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      1 /***************************************************************************/
      2 /*                                                                         */
      3 /*  pshalgo.c                                                              */
      4 /*                                                                         */
      5 /*    PostScript hinting algorithm (body).                                 */
      6 /*                                                                         */
      7 /*  Copyright 2001-2018 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_INTERNAL_OBJECTS_H
     21 #include FT_INTERNAL_DEBUG_H
     22 #include FT_INTERNAL_CALC_H
     23 #include "pshalgo.h"
     24 
     25 #include "pshnterr.h"
     26 
     27 
     28 #undef  FT_COMPONENT
     29 #define FT_COMPONENT  trace_pshalgo
     30 
     31 
     32 #ifdef DEBUG_HINTER
     33   PSH_Hint_Table  ps_debug_hint_table = NULL;
     34   PSH_HintFunc    ps_debug_hint_func  = NULL;
     35   PSH_Glyph       ps_debug_glyph      = NULL;
     36 #endif
     37 
     38 
     39 #define  COMPUTE_INFLEXS  /* compute inflection points to optimize `S' */
     40                           /* and similar glyphs                        */
     41 
     42 
     43   /*************************************************************************/
     44   /*************************************************************************/
     45   /*****                                                               *****/
     46   /*****                  BASIC HINTS RECORDINGS                       *****/
     47   /*****                                                               *****/
     48   /*************************************************************************/
     49   /*************************************************************************/
     50 
     51   /* return true if two stem hints overlap */
     52   static FT_Int
     53   psh_hint_overlap( PSH_Hint  hint1,
     54                     PSH_Hint  hint2 )
     55   {
     56     return hint1->org_pos + hint1->org_len >= hint2->org_pos &&
     57            hint2->org_pos + hint2->org_len >= hint1->org_pos;
     58   }
     59 
     60 
     61   /* destroy hints table */
     62   static void
     63   psh_hint_table_done( PSH_Hint_Table  table,
     64                        FT_Memory       memory )
     65   {
     66     FT_FREE( table->zones );
     67     table->num_zones = 0;
     68     table->zone      = NULL;
     69 
     70     FT_FREE( table->sort );
     71     FT_FREE( table->hints );
     72     table->num_hints   = 0;
     73     table->max_hints   = 0;
     74     table->sort_global = NULL;
     75   }
     76 
     77 
     78   /* deactivate all hints in a table */
     79   static void
     80   psh_hint_table_deactivate( PSH_Hint_Table  table )
     81   {
     82     FT_UInt   count = table->max_hints;
     83     PSH_Hint  hint  = table->hints;
     84 
     85 
     86     for ( ; count > 0; count--, hint++ )
     87     {
     88       psh_hint_deactivate( hint );
     89       hint->order = -1;
     90     }
     91   }
     92 
     93 
     94   /* internal function to record a new hint */
     95   static void
     96   psh_hint_table_record( PSH_Hint_Table  table,
     97                          FT_UInt         idx )
     98   {
     99     PSH_Hint  hint = table->hints + idx;
    100 
    101 
    102     if ( idx >= table->max_hints )
    103     {
    104       FT_TRACE0(( "psh_hint_table_record: invalid hint index %d\n", idx ));
    105       return;
    106     }
    107 
    108     /* ignore active hints */
    109     if ( psh_hint_is_active( hint ) )
    110       return;
    111 
    112     psh_hint_activate( hint );
    113 
    114     /* now scan the current active hint set to check */
    115     /* whether `hint' overlaps with another hint     */
    116     {
    117       PSH_Hint*  sorted = table->sort_global;
    118       FT_UInt    count  = table->num_hints;
    119       PSH_Hint   hint2;
    120 
    121 
    122       hint->parent = NULL;
    123       for ( ; count > 0; count--, sorted++ )
    124       {
    125         hint2 = sorted[0];
    126 
    127         if ( psh_hint_overlap( hint, hint2 ) )
    128         {
    129           hint->parent = hint2;
    130           break;
    131         }
    132       }
    133     }
    134 
    135     if ( table->num_hints < table->max_hints )
    136       table->sort_global[table->num_hints++] = hint;
    137     else
    138       FT_TRACE0(( "psh_hint_table_record: too many sorted hints!  BUG!\n" ));
    139   }
    140 
    141 
    142   static void
    143   psh_hint_table_record_mask( PSH_Hint_Table  table,
    144                               PS_Mask         hint_mask )
    145   {
    146     FT_Int    mask = 0, val = 0;
    147     FT_Byte*  cursor = hint_mask->bytes;
    148     FT_UInt   idx, limit;
    149 
    150 
    151     limit = hint_mask->num_bits;
    152 
    153     for ( idx = 0; idx < limit; idx++ )
    154     {
    155       if ( mask == 0 )
    156       {
    157         val  = *cursor++;
    158         mask = 0x80;
    159       }
    160 
    161       if ( val & mask )
    162         psh_hint_table_record( table, idx );
    163 
    164       mask >>= 1;
    165     }
    166   }
    167 
    168 
    169   /* create hints table */
    170   static FT_Error
    171   psh_hint_table_init( PSH_Hint_Table  table,
    172                        PS_Hint_Table   hints,
    173                        PS_Mask_Table   hint_masks,
    174                        PS_Mask_Table   counter_masks,
    175                        FT_Memory       memory )
    176   {
    177     FT_UInt   count;
    178     FT_Error  error;
    179 
    180     FT_UNUSED( counter_masks );
    181 
    182 
    183     count = hints->num_hints;
    184 
    185     /* allocate our tables */
    186     if ( FT_NEW_ARRAY( table->sort,  2 * count     ) ||
    187          FT_NEW_ARRAY( table->hints,     count     ) ||
    188          FT_NEW_ARRAY( table->zones, 2 * count + 1 ) )
    189       goto Exit;
    190 
    191     table->max_hints   = count;
    192     table->sort_global = table->sort + count;
    193     table->num_hints   = 0;
    194     table->num_zones   = 0;
    195     table->zone        = NULL;
    196 
    197     /* initialize the `table->hints' array */
    198     {
    199       PSH_Hint  write = table->hints;
    200       PS_Hint   read  = hints->hints;
    201 
    202 
    203       for ( ; count > 0; count--, write++, read++ )
    204       {
    205         write->org_pos = read->pos;
    206         write->org_len = read->len;
    207         write->flags   = read->flags;
    208       }
    209     }
    210 
    211     /* we now need to determine the initial `parent' stems; first  */
    212     /* activate the hints that are given by the initial hint masks */
    213     if ( hint_masks )
    214     {
    215       PS_Mask  mask = hint_masks->masks;
    216 
    217 
    218       count             = hint_masks->num_masks;
    219       table->hint_masks = hint_masks;
    220 
    221       for ( ; count > 0; count--, mask++ )
    222         psh_hint_table_record_mask( table, mask );
    223     }
    224 
    225     /* finally, do a linear parse in case some hints were left alone */
    226     if ( table->num_hints != table->max_hints )
    227     {
    228       FT_UInt  idx;
    229 
    230 
    231       FT_TRACE0(( "psh_hint_table_init: missing/incorrect hint masks\n" ));
    232 
    233       count = table->max_hints;
    234       for ( idx = 0; idx < count; idx++ )
    235         psh_hint_table_record( table, idx );
    236     }
    237 
    238   Exit:
    239     return error;
    240   }
    241 
    242 
    243   static void
    244   psh_hint_table_activate_mask( PSH_Hint_Table  table,
    245                                 PS_Mask         hint_mask )
    246   {
    247     FT_Int    mask = 0, val = 0;
    248     FT_Byte*  cursor = hint_mask->bytes;
    249     FT_UInt   idx, limit, count;
    250 
    251 
    252     limit = hint_mask->num_bits;
    253     count = 0;
    254 
    255     psh_hint_table_deactivate( table );
    256 
    257     for ( idx = 0; idx < limit; idx++ )
    258     {
    259       if ( mask == 0 )
    260       {
    261         val  = *cursor++;
    262         mask = 0x80;
    263       }
    264 
    265       if ( val & mask )
    266       {
    267         PSH_Hint  hint = &table->hints[idx];
    268 
    269 
    270         if ( !psh_hint_is_active( hint ) )
    271         {
    272           FT_UInt     count2;
    273 
    274 #if 0
    275           PSH_Hint*  sort = table->sort;
    276           PSH_Hint   hint2;
    277 
    278 
    279           for ( count2 = count; count2 > 0; count2--, sort++ )
    280           {
    281             hint2 = sort[0];
    282             if ( psh_hint_overlap( hint, hint2 ) )
    283               FT_TRACE0(( "psh_hint_table_activate_mask:"
    284                           " found overlapping hints\n" ))
    285           }
    286 #else
    287           count2 = 0;
    288 #endif
    289 
    290           if ( count2 == 0 )
    291           {
    292             psh_hint_activate( hint );
    293             if ( count < table->max_hints )
    294               table->sort[count++] = hint;
    295             else
    296               FT_TRACE0(( "psh_hint_tableactivate_mask:"
    297                           " too many active hints\n" ));
    298           }
    299         }
    300       }
    301 
    302       mask >>= 1;
