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      1 /***************************************************************************/
      2 /*                                                                         */
      3 /*  aflatin.c                                                              */
      4 /*                                                                         */
      5 /*    Auto-fitter hinting routines for latin script (body).                */
      6 /*                                                                         */
      7 /*  Copyright 2003-2011 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 #include <ft2build.h>
     20 #include FT_ADVANCES_H
     21 #include FT_INTERNAL_DEBUG_H
     22 
     23 #include "aflatin.h"
     24 #include "aferrors.h"
     25 
     26 
     27 #ifdef AF_CONFIG_OPTION_USE_WARPER
     28 #include "afwarp.h"
     29 #endif
     30 
     31 
     32   /*************************************************************************/
     33   /*                                                                       */
     34   /* The macro FT_COMPONENT is used in trace mode.  It is an implicit      */
     35   /* parameter of the FT_TRACE() and FT_ERROR() macros, used to print/log  */
     36   /* messages during execution.                                            */
     37   /*                                                                       */
     38 #undef  FT_COMPONENT
     39 #define FT_COMPONENT  trace_aflatin
     40 
     41 
     42   /*************************************************************************/
     43   /*************************************************************************/
     44   /*****                                                               *****/
     45   /*****            L A T I N   G L O B A L   M E T R I C S            *****/
     46   /*****                                                               *****/
     47   /*************************************************************************/
     48   /*************************************************************************/
     49 
     50 
     51   /* Find segments and links, compute all stem widths, and initialize */
     52   /* standard width and height for the glyph with given charcode.     */
     53 
     54   FT_LOCAL_DEF( void )
     55   af_latin_metrics_init_widths( AF_LatinMetrics  metrics,
     56                                 FT_Face          face,
     57                                 FT_ULong         charcode )
     58   {
     59     /* scan the array of segments in each direction */
     60     AF_GlyphHintsRec  hints[1];
     61 
     62 
     63     af_glyph_hints_init( hints, face->memory );
     64 
     65     metrics->axis[AF_DIMENSION_HORZ].width_count = 0;
     66     metrics->axis[AF_DIMENSION_VERT].width_count = 0;
     67 
     68     {
     69       FT_Error             error;
     70       FT_UInt              glyph_index;
     71       int                  dim;
     72       AF_LatinMetricsRec   dummy[1];
     73       AF_Scaler            scaler = &dummy->root.scaler;
     74 
     75 
     76       glyph_index = FT_Get_Char_Index( face, charcode );
     77       if ( glyph_index == 0 )
     78         goto Exit;
     79 
     80       error = FT_Load_Glyph( face, glyph_index, FT_LOAD_NO_SCALE );
     81       if ( error || face->glyph->outline.n_points <= 0 )
     82         goto Exit;
     83 
     84       FT_ZERO( dummy );
     85 
     86       dummy->units_per_em = metrics->units_per_em;
     87 
     88       scaler->x_scale = 0x10000L;
     89       scaler->y_scale = 0x10000L;
     90       scaler->x_delta = 0;
     91       scaler->y_delta = 0;
     92 
     93       scaler->face        = face;
     94       scaler->render_mode = FT_RENDER_MODE_NORMAL;
     95       scaler->flags       = 0;
     96 
     97       af_glyph_hints_rescale( hints, (AF_ScriptMetrics)dummy );
     98 
     99       error = af_glyph_hints_reload( hints, &face->glyph->outline );
    100       if ( error )
    101         goto Exit;
    102 
    103       for ( dim = 0; dim < AF_DIMENSION_MAX; dim++ )
    104       {
    105         AF_LatinAxis  axis    = &metrics->axis[dim];
    106         AF_AxisHints  axhints = &hints->axis[dim];
    107         AF_Segment    seg, limit, link;
    108         FT_UInt       num_widths = 0;
    109 
    110 
    111         error = af_latin_hints_compute_segments( hints,
    112                                                  (AF_Dimension)dim );
    113         if ( error )
    114           goto Exit;
    115 
    116         af_latin_hints_link_segments( hints,
    117                                       (AF_Dimension)dim );
    118 
    119         seg   = axhints->segments;
    120         limit = seg + axhints->num_segments;
    121 
    122         for ( ; seg < limit; seg++ )
    123         {
    124           link = seg->link;
    125 
    126           /* we only consider stem segments there! */
    127           if ( link && link->link == seg && link > seg )
    128           {
    129             FT_Pos  dist;
    130 
    131 
    132             dist = seg->pos - link->pos;
    133             if ( dist < 0 )
    134               dist = -dist;
    135 
    136             if ( num_widths < AF_LATIN_MAX_WIDTHS )
    137               axis->widths[ num_widths++ ].org = dist;
    138           }
    139         }
    140 
    141         af_sort_widths( num_widths, axis->widths );
    142         axis->width_count = num_widths;
    143       }
    144 
    145   Exit:
    146       for ( dim = 0; dim < AF_DIMENSION_MAX; dim++ )
    147       {
    148         AF_LatinAxis  axis = &metrics->axis[dim];
    149         FT_Pos        stdw;
    150 
    151 
    152         stdw = ( axis->width_count > 0 )
    153                  ? axis->widths[0].org
    154                  : AF_LATIN_CONSTANT( metrics, 50 );
    155 
    156         /* let's try 20% of the smallest width */
    157         axis->edge_distance_threshold = stdw / 5;
    158         axis->standard_width          = stdw;
    159         axis->extra_light             = 0;
    160       }
    161     }
    162 
    163     af_glyph_hints_done( hints );
    164   }
    165 
    166 
    167 
    168 #define AF_LATIN_MAX_TEST_CHARACTERS  12
    169 
    170 
    171   static const char af_latin_blue_chars[AF_LATIN_MAX_BLUES]
    172                                        [AF_LATIN_MAX_TEST_CHARACTERS + 1] =
    173   {
    174     "THEZOCQS",
    175     "HEZLOCUS",
    176     "fijkdbh",
    177     "xzroesc",
    178     "xzroesc",
    179     "pqgjy"
    180   };
    181 
    182 
    183   /* Find all blue zones.  Flat segments give the reference points, */
    184   /* round segments the overshoot positions.                        */
    185 
    186   static void
    187   af_latin_metrics_init_blues( AF_LatinMetrics  metrics,
    188                                FT_Face          face )
    189   {
    190     FT_Pos        flats [AF_LATIN_MAX_TEST_CHARACTERS];
    191     FT_Pos        rounds[AF_LATIN_MAX_TEST_CHARACTERS];
    192     FT_Int        num_flats;
    193     FT_Int        num_rounds;
    194     FT_Int        bb;
    195     AF_LatinBlue  blue;
    196     FT_Error      error;
    197     AF_LatinAxis  axis  = &metrics->axis[AF_DIMENSION_VERT];
    198     FT_GlyphSlot  glyph = face->glyph;
    199 
    200 
    201     /* we compute the blues simply by loading each character from the    */
    202     /* `af_latin_blue_chars[blues]' string, then finding its top-most or */
    203     /* bottom-most points (depending on `AF_IS_TOP_BLUE')                */
    204 
    205     FT_TRACE5(( "blue zones computation\n" ));
    206     FT_TRACE5(( "------------------------------------------------\n" ));
    207 
    208     for ( bb = 0; bb < AF_LATIN_BLUE_MAX; bb++ )
    209     {
    210       const char*  p     = af_latin_blue_chars[bb];
    211       const char*  limit = p + AF_LATIN_MAX_TEST_CHARACTERS;
    212       FT_Pos*      blue_ref;
    213       FT_Pos*      blue_shoot;
    214 
    215 
    216       FT_TRACE5(( "blue %3d: ", bb ));
    217 
    218       num_flats  = 0;
    219       num_rounds = 0;
    220 
    221       for ( ; p < limit && *p; p++ )
    222       {
    223         FT_UInt     glyph_index;
    224         FT_Pos      best_y; /* same as points.y */
    225         FT_Int      best_point, best_first, best_last;
    226         FT_Vector*  points;
    227         FT_Bool     round = 0;
    228 
    229 
    230         FT_TRACE5(( "'%c'", *p ));
    231 
    232         /* load the character in the face -- skip unknown or empty ones */
    233         glyph_index = FT_Get_Char_Index( face, (FT_UInt)*p );
    234         if ( glyph_index == 0 )
    235           continue;
    236 
    237         error = FT_Load_Glyph( face, glyph_index, FT_LOAD_NO_SCALE );
    238         if ( error || glyph->outline.n_points <= 0 )
    239           continue;
    240 
    241         /* now compute min or max point indices and coordinates */
    242         points      = glyph->outline.points;
    243         best_point  = -1;
    244         best_y      = 0;  /* make compiler happy */
    245         best_first  = 0;  /* ditto */
    246         best_last   = 0;  /* ditto */
    247 
    248         {
    249           FT_Int  nn;
    250           FT_Int  first = 0;
    251           FT_Int  last  = -1;
    252 
    253 
    254           for ( nn = 0;
    255                 nn < glyph->outline.n_contours;
    256                 first = last + 1, nn++ )
    257           {
    258             FT_Int  old_best_point = best_point;
    259             FT_Int  pp;
    260 
    261 
    262             last = glyph->outline.contours[nn];
    263 
    264             /* Avoid single-point contours since they are never rasterized. */
    265             /* In some fonts, they correspond to mark attachment points     */
    266             /* which are way outside of the glyph's real outline.           */
    267             if ( last <= first )
    268                 continue;
    269 
    270             if ( AF_LATIN_IS_TOP_BLUE( bb ) )
    271             {
    272               for ( pp = first; pp <= last; pp++ )
    273                 if ( best_point < 0 || points[pp].y > best_y )
    274                 {
    275                   best_point = pp;
    276                   best_y     = points[pp].y;
    277                 }
    278             }
    279             else
    280             {
    281               for ( pp = first; pp <= last; pp++ )
    282                 if ( best_point < 0 || points[pp].y < best_y )
    283                 {
    284                   best_point = pp;
    285                   best_y     = points[pp].y;
    286                 }
    287             }
    288 
    289             if ( best_point != old_best_point )
    290             {
    291               best_first = first;
    292               best_last  = last;
    293             }
    294           }
    295           FT_TRACE5(( "%5d", best_y ));
    296         }
    297 
    298         /* now check whether the point belongs to a straight or round   */
    299         /* segment; we first need to find in which contour the extremum */
    300         /* lies, then inspect its previous and next points              */
    301         if ( best_point >= 0 )
    302         {
    303           FT_Int  prev, next;
    304           FT_Pos  dist;
    305 
    306 
    307           /* now look for the previous and next points that are not on the */
    308           /* same Y coordinate.  Threshold the `closeness'...              */
    309           prev = best_point;
    310           next = prev;
    311 
    312           do
    313           {
    314             if ( prev > best_first )
    315               prev--;
    316             else
    317               prev = best_last;
    318 
    319             dist = points[prev].y - best_y;
    320             if ( dist < -5 || dist > 5 )
    321               break;
    322 
    323           } while ( prev != best_point );
    324 
    325           do
    326           {
    327             if ( next < best_last )
    328               next++;
    329             else
    330               next = best_first;
    331 
    332             dist = points[next].y - best_y;
    333             if ( dist < -5 || dist > 5 )
    334               break;
    335 
    336           } while ( next != best_point );
    337 
    338           /* now set the `round' flag depending on the segment's kind */
    339           round = FT_BOOL(
    340             FT_CURVE_TAG( glyph->outline.tags[prev] ) != FT_CURVE_TAG_ON ||
    341             FT_CURVE_TAG( glyph->outline.tags[next] ) != FT_CURVE_TAG_ON );
    342 
    343           FT_TRACE5(( "%c ", round ? 'r' : 'f' ));
    344         }
    345 
    346         if ( round )
    347           rounds[num_rounds++] = best_y;
    348         else
    349           flats[num_flats++]   = best_y;
    350       }
    351 
    352       FT_TRACE5(( "\n" ));
    353 
    354       if ( num_flats == 0 && num_rounds == 0 )
    355       {
    356         /*
    357          *  we couldn't find a single glyph to compute this blue zone,
    358          *  we will simply ignore it then
    359          */
    360         FT_TRACE5(( "empty\n" ));
    361         continue;
    362       }
    363 
    364       /* we have computed the contents of the `rounds' and `flats' tables, */
    365       /* now determine the reference and overshoot position of the blue -- */
    366       /* we simply take the median value after a simple sort               */
    367       af_sort_pos( num_rounds, rounds );
    368       af_sort_pos( num_flats,  flats );
    369 
    370       blue       = & axis->blues[axis->blue_count];
    371       blue_ref   = & blue->ref.org;
    372       blue_shoot = & blue->shoot.org;
    373 
    374       axis->blue_count++;
    375 
    376       if ( num_flats == 0 )
    377       {
    378         *blue_ref   =
    379         *blue_shoot = rounds[num_rounds / 2];
    380       }
    381       else if ( num_rounds == 0 )
    382       {
    383         *blue_ref   =
    384         *blue_shoot = flats[num_flats / 2];
    385       }
    386       else
    387       {
    388         *blue_ref   = flats[num_flats / 2];
    389         *blue_shoot = rounds[num_rounds / 2];
    390       }
    391 
    392       /* there are sometimes problems: if the overshoot position of top     */
    393       /* zones is under its reference position, or the opposite for bottom  */
    394       /* zones.  We must thus check everything there and correct the errors */
    395       if ( *blue_shoot != *blue_ref )
    396       {
    397         FT_Pos   ref      = *blue_ref;
    398         FT_Pos   shoot    = *blue_shoot;
    399         FT_Bool  over_ref = FT_BOOL( shoot > ref );
    400 
    401 
    402         if ( AF_LATIN_IS_TOP_BLUE( bb ) ^ over_ref )
    403           *blue_ref   =
    404           *blue_shoot = ( shoot + ref ) / 2;
    405       }
    406 
    407       blue->flags = 0;
    408       if ( AF_LATIN_IS_TOP_BLUE( bb ) )
    409         blue->flags |= AF_LATIN_BLUE_TOP;
    410 
    411       /*
    412        * The following flag is used later to adjust the y and x scales
    413        * in order to optimize the pixel grid alignment of the top of small
    414        * letters.
