edge2->fpos;

   542               if ( edge_delta < 0 )

   543                 edge_delta = -edge_delta;

   544 

   545               seg_delta = AF_SEGMENT_DIST( seg, seg2 );

   546 

   547               if ( seg_delta < edge_delta )

   548                 edge2 = seg2->edge;

   549             }

   550             else

   551               edge2 = seg2->edge;

   552 

   553             if ( is_serif )

   554             {

   555               edge->serif   = edge2;

   556               edge2->flags |= AF_EDGE_SERIF;

   557             }

   558             else

   559               edge->link  = edge2;

   560           }

   561 

   562           seg = seg->edge_next;

   563 

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

   565 

   566         /* set the round/straight flags */

   567         edge->flags = AF_EDGE_NORMAL;

   568 

   569         if ( is_round > 0 && is_round >= is_straight )

   570           edge->flags |= AF_EDGE_ROUND;

   571 

   572         /* get rid of serifs if link is set                 */

   573         /* XXX: This gets rid of many unpleasant artefacts! */

   574         /*      Example: the `c' in cour.pfa at size 13     */

   575 

   576         if ( edge->serif && edge->link )

   577           edge->serif = 0;

   578       }

   579     }

   580 

   581   Exit:

   582     return error;

   583   }

   584 

   585 

   586   static FT_Error

   587   af_cjk_hints_detect_features( AF_GlyphHints  hints,

   588                                 AF_Dimension   dim )

   589   {

   590     FT_Error  error;

   591 

   592 

   593     error = af_cjk_hints_compute_segments( hints, dim );

   594     if ( !error )

   595     {

   596       af_cjk_hints_link_segments( hints, dim );

   597 

   598       error = af_cjk_hints_compute_edges( hints, dim );

   599     }

   600     return error;

   601   }

   602 

   603 

   604   FT_LOCAL_DEF( FT_Error )

   605   af_cjk_hints_init( AF_GlyphHints    hints,

   606                      AF_LatinMetrics  metrics )

   607   {

   608     FT_Render_Mode  mode;

   609     FT_UInt32       scaler_flags, other_flags;

   610 

   611 

   612     af_glyph_hints_rescale( hints, (AF_ScriptMetrics)metrics );

   613 

   614     /*

   615      *  correct x_scale and y_scale when needed, since they may have

   616      *  been modified af_cjk_scale_dim above

   617      */

   618     hints->x_scale = metrics->axis[AF_DIMENSION_HORZ].scale;

   619     hints->x_delta = metrics->axis[AF_DIMENSION_HORZ].delta;

   620     hints->y_scale = metrics->axis[AF_DIMENSION_VERT].scale;

   621     hints->y_delta = metrics->axis[AF_DIMENSION_VERT].delta;

   622 

   623     /* compute flags depending on render mode, etc. */

   624     mode = metrics->root.scaler.render_mode;

   625 

   626 #ifdef AF_CONFIG_OPTION_USE_WARPER

   627     if ( mode == FT_RENDER_MODE_LCD || mode == FT_RENDER_MODE_LCD_V )

   628       metrics->root.scaler.render_mode = mode = FT_RENDER_MODE_NORMAL;

   629 #endif

   630 

   631     scaler_flags = hints->scaler_flags;

   632     other_flags  = 0;

   633 

   634     /*

   635      *  We snap the width of vertical stems for the monochrome and

   636      *  horizontal LCD rendering targets only.

   637      */

   638     if ( mode == FT_RENDER_MODE_MONO || mode == FT_RENDER_MODE_LCD )

   639       other_flags |= AF_LATIN_HINTS_HORZ_SNAP;

   640 

   641     /*

   642      *  We snap the width of horizontal stems for the monochrome and

   643      *  vertical LCD rendering targets only.

   644      */

   645     if ( mode == FT_RENDER_MODE_MONO || mode == FT_RENDER_MODE_LCD_V )

   646       other_flags |= AF_LATIN_HINTS_VERT_SNAP;

   647 

   648     /*

   649      *  We adjust stems to full pixels only if we don't use the `light' mode.