    303     }
    304     table->num_hints = count;
    305 
    306     /* now, sort the hints; they are guaranteed to not overlap */
    307     /* so we can compare their "org_pos" field directly        */
    308     {
    309       FT_Int     i1, i2;
    310       PSH_Hint   hint1, hint2;
    311       PSH_Hint*  sort = table->sort;
    312 
    313 
    314       /* a simple bubble sort will do, since in 99% of cases, the hints */
    315       /* will be already sorted -- and the sort will be linear          */
    316       for ( i1 = 1; i1 < (FT_Int)count; i1++ )
    317       {
    318         hint1 = sort[i1];
    319         for ( i2 = i1 - 1; i2 >= 0; i2-- )
    320         {
    321           hint2 = sort[i2];
    322 
    323           if ( hint2->org_pos < hint1->org_pos )
    324             break;
    325 
    326           sort[i2 + 1] = hint2;
    327           sort[i2]     = hint1;
    328         }
    329       }
    330     }
    331   }
    332 
    333 
    334   /*************************************************************************/
    335   /*************************************************************************/
    336   /*****                                                               *****/
    337   /*****               HINTS GRID-FITTING AND OPTIMIZATION             *****/
    338   /*****                                                               *****/
    339   /*************************************************************************/
    340   /*************************************************************************/
    341 
    342 #if 1
    343   static FT_Pos
    344   psh_dimension_quantize_len( PSH_Dimension  dim,
    345                               FT_Pos         len,
    346                               FT_Bool        do_snapping )
    347   {
    348     if ( len <= 64 )
    349       len = 64;
    350     else
    351     {
    352       FT_Pos  delta = len - dim->stdw.widths[0].cur;
    353 
    354 
    355       if ( delta < 0 )
    356         delta = -delta;
    357 
    358       if ( delta < 40 )
    359       {
    360         len = dim->stdw.widths[0].cur;
    361         if ( len < 48 )
    362           len = 48;
    363       }
    364 
    365       if ( len < 3 * 64 )
    366       {
    367         delta = ( len & 63 );
    368         len  &= -64;
    369 
    370         if ( delta < 10 )
    371           len += delta;
    372 
    373         else if ( delta < 32 )
    374           len += 10;
    375 
    376         else if ( delta < 54 )
    377           len += 54;
    378 
    379         else
    380           len += delta;
    381       }
    382       else
    383         len = FT_PIX_ROUND( len );
    384     }
    385 
    386     if ( do_snapping )
    387       len = FT_PIX_ROUND( len );
    388 
    389     return  len;
    390   }
    391 #endif /* 0 */
    392 
    393 
    394 #ifdef DEBUG_HINTER
    395 
    396   static void
    397   ps_simple_scale( PSH_Hint_Table  table,
    398                    FT_Fixed        scale,
    399                    FT_Fixed        delta,
    400                    FT_Int          dimension )
    401   {
    402     FT_UInt  count;
    403 
    404 
    405     for ( count = 0; count < table->max_hints; count++ )
    406     {
    407       PSH_Hint  hint = table->hints + count;
    408 
    409 
    410       hint->cur_pos = FT_MulFix( hint->org_pos, scale ) + delta;
    411       hint->cur_len = FT_MulFix( hint->org_len, scale );
    412 
    413       if ( ps_debug_hint_func )
    414         ps_debug_hint_func( hint, dimension );
    415     }
    416   }
    417 
    418 #endif /* DEBUG_HINTER */
    419 
    420 
    421   static FT_Fixed
    422   psh_hint_snap_stem_side_delta( FT_Fixed  pos,
    423                                  FT_Fixed  len )
    424   {
    425     FT_Fixed  delta1 = FT_PIX_ROUND( pos ) - pos;
    426     FT_Fixed  delta2 = FT_PIX_ROUND( pos + len ) - pos - len;
    427 
    428 
    429     if ( FT_ABS( delta1 ) <= FT_ABS( delta2 ) )
    430       return delta1;
    431     else
    432       return delta2;
    433   }
    434 
    435 
    436   static void
    437   psh_hint_align( PSH_Hint     hint,
    438                   PSH_Globals  globals,
    439                   FT_Int       dimension,
    440                   PSH_Glyph    glyph )
    441   {
    442     PSH_Dimension  dim   = &globals->dimension[dimension];
    443     FT_Fixed       scale = dim->scale_mult;
    444     FT_Fixed       delta = dim->scale_delta;
    445 
    446 
    447     if ( !psh_hint_is_fitted( hint ) )
    448     {
    449       FT_Pos  pos = FT_MulFix( hint->org_pos, scale ) + delta;
    450       FT_Pos  len = FT_MulFix( hint->org_len, scale );
    451 
    452       FT_Int            do_snapping;
    453       FT_Pos            fit_len;
    454       PSH_AlignmentRec  align;
    455 
    456 
    457       /* ignore stem alignments when requested through the hint flags */
    458       if ( ( dimension == 0 && !glyph->do_horz_hints ) ||
    459            ( dimension == 1 && !glyph->do_vert_hints ) )
    460       {
    461         hint->cur_pos = pos;
    462         hint->cur_len = len;
    463 
    464         psh_hint_set_fitted( hint );
    465         return;
    466       }
    467 
    468       /* perform stem snapping when requested - this is necessary
    469        * for monochrome and LCD hinting modes only
    470        */
    471       do_snapping = ( dimension == 0 && glyph->do_horz_snapping ) ||
    472                     ( dimension == 1 && glyph->do_vert_snapping );
    473 
    474       hint->cur_len = fit_len = len;
    475 
    476       /* check blue zones for horizontal stems */
    477       align.align     = PSH_BLUE_ALIGN_NONE;
    478       align.align_bot = align.align_top = 0;
    479 
    480       if ( dimension == 1 )
    481         psh_blues_snap_stem( &globals->blues,
    482                              hint->org_pos + hint->org_len,
    483                              hint->org_pos,
    484                              &align );
    485 
    486       switch ( align.align )
    487       {
    488       case PSH_BLUE_ALIGN_TOP:
    489         /* the top of the stem is aligned against a blue zone */
    490         hint->cur_pos = align.align_top - fit_len;
    491         break;
    492 
    493       case PSH_BLUE_ALIGN_BOT:
    494         /* the bottom of the stem is aligned against a blue zone */
    495         hint->cur_pos = align.align_bot;
    496         break;
    497 
    498       case PSH_BLUE_ALIGN_TOP | PSH_BLUE_ALIGN_BOT:
    499         /* both edges of the stem are aligned against blue zones */
    500         hint->cur_pos = align.align_bot;
    501         hint->cur_len = align.align_top - align.align_bot;
    502         break;
    503 
    504       default:
    505         {
    506           PSH_Hint  parent = hint->parent;
    507 
    508 
    509           if ( parent )
    510           {
    511             FT_Pos  par_org_center, par_cur_center;
    512             FT_Pos  cur_org_center, cur_delta;
    513 
    514 
    515             /* ensure that parent is already fitted */
    516             if ( !psh_hint_is_fitted( parent ) )
    517               psh_hint_align( parent, globals, dimension, glyph );
    518 
    519             /* keep original relation between hints, this is, use the */
    520             /* scaled distance between the centers of the hints to    */
    521             /* compute the new position                               */
    522             par_org_center = parent->org_pos + ( parent->org_len >> 1 );
    523             par_cur_center = parent->cur_pos + ( parent->cur_len >> 1 );
    524             cur_org_center = hint->org_pos   + ( hint->org_len   >> 1 );
    525 
    526             cur_delta = FT_MulFix( cur_org_center - par_org_center, scale );
    527             pos       = par_cur_center + cur_delta - ( len >> 1 );
    528           }
    529 
    530           hint->cur_pos = pos;
    531           hint->cur_len = fit_len;
    532 
    533           /* Stem adjustment tries to snap stem widths to standard
    534            * ones.  This is important to prevent unpleasant rounding
    535            * artefacts.
    536            */
    537           if ( glyph->do_stem_adjust )
    538           {
    539             if ( len <= 64 )
    540             {
    541               /* the stem is less than one pixel; we will center it
    542                * around the nearest pixel center
    543                */
    544               if ( len >= 32 )
    545               {
    546                 /* This is a special case where we also widen the stem
    547                  * and align it to the pixel grid.
    548                  *
    549                  *   stem_center          = pos + (len/2)
    550                  *   nearest_pixel_center = FT_ROUND(stem_center-32)+32
    551                  *   new_pos              = nearest_pixel_center-32
    552                  *                        = FT_ROUND(stem_center-32)
    553                  *                        = FT_FLOOR(stem_center-32+32)
    554                  *                        = FT_FLOOR(stem_center)
    555                  *   new_len              = 64
    556                  */
    557                 pos = FT_PIX_FLOOR( pos + ( len >> 1 ) );
    558                 len = 64;
    559               }
    560               else if ( len > 0 )
    561               {
    562                 /* This is a very small stem; we simply align it to the
    563                  * pixel grid, trying to find the minimum displacement.