    415        */
    416       if ( bb == AF_LATIN_BLUE_SMALL_TOP )
    417         blue->flags |= AF_LATIN_BLUE_ADJUSTMENT;
    418 
    419       FT_TRACE5(( "-- ref = %ld, shoot = %ld\n", *blue_ref, *blue_shoot ));
    420     }
    421 
    422     FT_TRACE5(( "\n" ));
    423 
    424     return;
    425   }
    426 
    427 
    428   /* Check whether all ASCII digits have the same advance width. */
    429 
    430   FT_LOCAL_DEF( void )
    431   af_latin_metrics_check_digits( AF_LatinMetrics  metrics,
    432                                  FT_Face          face )
    433   {
    434     FT_UInt   i;
    435     FT_Bool   started = 0, same_width = 1;
    436     FT_Fixed  advance, old_advance = 0;
    437 
    438 
    439     /* digit `0' is 0x30 in all supported charmaps                 */
    440     for ( i = 0x30; i <= 0x39; i++ )
    441     {
    442       FT_UInt  glyph_index;
    443 
    444 
    445       glyph_index = FT_Get_Char_Index( face, i );
    446       if ( glyph_index == 0 )
    447         continue;
    448 
    449       if ( FT_Get_Advance( face, glyph_index,
    450                            FT_LOAD_NO_SCALE         |
    451                            FT_LOAD_NO_HINTING       |
    452                            FT_LOAD_IGNORE_TRANSFORM,
    453                            &advance ) )
    454         continue;
    455 
    456       if ( started )
    457       {
    458         if ( advance != old_advance )
    459         {
    460           same_width = 0;
    461           break;
    462         }
    463       }
    464       else
    465       {
    466         old_advance = advance;
    467         started     = 1;
    468       }
    469     }
    470 
    471     metrics->root.digits_have_same_width = same_width;
    472   }
    473 
    474 
    475   /* Initialize global metrics. */
    476 
    477   FT_LOCAL_DEF( FT_Error )
    478   af_latin_metrics_init( AF_LatinMetrics  metrics,
    479                          FT_Face          face )
    480   {
    481     FT_Error    error = AF_Err_Ok;
    482     FT_CharMap  oldmap = face->charmap;
    483     FT_UInt     ee;
    484 
    485     static const FT_Encoding  latin_encodings[] =
    486     {
    487       FT_ENCODING_UNICODE,
    488       FT_ENCODING_APPLE_ROMAN,
    489       FT_ENCODING_ADOBE_STANDARD,
    490       FT_ENCODING_ADOBE_LATIN_1,
    491 
    492       FT_ENCODING_NONE  /* end of list */
    493     };
    494 
    495 
    496     metrics->units_per_em = face->units_per_EM;
    497 
    498     /* do we have a latin charmap in there? */
    499     for ( ee = 0; latin_encodings[ee] != FT_ENCODING_NONE; ee++ )
    500     {
    501       error = FT_Select_Charmap( face, latin_encodings[ee] );
    502       if ( !error )
    503         break;
    504     }
    505 
    506     if ( !error )
    507     {
    508       /* For now, compute the standard width and height from the `o'. */
    509       af_latin_metrics_init_widths( metrics, face, 'o' );
    510       af_latin_metrics_init_blues( metrics, face );
    511       af_latin_metrics_check_digits( metrics, face );
    512     }
    513 
    514     FT_Set_Charmap( face, oldmap );
    515     return AF_Err_Ok;
    516   }
    517 
    518 
    519   /* Adjust scaling value, then scale and shift widths   */
    520   /* and blue zones (if applicable) for given dimension. */
    521 
    522   static void
    523   af_latin_metrics_scale_dim( AF_LatinMetrics  metrics,
    524                               AF_Scaler        scaler,
    525                               AF_Dimension     dim )
    526   {
    527     FT_Fixed      scale;
    528     FT_Pos        delta;
    529     AF_LatinAxis  axis;
    530     FT_UInt       nn;
    531 
    532 
    533     if ( dim == AF_DIMENSION_HORZ )
    534     {
    535       scale = scaler->x_scale;
    536       delta = scaler->x_delta;
    537     }
    538     else
    539     {
    540       scale = scaler->y_scale;
    541       delta = scaler->y_delta;
    542     }
    543 
    544     axis = &metrics->axis[dim];
    545 
    546     if ( axis->org_scale == scale && axis->org_delta == delta )
    547       return;
    548 
    549     axis->org_scale = scale;
    550     axis->org_delta = delta;
    551 
    552     /*
    553      * correct X and Y scale to optimize the alignment of the top of small
    554      * letters to the pixel grid
    555      */
    556     {
    557       AF_LatinAxis  Axis = &metrics->axis[AF_DIMENSION_VERT];
    558       AF_LatinBlue  blue = NULL;
    559 
    560 
    561       for ( nn = 0; nn < Axis->blue_count; nn++ )
    562       {
    563         if ( Axis->blues[nn].flags & AF_LATIN_BLUE_ADJUSTMENT )
    564         {
    565           blue = &Axis->blues[nn];
    566           break;
    567         }
    568       }
    569 
    570       if ( blue )
    571       {
    572         FT_Pos  scaled = FT_MulFix( blue->shoot.org, scaler->y_scale );
    573         FT_Pos  fitted = ( scaled + 40 ) & ~63;
    574 
    575 
    576         if ( scaled != fitted )
    577         {
    578 #if 0
    579           if ( dim == AF_DIMENSION_HORZ )
    580           {
    581             if ( fitted < scaled )
    582               scale -= scale / 50;  /* scale *= 0.98 */
    583           }
    584           else
    585 #endif
    586           if ( dim == AF_DIMENSION_VERT )
    587             scale = FT_MulDiv( scale, fitted, scaled );
    588         }
    589       }
    590     }
    591 
    592     axis->scale = scale;
    593     axis->delta = delta;
    594 
    595     if ( dim == AF_DIMENSION_HORZ )
    596     {
    597       metrics->root.scaler.x_scale = scale;
    598       metrics->root.scaler.x_delta = delta;
    599     }
    600     else
    601     {
    602       metrics->root.scaler.y_scale = scale;
    603       metrics->root.scaler.y_delta = delta;
    604     }
    605 
    606     /* scale the widths */
    607     for ( nn = 0; nn < axis->width_count; nn++ )
    608     {
    609       AF_Width  width = axis->widths + nn;
    610 
    611 
    612       width->cur = FT_MulFix( width->org, scale );
    613       width->fit = width->cur;
    614     }
    615 
    616     /* an extra-light axis corresponds to a standard width that is */
    617     /* smaller than 5/8 pixels                                     */
    618     axis->extra_light =
    619       (FT_Bool)( FT_MulFix( axis->standard_width, scale ) < 32 + 8 );
    620 
    621     if ( dim == AF_DIMENSION_VERT )
    622     {
    623       /* scale the blue zones */
    624       for ( nn = 0; nn < axis->blue_count; nn++ )
    625       {
    626         AF_LatinBlue  blue = &axis->blues[nn];
    627         FT_Pos        dist;
    628 
    629 
    630         blue->ref.cur   = FT_MulFix( blue->ref.org, scale ) + delta;
    631         blue->ref.fit   = blue->ref.cur;
    632         blue->shoot.cur = FT_MulFix( blue->shoot.org, scale ) + delta;
    633         blue->shoot.fit = blue->shoot.cur;
    634         blue->flags    &= ~AF_LATIN_BLUE_ACTIVE;
    635 
    636         /* a blue zone is only active if it is less than 3/4 pixels tall */
    637         dist = FT_MulFix( blue->ref.org - blue->shoot.org, scale );
    638         if ( dist <= 48 && dist >= -48 )
    639         {
    640 #if 0
    641           FT_Pos  delta1;
    642 #endif
    643           FT_Pos  delta2;
    644 
    645 
    646           /* use discrete values for blue zone widths */
    647 
    648 #if 0
    649 
    650           /* generic, original code */
    651           delta1 = blue->shoot.org - blue->ref.org;
    652           delta2 = delta1;
    653           if ( delta1 < 0 )
    654             delta2 = -delta2;
    655 
    656           delta2 = FT_MulFix( delta2, scale );
    657 
    658           if ( delta2 < 32 )
    659             delta2 = 0;
    660           else if ( delta2 < 64 )
    661             delta2 = 32 + ( ( ( delta2 - 32 ) + 16 ) & ~31 );
    662           else
    663             delta2 = FT_PIX_ROUND( delta2 );
    664 
    665           if ( delta1 < 0 )
    666             delta2 = -delta2;
    667 
    668           blue->ref.fit   = FT_PIX_ROUND( blue->ref.cur );
    669           blue->shoot.fit = blue->ref.fit + delta2;
    670 
    671 #else
    672 
    673           /* simplified version due to abs(dist) <= 48 */
    674           delta2 = dist;
    675           if ( dist < 0 )
    676             delta2 = -delta2;
    677 
    678           if ( delta2 < 32 )
    679             delta2 = 0;
    680           else if ( delta < 48 )
    681             delta2 = 32;
    682           else
    683             delta2 = 64;
    684 
    685           if ( dist < 0 )
    686             delta2 = -delta2;
    687 
    688           blue->ref.fit   = FT_PIX_ROUND( blue->ref.cur );
    689           blue->shoot.fit = blue->ref.fit - delta2;
    690 
    691 #endif
    692 
    693           blue->flags |= AF_LATIN_BLUE_ACTIVE;
    694         }
    695       }
    696     }
    697   }
    698 
    699 
    700   /* Scale global values in both directions. */
    701 
    702   FT_LOCAL_DEF( void )
    703   af_latin_metrics_scale( AF_LatinMetrics  metrics,
    704                           AF_Scaler        scaler )
    705   {
    706     metrics->root.scaler.render_mode = scaler->render_mode;
    707     metrics->root.scaler.face        = scaler->face;
    708 
    709     af_latin_metrics_scale_dim( metrics, scaler, AF_DIMENSION_HORZ );
