src/sfnt/ttmtx.c

   1 /***************************************************************************/
   2 /*                                                                         */
   3 /*  ttmtx.c                                                                */
   4 /*                                                                         */
   5 /*    Load the metrics tables common to TTF and OTF fonts (body).          */
   6 /*                                                                         */
   7 /*  Copyright 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 FT_INTERNAL_DEBUG_H
  21 #include FT_INTERNAL_STREAM_H
  22 #include FT_TRUETYPE_TAGS_H
  23 #include "ttmtx.h"
  24
  25 #include "sferrors.h"
  26
  27
  28   /*************************************************************************/
  29   /*                                                                       */
  30   /* The macro FT_COMPONENT is used in trace mode.  It is an implicit      */
  31   /* parameter of the FT_TRACE() and FT_ERROR() macros, used to print/log  */
  32   /* messages during execution.                                            */
  33   /*                                                                       */
  34 #undef  FT_COMPONENT
  35 #define FT_COMPONENT  trace_ttmtx
  36
  37
  38   /*
  39    *  Unfortunately, we can't enable our memory optimizations if
  40    *  FT_CONFIG_OPTION_OLD_INTERNALS is defined.  This is because at least
  41    *  one rogue client (libXfont in the X.Org XServer) is directly accessing
  42    *  the metrics.
  43    */
  44
  45   /*************************************************************************/
  46   /*                                                                       */
  47   /* <Function>                                                            */
  48   /*    tt_face_load_hmtx                                                  */
  49   /*                                                                       */
  50   /* <Description>                                                         */
  51   /*    Load the `hmtx' or `vmtx' table into a face object.                */
  52   /*                                                                       */
  53   /* <Input>                                                               */
  54   /*    face     :: A handle to the target face object.                    */
  55   /*                                                                       */
  56   /*    stream   :: The input stream.                                      */
  57   /*                                                                       */
  58   /*    vertical :: A boolean flag.  If set, load `vmtx'.                  */
  59   /*                                                                       */
  60   /* <Return>                                                              */
  61   /*    FreeType error code.  0 means success.                             */
  62   /*                                                                       */
  63 #ifndef FT_CONFIG_OPTION_OLD_INTERNALS
  64
  65   FT_LOCAL_DEF( FT_Error )
  66   tt_face_load_hmtx( TT_Face    face,
  67                      FT_Stream  stream,
  68                      FT_Bool    vertical )
  69   {
  70     FT_Error   error;
  71     FT_ULong   tag, table_size;
  72     FT_ULong*  ptable_offset;
  73     FT_ULong*  ptable_size;
  74
  75
  76     if ( vertical )
  77     {
  78       tag           = TTAG_vmtx;
  79       ptable_offset = &face->vert_metrics_offset;
  80       ptable_size   = &face->vert_metrics_size;
  81     }
  82     else
  83     {
  84       tag           = TTAG_hmtx;
  85       ptable_offset = &face->horz_metrics_offset;
  86       ptable_size   = &face->horz_metrics_size;
  87     }
  88
  89     error = face->goto_table( face, tag, stream, &table_size );
  90     if ( error )
  91       goto Fail;
  92
  93     *ptable_size   = table_size;
  94     *ptable_offset = FT_STREAM_POS();
  95
  96   Fail:
  97     return error;
  98   }
  99
 100 #else /* !FT_CONFIG_OPTION_OLD_INTERNALS */
 101
 102   FT_LOCAL_DEF( FT_Error )
 103   tt_face_load_hmtx( TT_Face    face,
 104                      FT_Stream  stream,
 105                      FT_Bool    vertical )
 106   {
 107     FT_Error   error;
 108     FT_Memory  memory = stream->memory;
 109
 110     FT_ULong   table_len;
 111     FT_Long    num_shorts, num_longs, num_shorts_checked;
 112
 113     TT_LongMetrics*    longs;
 114     TT_ShortMetrics**  shorts;
 115     FT_Byte*           p;
 116
 117
 118     if ( vertical )
 119     {