    564                  *
    565                  * left               = pos
    566                  * right              = pos + len
    567                  * left_nearest_edge  = ROUND(pos)
    568                  * right_nearest_edge = ROUND(right)
    569                  *
    570                  * if ( ABS(left_nearest_edge - left) <=
    571                  *      ABS(right_nearest_edge - right) )
    572                  *    new_pos = left
    573                  * else
    574                  *    new_pos = right
    575                  */
    576                 FT_Pos  left_nearest  = FT_PIX_ROUND( pos );
    577                 FT_Pos  right_nearest = FT_PIX_ROUND( pos + len );
    578                 FT_Pos  left_disp     = left_nearest - pos;
    579                 FT_Pos  right_disp    = right_nearest - ( pos + len );
    580 
    581 
    582                 if ( left_disp < 0 )
    583                   left_disp = -left_disp;
    584                 if ( right_disp < 0 )
    585                   right_disp = -right_disp;
    586                 if ( left_disp <= right_disp )
    587                   pos = left_nearest;
    588                 else
    589                   pos = right_nearest;
    590               }
    591               else
    592               {
    593                 /* this is a ghost stem; we simply round it */
    594                 pos = FT_PIX_ROUND( pos );
    595               }
    596             }
    597             else
    598             {
    599               len = psh_dimension_quantize_len( dim, len, 0 );
    600             }
    601           }
    602 
    603           /* now that we have a good hinted stem width, try to position */
    604           /* the stem along a pixel grid integer coordinate             */
    605           hint->cur_pos = pos + psh_hint_snap_stem_side_delta( pos, len );
    606           hint->cur_len = len;
    607         }
    608       }
    609 
    610       if ( do_snapping )
    611       {
    612         pos = hint->cur_pos;
    613         len = hint->cur_len;
    614 
    615         if ( len < 64 )
    616           len = 64;
    617         else
    618           len = FT_PIX_ROUND( len );
    619 
    620         switch ( align.align )
    621         {
    622           case PSH_BLUE_ALIGN_TOP:
    623             hint->cur_pos = align.align_top - len;
    624             hint->cur_len = len;
    625             break;
    626 
    627           case PSH_BLUE_ALIGN_BOT:
    628             hint->cur_len = len;
    629             break;
    630 
    631           case PSH_BLUE_ALIGN_BOT | PSH_BLUE_ALIGN_TOP:
    632             /* don't touch */
    633             break;
    634 
    635 
    636           default:
    637             hint->cur_len = len;
    638             if ( len & 64 )
    639               pos = FT_PIX_FLOOR( pos + ( len >> 1 ) ) + 32;
    640             else
    641               pos = FT_PIX_ROUND( pos + ( len >> 1 ) );
    642 
    643             hint->cur_pos = pos - ( len >> 1 );
    644             hint->cur_len = len;
    645         }
    646       }
    647 
    648       psh_hint_set_fitted( hint );
    649 
    650 #ifdef DEBUG_HINTER
    651       if ( ps_debug_hint_func )
    652         ps_debug_hint_func( hint, dimension );
    653 #endif
    654     }
    655   }
    656 
    657 
    658 #if 0  /* not used for now, experimental */
    659 
    660  /*
    661   *  A variant to perform "light" hinting (i.e. FT_RENDER_MODE_LIGHT)
    662   *  of stems
    663   */
    664   static void
    665   psh_hint_align_light( PSH_Hint     hint,
    666                         PSH_Globals  globals,
    667                         FT_Int       dimension,
    668                         PSH_Glyph    glyph )
    669   {
    670     PSH_Dimension  dim   = &globals->dimension[dimension];
    671     FT_Fixed       scale = dim->scale_mult;
    672     FT_Fixed       delta = dim->scale_delta;
    673 
    674 
    675     if ( !psh_hint_is_fitted( hint ) )
    676     {
    677       FT_Pos  pos = FT_MulFix( hint->org_pos, scale ) + delta;
    678       FT_Pos  len = FT_MulFix( hint->org_len, scale );
    679 
    680       FT_Pos  fit_len;
    681 
    682       PSH_AlignmentRec  align;
    683 
    684 
    685       /* ignore stem alignments when requested through the hint flags */
    686       if ( ( dimension == 0 && !glyph->do_horz_hints ) ||
    687            ( dimension == 1 && !glyph->do_vert_hints ) )
    688       {
    689         hint->cur_pos = pos;
    690         hint->cur_len = len;
    691 
    692         psh_hint_set_fitted( hint );
    693         return;
    694       }
    695 
    696       fit_len = len;
    697 
    698       hint->cur_len = fit_len;
    699 
    700       /* check blue zones for horizontal stems */
    701       align.align = PSH_BLUE_ALIGN_NONE;
    702       align.align_bot = align.align_top = 0;
    703 
    704       if ( dimension == 1 )
    705         psh_blues_snap_stem( &globals->blues,
    706                              hint->org_pos + hint->org_len,
    707                              hint->org_pos,
    708                              &align );
    709 
    710       switch ( align.align )
    711       {
    712       case PSH_BLUE_ALIGN_TOP:
    713         /* the top of the stem is aligned against a blue zone */
    714         hint->cur_pos = align.align_top - fit_len;
    715         break;
    716 
    717       case PSH_BLUE_ALIGN_BOT:
    718         /* the bottom of the stem is aligned against a blue zone */
    719         hint->cur_pos = align.align_bot;
    720         break;
    721 
    722       case PSH_BLUE_ALIGN_TOP | PSH_BLUE_ALIGN_BOT:
    723         /* both edges of the stem are aligned against blue zones */
    724         hint->cur_pos = align.align_bot;
    725         hint->cur_len = align.align_top - align.align_bot;
    726         break;
    727 
    728       default:
    729         {
    730           PSH_Hint  parent = hint->parent;
    731 
    732 
    733           if ( parent )
    734           {
    735             FT_Pos  par_org_center, par_cur_center;
    736             FT_Pos  cur_org_center, cur_delta;
    737 
    738 
    739             /* ensure that parent is already fitted */
    740             if ( !psh_hint_is_fitted( parent ) )
    741               psh_hint_align_light( parent, globals, dimension, glyph );
    742 
    743             par_org_center = parent->org_pos + ( parent->org_len / 2 );
    744             par_cur_center = parent->cur_pos + ( parent->cur_len / 2 );
    745             cur_org_center = hint->org_pos   + ( hint->org_len   / 2 );
    746 
    747             cur_delta = FT_MulFix( cur_org_center - par_org_center, scale );
    748             pos       = par_cur_center + cur_delta - ( len >> 1 );
    749           }
    750 
    751           /* Stems less than one pixel wide are easy -- we want to
    752            * make them as dark as possible, so they must fall within
    753            * one pixel.  If the stem is split between two pixels
    754            * then snap the edge that is nearer to the pixel boundary
    755            * to the pixel boundary.
    756            */
    757           if ( len <= 64 )
    758           {
    759             if ( ( pos + len + 63 ) / 64  != pos / 64 + 1 )
    760               pos += psh_hint_snap_stem_side_delta ( pos, len );
    761           }
    762 
    763           /* Position stems other to minimize the amount of mid-grays.
    764            * There are, in general, two positions that do this,
    765            * illustrated as A) and B) below.
    766            *
    767            *   +                   +                   +                   +
    768            *
    769            * A)             |--------------------------------|
    770            * B)   |--------------------------------|
    771            * C)       |--------------------------------|
    772            *
    773            * Position A) (split the excess stem equally) should be better
    774            * for stems of width N + f where f < 0.5.
    775            *
    776            * Position B) (split the deficiency equally) should be better
    777            * for stems of width N + f where f > 0.5.
    778            *
    779            * It turns out though that minimizing the total number of lit
    780            * pixels is also important, so position C), with one edge
    781            * aligned with a pixel boundary is actually preferable
    782            * to A).  There are also more possible positions for C) than
    783            * for A) or B), so it involves less distortion of the overall
    784            * character shape.
    785            */
    786           else /* len > 64 */
    787           {
    788             FT_Fixed  frac_len = len & 63;
    789             FT_Fixed  center = pos + ( len >> 1 );
    790             FT_Fixed  delta_a, delta_b;
    791 
    792 
    793             if ( ( len / 64 ) & 1 )
    794             {
    795               delta_a = FT_PIX_FLOOR( center ) + 32 - center;
    796               delta_b = FT_PIX_ROUND( center ) - center;
    797             }
    798             else
    799             {
    800               delta_a = FT_PIX_ROUND( center ) - center;
    801               delta_b = FT_PIX_FLOOR( center ) + 32 - center;
    802             }
    803 
    804             /* We choose between B) and C) above based on the amount
    805              * of fractional stem width; for small amounts, choose
    806              * C) always, for large amounts, B) always, and inbetween,
    807              * pick whichever one involves less stem movement.