    710     af_latin_metrics_scale_dim( metrics, scaler, AF_DIMENSION_VERT );
    711   }
    712 
    713 
    714   /*************************************************************************/
    715   /*************************************************************************/
    716   /*****                                                               *****/
    717   /*****           L A T I N   G L Y P H   A N A L Y S I S             *****/
    718   /*****                                                               *****/
    719   /*************************************************************************/
    720   /*************************************************************************/
    721 
    722 
    723   /* Walk over all contours and compute its segments. */
    724 
    725   FT_LOCAL_DEF( FT_Error )
    726   af_latin_hints_compute_segments( AF_GlyphHints  hints,
    727                                    AF_Dimension   dim )
    728   {
    729     AF_AxisHints  axis          = &hints->axis[dim];
    730     FT_Memory     memory        = hints->memory;
    731     FT_Error      error         = AF_Err_Ok;
    732     AF_Segment    segment       = NULL;
    733     AF_SegmentRec seg0;
    734     AF_Point*     contour       = hints->contours;
    735     AF_Point*     contour_limit = contour + hints->num_contours;
    736     AF_Direction  major_dir, segment_dir;
    737 
    738 
    739     FT_ZERO( &seg0 );
    740     seg0.score = 32000;
    741     seg0.flags = AF_EDGE_NORMAL;
    742 
    743     major_dir   = (AF_Direction)FT_ABS( axis->major_dir );
    744     segment_dir = major_dir;
    745 
    746     axis->num_segments = 0;
    747 
    748     /* set up (u,v) in each point */
    749     if ( dim == AF_DIMENSION_HORZ )
    750     {
    751       AF_Point  point = hints->points;
    752       AF_Point  limit = point + hints->num_points;
    753 
    754 
    755       for ( ; point < limit; point++ )
    756       {
    757         point->u = point->fx;
    758         point->v = point->fy;
    759       }
    760     }
    761     else
    762     {
    763       AF_Point  point = hints->points;
    764       AF_Point  limit = point + hints->num_points;
    765 
    766 
    767       for ( ; point < limit; point++ )
    768       {
    769         point->u = point->fy;
    770         point->v = point->fx;
    771       }
    772     }
    773 
    774     /* do each contour separately */
    775     for ( ; contour < contour_limit; contour++ )
    776     {
    777       AF_Point  point   =  contour[0];
    778       AF_Point  last    =  point->prev;
    779       int       on_edge =  0;
    780       FT_Pos    min_pos =  32000;  /* minimum segment pos != min_coord */
    781       FT_Pos    max_pos = -32000;  /* maximum segment pos != max_coord */
    782       FT_Bool   passed;
    783 
    784 
    785       if ( point == last )  /* skip singletons -- just in case */
    786         continue;
    787 
    788       if ( FT_ABS( last->out_dir )  == major_dir &&
    789            FT_ABS( point->out_dir ) == major_dir )
    790       {
    791         /* we are already on an edge, try to locate its start */
    792         last = point;
    793 
    794         for (;;)
    795         {
    796           point = point->prev;
    797           if ( FT_ABS( point->out_dir ) != major_dir )
    798           {
    799             point = point->next;
    800             break;
    801           }
    802           if ( point == last )
    803             break;
    804         }
    805       }
    806 
    807       last   = point;
    808       passed = 0;
    809 
    810       for (;;)
    811       {
    812         FT_Pos  u, v;
    813 
    814 
    815         if ( on_edge )
    816         {
    817           u = point->u;
    818           if ( u < min_pos )
    819             min_pos = u;
    820           if ( u > max_pos )
    821             max_pos = u;
    822 
    823           if ( point->out_dir != segment_dir || point == last )
    824           {
    825             /* we are just leaving an edge; record a new segment! */
    826             segment->last = point;
    827             segment->pos  = (FT_Short)( ( min_pos + max_pos ) >> 1 );
    828 
    829             /* a segment is round if either its first or last point */
    830             /* is a control point                                   */
    831             if ( ( segment->first->flags | point->flags ) &
    832                    AF_FLAG_CONTROL                        )
    833               segment->flags |= AF_EDGE_ROUND;
    834 
    835             /* compute segment size */
    836             min_pos = max_pos = point->v;
    837 
    838             v = segment->first->v;
    839             if ( v < min_pos )
    840               min_pos = v;
    841             if ( v > max_pos )
    842               max_pos = v;
    843 
    844             segment->min_coord = (FT_Short)min_pos;
    845             segment->max_coord = (FT_Short)max_pos;
    846             segment->height    = (FT_Short)( segment->max_coord -
    847                                              segment->min_coord );
    848 
    849             on_edge = 0;
    850             segment = NULL;
    851             /* fallthrough */
    852           }
    853         }
    854 
    855         /* now exit if we are at the start/end point */
    856         if ( point == last )
    857         {
    858           if ( passed )
    859             break;
    860           passed = 1;
    861         }
    862 
    863         if ( !on_edge && FT_ABS( point->out_dir ) == major_dir )
    864         {
    865           /* this is the start of a new segment! */
    866           segment_dir = (AF_Direction)point->out_dir;
    867 
    868           /* clear all segment fields */
    869           error = af_axis_hints_new_segment( axis, memory, &segment );
    870           if ( error )
    871             goto Exit;
    872 
    873           segment[0]        = seg0;
    874           segment->dir      = (FT_Char)segment_dir;
    875           min_pos = max_pos = point->u;
    876           segment->first    = point;
    877           segment->last     = point;
    878           on_edge           = 1;
    879         }
    880 
    881         point = point->next;
    882       }
    883 
    884     } /* contours */
    885 
    886 
    887     /* now slightly increase the height of segments when this makes */
    888     /* sense -- this is used to better detect and ignore serifs     */
    889     {
    890       AF_Segment  segments     = axis->segments;
    891       AF_Segment  segments_end = segments + axis->num_segments;
    892 
    893 
    894       for ( segment = segments; segment < segments_end; segment++ )
    895       {
    896         AF_Point  first   = segment->first;
    897         AF_Point  last    = segment->last;
    898         FT_Pos    first_v = first->v;
    899         FT_Pos    last_v  = last->v;
    900 
    901 
    902         if ( first == last )
    903           continue;
    904 
    905         if ( first_v < last_v )
    906         {
    907           AF_Point  p;
    908 
    909 
    910           p = first->prev;
    911           if ( p->v < first_v )
    912             segment->height = (FT_Short)( segment->height +
    913                                           ( ( first_v - p->v ) >> 1 ) );
    914 
    915           p = last->next;
    916           if ( p->v > last_v )
    917             segment->height = (FT_Short)( segment->height +
    918                                           ( ( p->v - last_v ) >> 1 ) );
    919         }
    920         else
    921         {
    922           AF_Point  p;
    923 
    924 
    925           p = first->prev;
    926           if ( p->v > first_v )
    927             segment->height = (FT_Short)( segment->height +
    928                                           ( ( p->v - first_v ) >> 1 ) );
    929 
    930           p = last->next;
    931           if ( p->v < last_v )
    932             segment->height = (FT_Short)( segment->height +
    933                                           ( ( last_v - p->v ) >> 1 ) );
    934         }
    935       }
    936     }
    937 
    938   Exit:
    939     return error;
    940   }
    941 
    942 
    943   /* Link segments to form stems and serifs. */
    944 
    945   FT_LOCAL_DEF( void )
    946   af_latin_hints_link_segments( AF_GlyphHints  hints,
    947                                 AF_Dimension   dim )
    948   {
    949     AF_AxisHints  axis          = &hints->axis[dim];
    950     AF_Segment    segments      = axis->segments;
    951     AF_Segment    segment_limit = segments + axis->num_segments;
    952     FT_Pos        len_threshold, len_score;
    953     AF_Segment    seg1, seg2;
    954 
    955 
    956     len_threshold = AF_LATIN_CONSTANT( hints->metrics, 8 );
    957     if ( len_threshold == 0 )
    958       len_threshold = 1;
    959 
    960     len_score = AF_LATIN_CONSTANT( hints->metrics, 6000 );
    961 
    962     /* now compare each segment to the others */
    963     for ( seg1 = segments; seg1 < segment_limit; seg1++ )
    964     {
    965       /* the fake segments are introduced to hint the metrics -- */
    966       /* we must never link them to anything                     */
    967       if ( seg1->dir != axis->major_dir || seg1->first == seg1->last )