   650      */

   651     if ( mode != FT_RENDER_MODE_LIGHT )

   652       other_flags |= AF_LATIN_HINTS_STEM_ADJUST;

   653 

   654     if ( mode == FT_RENDER_MODE_MONO )

   655       other_flags |= AF_LATIN_HINTS_MONO;

   656 

   657     scaler_flags |= AF_SCALER_FLAG_NO_ADVANCE;

   658 

   659     hints->scaler_flags = scaler_flags;

   660     hints->other_flags  = other_flags;

   661 

   662     return 0;

   663   }

   664 

   665 

   666   /*************************************************************************/

   667   /*************************************************************************/

   668   /*****                                                               *****/

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

   670   /*****                                                               *****/

   671   /*************************************************************************/

   672   /*************************************************************************/

   673 

   674   /* snap a given width in scaled coordinates to one of the */

   675   /* current standard widths                                */

   676 

   677   static FT_Pos

   678   af_cjk_snap_width( AF_Width  widths,

   679                      FT_Int    count,

   680                      FT_Pos    width )

   681   {

   682     int     n;

   683     FT_Pos  best      = 64 + 32 + 2;

   684     FT_Pos  reference = width;

   685     FT_Pos  scaled;

   686 

   687 

   688     for ( n = 0; n < count; n++ )

   689     {

   690       FT_Pos  w;

   691       FT_Pos  dist;

   692 

   693 

   694       w = widths[n].cur;

   695       dist = width - w;

   696       if ( dist < 0 )

   697         dist = -dist;

   698       if ( dist < best )

   699       {

   700         best      = dist;

   701         reference = w;

   702       }

   703     }

   704 

   705     scaled = FT_PIX_ROUND( reference );

   706 

   707     if ( width >= reference )

   708     {

   709       if ( width < scaled + 48 )

   710         width = reference;

   711     }

   712     else

   713     {

   714       if ( width > scaled - 48 )

   715         width = reference;

   716     }

   717 

   718     return width;

   719   }

   720 

   721 

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

   723 

   724   static FT_Pos

   725   af_cjk_compute_stem_width( AF_GlyphHints  hints,

   726                              AF_Dimension   dim,

   727                              FT_Pos         width,

   728                              AF_Edge_Flags  base_flags,

   729                              AF_Edge_Flags  stem_flags )

   730   {

   731     AF_LatinMetrics  metrics  = (AF_LatinMetrics) hints->metrics;

   732     AF_LatinAxis     axis     = & metrics->axis[dim];

   733     FT_Pos           dist     = width;

   734     FT_Int           sign     = 0;

   735     FT_Int           vertical = ( dim == AF_DIMENSION_VERT );

   736 

   737     FT_UNUSED( base_flags );

   738     FT_UNUSED( stem_flags );

   739 

   740 

   741     if ( !AF_LATIN_HINTS_DO_STEM_ADJUST( hints ) )

   742       return width;

   743 

   744     if ( dist < 0 )

   745     {

   746       dist = -width;

   747       sign = 1;

   748     }

   749 

   750     if ( (  vertical && !AF_LATIN_HINTS_DO_VERT_SNAP( hints ) ) ||

   751          ( !vertical && !AF_LATIN_HINTS_DO_HORZ_SNAP( hints ) ) )

   752     {

   753       /* smooth hinting process: very lightly quantize the stem width */

   754 

   755       if ( axis->width_count > 0 )

   756       {

   757         if ( FT_ABS( dist - axis->widths[0].cur ) < 40 )

   758         {

   759           dist = axis->widths[0].cur;

   760           if ( dist < 48 )

   761             dist = 48;

   762 

   763           goto Done_Width;

   764         }

   765       }

   766 

   767       if ( dist < 54 )

   768         dist += ( 54 - dist ) / 2 ;

   769       else if ( dist < 3 * 64 )

   770       {

   771         FT_Pos  delta;

   772 

   773 

   774         delta  = dist & 63;

   775         dist  &= -64;

   776 

   777         if ( delta < 10 )

   778           dist += delta;

   779         else if ( delta < 22 )

   780           dist += 10;

   781         else if ( delta < 42 )

   782           dist += delta;

   783         else if ( delta < 54 )

   784           dist += 54;