    808              */
    809             if ( frac_len < 32 )
    810             {
    811               pos += psh_hint_snap_stem_side_delta ( pos, len );
    812             }
    813             else if ( frac_len < 48 )
    814             {
    815               FT_Fixed  side_delta = psh_hint_snap_stem_side_delta ( pos,
    816                                                                      len );
    817 
    818               if ( FT_ABS( side_delta ) < FT_ABS( delta_b ) )
    819                 pos += side_delta;
    820               else
    821                 pos += delta_b;
    822             }
    823             else
    824             {
    825               pos += delta_b;
    826             }
    827           }
    828 
    829           hint->cur_pos = pos;
    830         }
    831       }  /* switch */
    832 
    833       psh_hint_set_fitted( hint );
    834 
    835 #ifdef DEBUG_HINTER
    836       if ( ps_debug_hint_func )
    837         ps_debug_hint_func( hint, dimension );
    838 #endif
    839     }
    840   }
    841 
    842 #endif /* 0 */
    843 
    844 
    845   static void
    846   psh_hint_table_align_hints( PSH_Hint_Table  table,
    847                               PSH_Globals     globals,
    848                               FT_Int          dimension,
    849                               PSH_Glyph       glyph )
    850   {
    851     PSH_Hint       hint;
    852     FT_UInt        count;
    853 
    854 #ifdef DEBUG_HINTER
    855 
    856     PSH_Dimension  dim   = &globals->dimension[dimension];
    857     FT_Fixed       scale = dim->scale_mult;
    858     FT_Fixed       delta = dim->scale_delta;
    859 
    860 
    861     if ( ps_debug_no_vert_hints && dimension == 0 )
    862     {
    863       ps_simple_scale( table, scale, delta, dimension );
    864       return;
    865     }
    866 
    867     if ( ps_debug_no_horz_hints && dimension == 1 )
    868     {
    869       ps_simple_scale( table, scale, delta, dimension );
    870       return;
    871     }
    872 
    873 #endif /* DEBUG_HINTER*/
    874 
    875     hint  = table->hints;
    876     count = table->max_hints;
    877 
    878     for ( ; count > 0; count--, hint++ )
    879       psh_hint_align( hint, globals, dimension, glyph );
    880   }
    881 
    882 
    883   /*************************************************************************/
    884   /*************************************************************************/
    885   /*****                                                               *****/
    886   /*****                POINTS INTERPOLATION ROUTINES                  *****/
    887   /*****                                                               *****/
    888   /*************************************************************************/
    889   /*************************************************************************/
    890 
    891 #define xxDEBUG_ZONES
    892 
    893 
    894 #ifdef DEBUG_ZONES
    895 
    896 #include FT_CONFIG_STANDARD_LIBRARY_H
    897 
    898   static void
    899   psh_print_zone( PSH_Zone  zone )
    900   {
    901     printf( "zone [scale,delta,min,max] = [%.5f,%.2f,%d,%d]\n",
    902              zone->scale / 65536.0,
    903              zone->delta / 64.0,
    904              zone->min,
    905              zone->max );
    906   }
    907 
    908 #endif /* DEBUG_ZONES */
    909 
    910 
    911   /*************************************************************************/
    912   /*************************************************************************/
    913   /*****                                                               *****/
    914   /*****                    HINTER GLYPH MANAGEMENT                    *****/
    915   /*****                                                               *****/
    916   /*************************************************************************/
    917   /*************************************************************************/
    918 
    919 #define  psh_corner_is_flat      ft_corner_is_flat
    920 #define  psh_corner_orientation  ft_corner_orientation
    921 
    922 
    923 #ifdef COMPUTE_INFLEXS
    924 
    925   /* compute all inflex points in a given glyph */
    926   static void
    927   psh_glyph_compute_inflections( PSH_Glyph  glyph )
    928   {
    929     FT_UInt  n;
    930 
    931 
    932     for ( n = 0; n < glyph->num_contours; n++ )
    933     {
    934       PSH_Point  first, start, end, before, after;
    935       FT_Pos     in_x, in_y, out_x, out_y;
    936       FT_Int     orient_prev, orient_cur;
    937       FT_Int     finished = 0;
    938 
    939 
    940       /* we need at least 4 points to create an inflection point */
    941       if ( glyph->contours[n].count < 4 )
    942         continue;
    943 
    944       /* compute first segment in contour */
    945       first = glyph->contours[n].start;
    946 
    947       start = end = first;
    948       do
    949       {
    950         end = end->next;
    951         if ( end == first )
    952           goto Skip;
    953 
    954         in_x = end->org_u - start->org_u;
    955         in_y = end->org_v - start->org_v;
    956 
    957       } while ( in_x == 0 && in_y == 0 );
    958 
    959       /* extend the segment start whenever possible */
    960       before = start;
    961       do
    962       {
    963         do
    964         {
    965           start  = before;
    966           before = before->prev;
    967           if ( before == first )
    968             goto Skip;
    969 
    970           out_x = start->org_u - before->org_u;
    971           out_y = start->org_v - before->org_v;
    972 
    973         } while ( out_x == 0 && out_y == 0 );
    974 
    975         orient_prev = psh_corner_orientation( in_x, in_y, out_x, out_y );
    976 
    977       } while ( orient_prev == 0 );
    978 
    979       first = start;
    980       in_x  = out_x;
    981       in_y  = out_y;
    982 
    983       /* now, process all segments in the contour */
    984       do
    985       {
    986         /* first, extend current segment's end whenever possible */
    987         after = end;
    988         do
    989         {
    990           do
    991           {
    992             end   = after;
    993             after = after->next;
    994             if ( after == first )
    995               finished = 1;
    996 
    997             out_x = after->org_u - end->org_u;
    998             out_y = after->org_v - end->org_v;
    999 
   1000           } while ( out_x == 0 && out_y == 0 );
   1001 
   1002           orient_cur = psh_corner_orientation( in_x, in_y, out_x, out_y );
   1003 
   1004         } while ( orient_cur == 0 );
   1005 
   1006         if ( ( orient_cur ^ orient_prev ) < 0 )
   1007         {
   1008           do
   1009           {
   1010             psh_point_set_inflex( start );
   1011             start = start->next;
   1012           }
   1013           while ( start != end );
   1014 
   1015           psh_point_set_inflex( start );
   1016         }
   1017 
   1018         start       = end;
   1019         end         = after;
   1020         orient_prev = orient_cur;
   1021         in_x        = out_x;
   1022         in_y        = out_y;
   1023 
   1024       } while ( !finished );
   1025 
   1026     Skip:
   1027       ;
   1028     }
   1029   }
   1030 
   1031 #endif /* COMPUTE_INFLEXS */
   1032 
   1033 
   1034   static void
   1035   psh_glyph_done( PSH_Glyph  glyph )
   1036   {
   1037     FT_Memory  memory = glyph->memory;
   1038 
   1039 
   1040     psh_hint_table_done( &glyph->hint_tables[1], memory );
   1041     psh_hint_table_done( &glyph->hint_tables[0], memory );
   1042 
   1043     FT_FREE( glyph->points );
   1044     FT_FREE( glyph->contours );
   1045 
   1046     glyph->num_points   = 0;
   1047     glyph->num_contours = 0;
   1048 
   1049     glyph->memory = NULL;
   1050   }
   1051 
   1052 
   1053   static int
   1054   psh_compute_dir( FT_Pos  dx,
   1055                    FT_Pos  dy )
   1056   {
   1057     FT_Pos  ax, ay;
   1058     int     result = PSH_DIR_NONE;
   1059 
   1060 
   1061     ax = FT_ABS( dx );
   1062     ay = FT_ABS( dy );
   1063 
   1064     if ( ay * 12 < ax )
   1065     {
   1066       /* |dy| <<< |dx|  means a near-horizontal segment */
   1067       result = ( dx >= 0 ) ? PSH_DIR_RIGHT : PSH_DIR_LEFT;
   1068     }
   1069     else if ( ax * 12 < ay )
   1070     {
   1071       /* |dx| <<< |dy|  means a near-vertical segment */
   1072       result = ( dy >= 0 ) ? PSH_DIR_UP : PSH_DIR_DOWN;
   1073     }
   1074 
   1075     return result;
   1076   }
   1077 
   1078 
   1079   /* load outline point coordinates into hinter glyph */
   1080   static void
   1081   psh_glyph_load_points( PSH_Glyph  glyph,
   1082                          FT_Int     dimension )
   1083   {
   1084     FT_Vector*  vec   = glyph->outline->points;
   1085     PSH_Point   point = glyph->points;
   1086     FT_UInt     count = glyph->num_points;
   1087 
   1088 
   1089     for ( ; count > 0; count--, point++, vec++ )
   1090     {
   1091       point->flags2 = 0;
   1092       point->hint   = NULL;
   1093       if ( dimension == 0 )
   1094       {