    968         continue;
    969 
    970       /* search for stems having opposite directions, */
    971       /* with seg1 to the `left' of seg2              */
    972       for ( seg2 = segments; seg2 < segment_limit; seg2++ )
    973         {
    974           FT_Pos  pos1 = seg1->pos;
    975           FT_Pos  pos2 = seg2->pos;
    976 
    977 
    978         if ( seg1->dir + seg2->dir == 0 && pos2 > pos1 )
    979         {
    980           /* compute distance between the two segments */
    981           FT_Pos  dist = pos2 - pos1;
    982             FT_Pos  min = seg1->min_coord;
    983             FT_Pos  max = seg1->max_coord;
    984             FT_Pos  len, score;
    985 
    986 
    987             if ( min < seg2->min_coord )
    988               min = seg2->min_coord;
    989 
    990             if ( max > seg2->max_coord )
    991               max = seg2->max_coord;
    992 
    993           /* compute maximum coordinate difference of the two segments */
    994             len = max - min;
    995             if ( len >= len_threshold )
    996             {
    997             /* small coordinate differences cause a higher score, and     */
    998             /* segments with a greater distance cause a higher score also */
    999               score = dist + len_score / len;
   1000 
   1001             /* and we search for the smallest score */
   1002             /* of the sum of the two values         */
   1003               if ( score < seg1->score )
   1004               {
   1005                 seg1->score = score;
   1006                 seg1->link  = seg2;
   1007               }
   1008 
   1009               if ( score < seg2->score )
   1010               {
   1011                 seg2->score = score;
   1012                 seg2->link  = seg1;
   1013               }
   1014             }
   1015           }
   1016         }
   1017     }
   1018 
   1019     /* now compute the `serif' segments, cf. explanations in `afhints.h' */
   1020     for ( seg1 = segments; seg1 < segment_limit; seg1++ )
   1021     {
   1022       seg2 = seg1->link;
   1023 
   1024       if ( seg2 )
   1025       {
   1026         if ( seg2->link != seg1 )
   1027         {
   1028           seg1->link  = 0;
   1029           seg1->serif = seg2->link;
   1030         }
   1031       }
   1032     }
   1033   }
   1034 
   1035 
   1036   /* Link segments to edges, using feature analysis for selection. */
   1037 
   1038   FT_LOCAL_DEF( FT_Error )
   1039   af_latin_hints_compute_edges( AF_GlyphHints  hints,
   1040                                 AF_Dimension   dim )
   1041   {
   1042     AF_AxisHints  axis   = &hints->axis[dim];
   1043     FT_Error      error  = AF_Err_Ok;
   1044     FT_Memory     memory = hints->memory;
   1045     AF_LatinAxis  laxis  = &((AF_LatinMetrics)hints->metrics)->axis[dim];
   1046 
   1047     AF_Segment    segments      = axis->segments;
   1048     AF_Segment    segment_limit = segments + axis->num_segments;
   1049     AF_Segment    seg;
   1050 
   1051 #if 0
   1052     AF_Direction  up_dir;
   1053 #endif
   1054     FT_Fixed      scale;
   1055     FT_Pos        edge_distance_threshold;
   1056     FT_Pos        segment_length_threshold;
   1057 
   1058 
   1059     axis->num_edges = 0;
   1060 
   1061     scale = ( dim == AF_DIMENSION_HORZ ) ? hints->x_scale
   1062                                          : hints->y_scale;
   1063 
   1064 #if 0
   1065     up_dir = ( dim == AF_DIMENSION_HORZ ) ? AF_DIR_UP
   1066                                           : AF_DIR_RIGHT;
   1067 #endif
   1068 
   1069     /*
   1070      *  We ignore all segments that are less than 1 pixel in length
   1071      *  to avoid many problems with serif fonts.  We compute the
   1072      *  corresponding threshold in font units.
   1073      */
   1074     if ( dim == AF_DIMENSION_HORZ )
   1075         segment_length_threshold = FT_DivFix( 64, hints->y_scale );
   1076     else
   1077         segment_length_threshold = 0;
   1078 
   1079     /*********************************************************************/
   1080     /*                                                                   */
   1081     /* We begin by generating a sorted table of edges for the current    */
   1082     /* direction.  To do so, we simply scan each segment and try to find */
   1083     /* an edge in our table that corresponds to its position.            */
   1084     /*                                                                   */
   1085     /* If no edge is found, we create and insert a new edge in the       */
   1086     /* sorted table.  Otherwise, we simply add the segment to the edge's */
   1087     /* list which gets processed in the second step to compute the       */
   1088     /* edge's properties.                                                */
   1089     /*                                                                   */
   1090     /* Note that the table of edges is sorted along the segment/edge     */
   1091     /* position.                                                         */
   1092     /*                                                                   */
   1093     /*********************************************************************/
   1094 
   1095     /* assure that edge distance threshold is at most 0.25px */
   1096     edge_distance_threshold = FT_MulFix( laxis->edge_distance_threshold,
   1097                                          scale );
   1098     if ( edge_distance_threshold > 64 / 4 )
   1099       edge_distance_threshold = 64 / 4;
   1100 
   1101     edge_distance_threshold = FT_DivFix( edge_distance_threshold,
   1102                                          scale );
   1103 
   1104     for ( seg = segments; seg < segment_limit; seg++ )
   1105     {
   1106       AF_Edge  found = NULL;
   1107       FT_Int   ee;
   1108 
   1109 
   1110       if ( seg->height < segment_length_threshold )
   1111         continue;
   1112 
   1113       /* A special case for serif edges: If they are smaller than */
   1114       /* 1.5 pixels we ignore them.                               */
   1115       if ( seg->serif                                     &&
   1116            2 * seg->height < 3 * segment_length_threshold )
   1117         continue;
   1118 
   1119       /* look for an edge corresponding to the segment */
   1120       for ( ee = 0; ee < axis->num_edges; ee++ )
   1121       {
   1122         AF_Edge  edge = axis->edges + ee;
   1123         FT_Pos   dist;
   1124 
   1125 
   1126         dist = seg->pos - edge->fpos;
   1127         if ( dist < 0 )
   1128           dist = -dist;
   1129 
   1130         if ( dist < edge_distance_threshold && edge->dir == seg->dir )
   1131         {
   1132           found = edge;
   1133           break;
   1134         }
   1135       }
   1136 
   1137       if ( !found )
   1138       {
   1139         AF_Edge  edge;
   1140 
   1141 
   1142         /* insert a new edge in the list and */
   1143         /* sort according to the position    */
   1144         error = af_axis_hints_new_edge( axis, seg->pos,
   1145                                         (AF_Direction)seg->dir,
   1146                                         memory, &edge );
   1147         if ( error )
   1148           goto Exit;
   1149 
   1150         /* add the segment to the new edge's list */
   1151         FT_ZERO( edge );
   1152 
   1153         edge->first    = seg;
   1154         edge->last     = seg;
   1155         edge->dir      = seg->dir;
   1156         edge->fpos     = seg->pos;
   1157         edge->opos     = FT_MulFix( seg->pos, scale );
   1158         edge->pos      = edge->opos;
   1159         seg->edge_next = seg;
   1160       }
   1161       else
   1162       {
   1163         /* if an edge was found, simply add the segment to the edge's */
   1164         /* list                                                       */
   1165         seg->edge_next         = found->first;
   1166         found->last->edge_next = seg;
   1167         found->last            = seg;
   1168       }
   1169     }
   1170 
   1171 
   1172     /*********************************************************************/
   1173     /*                                                                   */
   1174     /* Good, we will now compute each edge's properties according to     */
   1175     /* the segments found on its position.  Basically, these are         */
   1176     /*                                                                   */
   1177     /*  - the edge's main direction                                      */
   1178     /*  - stem edge, serif edge or both (which defaults to stem then)    */
   1179     /*  - rounded edge, straight or both (which defaults to straight)    */
   1180     /*  - link for edge                                                  */
   1181     /*                                                                   */
   1182     /*********************************************************************/
   1183 
   1184     /* first of all, set the `edge' field in each segment -- this is */
   1185     /* required in order to compute edge links                       */
   1186 
   1187     /*
   1188      * Note that removing this loop and setting the `edge' field of each
   1189      * segment directly in the code above slows down execution speed for
   1190      * some reasons on platforms like the Sun.