   785         else

   786           dist += delta;

   787       }

   788     }

   789     else

   790     {

   791       /* strong hinting process: snap the stem width to integer pixels */

   792 

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

   794 

   795       if ( vertical )

   796       {

   797         /* in the case of vertical hinting, always round */

   798         /* the stem heights to integer pixels            */

   799 

   800         if ( dist >= 64 )

   801           dist = ( dist + 16 ) & ~63;

   802         else

   803           dist = 64;

   804       }

   805       else

   806       {

   807         if ( AF_LATIN_HINTS_DO_MONO( hints ) )

   808         {

   809           /* monochrome horizontal hinting: snap widths to integer pixels */

   810           /* with a different threshold                                   */

   811 

   812           if ( dist < 64 )

   813             dist = 64;

   814           else

   815             dist = ( dist + 32 ) & ~63;

   816         }

   817         else

   818         {

   819           /* for horizontal anti-aliased hinting, we adopt a more subtle */

   820           /* approach: we strengthen small stems, round stems whose size */

   821           /* is between 1 and 2 pixels to an integer, otherwise nothing  */

   822 

   823           if ( dist < 48 )

   824             dist = ( dist + 64 ) >> 1;

   825 

   826           else if ( dist < 128 )

   827             dist = ( dist + 22 ) & ~63;

   828           else

   829             /* round otherwise to prevent color fringes in LCD mode */

   830             dist = ( dist + 32 ) & ~63;

   831         }

   832       }

   833     }

   834 

   835   Done_Width:

   836     if ( sign )

   837       dist = -dist;

   838 

   839     return dist;

   840   }

   841 

   842 

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

   844 

   845   static void

   846   af_cjk_align_linked_edge( AF_GlyphHints  hints,

   847                             AF_Dimension   dim,

   848                             AF_Edge        base_edge,

   849                             AF_Edge        stem_edge )

   850   {

   851     FT_Pos  dist = stem_edge->opos - base_edge->opos;

   852 

   853     FT_Pos  fitted_width = af_cjk_compute_stem_width(

   854                              hints, dim, dist,

   855                              (AF_Edge_Flags)base_edge->flags,

   856                              (AF_Edge_Flags)stem_edge->flags );

   857 

   858 

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

   860   }

   861 

   862 

   863   static void

   864   af_cjk_align_serif_edge( AF_GlyphHints  hints,

   865                            AF_Edge        base,

   866                            AF_Edge        serif )

   867   {

   868     FT_UNUSED( hints );

   869 

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

   871   }

   872 

   873 

   874   /*************************************************************************/

   875   /*************************************************************************/

   876   /*************************************************************************/

   877   /****                                                                 ****/

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

   879   /****                                                                 ****/

   880   /*************************************************************************/

   881   /*************************************************************************/

   882   /*************************************************************************/

   883 

   884 

   885 #define AF_LIGHT_MODE_MAX_HORZ_GAP    9

   886 #define AF_LIGHT_MODE_MAX_VERT_GAP   15

   887 #define AF_LIGHT_MODE_MAX_DELTA_ABS  14

   888 

   889 

   890   static FT_Pos

   891   af_hint_normal_stem( AF_GlyphHints  hints,

   892                        AF_Edge        edge,

   893                        AF_Edge        edge2,

   894                        FT_Pos         anchor,

   895                        AF_Dimension   dim )

   896   {

   897     FT_Pos  org_len, cur_len, org_center;

   898     FT_Pos  cur_pos1, cur_pos2;

   899     FT_Pos  d_off1, u_off1, d_off2, u_off2, delta;

   900     FT_Pos  offset;

   901     FT_Pos  threshold = 64;

   902 

   903 

   904     if ( !AF_LATIN_HINTS_DO_STEM_ADJUST( hints ) )

   905     {

   906       if ( ( edge->flags  & AF_EDGE_ROUND ) &&

   907            ( edge2->flags & AF_EDGE_ROUND ) )

   908       {

   909         if ( dim == AF_DIMENSION_VERT )

   910           threshold = 64 - AF_LIGHT_MODE_MAX_HORZ_GAP;

