src/freetype/type1/t1afm.c

   1 /***************************************************************************/
   2 /*                                                                         */
   3 /*  t1afm.c                                                                */
   4 /*                                                                         */
   5 /*    AFM support for Type 1 fonts (body).                                 */
   6 /*                                                                         */
   7 /*  Copyright 1996-2000 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 #ifdef FT_FLAT_COMPILE
  20
  21 #include "t1afm.h"
  22
  23 #else
  24
  25 #include <type1/t1afm.h>
  26
  27 #endif
  28
  29
  30 #include <freetype/internal/ftstream.h>
  31 #include <freetype/internal/t1types.h>
  32
  33 #include <stdlib.h>  /* for qsort()   */
  34 #include <string.h>  /* for strcmp()  */
  35 #include <ctype.h>   /* for isalnum() */
  36
  37
  38   /*************************************************************************/
  39   /*                                                                       */
  40   /* The macro FT_COMPONENT is used in trace mode.  It is an implicit      */
  41   /* parameter of the FT_TRACE() and FT_ERROR() macros, used to print/log  */
  42   /* messages during execution.                                            */
  43   /*                                                                       */
  44 #undef  FT_COMPONENT
  45 #define FT_COMPONENT  trace_t1afm
  46
  47
  48   LOCAL_FUNC
  49   void  T1_Done_AFM( FT_Memory  memory,
  50                      T1_AFM*    afm )
  51   {
  52     FREE( afm->kern_pairs );
  53     afm->num_pairs = 0;
  54   }
  55
  56
  57 #undef  IS_KERN_PAIR
  58 #define IS_KERN_PAIR( p )  ( p[0] == 'K' && p[1] == 'P' )
  59
  60 #define IS_ALPHANUM( c )  ( isalnum( c ) || \
  61                             c == '_'     || \
  62                             c == '.'     )
  63
  64
  65   /* read a glyph name and return the equivalent glyph index */
  66   static
  67   FT_UInt  afm_atoindex( FT_Byte**  start,
  68                          FT_Byte*   limit,
  69                          T1_Font*   type1 )
  70   {
  71     FT_Byte*  p = *start;
  72     FT_Int    len;
  73     FT_UInt   result = 0;
  74     char      temp[64];
  75
  76
  77     /* skip whitespace */
  78     while ( ( *p == ' ' || *p == '\t' || *p == ':' || *p == ';' ) &&
  79             p < limit                                             )
  80       p++;
  81     *start = p;
  82
  83     /* now, read glyph name */
  84     while ( IS_ALPHANUM( *p ) && p < limit )
  85       p++;
  86
  87     len = p - *start;
  88
  89     if ( len > 0 && len < 64 )
  90     {
  91       FT_Int  n;
  92
  93
  94       /* copy glyph name to intermediate array */
  95       MEM_Copy( temp, *start, len );
  96       temp[len] = 0;
  97
  98       /* lookup glyph name in face array */
  99       for ( n = 0; n < type1->num_glyphs; n++ )
 100       {
 101         char*  gname = (char*)type1->glyph_names[n];
 102
 103
 104         if ( gname && gname[0] == temp[0] && strcmp( gname, temp ) == 0 )
 105         {
 106           result = n;
 107           break;
 108         }
 109       }
 110     }
 111     *start = p;
 112     return result;
 113   }
 114
 115
 116   /* read an integer */
 117   static
 118   int  afm_atoi( FT_Byte**  start,
 119                  FT_Byte*   limit )
 120   {
 121     FT_Byte*  p    = *start;
 122     int       sum  = 0;
 123     int       sign = 1;
 124
 125
 126     /* skip everything that is not a number */
 127     while ( p < limit && !isdigit( *p ) )
 128     {
 129       sign = 1;
 130       if ( *p == '-' )
 131         sign = -1;
 132
 133       p++;
 134     }
 135
 136     while ( p < limit && isdigit( *p ) )
 137     {
 138       sum = sum * 10 + ( *p - '0' );
 139       p++;
 140     }
 141     *start = p;
 142
 143     return sum * sign;
 144   }
 145
 146
 147 #undef  KERN_INDEX