   1095         point->org_u = vec->x;
   1096         point->org_v = vec->y;
   1097       }
   1098       else
   1099       {
   1100         point->org_u = vec->y;
   1101         point->org_v = vec->x;
   1102       }
   1103 
   1104 #ifdef DEBUG_HINTER
   1105       point->org_x = vec->x;
   1106       point->org_y = vec->y;
   1107 #endif
   1108 
   1109     }
   1110   }
   1111 
   1112 
   1113   /* save hinted point coordinates back to outline */
   1114   static void
   1115   psh_glyph_save_points( PSH_Glyph  glyph,
   1116                          FT_Int     dimension )
   1117   {
   1118     FT_UInt     n;
   1119     PSH_Point   point = glyph->points;
   1120     FT_Vector*  vec   = glyph->outline->points;
   1121     char*       tags  = glyph->outline->tags;
   1122 
   1123 
   1124     for ( n = 0; n < glyph->num_points; n++ )
   1125     {
   1126       if ( dimension == 0 )
   1127         vec[n].x = point->cur_u;
   1128       else
   1129         vec[n].y = point->cur_u;
   1130 
   1131       if ( psh_point_is_strong( point ) )
   1132         tags[n] |= (char)( ( dimension == 0 ) ? 32 : 64 );
   1133 
   1134 #ifdef DEBUG_HINTER
   1135 
   1136       if ( dimension == 0 )
   1137       {
   1138         point->cur_x   = point->cur_u;
   1139         point->flags_x = point->flags2 | point->flags;
   1140       }
   1141       else
   1142       {
   1143         point->cur_y   = point->cur_u;
   1144         point->flags_y = point->flags2 | point->flags;
   1145       }
   1146 
   1147 #endif
   1148 
   1149       point++;
   1150     }
   1151   }
   1152 
   1153 
   1154   static FT_Error
   1155   psh_glyph_init( PSH_Glyph    glyph,
   1156                   FT_Outline*  outline,
   1157                   PS_Hints     ps_hints,
   1158                   PSH_Globals  globals )
   1159   {
   1160     FT_Error   error;
   1161     FT_Memory  memory;
   1162 
   1163 
   1164     /* clear all fields */
   1165     FT_ZERO( glyph );
   1166 
   1167     memory = glyph->memory = globals->memory;
   1168 
   1169     /* allocate and setup points + contours arrays */
   1170     if ( FT_NEW_ARRAY( glyph->points,   outline->n_points   ) ||
   1171          FT_NEW_ARRAY( glyph->contours, outline->n_contours ) )
   1172       goto Exit;
   1173 
   1174     glyph->num_points   = (FT_UInt)outline->n_points;
   1175     glyph->num_contours = (FT_UInt)outline->n_contours;
   1176 
   1177     {
   1178       FT_UInt      first = 0, next, n;
   1179       PSH_Point    points  = glyph->points;
   1180       PSH_Contour  contour = glyph->contours;
   1181 
   1182 
   1183       for ( n = 0; n < glyph->num_contours; n++ )
   1184       {
   1185         FT_UInt    count;
   1186         PSH_Point  point;
   1187 
   1188 
   1189         next  = (FT_UInt)outline->contours[n] + 1;
   1190         count = next - first;
   1191 
   1192         contour->start = points + first;
   1193         contour->count = count;
   1194 
   1195         if ( count > 0 )
   1196         {
   1197           point = points + first;
   1198 
   1199           point->prev    = points + next - 1;
   1200           point->contour = contour;
   1201 
   1202           for ( ; count > 1; count-- )
   1203           {
   1204             point[0].next = point + 1;
   1205             point[1].prev = point;
   1206             point++;
   1207             point->contour = contour;
   1208           }
   1209           point->next = points + first;
   1210         }
   1211 
   1212         contour++;
   1213         first = next;
   1214       }
   1215     }
   1216 
   1217     {
   1218       PSH_Point   points = glyph->points;
   1219       PSH_Point   point  = points;
   1220       FT_Vector*  vec    = outline->points;
   1221       FT_UInt     n;
   1222 
   1223 
   1224       for ( n = 0; n < glyph->num_points; n++, point++ )
   1225       {
   1226         FT_Int  n_prev = (FT_Int)( point->prev - points );
   1227         FT_Int  n_next = (FT_Int)( point->next - points );
   1228         FT_Pos  dxi, dyi, dxo, dyo;
   1229 
   1230 
   1231         if ( !( outline->tags[n] & FT_CURVE_TAG_ON ) )
   1232           point->flags = PSH_POINT_OFF;
   1233 
   1234         dxi = vec[n].x - vec[n_prev].x;
   1235         dyi = vec[n].y - vec[n_prev].y;
   1236 
   1237         point->dir_in = (FT_Char)psh_compute_dir( dxi, dyi );
   1238 
   1239         dxo = vec[n_next].x - vec[n].x;
   1240         dyo = vec[n_next].y - vec[n].y;
   1241 
   1242         point->dir_out = (FT_Char)psh_compute_dir( dxo, dyo );
   1243 
   1244         /* detect smooth points */
   1245         if ( point->flags & PSH_POINT_OFF )
   1246           point->flags |= PSH_POINT_SMOOTH;
   1247 
   1248         else if ( point->dir_in == point->dir_out )
   1249         {
   1250           if ( point->dir_out != PSH_DIR_NONE           ||
   1251                psh_corner_is_flat( dxi, dyi, dxo, dyo ) )
   1252             point->flags |= PSH_POINT_SMOOTH;
   1253         }
   1254       }
   1255     }
   1256 
   1257     glyph->outline = outline;
   1258     glyph->globals = globals;
   1259 
   1260 #ifdef COMPUTE_INFLEXS
   1261     psh_glyph_load_points( glyph, 0 );
   1262     psh_glyph_compute_inflections( glyph );
   1263 #endif /* COMPUTE_INFLEXS */
   1264 
   1265     /* now deal with hints tables */
   1266     error = psh_hint_table_init( &glyph->hint_tables [0],
   1267                                  &ps_hints->dimension[0].hints,
   1268                                  &ps_hints->dimension[0].masks,
   1269                                  &ps_hints->dimension[0].counters,
   1270                                  memory );
   1271     if ( error )
   1272       goto Exit;
   1273 
   1274     error = psh_hint_table_init( &glyph->hint_tables [1],
   1275                                  &ps_hints->dimension[1].hints,
   1276                                  &ps_hints->dimension[1].masks,
   1277                                  &ps_hints->dimension[1].counters,
   1278                                  memory );
   1279     if ( error )
   1280       goto Exit;
   1281 
   1282   Exit:
   1283     return error;
   1284   }
   1285 
   1286 
   1287   /* compute all extrema in a glyph for a given dimension */
   1288   static void
   1289   psh_glyph_compute_extrema( PSH_Glyph  glyph )
   1290   {
   1291     FT_UInt  n;
   1292 
   1293 
   1294     /* first of all, compute all local extrema */
   1295     for ( n = 0; n < glyph->num_contours; n++ )
   1296     {
   1297       PSH_Point  first = glyph->contours[n].start;
   1298       PSH_Point  point, before, after;
   1299 
   1300 
   1301       if ( glyph->contours[n].count == 0 )
   1302         continue;
   1303 
   1304       point  = first;
   1305       before = point;
   1306 
   1307       do
   1308       {
   1309         before = before->prev;
   1310         if ( before == first )
   1311           goto Skip;
   1312 
   1313       } while ( before->org_u == point->org_u );
   1314 
   1315       first = point = before->next;
   1316 
   1317       for (;;)
   1318       {
   1319         after = point;
   1320         do
   1321         {
   1322           after = after->next;
   1323           if ( after == first )
   1324             goto Next;
   1325 
   1326         } while ( after->org_u == point->org_u );
   1327 
   1328         if ( before->org_u < point->org_u )
   1329         {
   1330           if ( after->org_u < point->org_u )
   1331           {
   1332             /* local maximum */
   1333             goto Extremum;
   1334           }
   1335         }
   1336         else /* before->org_u > point->org_u */
   1337         {
   1338           if ( after->org_u > point->org_u )
   1339           {
   1340             /* local minimum */
   1341           Extremum:
   1342             do
   1343             {
   1344               psh_point_set_extremum( point );
   1345               point = point->next;
   1346 
   1347             } while ( point != after );
   1348           }
   1349         }
   1350 
   1351         before = after->prev;
   1352         point  = after;
   1353 
   1354       } /* for  */
   1355 
   1356     Next:
   1357       ;
   1358     }
   1359 
   1360     /* for each extremum, determine its direction along the */
   1361     /* orthogonal axis                                      */
   1362     for ( n = 0; n < glyph->num_points; n++ )
   1363     {
   1364       PSH_Point  point, before, after;
   1365 
   1366 
   1367       point  = &glyph->points[n];
   1368       before = point;
   1369       after  = point;
   1370 
   1371       if ( psh_point_is_extremum( point ) )
   1372       {
   1373         do
   1374         {
   1375           before = before->prev;
   1376           if ( before == point )
   1377             goto Skip;
   1378 
   1379         } while ( before->org_v == point->org_v );
   1380 
   1381         do
   1382         {
   1383           after = after->next;
   1384           if ( after == point )
   1385             goto Skip;
   1386 
   1387         } while ( after->org_v == point->org_v );
   1388       }
   1389 
   1390       if ( before->org_v < point->org_v &&
   1391            after->org_v  > point->org_v )
   1392       {
   1393         psh_point_set_positive( point );
   1394       }
   1395       else if ( before->org_v > point->org_v &&