 120       void*   lm = &face->vertical.long_metrics;
 121       void**  sm = &face->vertical.short_metrics;
 122
 123
 124       error = face->goto_table( face, TTAG_vmtx, stream, &table_len );
 125       if ( error )
 126         goto Fail;
 127
 128       num_longs = face->vertical.number_Of_VMetrics;
 129       if ( (FT_ULong)num_longs > table_len / 4 )
 130         num_longs = (FT_Long)( table_len / 4 );
 131
 132       face->vertical.number_Of_VMetrics = 0;
 133
 134       longs  = (TT_LongMetrics*)lm;
 135       shorts = (TT_ShortMetrics**)sm;
 136     }
 137     else
 138     {
 139       void*   lm = &face->horizontal.long_metrics;
 140       void**  sm = &face->horizontal.short_metrics;
 141
 142
 143       error = face->goto_table( face, TTAG_hmtx, stream, &table_len );
 144       if ( error )
 145         goto Fail;
 146
 147       num_longs = face->horizontal.number_Of_HMetrics;
 148       if ( (FT_ULong)num_longs > table_len / 4 )
 149         num_longs = (FT_Long)( table_len / 4 );
 150
 151       face->horizontal.number_Of_HMetrics = 0;
 152
 153       longs  = (TT_LongMetrics*)lm;
 154       shorts = (TT_ShortMetrics**)sm;
 155     }
 156
 157     /* never trust derived values */
 158
 159     num_shorts         = face->max_profile.numGlyphs - num_longs;
 160     num_shorts_checked = ( table_len - num_longs * 4L ) / 2;
 161
 162     if ( num_shorts < 0 )
 163     {
 164       FT_TRACE0(( "tt_face_load_hmtx:"
 165                   " %cmtx has more metrics than glyphs.\n",
 166                   vertical ? "v" : "h" ));
 167
 168       /* Adobe simply ignores this problem.  So we shall do the same. */
 169 #if 0
 170       error = vertical ? SFNT_Err_Invalid_Vert_Metrics
 171                        : SFNT_Err_Invalid_Horiz_Metrics;
 172       goto Exit;
 173 #else
 174       num_shorts = 0;
 175 #endif
 176     }
 177
 178     if ( FT_QNEW_ARRAY( *longs,  num_longs  ) ||
 179          FT_QNEW_ARRAY( *shorts, num_shorts ) )
 180       goto Fail;
 181
 182     if ( FT_FRAME_ENTER( table_len ) )
 183       goto Fail;
 184
 185     p = stream->cursor;
 186
 187     {
 188       TT_LongMetrics  cur   = *longs;
 189       TT_LongMetrics  limit = cur + num_longs;
 190
 191
 192       for ( ; cur < limit; cur++ )
 193       {
 194         cur->advance = FT_NEXT_USHORT( p );
 195         cur->bearing = FT_NEXT_SHORT( p );
 196       }
 197     }
 198
 199     /* do we have an inconsistent number of metric values? */
 200     {
 201       TT_ShortMetrics*  cur   = *shorts;
 202       TT_ShortMetrics*  limit = cur +
 203                                 FT_MIN( num_shorts, num_shorts_checked );
 204
 205
 206       for ( ; cur < limit; cur++ )
 207         *cur = FT_NEXT_SHORT( p );
 208
 209       /* We fill up the missing left side bearings with the     */
 210       /* last valid value.  Since this will occur for buggy CJK */
 211       /* fonts usually only, nothing serious will happen.       */
 212       if ( num_shorts > num_shorts_checked && num_shorts_checked > 0 )
 213       {
 214         FT_Short  val = (*shorts)[num_shorts_checked - 1];
 215
 216
 217         limit = *shorts + num_shorts;
 218         for ( ; cur < limit; cur++ )
 219           *cur = val;
 220       }
 221     }
 222
 223     FT_FRAME_EXIT();
 224
 225     if ( vertical )
 226       face->vertical.number_Of_VMetrics = (FT_UShort)num_longs;
 227     else
 228       face->horizontal.number_Of_HMetrics = (FT_UShort)num_longs;
 229
 230   Fail:
 231     return error;
 232   }
 233
 234 #endif /* !FT_CONFIG_OPTION_OLD_INTERNALS */
 235
 236
 237   /*************************************************************************/
 238   /*                                                                       */
 239   /* <Function>                                                            */
 240   /*    tt_face_load_hhea                                                  */
 241   /*                                                                       */
 242   /* <Description>                                                         */
 243   /*    Load the `hhea' or 'vhea' table into a face object.                */
 244   /*                                                                       */
 245   /* <Input>                                                               */
 246   /*    face     :: A handle to the target face object.                    */
 247   /*                                                                       */
 248   /*    stream   :: The input stream.                                      */
 249   /*                                                                       */
