thirdparty/freetype-2.3.12/src/type1/t1afm.c

   1 /***************************************************************************/
   2 /*                                                                         */
   3 /*  t1afm.c                                                                */
   4 /*                                                                         */
   5 /*    AFM support for Type 1 fonts (body).                                 */
   6 /*                                                                         */
   7 /*  Copyright 1996-2001, 2002, 2003, 2004, 2005, 2006, 2007, 2008, 2009 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 "t1afm.h"
  21 #include "t1errors.h"
  22 #include FT_INTERNAL_STREAM_H
  23 #include FT_INTERNAL_POSTSCRIPT_AUX_H
  24
  25
  26   /*************************************************************************/
  27   /*                                                                       */
  28   /* The macro FT_COMPONENT is used in trace mode.  It is an implicit      */
  29   /* parameter of the FT_TRACE() and FT_ERROR() macros, used to print/log  */
  30   /* messages during execution.                                            */
  31   /*                                                                       */
  32 #undef  FT_COMPONENT
  33 #define FT_COMPONENT  trace_t1afm
  34
  35
  36   FT_LOCAL_DEF( void )
  37   T1_Done_Metrics( FT_Memory     memory,
  38                    AFM_FontInfo  fi )
  39   {
  40     FT_FREE( fi->KernPairs );
  41     fi->NumKernPair = 0;
  42
  43     FT_FREE( fi->TrackKerns );
  44     fi->NumTrackKern = 0;
  45
  46     FT_FREE( fi );
  47   }
  48
  49
  50   /* read a glyph name and return the equivalent glyph index */
  51   static FT_Int
  52   t1_get_index( const char*  name,
  53                 FT_Offset    len,
  54                 void*        user_data )
  55   {
  56     T1_Font  type1 = (T1_Font)user_data;
  57     FT_Int   n;
  58
  59
  60     /* PS string/name length must be < 16-bit */
  61     if ( len > 0xFFFFU )
  62       return 0;
  63
  64     for ( n = 0; n < type1->num_glyphs; n++ )
  65     {
  66       char*  gname = (char*)type1->glyph_names[n];
  67
  68
  69       if ( gname && gname[0] == name[0]        &&
  70            ft_strlen( gname ) == len           &&
  71            ft_strncmp( gname, name, len ) == 0 )
  72         return n;
  73     }
  74
  75     return 0;
  76   }
  77
  78
  79 #undef  KERN_INDEX
  80 #define KERN_INDEX( g1, g2 )  ( ( (FT_ULong)(g1) << 16 ) | (g2) )
  81
  82
  83   /* compare two kerning pairs */
  84   FT_CALLBACK_DEF( int )
  85   compare_kern_pairs( const void*  a,
  86                       const void*  b )
  87   {
  88     AFM_KernPair  pair1 = (AFM_KernPair)a;
  89     AFM_KernPair  pair2 = (AFM_KernPair)b;
  90
  91     FT_ULong  index1 = KERN_INDEX( pair1->index1, pair1->index2 );
  92     FT_ULong  index2 = KERN_INDEX( pair2->index1, pair2->index2 );
  93
  94
  95     if ( index1 > index2 )
  96       return 1;
  97     else if ( index1 < index2 )
  98       return -1;
  99     else
 100       return 0;
 101   }
 102
 103
 104   /* parse a PFM file -- for now, only read the kerning pairs */
 105   static FT_Error
 106   T1_Read_PFM( FT_Face       t1_face,
 107                FT_Stream     stream,
 108                AFM_FontInfo  fi )
 109   {
 110     FT_Error      error = T1_Err_Ok;
 111     FT_Memory     memory = stream->memory;
 112     FT_Byte*      start;
 113     FT_Byte*      limit;
 114     FT_Byte*      p;
 115     AFM_KernPair  kp;
 116     FT_Int        width_table_length;
 117     FT_CharMap    oldcharmap;
 118     FT_CharMap    charmap;
 119     FT_Int        n;
 120
 121
 122     start = (FT_Byte*)stream->cursor;
 123     limit = (FT_Byte*)stream->limit;
 124     p     = start;
 125
 126     /* Figure out how long the width table is.          */
 127     /* This info is a little-endian short at offset 99. */
 128     p = start + 99;
 129     if ( p + 2 > limit )
 130     {
 131       error = T1_Err_Unknown_File_Format;