   1396                 after->org_v  < point->org_v )
   1397       {
   1398         psh_point_set_negative( point );
   1399       }
   1400 
   1401     Skip:
   1402       ;
   1403     }
   1404   }
   1405 
   1406 
   1407   /* major_dir is the direction for points on the bottom/left of the stem; */
   1408   /* Points on the top/right of the stem will have a direction of          */
   1409   /* -major_dir.                                                           */
   1410 
   1411   static void
   1412   psh_hint_table_find_strong_points( PSH_Hint_Table  table,
   1413                                      PSH_Point       point,
   1414                                      FT_UInt         count,
   1415                                      FT_Int          threshold,
   1416                                      FT_Int          major_dir )
   1417   {
   1418     PSH_Hint*  sort      = table->sort;
   1419     FT_UInt    num_hints = table->num_hints;
   1420 
   1421 
   1422     for ( ; count > 0; count--, point++ )
   1423     {
   1424       FT_Int  point_dir = 0;
   1425       FT_Pos  org_u     = point->org_u;
   1426 
   1427 
   1428       if ( psh_point_is_strong( point ) )
   1429         continue;
   1430 
   1431       if ( PSH_DIR_COMPARE( point->dir_in, major_dir ) )
   1432         point_dir = point->dir_in;
   1433 
   1434       else if ( PSH_DIR_COMPARE( point->dir_out, major_dir ) )
   1435         point_dir = point->dir_out;
   1436 
   1437       if ( point_dir )
   1438       {
   1439         if ( point_dir == major_dir )
   1440         {
   1441           FT_UInt  nn;
   1442 
   1443 
   1444           for ( nn = 0; nn < num_hints; nn++ )
   1445           {
   1446             PSH_Hint  hint = sort[nn];
   1447             FT_Pos    d    = org_u - hint->org_pos;
   1448 
   1449 
   1450             if ( d < threshold && -d < threshold )
   1451             {
   1452               psh_point_set_strong( point );
   1453               point->flags2 |= PSH_POINT_EDGE_MIN;
   1454               point->hint    = hint;
   1455               break;
   1456             }
   1457           }
   1458         }
   1459         else if ( point_dir == -major_dir )
   1460         {
   1461           FT_UInt  nn;
   1462 
   1463 
   1464           for ( nn = 0; nn < num_hints; nn++ )
   1465           {
   1466             PSH_Hint  hint = sort[nn];
   1467             FT_Pos    d    = org_u - hint->org_pos - hint->org_len;
   1468 
   1469 
   1470             if ( d < threshold && -d < threshold )
   1471             {
   1472               psh_point_set_strong( point );
   1473               point->flags2 |= PSH_POINT_EDGE_MAX;
   1474               point->hint    = hint;
   1475               break;
   1476             }
   1477           }
   1478         }
   1479       }
   1480 
   1481 #if 1
   1482       else if ( psh_point_is_extremum( point ) )
   1483       {
   1484         /* treat extrema as special cases for stem edge alignment */
   1485         FT_UInt  nn, min_flag, max_flag;
   1486 
   1487 
   1488         if ( major_dir == PSH_DIR_HORIZONTAL )
   1489         {
   1490           min_flag = PSH_POINT_POSITIVE;
   1491           max_flag = PSH_POINT_NEGATIVE;
   1492         }
   1493         else
   1494         {
   1495           min_flag = PSH_POINT_NEGATIVE;
   1496           max_flag = PSH_POINT_POSITIVE;
   1497         }
   1498 
   1499         if ( point->flags2 & min_flag )
   1500         {
   1501           for ( nn = 0; nn < num_hints; nn++ )
   1502           {
   1503             PSH_Hint  hint = sort[nn];
   1504             FT_Pos    d    = org_u - hint->org_pos;
   1505 
   1506 
   1507             if ( d < threshold && -d < threshold )
   1508             {
   1509               point->flags2 |= PSH_POINT_EDGE_MIN;
   1510               point->hint    = hint;
   1511               psh_point_set_strong( point );
   1512               break;
   1513             }
   1514           }
   1515         }
   1516         else if ( point->flags2 & max_flag )
   1517         {
   1518           for ( nn = 0; nn < num_hints; nn++ )
   1519           {
   1520             PSH_Hint  hint = sort[nn];
   1521             FT_Pos    d    = org_u - hint->org_pos - hint->org_len;
   1522 
   1523 
   1524             if ( d < threshold && -d < threshold )
   1525             {
   1526               point->flags2 |= PSH_POINT_EDGE_MAX;
   1527               point->hint    = hint;
   1528               psh_point_set_strong( point );
   1529               break;
   1530             }
   1531           }
   1532         }
   1533 
   1534         if ( !point->hint )
   1535         {
   1536           for ( nn = 0; nn < num_hints; nn++ )
   1537           {
   1538             PSH_Hint  hint = sort[nn];
   1539 
   1540 
   1541             if ( org_u >= hint->org_pos                 &&
   1542                 org_u <= hint->org_pos + hint->org_len )
   1543             {
   1544               point->hint = hint;
   1545               break;
   1546             }
   1547           }
   1548         }
   1549       }
   1550 
   1551 #endif /* 1 */
   1552     }
   1553   }
   1554 
   1555 
   1556   /* the accepted shift for strong points in fractional pixels */
   1557 #define PSH_STRONG_THRESHOLD  32
   1558 
   1559   /* the maximum shift value in font units */
   1560 #define PSH_STRONG_THRESHOLD_MAXIMUM  30
   1561 
   1562 
   1563   /* find strong points in a glyph */
   1564   static void
   1565   psh_glyph_find_strong_points( PSH_Glyph  glyph,
   1566                                 FT_Int     dimension )
   1567   {
   1568     /* a point is `strong' if it is located on a stem edge and       */
   1569     /* has an `in' or `out' tangent parallel to the hint's direction */
   1570 
   1571     PSH_Hint_Table  table     = &glyph->hint_tables[dimension];
   1572     PS_Mask         mask      = table->hint_masks->masks;
   1573     FT_UInt         num_masks = table->hint_masks->num_masks;
   1574     FT_UInt         first     = 0;
   1575     FT_Int          major_dir = ( dimension == 0 ) ? PSH_DIR_VERTICAL
   1576                                                    : PSH_DIR_HORIZONTAL;
   1577     PSH_Dimension   dim       = &glyph->globals->dimension[dimension];
   1578     FT_Fixed        scale     = dim->scale_mult;
   1579     FT_Int          threshold;
   1580 
   1581 
   1582     threshold = (FT_Int)FT_DivFix( PSH_STRONG_THRESHOLD, scale );
   1583     if ( threshold > PSH_STRONG_THRESHOLD_MAXIMUM )
   1584       threshold = PSH_STRONG_THRESHOLD_MAXIMUM;
   1585 
   1586     /* process secondary hints to `selected' points */
   1587     if ( num_masks > 1 && glyph->num_points > 0 )
   1588     {
   1589       /* the `endchar' op can reduce the number of points */
   1590       first = mask->end_point > glyph->num_points
   1591                 ? glyph->num_points
   1592                 : mask->end_point;
   1593       mask++;
   1594       for ( ; num_masks > 1; num_masks--, mask++ )
   1595       {
   1596         FT_UInt  next = FT_MIN( mask->end_point, glyph->num_points );
   1597 
   1598 
   1599         if ( next > first )
   1600         {
   1601           FT_UInt    count = next - first;
   1602           PSH_Point  point = glyph->points + first;
   1603 
   1604 
   1605           psh_hint_table_activate_mask( table, mask );
   1606 
   1607           psh_hint_table_find_strong_points( table, point, count,
   1608                                              threshold, major_dir );
   1609         }
   1610         first = next;
   1611       }
   1612     }
   1613 
   1614     /* process primary hints for all points */
   1615     if ( num_masks == 1 )
   1616     {
   1617       FT_UInt    count = glyph->num_points;
   1618       PSH_Point  point = glyph->points;
   1619 
   1620 
   1621       psh_hint_table_activate_mask( table, table->hint_masks->masks );
   1622 
   1623       psh_hint_table_find_strong_points( table, point, count,
   1624                                          threshold, major_dir );
   1625     }
   1626 
   1627     /* now, certain points may have been attached to a hint and */
   1628     /* not marked as strong; update their flags then            */
   1629     {
   1630       FT_UInt    count = glyph->num_points;
   1631       PSH_Point  point = glyph->points;
   1632 
   1633 
   1634       for ( ; count > 0; count--, point++ )
   1635         if ( point->hint && !psh_point_is_strong( point ) )
   1636           psh_point_set_strong( point );
   1637     }
   1638   }
   1639 
   1640 
   1641   /* find points in a glyph which are in a blue zone and have `in' or */
   1642   /* `out' tangents parallel to the horizontal axis                   */
   1643   static void
   1644   psh_glyph_find_blue_points( PSH_Blues  blues,
   1645                               PSH_Glyph  glyph )
   1646   {
   1647     PSH_Blue_Table  table;
   1648     PSH_Blue_Zone   zone;
   1649     FT_UInt         glyph_count = glyph->num_points;
   1650     FT_UInt         blue_count;
   1651     PSH_Point       point = glyph->points;
   1652 
   1653 
   1654     for ( ; glyph_count > 0; glyph_count--, point++ )
   1655     {
   1656       FT_Pos  y;
   1657 
   1658 
   1659       /* check tangents */
   1660       if ( !PSH_DIR_COMPARE( point->dir_in,  PSH_DIR_HORIZONTAL ) &&