   1191      */
   1192     {
   1193       AF_Edge  edges      = axis->edges;
   1194       AF_Edge  edge_limit = edges + axis->num_edges;
   1195       AF_Edge  edge;
   1196 
   1197 
   1198       for ( edge = edges; edge < edge_limit; edge++ )
   1199       {
   1200         seg = edge->first;
   1201         if ( seg )
   1202           do
   1203           {
   1204             seg->edge = edge;
   1205             seg       = seg->edge_next;
   1206 
   1207           } while ( seg != edge->first );
   1208       }
   1209 
   1210       /* now compute each edge properties */
   1211       for ( edge = edges; edge < edge_limit; edge++ )
   1212       {
   1213         FT_Int  is_round    = 0;  /* does it contain round segments?    */
   1214         FT_Int  is_straight = 0;  /* does it contain straight segments? */
   1215 #if 0
   1216         FT_Pos  ups         = 0;  /* number of upwards segments         */
   1217         FT_Pos  downs       = 0;  /* number of downwards segments       */
   1218 #endif
   1219 
   1220 
   1221         seg = edge->first;
   1222 
   1223         do
   1224         {
   1225           FT_Bool  is_serif;
   1226 
   1227 
   1228           /* check for roundness of segment */
   1229           if ( seg->flags & AF_EDGE_ROUND )
   1230             is_round++;
   1231           else
   1232             is_straight++;
   1233 
   1234 #if 0
   1235           /* check for segment direction */
   1236           if ( seg->dir == up_dir )
   1237             ups   += seg->max_coord-seg->min_coord;
   1238           else
   1239             downs += seg->max_coord-seg->min_coord;
   1240 #endif
   1241 
   1242           /* check for links -- if seg->serif is set, then seg->link must */
   1243           /* be ignored                                                   */
   1244           is_serif = (FT_Bool)( seg->serif               &&
   1245                                 seg->serif->edge         &&
   1246                                 seg->serif->edge != edge );
   1247 
   1248           if ( ( seg->link && seg->link->edge != NULL ) || is_serif )
   1249           {
   1250             AF_Edge     edge2;
   1251             AF_Segment  seg2;
   1252 
   1253 
   1254             edge2 = edge->link;
   1255             seg2  = seg->link;
   1256 
   1257             if ( is_serif )
   1258             {
   1259               seg2  = seg->serif;
   1260               edge2 = edge->serif;
   1261             }
   1262 
   1263             if ( edge2 )
   1264             {
   1265               FT_Pos  edge_delta;
   1266               FT_Pos  seg_delta;
   1267 
   1268 
   1269               edge_delta = edge->fpos - edge2->fpos;
   1270               if ( edge_delta < 0 )
   1271                 edge_delta = -edge_delta;
   1272 
   1273               seg_delta = seg->pos - seg2->pos;
   1274               if ( seg_delta < 0 )
   1275                 seg_delta = -seg_delta;
   1276 
   1277               if ( seg_delta < edge_delta )
   1278                 edge2 = seg2->edge;
   1279             }
   1280             else
   1281               edge2 = seg2->edge;
   1282 
   1283             if ( is_serif )
   1284             {
   1285               edge->serif   = edge2;
   1286               edge2->flags |= AF_EDGE_SERIF;
   1287             }
   1288             else
   1289               edge->link  = edge2;
   1290           }
   1291 
   1292           seg = seg->edge_next;
   1293 
   1294         } while ( seg != edge->first );
   1295 
   1296         /* set the round/straight flags */
   1297         edge->flags = AF_EDGE_NORMAL;
   1298 
   1299         if ( is_round > 0 && is_round >= is_straight )
   1300           edge->flags |= AF_EDGE_ROUND;
   1301 
   1302 #if 0
   1303         /* set the edge's main direction */
   1304         edge->dir = AF_DIR_NONE;
   1305 
   1306         if ( ups > downs )
   1307           edge->dir = (FT_Char)up_dir;
   1308 
   1309         else if ( ups < downs )
   1310           edge->dir = (FT_Char)-up_dir;
   1311 
   1312         else if ( ups == downs )
   1313           edge->dir = 0;  /* both up and down! */
   1314 #endif
   1315 
   1316         /* get rid of serifs if link is set                 */
   1317         /* XXX: This gets rid of many unpleasant artefacts! */
   1318         /*      Example: the `c' in cour.pfa at size 13     */
   1319 
   1320         if ( edge->serif && edge->link )
   1321           edge->serif = 0;
   1322       }
   1323     }
   1324 
   1325   Exit:
   1326     return error;
   1327   }
   1328 
   1329 
   1330   /* Detect segments and edges for given dimension. */
   1331 
   1332   FT_LOCAL_DEF( FT_Error )
   1333   af_latin_hints_detect_features( AF_GlyphHints  hints,
   1334                                   AF_Dimension   dim )
   1335   {
   1336     FT_Error  error;
   1337 
   1338 
   1339     error = af_latin_hints_compute_segments( hints, dim );
   1340     if ( !error )
   1341     {
   1342       af_latin_hints_link_segments( hints, dim );
   1343 
   1344       error = af_latin_hints_compute_edges( hints, dim );
   1345     }
   1346 
   1347     return error;
   1348   }
   1349 
   1350 
   1351   /* Compute all edges which lie within blue zones. */
   1352 
   1353   FT_LOCAL_DEF( void )
   1354   af_latin_hints_compute_blue_edges( AF_GlyphHints    hints,
   1355                                      AF_LatinMetrics  metrics )
   1356   {
   1357     AF_AxisHints  axis       = &hints->axis[ AF_DIMENSION_VERT ];
   1358     AF_Edge       edge       = axis->edges;
   1359     AF_Edge       edge_limit = edge + axis->num_edges;
   1360     AF_LatinAxis  latin      = &metrics->axis[ AF_DIMENSION_VERT ];
   1361     FT_Fixed      scale      = latin->scale;
   1362 
   1363 
   1364     /* compute which blue zones are active, i.e. have their scaled */
   1365     /* size < 3/4 pixels                                           */
   1366 
   1367     /* for each horizontal edge search the blue zone which is closest */
   1368     for ( ; edge < edge_limit; edge++ )
   1369     {
   1370       FT_Int    bb;
   1371       AF_Width  best_blue = NULL;
   1372       FT_Pos    best_dist;  /* initial threshold */
   1373 
   1374 
   1375       /* compute the initial threshold as a fraction of the EM size */
   1376       /* (the value 40 is heuristic)                                */
   1377       best_dist = FT_MulFix( metrics->units_per_em / 40, scale );
   1378 
   1379       /* assure a minimum distance of 0.5px */
   1380       if ( best_dist > 64 / 2 )
   1381         best_dist = 64 / 2;
   1382 
   1383       for ( bb = 0; bb < AF_LATIN_BLUE_MAX; bb++ )
   1384       {
   1385         AF_LatinBlue  blue = latin->blues + bb;
   1386         FT_Bool       is_top_blue, is_major_dir;
   1387 
   1388 
   1389         /* skip inactive blue zones (i.e., those that are too large) */
   1390         if ( !( blue->flags & AF_LATIN_BLUE_ACTIVE ) )
   1391           continue;
   1392 
   1393         /* if it is a top zone, check for right edges -- if it is a bottom */
   1394         /* zone, check for left edges                                      */
   1395         /*                                                                 */
   1396         /* of course, that's for TrueType                                  */
   1397         is_top_blue  = (FT_Byte)( ( blue->flags & AF_LATIN_BLUE_TOP ) != 0 );
   1398         is_major_dir = FT_BOOL( edge->dir == axis->major_dir );
   1399 
   1400         /* if it is a top zone, the edge must be against the major    */
   1401         /* direction; if it is a bottom zone, it must be in the major */
   1402         /* direction                                                  */
   1403         if ( is_top_blue ^ is_major_dir )
   1404         {
   1405           FT_Pos  dist;
   1406 
   1407 
   1408           /* first of all, compare it to the reference position */
   1409           dist = edge->fpos - blue->ref.org;
   1410           if ( dist < 0 )
   1411             dist = -dist;
   1412 
   1413           dist = FT_MulFix( dist, scale );
   1414           if ( dist < best_dist )
   1415           {
   1416             best_dist = dist;
   1417             best_blue = & blue->ref;
   1418           }
   1419 
   1420           /* now compare it to the overshoot position and check whether */
   1421           /* the edge is rounded, and whether the edge is over the      */
   1422           /* reference position of a top zone, or under the reference   */
   1423           /* position of a bottom zone                                  */
   1424           if ( edge->flags & AF_EDGE_ROUND && dist != 0 )
   1425           {
   1426             FT_Bool  is_under_ref = FT_BOOL( edge->fpos < blue->ref.org );
   1427 
   1428 
   1429             if ( is_top_blue ^ is_under_ref )
   1430             {
   1431               dist = edge->fpos - blue->shoot.org;
   1432               if ( dist < 0 )
   1433                 dist = -dist;
   1434 
   1435               dist = FT_MulFix( dist, scale );
   1436               if ( dist < best_dist )
   1437               {
   1438                 best_dist = dist;
   1439                 best_blue = & blue->shoot;
   1440               }
   1441             }
   1442           }
   1443         }
   1444       }
   1445 
   1446       if ( best_blue )
   1447         edge->blue_edge = best_blue;
   1448     }
   1449   }
   1450 
   1451 
   1452   /* Initalize hinting engine. */
   1453 
   1454   static FT_Error
   1455   af_latin_hints_init( AF_GlyphHints    hints,
   1456                        AF_LatinMetrics  metrics )
   1457   {
   1458     FT_Render_Mode  mode;
   1459     FT_UInt32       scaler_flags, other_flags;
   1460     FT_Face         face = metrics->root.scaler.face;
   1461 
   1462 
   1463     af_glyph_hints_rescale( hints, (AF_ScriptMetrics)metrics );
   1464 
   1465     /*
   1466      *  correct x_scale and y_scale if needed, since they may have
   1467      *  been modified by `af_latin_metrics_scale_dim' above
   1468      */
   1469     hints->x_scale = metrics->axis[AF_DIMENSION_HORZ].scale;
   1470     hints->x_delta = metrics->axis[AF_DIMENSION_HORZ].delta;
   1471     hints->y_scale = metrics->axis[AF_DIMENSION_VERT].scale;
   1472     hints->y_delta = metrics->axis[AF_DIMENSION_VERT].delta;
   1473 
   1474     /* compute flags depending on render mode, etc. */
   1475     mode = metrics->root.scaler.render_mode;
   1476 
   1477 #if 0 /* #ifdef AF_CONFIG_OPTION_USE_WARPER */
   1478     if ( mode == FT_RENDER_MODE_LCD || mode == FT_RENDER_MODE_LCD_V )
   1479     {
   1480       metrics->root.scaler.render_mode = mode = FT_RENDER_MODE_NORMAL;
   1481     }
   1482 #endif
   1483 
   1484     scaler_flags = hints->scaler_flags;
   1485     other_flags  = 0;
   1486 
   1487     /*
   1488      *  We snap the width of vertical stems for the monochrome and
   1489      *  horizontal LCD rendering targets only.
   1490      */
   1491     if ( mode == FT_RENDER_MODE_MONO || mode == FT_RENDER_MODE_LCD )
   1492       other_flags |= AF_LATIN_HINTS_HORZ_SNAP;
   1493 
   1494     /*
   1495      *  We snap the width of horizontal stems for the monochrome and
   1496      *  vertical LCD rendering targets only.
   1497      */
   1498     if ( mode == FT_RENDER_MODE_MONO || mode == FT_RENDER_MODE_LCD_V )
   1499       other_flags |= AF_LATIN_HINTS_VERT_SNAP;
   1500 
   1501     /*
   1502      *  We adjust stems to full pixels only if we don't use the `light' mode.
   1503      */
   1504     if ( mode != FT_RENDER_MODE_LIGHT )
   1505       other_flags |= AF_LATIN_HINTS_STEM_ADJUST;
   1506 
   1507     if ( mode == FT_RENDER_MODE_MONO )
   1508       other_flags |= AF_LATIN_HINTS_MONO;
   1509 
   1510     /*
   1511      *  In `light' hinting mode we disable horizontal hinting completely.
   1512      *  We also do it if the face is italic.