   911         else

   912           threshold = 64 - AF_LIGHT_MODE_MAX_VERT_GAP;

   913       }

   914       else

   915       {

   916         if ( dim == AF_DIMENSION_VERT )

   917           threshold = 64 - AF_LIGHT_MODE_MAX_HORZ_GAP / 3;

   918         else

   919           threshold = 64 - AF_LIGHT_MODE_MAX_VERT_GAP / 3;

   920       }

   921     }

   922 

   923     org_len    = edge2->opos - edge->opos;

   924     cur_len    = af_cjk_compute_stem_width( hints, dim, org_len,

   925                                             (AF_Edge_Flags)edge->flags,

   926                                             (AF_Edge_Flags)edge2->flags );

   927 

   928     org_center = ( edge->opos + edge2->opos ) / 2 + anchor;

   929     cur_pos1   = org_center - cur_len / 2;

   930     cur_pos2   = cur_pos1 + cur_len;

   931     d_off1     = cur_pos1 - FT_PIX_FLOOR( cur_pos1 );

   932     d_off2     = cur_pos2 - FT_PIX_FLOOR( cur_pos2 );

   933     u_off1     = 64 - d_off1;

   934     u_off2     = 64 - d_off2;

   935     delta      = 0;

   936 

   937 

   938     if ( d_off1 == 0 || d_off2 == 0 )

   939       goto Exit;

   940 

   941     if ( cur_len <= threshold )

   942     {

   943       if ( d_off2 < cur_len )

   944       {

   945         if ( u_off1 <= d_off2 )

   946           delta =  u_off1;

   947         else

   948           delta = -d_off2;

   949       }

   950 

   951       goto Exit;

   952     }

   953 

   954     if ( threshold < 64 )

   955     {

   956       if ( d_off1 >= threshold || u_off1 >= threshold ||

   957            d_off2 >= threshold || u_off2 >= threshold )

   958         goto Exit;

   959     }

   960 

   961     offset = cur_len % 64;

   962 

   963     if ( offset < 32 )

   964     {

   965       if ( u_off1 <= offset || d_off2 <= offset )

   966         goto Exit;

   967     }

   968     else

   969       offset = 64 - threshold;

   970 

   971     d_off1 = threshold - u_off1;

   972     u_off1 = u_off1    - offset;

   973     u_off2 = threshold - d_off2;

   974     d_off2 = d_off2    - offset;

   975 

   976     if ( d_off1 <= u_off1 )

   977       u_off1 = -d_off1;

   978 

   979     if ( d_off2 <= u_off2 )

   980       u_off2 = -d_off2;

   981 

   982     if ( FT_ABS( u_off1 ) <= FT_ABS( u_off2 ) )

   983       delta = u_off1;

   984     else

   985       delta = u_off2;

   986 

   987   Exit:

   988 

   989 #if 1

   990     if ( !AF_LATIN_HINTS_DO_STEM_ADJUST( hints ) )

   991     {

   992       if ( delta > AF_LIGHT_MODE_MAX_DELTA_ABS )

   993         delta = AF_LIGHT_MODE_MAX_DELTA_ABS;

   994       else if ( delta < -AF_LIGHT_MODE_MAX_DELTA_ABS )

   995         delta = -AF_LIGHT_MODE_MAX_DELTA_ABS;

   996     }

   997 #endif

   998 

   999     cur_pos1 += delta;

  1000 

  1001     if ( edge->opos < edge2->opos )

  1002     {

  1003       edge->pos  = cur_pos1;

  1004       edge2->pos = cur_pos1 + cur_len;

  1005     }

  1006     else

  1007     {

  1008       edge->pos  = cur_pos1 + cur_len;

  1009       edge2->pos = cur_pos1;

  1010     }

  1011 

  1012     return delta;