   1661            !PSH_DIR_COMPARE( point->dir_out, PSH_DIR_HORIZONTAL ) )
   1662         continue;
   1663 
   1664       /* skip strong points */
   1665       if ( psh_point_is_strong( point ) )
   1666         continue;
   1667 
   1668       y = point->org_u;
   1669 
   1670       /* look up top zones */
   1671       table      = &blues->normal_top;
   1672       blue_count = table->count;
   1673       zone       = table->zones;
   1674 
   1675       for ( ; blue_count > 0; blue_count--, zone++ )
   1676       {
   1677         FT_Pos  delta = y - zone->org_bottom;
   1678 
   1679 
   1680         if ( delta < -blues->blue_fuzz )
   1681           break;
   1682 
   1683         if ( y <= zone->org_top + blues->blue_fuzz )
   1684           if ( blues->no_overshoots || delta <= blues->blue_threshold )
   1685           {
   1686             point->cur_u = zone->cur_bottom;
   1687             psh_point_set_strong( point );
   1688             psh_point_set_fitted( point );
   1689           }
   1690       }
   1691 
   1692       /* look up bottom zones */
   1693       table      = &blues->normal_bottom;
   1694       blue_count = table->count;
   1695       zone       = table->zones + blue_count - 1;
   1696 
   1697       for ( ; blue_count > 0; blue_count--, zone-- )
   1698       {
   1699         FT_Pos  delta = zone->org_top - y;
   1700 
   1701 
   1702         if ( delta < -blues->blue_fuzz )
   1703           break;
   1704 
   1705         if ( y >= zone->org_bottom - blues->blue_fuzz )
   1706           if ( blues->no_overshoots || delta < blues->blue_threshold )
   1707           {
   1708             point->cur_u = zone->cur_top;
   1709             psh_point_set_strong( point );
   1710             psh_point_set_fitted( point );
   1711           }
   1712       }
   1713     }
   1714   }
   1715 
   1716 
   1717   /* interpolate strong points with the help of hinted coordinates */
   1718   static void
   1719   psh_glyph_interpolate_strong_points( PSH_Glyph  glyph,
   1720                                        FT_Int     dimension )
   1721   {
   1722     PSH_Dimension  dim   = &glyph->globals->dimension[dimension];
   1723     FT_Fixed       scale = dim->scale_mult;
   1724 
   1725     FT_UInt        count = glyph->num_points;
   1726     PSH_Point      point = glyph->points;
   1727 
   1728 
   1729     for ( ; count > 0; count--, point++ )
   1730     {
   1731       PSH_Hint  hint = point->hint;
   1732 
   1733 
   1734       if ( hint )
   1735       {
   1736         FT_Pos  delta;
   1737 
   1738 
   1739         if ( psh_point_is_edge_min( point ) )
   1740           point->cur_u = hint->cur_pos;
   1741 
   1742         else if ( psh_point_is_edge_max( point ) )
   1743           point->cur_u = hint->cur_pos + hint->cur_len;
   1744 
   1745         else
   1746         {
   1747           delta = point->org_u - hint->org_pos;
   1748 
   1749           if ( delta <= 0 )
   1750             point->cur_u = hint->cur_pos + FT_MulFix( delta, scale );
   1751 
   1752           else if ( delta >= hint->org_len )
   1753             point->cur_u = hint->cur_pos + hint->cur_len +
   1754                              FT_MulFix( delta - hint->org_len, scale );
   1755 
   1756           else /* hint->org_len > 0 */
   1757             point->cur_u = hint->cur_pos +
   1758                              FT_MulDiv( delta, hint->cur_len,
   1759                                         hint->org_len );
   1760         }
   1761         psh_point_set_fitted( point );
   1762       }
   1763     }
   1764   }
   1765 
   1766 
   1767 #define  PSH_MAX_STRONG_INTERNAL  16
   1768 
   1769   static void
   1770   psh_glyph_interpolate_normal_points( PSH_Glyph  glyph,
   1771                                        FT_Int     dimension )
   1772   {
   1773 
   1774 #if 1
   1775     /* first technique: a point is strong if it is a local extremum */
   1776 
   1777     PSH_Dimension  dim    = &glyph->globals->dimension[dimension];
   1778     FT_Fixed       scale  = dim->scale_mult;
   1779     FT_Memory      memory = glyph->memory;
   1780 
   1781     PSH_Point*     strongs     = NULL;
   1782     PSH_Point      strongs_0[PSH_MAX_STRONG_INTERNAL];
   1783     FT_UInt        num_strongs = 0;
   1784 
   1785     PSH_Point      points = glyph->points;
   1786     PSH_Point      points_end = points + glyph->num_points;
   1787     PSH_Point      point;
   1788 
   1789 
   1790     /* first count the number of strong points */
   1791     for ( point = points; point < points_end; point++ )
   1792     {
   1793       if ( psh_point_is_strong( point ) )
   1794         num_strongs++;
   1795     }
   1796 
   1797     if ( num_strongs == 0 )  /* nothing to do here */
   1798       return;
   1799 
   1800     /* allocate an array to store a list of points, */
   1801     /* stored in increasing org_u order             */
   1802     if ( num_strongs <= PSH_MAX_STRONG_INTERNAL )
   1803       strongs = strongs_0;
   1804     else
   1805     {
   1806       FT_Error  error;
   1807 
   1808 
   1809       if ( FT_NEW_ARRAY( strongs, num_strongs ) )
   1810         return;
   1811     }
   1812 
   1813     num_strongs = 0;
   1814     for ( point = points; point < points_end; point++ )
   1815     {
   1816       PSH_Point*  insert;
   1817 
   1818 
   1819       if ( !psh_point_is_strong( point ) )
   1820         continue;
   1821 
   1822       for ( insert = strongs + num_strongs; insert > strongs; insert-- )
   1823       {
   1824         if ( insert[-1]->org_u <= point->org_u )
   1825           break;
   1826 
   1827         insert[0] = insert[-1];
   1828       }
   1829       insert[0] = point;
   1830       num_strongs++;
   1831     }
   1832 
   1833     /* now try to interpolate all normal points */
   1834     for ( point = points; point < points_end; point++ )
   1835     {
   1836       if ( psh_point_is_strong( point ) )
   1837         continue;
   1838 
   1839       /* sometimes, some local extrema are smooth points */
   1840       if ( psh_point_is_smooth( point ) )
   1841       {
   1842         if ( point->dir_in == PSH_DIR_NONE   ||
   1843              point->dir_in != point->dir_out )
   1844           continue;
   1845 
   1846         if ( !psh_point_is_extremum( point ) &&
   1847              !psh_point_is_inflex( point )   )
   1848           continue;
   1849 
   1850         point->flags &= ~PSH_POINT_SMOOTH;
   1851       }
   1852 
   1853       /* find best enclosing point coordinates then interpolate */
   1854       {
   1855         PSH_Point   before, after;
   1856         FT_UInt     nn;
   1857 
   1858 
   1859         for ( nn = 0; nn < num_strongs; nn++ )
   1860           if ( strongs[nn]->org_u > point->org_u )
   1861             break;
   1862 
   1863         if ( nn == 0 )  /* point before the first strong point */
   1864         {
   1865           after = strongs[0];
   1866 
   1867           point->cur_u = after->cur_u +
   1868                            FT_MulFix( point->org_u - after->org_u,
   1869                                       scale );
   1870         }
   1871         else
   1872         {
   1873           before = strongs[nn - 1];
   1874 
   1875           for ( nn = num_strongs; nn > 0; nn-- )
   1876             if ( strongs[nn - 1]->org_u < point->org_u )
   1877               break;
   1878 
   1879           if ( nn == num_strongs )  /* point is after last strong point */
   1880           {
   1881             before = strongs[nn - 1];
   1882 
   1883             point->cur_u = before->cur_u +
   1884                              FT_MulFix( point->org_u - before->org_u,
   1885                                         scale );
   1886           }
   1887           else
   1888           {
   1889             FT_Pos  u;
   1890 
   1891 
   1892             after = strongs[nn];
   1893 
   1894             /* now interpolate point between before and after */
   1895             u = point->org_u;
   1896 
   1897             if ( u == before->org_u )
   1898               point->cur_u = before->cur_u;
   1899 
   1900             else if ( u == after->org_u )
   1901               point->cur_u = after->cur_u;
   1902 
   1903             else
   1904               point->cur_u = before->cur_u +
   1905                                FT_MulDiv( u - before->org_u,
   1906                                           after->cur_u - before->cur_u,
   1907                                           after->org_u - before->org_u );
   1908           }
   1909         }
   1910         psh_point_set_fitted( point );
   1911       }
   1912     }
   1913 
   1914     if ( strongs != strongs_0 )
   1915       FT_FREE( strongs );
   1916 
   1917 #endif /* 1 */
   1918 
   1919   }
   1920 
   1921 
   1922   /* interpolate other points */
   1923   static void
   1924   psh_glyph_interpolate_other_points( PSH_Glyph  glyph,
   1925                                       FT_Int     dimension )
   1926   {
   1927     PSH_Dimension  dim          = &glyph->globals->dimension[dimension];
   1928     FT_Fixed       scale        = dim->scale_mult;
   1929     FT_Fixed       delta        = dim->scale_delta;
   1930     PSH_Contour    contour      = glyph->contours;
   1931     FT_UInt        num_contours = glyph->num_contours;
   1932 
   1933 