   1513      */
   1514     if ( mode == FT_RENDER_MODE_LIGHT                    ||
   1515          (face->style_flags & FT_STYLE_FLAG_ITALIC) != 0 )
   1516       scaler_flags |= AF_SCALER_FLAG_NO_HORIZONTAL;
   1517 
   1518     hints->scaler_flags = scaler_flags;
   1519     hints->other_flags  = other_flags;
   1520 
   1521     return AF_Err_Ok;
   1522   }
   1523 
   1524 
   1525   /*************************************************************************/
   1526   /*************************************************************************/
   1527   /*****                                                               *****/
   1528   /*****        L A T I N   G L Y P H   G R I D - F I T T I N G        *****/
   1529   /*****                                                               *****/
   1530   /*************************************************************************/
   1531   /*************************************************************************/
   1532 
   1533   /* Snap a given width in scaled coordinates to one of the */
   1534   /* current standard widths.                               */
   1535 
   1536   static FT_Pos
   1537   af_latin_snap_width( AF_Width  widths,
   1538                        FT_Int    count,
   1539                        FT_Pos    width )
   1540   {
   1541     int     n;
   1542     FT_Pos  best      = 64 + 32 + 2;
   1543     FT_Pos  reference = width;
   1544     FT_Pos  scaled;
   1545 
   1546 
   1547     for ( n = 0; n < count; n++ )
   1548     {
   1549       FT_Pos  w;
   1550       FT_Pos  dist;
   1551 
   1552 
   1553       w = widths[n].cur;
   1554       dist = width - w;
   1555       if ( dist < 0 )
   1556         dist = -dist;
   1557       if ( dist < best )
   1558       {
   1559         best      = dist;
   1560         reference = w;
   1561       }
   1562     }
   1563 
   1564     scaled = FT_PIX_ROUND( reference );
   1565 
   1566     if ( width >= reference )
   1567     {
   1568       if ( width < scaled + 48 )
   1569         width = reference;
   1570     }
   1571     else
   1572     {
   1573       if ( width > scaled - 48 )
   1574         width = reference;
   1575     }
   1576 
   1577     return width;
   1578   }
   1579 
   1580 
   1581   /* Compute the snapped width of a given stem, ignoring very thin ones. */
   1582   /* There is a lot of voodoo in this function; changing the hard-coded  */
   1583   /* parameters influence the whole hinting process.                     */
   1584 
   1585   static FT_Pos
   1586   af_latin_compute_stem_width( AF_GlyphHints  hints,
   1587                                AF_Dimension   dim,
   1588                                FT_Pos         width,
   1589                                AF_Edge_Flags  base_flags,
   1590                                AF_Edge_Flags  stem_flags )
   1591   {
   1592     AF_LatinMetrics  metrics  = (AF_LatinMetrics) hints->metrics;
   1593     AF_LatinAxis     axis     = & metrics->axis[dim];
   1594     FT_Pos           dist     = width;
   1595     FT_Int           sign     = 0;
   1596     FT_Int           vertical = ( dim == AF_DIMENSION_VERT );
   1597 
   1598 
   1599     if ( !AF_LATIN_HINTS_DO_STEM_ADJUST( hints ) ||
   1600           axis->extra_light                      )
   1601       return width;
   1602 
   1603     if ( dist < 0 )
   1604     {
   1605       dist = -width;
   1606       sign = 1;
   1607     }
   1608 
   1609     if ( (  vertical && !AF_LATIN_HINTS_DO_VERT_SNAP( hints ) ) ||
   1610          ( !vertical && !AF_LATIN_HINTS_DO_HORZ_SNAP( hints ) ) )
   1611     {
   1612       /* smooth hinting process: very lightly quantize the stem width */
   1613 
   1614       /* leave the widths of serifs alone */
   1615       if ( ( stem_flags & AF_EDGE_SERIF ) &&
   1616            vertical                       &&
   1617            ( dist < 3 * 64 )              )
   1618         goto Done_Width;
   1619 
   1620       else if ( base_flags & AF_EDGE_ROUND )
   1621       {
   1622         if ( dist < 80 )
   1623           dist = 64;
   1624       }
   1625       else if ( dist < 56 )
   1626         dist = 56;
   1627 
   1628       if ( axis->width_count > 0 )
   1629       {
   1630         FT_Pos  delta;
   1631 
   1632 
   1633         /* compare to standard width */
   1634           delta = dist - axis->widths[0].cur;
   1635 
   1636           if ( delta < 0 )
   1637             delta = -delta;
   1638 
   1639           if ( delta < 40 )
   1640           {
   1641             dist = axis->widths[0].cur;
   1642             if ( dist < 48 )
   1643               dist = 48;
   1644 
   1645             goto Done_Width;
   1646           }
   1647 
   1648         if ( dist < 3 * 64 )
   1649         {
   1650           delta  = dist & 63;
   1651           dist  &= -64;
   1652 
   1653           if ( delta < 10 )
   1654             dist += delta;
   1655 
   1656           else if ( delta < 32 )
   1657             dist += 10;
   1658 
   1659           else if ( delta < 54 )
   1660             dist += 54;
   1661 
   1662           else
   1663             dist += delta;
   1664         }
   1665         else
   1666           dist = ( dist + 32 ) & ~63;
   1667       }
   1668     }
   1669     else
   1670     {
   1671       /* strong hinting process: snap the stem width to integer pixels */
   1672 
   1673       FT_Pos  org_dist = dist;
   1674 
   1675 
   1676       dist = af_latin_snap_width( axis->widths, axis->width_count, dist );
   1677 
   1678       if ( vertical )
   1679       {
   1680         /* in the case of vertical hinting, always round */
   1681         /* the stem heights to integer pixels            */
   1682 
   1683         if ( dist >= 64 )
   1684           dist = ( dist + 16 ) & ~63;
   1685         else
   1686           dist = 64;
   1687       }
   1688       else
   1689       {
   1690         if ( AF_LATIN_HINTS_DO_MONO( hints ) )
   1691         {
   1692           /* monochrome horizontal hinting: snap widths to integer pixels */
   1693           /* with a different threshold                                   */
   1694 
   1695           if ( dist < 64 )
   1696             dist = 64;
   1697           else
   1698             dist = ( dist + 32 ) & ~63;
   1699         }
   1700         else
   1701         {
   1702           /* for horizontal anti-aliased hinting, we adopt a more subtle */
   1703           /* approach: we strengthen small stems, round stems whose size */
   1704           /* is between 1 and 2 pixels to an integer, otherwise nothing  */
   1705 
   1706           if ( dist < 48 )
   1707             dist = ( dist + 64 ) >> 1;
   1708 
   1709           else if ( dist < 128 )
   1710           {
   1711             /* We only round to an integer width if the corresponding */
   1712             /* distortion is less than 1/4 pixel.  Otherwise this     */
   1713             /* makes everything worse since the diagonals, which are  */
   1714             /* not hinted, appear a lot bolder or thinner than the    */
   1715             /* vertical stems.                                        */
   1716 
   1717             FT_Pos  delta;
   1718 
   1719 
   1720             dist = ( dist + 22 ) & ~63;
   1721             delta = dist - org_dist;
   1722             if ( delta < 0 )
   1723               delta = -delta;
   1724 
   1725             if (delta >= 16)
   1726             {
   1727               dist = org_dist;
   1728               if ( dist < 48 )
   1729                 dist = ( dist + 64 ) >> 1;
   1730             }
   1731           }
   1732           else
   1733             /* round otherwise to prevent color fringes in LCD mode */
   1734             dist = ( dist + 32 ) & ~63;
   1735         }
   1736       }
   1737     }
   1738 
   1739   Done_Width:
   1740     if ( sign )
   1741       dist = -dist;
   1742 
   1743     return dist;
   1744   }
   1745 
   1746 
   1747   /* Align one stem edge relative to the previous stem edge. */
   1748 
   1749   static void
   1750   af_latin_align_linked_edge( AF_GlyphHints  hints,
   1751                               AF_Dimension   dim,
   1752                               AF_Edge        base_edge,
   1753                               AF_Edge        stem_edge )
   1754   {
   1755     FT_Pos  dist = stem_edge->opos - base_edge->opos;
   1756 
   1757     FT_Pos  fitted_width = af_latin_compute_stem_width(
   1758                              hints, dim, dist,
   1759                              (AF_Edge_Flags)base_edge->flags,
   1760                              (AF_Edge_Flags)stem_edge->flags );
   1761 
   1762 
   1763     stem_edge->pos = base_edge->pos + fitted_width;
   1764 
   1765     FT_TRACE5(( "  LINK: edge %d (opos=%.2f) linked to (%.2f),"
   1766              "dist was %.2f, now %.2f\n",
   1767              stem_edge-hints->axis[dim].edges, stem_edge->opos / 64.0,
   1768              stem_edge->pos / 64.0, dist / 64.0, fitted_width / 64.0 ));
   1769   }
   1770 
   1771 
   1772   /* Shift the coordinates of the `serif' edge by the same amount */
   1773   /* as the corresponding `base' edge has been moved already.     */
   1774 
   1775   static void
   1776   af_latin_align_serif_edge( AF_GlyphHints  hints,
   1777                              AF_Edge        base,
   1778                              AF_Edge        serif )
   1779   {
   1780     FT_UNUSED( hints );
   1781 
   1782     serif->pos = base->pos + (serif->opos - base->opos);
   1783   }
   1784 
   1785 
   1786   /*************************************************************************/
   1787   /*************************************************************************/
   1788   /*************************************************************************/
   1789   /****                                                                 ****/
   1790   /****                    E D G E   H I N T I N G                      ****/
   1791   /****                                                                 ****/
   1792   /*************************************************************************/
   1793   /*************************************************************************/
   1794   /*************************************************************************/
   1795 
   1796 
   1797   /* The main grid-fitting routine. */
   1798 
   1799   FT_LOCAL_DEF( void )
   1800   af_latin_hint_edges( AF_GlyphHints  hints,
   1801                        AF_Dimension   dim )
   1802   {
   1803     AF_AxisHints  axis       = &hints->axis[dim];
   1804     AF_Edge       edges      = axis->edges;
   1805     AF_Edge       edge_limit = edges + axis->num_edges;
   1806     FT_PtrDist    n_edges;
   1807     AF_Edge       edge;
   1808     AF_Edge       anchor     = NULL;
   1809     FT_Int        has_serifs = 0;
   1810 
   1811 
   1812     FT_TRACE5(("%s edge hinting\n", dim == AF_DIMENSION_VERT ? "horizontal"