  1013   }

  1014 

  1015 

  1016   static void

  1017   af_cjk_hint_edges( AF_GlyphHints  hints,

  1018                      AF_Dimension   dim )

  1019   {

  1020     AF_AxisHints  axis       = &hints->axis[dim];

  1021     AF_Edge       edges      = axis->edges;

  1022     AF_Edge       edge_limit = edges + axis->num_edges;

  1023     FT_PtrDist    n_edges;

  1024     AF_Edge       edge;

  1025     AF_Edge       anchor   = 0;

  1026     FT_Pos        delta    = 0;

  1027     FT_Int        skipped  = 0;

  1028     FT_Bool       has_last_stem = FALSE;

  1029     FT_Pos        last_stem_pos = 0;

  1030 

  1031 

  1032     /* now we align all stem edges. */

  1033     for ( edge = edges; edge < edge_limit; edge++ )

  1034     {

  1035       AF_Edge  edge2;

  1036 

  1037 

  1038       if ( edge->flags & AF_EDGE_DONE )

  1039         continue;

  1040 

  1041       /* skip all non-stem edges */

  1042       edge2 = edge->link;

  1043       if ( !edge2 )

  1044       {

  1045         skipped++;

  1046         continue;

  1047       }

  1048 

  1049       /* Some CJK characters have so many stems that

  1050        * the hinter is likely to merge two adjacent ones.

  1051        * To solve this problem, if either edge of a stem

  1052        * is too close to the previous one, we avoid

  1053        * aligning the two edges, but rather interpolate

  1054        * their locations at the end of this function in

  1055        * order to preserve the space between the stems.

  1056        */

  1057       if ( has_last_stem                       &&

  1058            ( edge->pos  < last_stem_pos + 64 ||

  1059              edge2->pos < last_stem_pos + 64 ) )

  1060       {

  1061         skipped++;

  1062         continue;

  1063       }

  1064 

  1065       /* now align the stem */

  1066 

  1067       if ( edge2 < edge )

  1068       {

  1069         af_cjk_align_linked_edge( hints, dim, edge2, edge );

  1070         edge->flags |= AF_EDGE_DONE;

  1071         /* We rarely reaches here it seems;

  1072          * usually the two edges belonging

  1073          * to one stem are marked as DONE together

  1074          */

  1075         has_last_stem = TRUE;

  1076         last_stem_pos = edge->pos;

  1077         continue;

  1078       }

  1079 

  1080       if ( dim != AF_DIMENSION_VERT && !anchor )

  1081       {

  1082 

  1083 #if 0

  1084         if ( fixedpitch )

  1085         {

  1086           AF_Edge     left  = edge;

  1087           AF_Edge     right = edge_limit - 1;

  1088           AF_EdgeRec  left1, left2, right1, right2;

  1089           FT_Pos      target, center1, center2;

  1090           FT_Pos      delta1, delta2, d1, d2;

  1091 

  1092 

  1093           while ( right > left && !right->link )

  1094             right--;

  1095 

  1096           left1  = *left;

  1097           left2  = *left->link;

  1098           right1 = *right->link;

  1099           right2 = *right;

  1100 

  1101           delta  = ( ( ( hinter->pp2.x + 32 ) & -64 ) - hinter->pp2.x ) / 2;

  1102           target = left->opos + ( right->opos - left->opos ) / 2 + delta - 16;

  1103 

  1104           delta1  = delta;

  1105           delta1 += af_hint_normal_stem( hints, left, left->link,

  1106                                          delta1, 0 );

  1107 

  1108           if ( left->link != right )

  1109             af_hint_normal_stem( hints, right->link, right, delta1, 0 );

  1110 

  1111           center1 = left->pos + ( right->pos - left->pos ) / 2;

  1112 

  1113           if ( center1 >= target )

  1114             delta2 = delta - 32;

  1115           else

  1116             delta2 = delta + 32;

  1117 

  1118           delta2 += af_hint_normal_stem( hints, &left1, &left2, delta2, 0 );

  1119 

  1120           if ( delta1 != delta2 )

  1121           {

  1122             if ( left->link != right )

  1123               af_hint_normal_stem( hints, &right1, &right2, delta2, 0 );

  1124 

  1125             center2 = left1.pos + ( right2.pos - left1.pos ) / 2;

  1126 

  1127             d1 = center1 - target;

  1128             d2 = center2 - target;

  1129 

  1130             if ( FT_ABS( d2 ) < FT_ABS( d1 ) )

  1131             {

  1132               left->pos       = left1.pos;

  1133               left->link->pos = left2.pos;

  1134