   1934     for ( ; num_contours > 0; num_contours--, contour++ )
   1935     {
   1936       PSH_Point  start = contour->start;
   1937       PSH_Point  first, next, point;
   1938       FT_UInt    fit_count;
   1939 
   1940 
   1941       /* count the number of strong points in this contour */
   1942       next      = start + contour->count;
   1943       fit_count = 0;
   1944       first     = NULL;
   1945 
   1946       for ( point = start; point < next; point++ )
   1947         if ( psh_point_is_fitted( point ) )
   1948         {
   1949           if ( !first )
   1950             first = point;
   1951 
   1952           fit_count++;
   1953         }
   1954 
   1955       /* if there are less than 2 fitted points in the contour, we */
   1956       /* simply scale and eventually translate the contour points  */
   1957       if ( fit_count < 2 )
   1958       {
   1959         if ( fit_count == 1 )
   1960           delta = first->cur_u - FT_MulFix( first->org_u, scale );
   1961 
   1962         for ( point = start; point < next; point++ )
   1963           if ( point != first )
   1964             point->cur_u = FT_MulFix( point->org_u, scale ) + delta;
   1965 
   1966         goto Next_Contour;
   1967       }
   1968 
   1969       /* there are more than 2 strong points in this contour; we */
   1970       /* need to interpolate weak points between them            */
   1971       start = first;
   1972       do
   1973       {
   1974         /* skip consecutive fitted points */
   1975         for (;;)
   1976         {
   1977           next = first->next;
   1978           if ( next == start )
   1979             goto Next_Contour;
   1980 
   1981           if ( !psh_point_is_fitted( next ) )
   1982             break;
   1983 
   1984           first = next;
   1985         }
   1986 
   1987         /* find next fitted point after unfitted one */
   1988         for (;;)
   1989         {
   1990           next = next->next;
   1991           if ( psh_point_is_fitted( next ) )
   1992             break;
   1993         }
   1994 
   1995         /* now interpolate between them */
   1996         {
   1997           FT_Pos    org_a, org_ab, cur_a, cur_ab;
   1998           FT_Pos    org_c, org_ac, cur_c;
   1999           FT_Fixed  scale_ab;
   2000 
   2001 
   2002           if ( first->org_u <= next->org_u )
   2003           {
   2004             org_a  = first->org_u;
   2005             cur_a  = first->cur_u;
   2006             org_ab = next->org_u - org_a;
   2007             cur_ab = next->cur_u - cur_a;
   2008           }
   2009           else
   2010           {
   2011             org_a  = next->org_u;
   2012             cur_a  = next->cur_u;
   2013             org_ab = first->org_u - org_a;
   2014             cur_ab = first->cur_u - cur_a;
   2015           }
   2016 
   2017           scale_ab = 0x10000L;
   2018           if ( org_ab > 0 )
   2019             scale_ab = FT_DivFix( cur_ab, org_ab );
   2020 
   2021           point = first->next;
   2022           do
   2023           {
   2024             org_c  = point->org_u;
   2025             org_ac = org_c - org_a;
   2026 
   2027             if ( org_ac <= 0 )
   2028             {
   2029               /* on the left of the interpolation zone */
   2030               cur_c = cur_a + FT_MulFix( org_ac, scale );
   2031             }
   2032             else if ( org_ac >= org_ab )
   2033             {
   2034               /* on the right on the interpolation zone */
   2035               cur_c = cur_a + cur_ab + FT_MulFix( org_ac - org_ab, scale );
   2036             }
   2037             else
   2038             {
   2039               /* within the interpolation zone */
   2040               cur_c = cur_a + FT_MulFix( org_ac, scale_ab );
   2041             }
   2042 
   2043             point->cur_u = cur_c;
   2044 
   2045             point = point->next;
   2046 
   2047           } while ( point != next );
   2048         }
   2049 
   2050         /* keep going until all points in the contours have been processed */
   2051         first = next;
   2052 
   2053       } while ( first != start );
   2054 
   2055     Next_Contour:
   2056       ;
   2057     }
   2058   }
   2059 
   2060 
   2061   /*************************************************************************/
   2062   /*************************************************************************/
   2063   /*****                                                               *****/
   2064   /*****                     HIGH-LEVEL INTERFACE                      *****/
   2065   /*****                                                               *****/
   2066   /*************************************************************************/
   2067   /*************************************************************************/
   2068 
   2069   FT_Error
   2070   ps_hints_apply( PS_Hints        ps_hints,
   2071                   FT_Outline*     outline,
   2072                   PSH_Globals     globals,
   2073                   FT_Render_Mode  hint_mode )
   2074   {
   2075     PSH_GlyphRec  glyphrec;
   2076     PSH_Glyph     glyph = &glyphrec;
   2077     FT_Error      error;
   2078 #ifdef DEBUG_HINTER
   2079     FT_Memory     memory;
   2080 #endif
   2081     FT_Int        dimension;
   2082 
   2083 
   2084     /* something to do? */
   2085     if ( outline->n_points == 0 || outline->n_contours == 0 )
   2086       return FT_Err_Ok;
   2087 
   2088 #ifdef DEBUG_HINTER
   2089 
   2090     memory = globals->memory;
   2091 
   2092     if ( ps_debug_glyph )
   2093     {
   2094       psh_glyph_done( ps_debug_glyph );
   2095       FT_FREE( ps_debug_glyph );
   2096     }
   2097 
   2098     if ( FT_NEW( glyph ) )
   2099       return error;
   2100 
   2101     ps_debug_glyph = glyph;
   2102 
   2103 #endif /* DEBUG_HINTER */
   2104 
   2105     error = psh_glyph_init( glyph, outline, ps_hints, globals );
   2106     if ( error )
   2107       goto Exit;
   2108 
   2109     /* try to optimize the y_scale so that the top of non-capital letters
   2110      * is aligned on a pixel boundary whenever possible
   2111      */
   2112     {
   2113       PSH_Dimension  dim_x = &glyph->globals->dimension[0];
   2114       PSH_Dimension  dim_y = &glyph->globals->dimension[1];
   2115 
   2116       FT_Fixed  x_scale = dim_x->scale_mult;
   2117       FT_Fixed  y_scale = dim_y->scale_mult;
   2118 
   2119       FT_Fixed  old_x_scale = x_scale;
   2120       FT_Fixed  old_y_scale = y_scale;
   2121 
   2122       FT_Fixed  scaled;
   2123       FT_Fixed  fitted;
   2124 
   2125       FT_Bool  rescale = FALSE;
   2126 
   2127 
   2128       scaled = FT_MulFix( globals->blues.normal_top.zones->org_ref, y_scale );
   2129       fitted = FT_PIX_ROUND( scaled );
   2130 
   2131       if ( fitted != 0 && scaled != fitted )
   2132       {
   2133         rescale = TRUE;
   2134 
   2135         y_scale = FT_MulDiv( y_scale, fitted, scaled );
   2136 
   2137         if ( fitted < scaled )
   2138           x_scale -= x_scale / 50;
   2139 
   2140         psh_globals_set_scale( glyph->globals, x_scale, y_scale, 0, 0 );
   2141       }
   2142 
   2143       glyph->do_horz_hints = 1;
   2144       glyph->do_vert_hints = 1;
   2145 
   2146       glyph->do_horz_snapping = FT_BOOL( hint_mode == FT_RENDER_MODE_MONO ||
   2147                                          hint_mode == FT_RENDER_MODE_LCD  );
   2148 
   2149       glyph->do_vert_snapping = FT_BOOL( hint_mode == FT_RENDER_MODE_MONO  ||
   2150                                          hint_mode == FT_RENDER_MODE_LCD_V );
   2151 
   2152       glyph->do_stem_adjust   = FT_BOOL( hint_mode != FT_RENDER_MODE_LIGHT );
   2153 
   2154       for ( dimension = 0; dimension < 2; dimension++ )
   2155       {
   2156         /* load outline coordinates into glyph */
   2157         psh_glyph_load_points( glyph, dimension );
   2158 
   2159         /* compute local extrema */
   2160         psh_glyph_compute_extrema( glyph );
   2161 
   2162         /* compute aligned stem/hints positions */
   2163         psh_hint_table_align_hints( &glyph->hint_tables[dimension],
   2164                                     glyph->globals,
   2165                                     dimension,
   2166                                     glyph );
   2167 
   2168         /* find strong points, align them, then interpolate others */
   2169         psh_glyph_find_strong_points( glyph, dimension );
   2170         if ( dimension == 1 )
   2171           psh_glyph_find_blue_points( &globals->blues, glyph );
   2172         psh_glyph_interpolate_strong_points( glyph, dimension );
   2173         psh_glyph_interpolate_normal_points( glyph, dimension );
   2174         psh_glyph_interpolate_other_points( glyph, dimension );
   2175 
   2176         /* save hinted coordinates back to outline */
   2177         psh_glyph_save_points( glyph, dimension );
   2178 
   2179         if ( rescale )
   2180           psh_globals_set_scale( glyph->globals,
   2181                                  old_x_scale, old_y_scale, 0, 0 );
   2182       }
   2183     }
   2184 
   2185   Exit:
   2186 
   2187 #ifndef DEBUG_HINTER
   2188     psh_glyph_done( glyph );
   2189 #endif
   2190 
   2191     return error;
   2192   }
   2193 
   2194 
   2195 /* END */
   2196