   1813                                                              : "vertical"));
   1814 
   1815     /* we begin by aligning all stems relative to the blue zone */
   1816     /* if needed -- that's only for horizontal edges            */
   1817 
   1818     if ( dim == AF_DIMENSION_VERT && AF_HINTS_DO_BLUES( hints ) )
   1819     {
   1820       for ( edge = edges; edge < edge_limit; edge++ )
   1821       {
   1822         AF_Width  blue;
   1823         AF_Edge   edge1, edge2; /* these edges form the stem to check */
   1824 
   1825 
   1826         if ( edge->flags & AF_EDGE_DONE )
   1827           continue;
   1828 
   1829         blue  = edge->blue_edge;
   1830         edge1 = NULL;
   1831         edge2 = edge->link;
   1832 
   1833         if ( blue )
   1834           edge1 = edge;
   1835 
   1836         /* flip edges if the other stem is aligned to a blue zone */
   1837         else if ( edge2 && edge2->blue_edge )
   1838         {
   1839           blue  = edge2->blue_edge;
   1840           edge1 = edge2;
   1841           edge2 = edge;
   1842         }
   1843 
   1844         if ( !edge1 )
   1845           continue;
   1846 
   1847         FT_TRACE5(( "  BLUE: edge %d (opos=%.2f) snapped to (%.2f),"
   1848                  "was (%.2f)\n",
   1849                  edge1-edges, edge1->opos / 64.0, blue->fit / 64.0,
   1850                  edge1->pos / 64.0 ));
   1851 
   1852         edge1->pos    = blue->fit;
   1853         edge1->flags |= AF_EDGE_DONE;
   1854 
   1855         if ( edge2 && !edge2->blue_edge )
   1856         {
   1857           af_latin_align_linked_edge( hints, dim, edge1, edge2 );
   1858           edge2->flags |= AF_EDGE_DONE;
   1859         }
   1860 
   1861         if ( !anchor )
   1862           anchor = edge;
   1863       }
   1864     }
   1865 
   1866     /* now we align all other stem edges, trying to maintain the */
   1867     /* relative order of stems in the glyph                     */
   1868     for ( edge = edges; edge < edge_limit; edge++ )
   1869     {
   1870       AF_Edge  edge2;
   1871 
   1872 
   1873       if ( edge->flags & AF_EDGE_DONE )
   1874         continue;
   1875 
   1876       /* skip all non-stem edges */
   1877       edge2 = edge->link;
   1878       if ( !edge2 )
   1879       {
   1880         has_serifs++;
   1881         continue;
   1882       }
   1883 
   1884       /* now align the stem */
   1885 
   1886       /* this should not happen, but it's better to be safe */
   1887       if ( edge2->blue_edge )
   1888       {
   1889         FT_TRACE5(( "  ASSERTION FAILED for edge %d\n", edge2-edges ));
   1890 
   1891         af_latin_align_linked_edge( hints, dim, edge2, edge );
   1892         edge->flags |= AF_EDGE_DONE;
   1893         continue;
   1894       }
   1895 
   1896       if ( !anchor )
   1897       {
   1898         /* if we reach this if clause, no stem has been aligned yet */
   1899 
   1900         FT_Pos  org_len, org_center, cur_len;
   1901         FT_Pos  cur_pos1, error1, error2, u_off, d_off;
   1902 
   1903 
   1904         org_len = edge2->opos - edge->opos;
   1905         cur_len = af_latin_compute_stem_width(
   1906                     hints, dim, org_len,
   1907                     (AF_Edge_Flags)edge->flags,
   1908                     (AF_Edge_Flags)edge2->flags );
   1909 
   1910         /* some voodoo to specially round edges for small stem widths; */
   1911         /* the idea is to align the center of a stem, then shifting    */
   1912         /* the stem edges to suitable positions                        */
   1913         if ( cur_len <= 64 )
   1914         {
   1915           /* width <= 1px */
   1916           u_off = 32;
   1917           d_off = 32;
   1918         }
   1919         else
   1920         {
   1921           /* 1px < width < 1.5px */
   1922           u_off = 38;
   1923           d_off = 26;
   1924         }
   1925 
   1926         if ( cur_len < 96 )
   1927         {
   1928           org_center = edge->opos + ( org_len >> 1 );
   1929           cur_pos1   = FT_PIX_ROUND( org_center );
   1930 
   1931           error1 = org_center - ( cur_pos1 - u_off );
   1932           if ( error1 < 0 )
   1933             error1 = -error1;
   1934 
   1935           error2 = org_center - ( cur_pos1 + d_off );
   1936           if ( error2 < 0 )
   1937             error2 = -error2;
   1938 
   1939           if ( error1 < error2 )
   1940             cur_pos1 -= u_off;
   1941           else
   1942             cur_pos1 += d_off;
   1943 
   1944           edge->pos  = cur_pos1 - cur_len / 2;
   1945           edge2->pos = edge->pos + cur_len;
   1946         }
   1947         else
   1948           edge->pos = FT_PIX_ROUND( edge->opos );
   1949 
   1950         FT_TRACE5(( "  ANCHOR: edge %d (opos=%.2f) and %d (opos=%.2f)"
   1951                  "snapped to (%.2f) (%.2f)\n",
   1952                  edge-edges, edge->opos / 64.0,
   1953                  edge2-edges, edge2->opos / 64.0,
   1954                  edge->pos / 64.0, edge2->pos / 64.0 ));
   1955         anchor = edge;
   1956 
   1957         edge->flags |= AF_EDGE_DONE;
   1958 
   1959         af_latin_align_linked_edge( hints, dim, edge, edge2 );
   1960       }
   1961       else
   1962       {
   1963         FT_Pos  org_pos, org_len, org_center, cur_len;
   1964         FT_Pos  cur_pos1, cur_pos2, delta1, delta2;
   1965 
   1966 
   1967         org_pos    = anchor->pos + ( edge->opos - anchor->opos );
   1968         org_len    = edge2->opos - edge->opos;
   1969         org_center = org_pos + ( org_len >> 1 );
   1970 
   1971         cur_len = af_latin_compute_stem_width(
   1972                    hints, dim, org_len,
   1973                    (AF_Edge_Flags)edge->flags,
   1974                    (AF_Edge_Flags)edge2->flags );
   1975 
   1976         if ( edge2->flags & AF_EDGE_DONE )
   1977         {
   1978           FT_TRACE5(( "  ADJUST: edge %d (pos=%.2f) moved to %.2f\n",
   1979                       edge - edges, edge->pos / 64.0,
   1980                       ( edge2->pos - cur_len ) / 64.0 ));
   1981 
   1982           edge->pos = edge2->pos - cur_len;
   1983         }
   1984 
   1985         else if ( cur_len < 96 )
   1986         {
   1987           FT_Pos  u_off, d_off;
   1988 
   1989 
   1990           cur_pos1 = FT_PIX_ROUND( org_center );
   1991 
   1992           if (cur_len <= 64 )
   1993           {
   1994             u_off = 32;
   1995             d_off = 32;
   1996           }
   1997           else
   1998           {
   1999             u_off = 38;
   2000             d_off = 26;
   2001           }
   2002 
   2003           delta1 = org_center - ( cur_pos1 - u_off );
   2004           if ( delta1 < 0 )
   2005             delta1 = -delta1;
   2006 
   2007           delta2 = org_center - ( cur_pos1 + d_off );
   2008           if ( delta2 < 0 )
   2009             delta2 = -delta2;
   2010 
   2011           if ( delta1 < delta2 )
   2012             cur_pos1 -= u_off;
   2013           else
   2014             cur_pos1 += d_off;
   2015 
   2016           edge->pos  = cur_pos1 - cur_len / 2;
   2017           edge2->pos = cur_pos1 + cur_len / 2;
   2018 
   2019           FT_TRACE5(( "  STEM: %d (opos=%.2f) to %d (opos=%.2f)"
   2020                    "snapped to (%.2f) and (%.2f)\n",
   2021                    edge-edges, edge->opos / 64.0,
   2022                    edge2-edges, edge2->opos / 64.0,
   2023                    edge->pos / 64.0, edge2->pos / 64.0 ));
   2024         }
   2025         else
   2026         {
   2027           org_pos    = anchor->pos + ( edge->opos - anchor->opos );
   2028           org_len    = edge2->opos - edge->opos;
   2029           org_center = org_pos + ( org_len >> 1 );
   2030 
   2031           cur_len    = af_latin_compute_stem_width(
   2032                          hints, dim, org_len,
   2033                          (AF_Edge_Flags)edge->flags,
   2034                          (AF_Edge_Flags)edge2->flags );
   2035 
   2036           cur_pos1   = FT_PIX_ROUND( org_pos );
   2037           delta1     = cur_pos1 + ( cur_len >> 1 ) - org_center;
   2038           if ( delta1 < 0 )
   2039             delta1 = -delta1;
   2040 
   2041           cur_pos2   = FT_PIX_ROUND( org_pos + org_len ) - cur_len;
   2042           delta2     = cur_pos2 + ( cur_len >> 1 ) - org_center;
   2043           if ( delta2 < 0 )
   2044             delta2 = -delta2;
   2045 
   2046           edge->pos  = ( delta1 < delta2 ) ? cur_pos1 : cur_pos2;
   2047           edge2->pos = edge->pos + cur_len;
   2048 
   2049           FT_TRACE5(( "  STEM: %d (opos=%.2f) to %d (opos=%.2f)"
   2050                    "snapped to (%.2f) and (%.2f)\n",
   2051                    edge-edges, edge->opos / 64.0,
   2052                    edge2-edges, edge2->opos / 64.0,
   2053                    edge->pos / 64.0, edge2->pos / 64.0 ));
   2054         }
   2055 
   2056         edge->flags  |= AF_EDGE_DONE;
   2057         edge2->flags |= AF_EDGE_DONE;
   2058 
   2059         if ( edge > edges && edge->pos < edge[-1].pos )
   2060         {
   2061           FT_TRACE5(( "  BOUND: %d (pos=%.2f) to (%.2f)\n",
   2062                    edge-edges, edge->pos / 64.0, edge[-1].pos / 64.0 ));
   2063           edge->pos = edge[-1].pos;
   2064         }
   2065       }
   2066     }
   2067 
   2068     /* make sure that lowercase m's maintain their symmetry */
   2069 
   2070     /* In general, lowercase m's have six vertical edges if they are sans */
   2071     /* serif, or twelve if they are with serifs.  This implementation is  */
   2072     /* based on that assumption, and seems to work very well with most    */
   2073     /* faces.  However, if for a certain face this assumption is not      */
   2074     /* true, the m is just rendered like before.  In addition, any stem   */
   2075     /* correction will only be applied to symmetrical glyphs (even if the */
   2076     /* glyph is not an m), so the potential for unwanted distortion is    */
   2077     /* relatively low.                                                    */
   2078 
   2079     /* We don't handle horizontal edges since we can't easily assure that */
   2080     /* the third (lowest) stem aligns with the base line; it might end up */
   2081     /* one pixel higher or lower.                                         */
   2082 
   2083     n_edges = edge_limit - edges;
   2084     if ( dim == AF_DIMENSION_HORZ && ( n_edges == 6 || n_edges == 12 ) )
   2085     {
   2086       AF_Edge  edge1, edge2, edge3;
   2087       FT_Pos   dist1, dist2, span, delta;
   2088 
   2089 
   2090       if ( n_edges == 6 )
   2091       {
   2092         edge1 = edges;
   2093         edge2 = edges + 2;
   2094         edge3 = edges + 4;
   2095       }
   2096       else
   2097       {
   2098         edge1 = edges + 1;