 132       goto Exit;
 133     }
 134     width_table_length = FT_PEEK_USHORT_LE( p );
 135
 136     p += 18 + width_table_length;
 137     if ( p + 0x12 > limit || FT_PEEK_USHORT_LE( p ) < 0x12 )
 138       /* extension table is probably optional */
 139       goto Exit;
 140
 141     /* Kerning offset is 14 bytes from start of extensions table. */
 142     p += 14;
 143     p = start + FT_PEEK_ULONG_LE( p );
 144
 145     if ( p == start )
 146       /* zero offset means no table */
 147       goto Exit;
 148
 149     if ( p + 2 > limit )
 150     {
 151       error = T1_Err_Unknown_File_Format;
 152       goto Exit;
 153     }
 154
 155     fi->NumKernPair = FT_PEEK_USHORT_LE( p );
 156     p += 2;
 157     if ( p + 4 * fi->NumKernPair > limit )
 158     {
 159       error = T1_Err_Unknown_File_Format;
 160       goto Exit;
 161     }
 162
 163     /* Actually, kerning pairs are simply optional! */
 164     if ( fi->NumKernPair == 0 )
 165       goto Exit;
 166
 167     /* allocate the pairs */
 168     if ( FT_QNEW_ARRAY( fi->KernPairs, fi->NumKernPair ) )
 169       goto Exit;
 170
 171     /* now, read each kern pair */
 172     kp             = fi->KernPairs;
 173     limit          = p + 4 * fi->NumKernPair;
 174
 175     /* PFM kerning data are stored by encoding rather than glyph index, */
 176     /* so find the PostScript charmap of this font and install it       */
 177     /* temporarily.  If we find no PostScript charmap, then just use    */
 178     /* the default and hope it is the right one.                        */
 179     oldcharmap = t1_face->charmap;
 180     charmap    = NULL;
 181
 182     for ( n = 0; n < t1_face->num_charmaps; n++ )
 183     {
 184       charmap = t1_face->charmaps[n];
 185       /* check against PostScript pseudo platform */
 186       if ( charmap->platform_id == 7 )
 187       {
 188         error = FT_Set_Charmap( t1_face, charmap );
 189         if ( error )
 190           goto Exit;
 191         break;
 192       }
 193     }
 194
 195     /* Kerning info is stored as:             */
 196     /*                                        */
 197     /*   encoding of first glyph (1 byte)     */
 198     /*   encoding of second glyph (1 byte)    */
 199     /*   offset (little-endian short)         */
 200     for ( ; p < limit ; p += 4 )
 201     {
 202       kp->index1 = FT_Get_Char_Index( t1_face, p[0] );
 203       kp->index2 = FT_Get_Char_Index( t1_face, p[1] );
 204
 205       kp->x = (FT_Int)FT_PEEK_SHORT_LE(p + 2);
 206       kp->y = 0;
 207
 208       kp++;
 209     }
 210
 211     if ( oldcharmap != NULL )
 212       error = FT_Set_Charmap( t1_face, oldcharmap );
 213     if ( error )
 214       goto Exit;
 215
 216     /* now, sort the kern pairs according to their glyph indices */
 217     ft_qsort( fi->KernPairs, fi->NumKernPair, sizeof ( AFM_KernPairRec ),
 218               compare_kern_pairs );
 219
 220   Exit:
 221     if ( error )
 222     {
 223       FT_FREE( fi->KernPairs );
 224       fi->NumKernPair = 0;
 225     }
 226
 227     return error;
 228   }
 229
 230
 231   /* parse a metrics file -- either AFM or PFM depending on what */
 232   /* it turns out to be                                          */
 233   FT_LOCAL_DEF( FT_Error )
 234   T1_Read_Metrics( FT_Face    t1_face,
 235                    FT_Stream  stream )
 236   {
 237     PSAux_Service  psaux;
 238     FT_Memory      memory = stream->memory;
 239     AFM_ParserRec  parser;
 240     AFM_FontInfo   fi;
 241     FT_Error       error = T1_Err_Unknown_File_Format;
 242     T1_Font        t1_font = &( (T1_Face)t1_face )->type1;
 243
 244
 245     if ( FT_NEW( fi )                   ||
 246          FT_FRAME_ENTER( stream->size ) )
 247       goto Exit;
 248
 249     fi->FontBBox  = t1_font->font_bbox;
 250     fi->Ascender  = t1_font->font_bbox.yMax;
 251     fi->Descender = t1_font->font_bbox.yMin;
 252
 253     psaux = (PSAux_Service)( (T1_Face)t1_face )->psaux;
 254     if ( psaux && psaux->afm_parser_funcs )
 255     {
 256       error = psaux->afm_parser_funcs->init( &parser,