 148 #define KERN_INDEX( g1, g2 )  ( ( (FT_ULong)g1 << 16 ) | g2 )
 149
 150
 151   /* compare two kerning pairs */
 152   static
 153   int  compare_kern_pairs( const void*  a,
 154                            const void*  b )
 155   {
 156     T1_Kern_Pair*  pair1 = (T1_Kern_Pair*)a;
 157     T1_Kern_Pair*  pair2 = (T1_Kern_Pair*)b;
 158
 159     FT_ULong  index1 = KERN_INDEX( pair1->glyph1, pair1->glyph2 );
 160     FT_ULong  index2 = KERN_INDEX( pair2->glyph1, pair2->glyph2 );
 161
 162
 163     return ( index1 - index2 );
 164   }
 165
 166
 167   /* parse an AFM file -- for now, only read the kerning pairs */
 168   LOCAL_FUNC
 169   FT_Error  T1_Read_AFM( FT_Face    t1_face,
 170                          FT_Stream  stream )
 171   {
 172     FT_Error       error;
 173     FT_Memory      memory = stream->memory;
 174     FT_Byte*       start;
 175     FT_Byte*       limit;
 176     FT_Byte*       p;
 177     FT_Int         count = 0;
 178     T1_Kern_Pair*  pair;
 179     T1_Font*       type1 = &((T1_Face)t1_face)->type1;
 180     T1_AFM*        afm   = 0;
 181
 182
 183     if ( ACCESS_Frame( stream->size ) )
 184       return error;
 185
 186     start = (FT_Byte*)stream->cursor;
 187     limit = (FT_Byte*)stream->limit;
 188     p     = start;
 189
 190     /* we are now going to count the occurences of `KP' or `KPX' in */
 191     /* the AFM file                                                 */
 192     count = 0;
 193     for ( p = start; p < limit - 3; p++ )
 194     {
 195       if ( IS_KERN_PAIR( p ) )
 196         count++;
 197     }
 198
 199     /* Actually, kerning pairs are simply optional! */
 200     if ( count == 0 )
 201       goto Exit;
 202
 203     /* allocate the pairs */
 204     if ( ALLOC( afm, sizeof ( *afm ) )                       ||
 205          ALLOC_ARRAY( afm->kern_pairs, count, T1_Kern_Pair ) )
 206       goto Exit;
 207
 208     /* now, read each kern pair */
 209     pair           = afm->kern_pairs;
 210     afm->num_pairs = count;
 211
 212     /* save in face object */
 213     ((T1_Face)t1_face)->afm_data = afm;
 214
 215     for ( p = start; p < limit - 3; p++ )
 216     {
 217       if ( IS_KERN_PAIR( p ) )
 218       {
 219         FT_Byte*  q;
 220
 221
 222         /* skip keyword (KP or KPX) */
 223         q = p + 2;
 224         if ( *q == 'X' )
 225           q++;
 226
 227         pair->glyph1    = afm_atoindex( &q, limit, type1 );
 228         pair->glyph2    = afm_atoindex( &q, limit, type1 );
 229         pair->kerning.x = afm_atoi( &q, limit );
 230
 231         pair->kerning.y = 0;
 232         if ( p[2] != 'X' )
 233           pair->kerning.y = afm_atoi( &q, limit );
 234
 235         pair++;
 236       }
 237     }
 238
 239     /* now, sort the kern pairs according to their glyph indices */
 240     qsort( afm->kern_pairs, count, sizeof ( T1_Kern_Pair ),
 241            compare_kern_pairs );
 242
 243   Exit:
 244     if ( error )
 245       FREE( afm );
 246
 247     FORGET_Frame();
 248
 249     return error;
 250   }
 251
 252
 253   /* find the kerning for a given glyph pair */
 254   LOCAL_FUNC
 255   void  T1_Get_Kerning( T1_AFM*     afm,
 256                         FT_UInt     glyph1,
 257                         FT_UInt     glyph2,
 258                         FT_Vector*  kerning )
 259   {
 260     T1_Kern_Pair  *min, *mid, *max;
 261     FT_ULong      index = KERN_INDEX( glyph1, glyph2 );
 262
 263
 264     /* simple binary search */
 265     min = afm->kern_pairs;
 266     max = min + afm->num_pairs - 1;
 267
 268     while ( min <= max )
 269     {
 270       FT_ULong  midi;
 271
 272
 273       mid  = min + ( max - min ) / 2;
 274       midi = KERN_INDEX( mid->glyph1, mid->glyph2 );
 275
 276       if ( midi == index )
 277       {
 278         *kerning = mid->kerning;
 279         return;
 280       }
 281
 282       if ( midi < index )
 283         min = mid + 1;
 284       else
 285         max = mid - 1;
 286     }
 287
 288     kerning->x = 0;
 289     kerning->y = 0;
 290   }
 291
 292
 293 /* END */