   2099         edge2 = edges + 5;
   2100         edge3 = edges + 9;
   2101       }
   2102 
   2103       dist1 = edge2->opos - edge1->opos;
   2104       dist2 = edge3->opos - edge2->opos;
   2105 
   2106       span = dist1 - dist2;
   2107       if ( span < 0 )
   2108         span = -span;
   2109 
   2110       if ( span < 8 )
   2111       {
   2112         delta = edge3->pos - ( 2 * edge2->pos - edge1->pos );
   2113         edge3->pos -= delta;
   2114         if ( edge3->link )
   2115           edge3->link->pos -= delta;
   2116 
   2117         /* move the serifs along with the stem */
   2118         if ( n_edges == 12 )
   2119         {
   2120           ( edges + 8 )->pos -= delta;
   2121           ( edges + 11 )->pos -= delta;
   2122         }
   2123 
   2124         edge3->flags |= AF_EDGE_DONE;
   2125         if ( edge3->link )
   2126           edge3->link->flags |= AF_EDGE_DONE;
   2127       }
   2128     }
   2129 
   2130     if ( has_serifs || !anchor )
   2131     {
   2132       /*
   2133        *  now hint the remaining edges (serifs and single) in order
   2134        *  to complete our processing
   2135        */
   2136       for ( edge = edges; edge < edge_limit; edge++ )
   2137       {
   2138         FT_Pos  delta;
   2139 
   2140 
   2141         if ( edge->flags & AF_EDGE_DONE )
   2142           continue;
   2143 
   2144         delta = 1000;
   2145 
   2146         if ( edge->serif )
   2147         {
   2148           delta = edge->serif->opos - edge->opos;
   2149           if ( delta < 0 )
   2150             delta = -delta;
   2151         }
   2152 
   2153         if ( delta < 64 + 16 )
   2154         {
   2155           af_latin_align_serif_edge( hints, edge->serif, edge );
   2156           FT_TRACE5(( "  SERIF: edge %d (opos=%.2f) serif to %d (opos=%.2f)"
   2157                    "aligned to (%.2f)\n",
   2158                    edge-edges, edge->opos / 64.0,
   2159                    edge->serif - edges, edge->serif->opos / 64.0,
   2160                    edge->pos / 64.0 ));
   2161         }
   2162         else if ( !anchor )
   2163         {
   2164           edge->pos = FT_PIX_ROUND( edge->opos );
   2165           anchor    = edge;
   2166           FT_TRACE5(( "  SERIF_ANCHOR: edge %d (opos=%.2f)"
   2167                       " snapped to (%.2f)\n",
   2168                       edge-edges, edge->opos / 64.0, edge->pos / 64.0 ));
   2169         }
   2170         else
   2171         {
   2172           AF_Edge  before, after;
   2173 
   2174 
   2175           for ( before = edge - 1; before >= edges; before-- )
   2176             if ( before->flags & AF_EDGE_DONE )
   2177               break;
   2178 
   2179           for ( after = edge + 1; after < edge_limit; after++ )
   2180             if ( after->flags & AF_EDGE_DONE )
   2181               break;
   2182 
   2183           if ( before >= edges && before < edge   &&
   2184                after < edge_limit && after > edge )
   2185           {
   2186             if ( after->opos == before->opos )
   2187               edge->pos = before->pos;
   2188             else
   2189               edge->pos = before->pos +
   2190                           FT_MulDiv( edge->opos - before->opos,
   2191                                      after->pos - before->pos,
   2192                                      after->opos - before->opos );
   2193 
   2194             FT_TRACE5(( "  SERIF_LINK1: edge %d (opos=%.2f) snapped to (%.2f)"
   2195                      "from %d (opos=%.2f)\n",
   2196                      edge-edges, edge->opos / 64.0,
   2197                         edge->pos / 64.0,
   2198                         before - edges, before->opos / 64.0 ));
   2199           }
   2200           else
   2201           {
   2202             edge->pos = anchor->pos +
   2203                         ( ( edge->opos - anchor->opos + 16 ) & ~31 );
   2204 
   2205             FT_TRACE5(( "  SERIF_LINK2: edge %d (opos=%.2f)"
   2206                         " snapped to (%.2f)\n",
   2207                      edge-edges, edge->opos / 64.0, edge->pos / 64.0 ));
   2208           }
   2209         }
   2210 
   2211         edge->flags |= AF_EDGE_DONE;
   2212 
   2213         if ( edge > edges && edge->pos < edge[-1].pos )
   2214           edge->pos = edge[-1].pos;
   2215 
   2216         if ( edge + 1 < edge_limit        &&
   2217              edge[1].flags & AF_EDGE_DONE &&
   2218              edge->pos > edge[1].pos      )
   2219           edge->pos = edge[1].pos;
   2220       }
   2221     }
   2222 
   2223     FT_TRACE5(( "\n" ));
   2224   }
   2225 
   2226 
   2227   /* Apply the complete hinting algorithm to a latin glyph. */
   2228 
   2229   static FT_Error
   2230   af_latin_hints_apply( AF_GlyphHints    hints,
   2231                         FT_Outline*      outline,
   2232                         AF_LatinMetrics  metrics )
   2233   {
   2234     FT_Error  error;
   2235     int       dim;
   2236 
   2237 
   2238     error = af_glyph_hints_reload( hints, outline );
   2239     if ( error )
   2240       goto Exit;
   2241 
   2242     /* analyze glyph outline */
   2243 #ifdef AF_CONFIG_OPTION_USE_WARPER
   2244     if ( metrics->root.scaler.render_mode == FT_RENDER_MODE_LIGHT ||
   2245          AF_HINTS_DO_HORIZONTAL( hints ) )
   2246 #else
   2247     if ( AF_HINTS_DO_HORIZONTAL( hints ) )
   2248 #endif
   2249     {
   2250       error = af_latin_hints_detect_features( hints, AF_DIMENSION_HORZ );
   2251       if ( error )
   2252         goto Exit;
   2253     }
   2254 
   2255     if ( AF_HINTS_DO_VERTICAL( hints ) )
   2256     {
   2257       error = af_latin_hints_detect_features( hints, AF_DIMENSION_VERT );
   2258       if ( error )
   2259         goto Exit;
   2260 
   2261       af_latin_hints_compute_blue_edges( hints, metrics );
   2262     }
   2263 
   2264     /* grid-fit the outline */
   2265     for ( dim = 0; dim < AF_DIMENSION_MAX; dim++ )
   2266     {
   2267 #ifdef AF_CONFIG_OPTION_USE_WARPER
   2268       if ( dim == AF_DIMENSION_HORZ                                 &&
   2269            metrics->root.scaler.render_mode == FT_RENDER_MODE_LIGHT )
   2270       {
   2271         AF_WarperRec  warper;
   2272         FT_Fixed      scale;
   2273         FT_Pos        delta;
   2274 
   2275 
   2276         af_warper_compute( &warper, hints, (AF_Dimension)dim,
   2277                            &scale, &delta );
   2278         af_glyph_hints_scale_dim( hints, (AF_Dimension)dim,
   2279                                   scale, delta );
   2280         continue;
   2281       }
   2282 #endif
   2283 
   2284       if ( ( dim == AF_DIMENSION_HORZ && AF_HINTS_DO_HORIZONTAL( hints ) ) ||
   2285            ( dim == AF_DIMENSION_VERT && AF_HINTS_DO_VERTICAL( hints ) )   )
   2286       {
   2287         af_latin_hint_edges( hints, (AF_Dimension)dim );
   2288         af_glyph_hints_align_edge_points( hints, (AF_Dimension)dim );
   2289         af_glyph_hints_align_strong_points( hints, (AF_Dimension)dim );
   2290         af_glyph_hints_align_weak_points( hints, (AF_Dimension)dim );
   2291       }
   2292     }
   2293     af_glyph_hints_save( hints, outline );
   2294 
   2295   Exit:
   2296     return error;
   2297   }
   2298 
   2299 
   2300   /*************************************************************************/
   2301   /*************************************************************************/
   2302   /*****                                                               *****/
   2303   /*****              L A T I N   S C R I P T   C L A S S              *****/
   2304   /*****                                                               *****/
   2305   /*************************************************************************/
   2306   /*************************************************************************/
   2307 
   2308 
   2309   /* XXX: this should probably fine tuned to differentiate better between */
   2310   /*      scripts...                                                      */
   2311 
   2312   static const AF_Script_UniRangeRec  af_latin_uniranges[] =
   2313   {
   2314     AF_UNIRANGE_REC(  0x0020UL,  0x007FUL ),  /* Basic Latin (no control chars) */
   2315     AF_UNIRANGE_REC(  0x00A0UL,  0x00FFUL ),  /* Latin-1 Supplement (no control chars) */
   2316     AF_UNIRANGE_REC(  0x0100UL,  0x017FUL ),  /* Latin Extended-A */
   2317     AF_UNIRANGE_REC(  0x0180UL,  0x024FUL ),  /* Latin Extended-B */
   2318     AF_UNIRANGE_REC(  0x0250UL,  0x02AFUL ),  /* IPA Extensions */
   2319     AF_UNIRANGE_REC(  0x02B0UL,  0x02FFUL ),  /* Spacing Modifier Letters */
   2320     AF_UNIRANGE_REC(  0x0300UL,  0x036FUL ),  /* Combining Diacritical Marks */
   2321     AF_UNIRANGE_REC(  0x0370UL,  0x03FFUL ),  /* Greek and Coptic */
   2322     AF_UNIRANGE_REC(  0x0400UL,  0x04FFUL ),  /* Cyrillic */
   2323     AF_UNIRANGE_REC(  0x0500UL,  0x052FUL ),  /* Cyrillic Supplement */
   2324     AF_UNIRANGE_REC(  0x1D00UL,  0x1D7FUL ),  /* Phonetic Extensions */
   2325     AF_UNIRANGE_REC(  0x1D80UL,  0x1DBFUL ),  /* Phonetic Extensions Supplement */
   2326     AF_UNIRANGE_REC(  0x1DC0UL,  0x1DFFUL ),  /* Combining Diacritical Marks Supplement */
   2327     AF_UNIRANGE_REC(  0x1E00UL,  0x1EFFUL ),  /* Latin Extended Additional */
   2328     AF_UNIRANGE_REC(  0x1F00UL,  0x1FFFUL ),  /* Greek Extended */
   2329     AF_UNIRANGE_REC(  0x2000UL,  0x206FUL ),  /* General Punctuation */
   2330     AF_UNIRANGE_REC(  0x2070UL,  0x209FUL ),  /* Superscripts and Subscripts */
   2331     AF_UNIRANGE_REC(  0x20A0UL,  0x20CFUL ),  /* Currency Symbols */
   2332     AF_UNIRANGE_REC(  0x2150UL,  0x218FUL ),  /* Number Forms */
   2333     AF_UNIRANGE_REC(  0x2460UL,  0x24FFUL ),  /* Enclosed Alphanumerics */
   2334     AF_UNIRANGE_REC(  0x2C60UL,  0x2C7FUL ),  /* Latin Extended-C */
   2335     AF_UNIRANGE_REC(  0x2DE0UL,  0x2DFFUL ),  /* Cyrillic Extended-A */
   2336     AF_UNIRANGE_REC(  0xA640UL,  0xA69FUL ),  /* Cyrillic Extended-B */
   2337     AF_UNIRANGE_REC(  0xA720UL,  0xA7FFUL ),  /* Latin Extended-D */
   2338     AF_UNIRANGE_REC(  0xFB00UL,  0xFB06UL ),  /* Alphab. Present. Forms (Latin Ligs) */
   2339     AF_UNIRANGE_REC( 0x1D400UL, 0x1D7FFUL ),  /* Mathematical Alphanumeric Symbols */
   2340     AF_UNIRANGE_REC(       0UL,       0UL )
   2341   };
   2342 
   2343 
   2344   AF_DEFINE_SCRIPT_CLASS(af_latin_script_class,
   2345     AF_SCRIPT_LATIN,
   2346     af_latin_uniranges,
   2347 
   2348     sizeof( AF_LatinMetricsRec ),
   2349 
   2350     (AF_Script_InitMetricsFunc) af_latin_metrics_init,
   2351     (AF_Script_ScaleMetricsFunc)af_latin_metrics_scale,
   2352     (AF_Script_DoneMetricsFunc) NULL,
   2353 
   2354     (AF_Script_InitHintsFunc)   af_latin_hints_init,
   2355     (AF_Script_ApplyHintsFunc)  af_latin_hints_apply
   2356   )
   2357 
   2358 
   2359 /* END */
   2360