 257                                              stream->memory,
 258                                              stream->cursor,
 259                                              stream->limit );
 260
 261       if ( !error )
 262       {
 263         parser.FontInfo  = fi;
 264         parser.get_index = t1_get_index;
 265         parser.user_data = t1_font;
 266
 267         error = psaux->afm_parser_funcs->parse( &parser );
 268         psaux->afm_parser_funcs->done( &parser );
 269       }
 270     }
 271
 272     if ( error == T1_Err_Unknown_File_Format )
 273     {
 274       FT_Byte*  start = stream->cursor;
 275
 276
 277       /* MS Windows allows versions up to 0x3FF without complaining */
 278       if ( stream->size > 6                              &&
 279            start[1] < 4                                  &&
 280            FT_PEEK_ULONG_LE( start + 2 ) == stream->size )
 281         error = T1_Read_PFM( t1_face, stream, fi );
 282     }
 283
 284     if ( !error )
 285     {
 286       t1_font->font_bbox = fi->FontBBox;
 287
 288       t1_face->bbox.xMin =   fi->FontBBox.xMin            >> 16;
 289       t1_face->bbox.yMin =   fi->FontBBox.yMin            >> 16;
 290       /* no `U' suffix here to 0xFFFF! */
 291       t1_face->bbox.xMax = ( fi->FontBBox.xMax + 0xFFFF ) >> 16;
 292       t1_face->bbox.yMax = ( fi->FontBBox.yMax + 0xFFFF ) >> 16;
 293
 294       /* no `U' suffix here to 0x8000! */
 295       t1_face->ascender  = (FT_Short)( ( fi->Ascender  + 0x8000 ) >> 16 );
 296       t1_face->descender = (FT_Short)( ( fi->Descender + 0x8000 ) >> 16 );
 297
 298       if ( fi->NumKernPair )
 299       {
 300         t1_face->face_flags |= FT_FACE_FLAG_KERNING;
 301         ( (T1_Face)t1_face )->afm_data = fi;
 302         fi = NULL;
 303       }
 304     }
 305
 306     FT_FRAME_EXIT();
 307
 308   Exit:
 309     if ( fi != NULL )
 310       T1_Done_Metrics( memory, fi );
 311
 312     return error;
 313   }
 314
 315
 316   /* find the kerning for a given glyph pair */
 317   FT_LOCAL_DEF( void )
 318   T1_Get_Kerning( AFM_FontInfo  fi,
 319                   FT_UInt       glyph1,
 320                   FT_UInt       glyph2,
 321                   FT_Vector*    kerning )
 322   {
 323     AFM_KernPair  min, mid, max;
 324     FT_ULong      idx = KERN_INDEX( glyph1, glyph2 );
 325
 326
 327     /* simple binary search */
 328     min = fi->KernPairs;
 329     max = min + fi->NumKernPair - 1;
 330
 331     while ( min <= max )
 332     {
 333       FT_ULong  midi;
 334
 335
 336       mid  = min + ( max - min ) / 2;
 337       midi = KERN_INDEX( mid->index1, mid->index2 );
 338
 339       if ( midi == idx )
 340       {
 341         kerning->x = mid->x;
 342         kerning->y = mid->y;
 343
 344         return;
 345       }
 346
 347       if ( midi < idx )
 348         min = mid + 1;
 349       else
 350         max = mid - 1;
 351     }
 352
 353     kerning->x = 0;
 354     kerning->y = 0;
 355   }
 356
 357
 358   FT_LOCAL_DEF( FT_Error )
 359   T1_Get_Track_Kerning( FT_Face    face,
 360                         FT_Fixed   ptsize,
 361                         FT_Int     degree,
 362                         FT_Fixed*  kerning )
 363   {
 364     AFM_FontInfo  fi = (AFM_FontInfo)( (T1_Face)face )->afm_data;
 365     FT_Int        i;
 366
 367
 368     if ( !fi )
 369       return T1_Err_Invalid_Argument;
 370
 371     for ( i = 0; i < fi->NumTrackKern; i++ )
 372     {
 373       AFM_TrackKern  tk = fi->TrackKerns + i;
 374
 375
 376       if ( tk->degree != degree )
 377         continue;
 378
 379       if ( ptsize < tk->min_ptsize )
 380         *kerning = tk->min_kern;
 381       else if ( ptsize > tk->max_ptsize )
 382         *kerning = tk->max_kern;
 383       else
 384       {
 385         *kerning = FT_MulDiv( ptsize - tk->min_ptsize,
 386                               tk->max_kern - tk->min_kern,
 387                               tk->max_ptsize - tk->min_ptsize ) +
 388                    tk->min_kern;
 389       }
 390     }
 391
 392     return T1_Err_Ok;
 393   }
 394
 395
 396 /* END */