 250   /*    vertical :: A boolean flag.  If set, load `vhea'.                  */
 251   /*                                                                       */
 252   /* <Return>                                                              */
 253   /*    FreeType error code.  0 means success.                             */
 254   /*                                                                       */
 255   FT_LOCAL_DEF( FT_Error )
 256   tt_face_load_hhea( TT_Face    face,
 257                      FT_Stream  stream,
 258                      FT_Bool    vertical )
 259   {
 260     FT_Error        error;
 261     TT_HoriHeader*  header;
 262
 263     const FT_Frame_Field  metrics_header_fields[] =
 264     {
 265 #undef  FT_STRUCTURE
 266 #define FT_STRUCTURE  TT_HoriHeader
 267
 268       FT_FRAME_START( 36 ),
 269         FT_FRAME_ULONG ( Version ),
 270         FT_FRAME_SHORT ( Ascender ),
 271         FT_FRAME_SHORT ( Descender ),
 272         FT_FRAME_SHORT ( Line_Gap ),
 273         FT_FRAME_USHORT( advance_Width_Max ),
 274         FT_FRAME_SHORT ( min_Left_Side_Bearing ),
 275         FT_FRAME_SHORT ( min_Right_Side_Bearing ),
 276         FT_FRAME_SHORT ( xMax_Extent ),
 277         FT_FRAME_SHORT ( caret_Slope_Rise ),
 278         FT_FRAME_SHORT ( caret_Slope_Run ),
 279         FT_FRAME_SHORT ( caret_Offset ),
 280         FT_FRAME_SHORT ( Reserved[0] ),
 281         FT_FRAME_SHORT ( Reserved[1] ),
 282         FT_FRAME_SHORT ( Reserved[2] ),
 283         FT_FRAME_SHORT ( Reserved[3] ),
 284         FT_FRAME_SHORT ( metric_Data_Format ),
 285         FT_FRAME_USHORT( number_Of_HMetrics ),
 286       FT_FRAME_END
 287     };
 288
 289
 290     if ( vertical )
 291     {
 292       void  *v = &face->vertical;
 293
 294
 295       error = face->goto_table( face, TTAG_vhea, stream, 0 );
 296       if ( error )
 297         goto Fail;
 298
 299       header = (TT_HoriHeader*)v;
 300     }
 301     else
 302     {
 303       error = face->goto_table( face, TTAG_hhea, stream, 0 );
 304       if ( error )
 305         goto Fail;
 306
 307       header = &face->horizontal;
 308     }
 309
 310     if ( FT_STREAM_READ_FIELDS( metrics_header_fields, header ) )
 311       goto Fail;
 312
 313     FT_TRACE3(( "Ascender:          %5d\n", header->Ascender ));
 314     FT_TRACE3(( "Descender:         %5d\n", header->Descender ));
 315     FT_TRACE3(( "number_Of_Metrics: %5u\n", header->number_Of_HMetrics ));
 316
 317     header->long_metrics  = NULL;
 318     header->short_metrics = NULL;
 319
 320   Fail:
 321     return error;
 322   }
 323
 324
 325   /*************************************************************************/
 326   /*                                                                       */
 327   /* <Function>                                                            */
 328   /*    tt_face_get_metrics                                                */
 329   /*                                                                       */
 330   /* <Description>                                                         */
 331   /*    Returns the horizontal or vertical metrics in font units for a     */
 332   /*    given glyph.  The metrics are the left side bearing (resp. top     */
 333   /*    side bearing) and advance width (resp. advance height).            */
 334   /*                                                                       */
 335   /* <Input>                                                               */
 336   /*    header  :: A pointer to either the horizontal or vertical metrics  */
 337   /*               structure.                                              */
 338   /*                                                                       */
 339   /*    idx     :: The glyph index.                                        */
 340   /*                                                                       */
 341   /* <Output>                                                              */
 342   /*    bearing :: The bearing, either left side or top side.              */
 343   /*                                                                       */
 344   /*    advance :: The advance width resp. advance height.                 */
 345   /*                                                                       */
 346 #ifndef FT_CONFIG_OPTION_OLD_INTERNALS
 347
 348   FT_LOCAL_DEF( FT_Error )
 349   tt_face_get_metrics( TT_Face     face,
 350                        FT_Bool     vertical,
 351                        FT_UInt     gindex,
 352                        FT_Short   *abearing,
 353                        FT_UShort  *aadvance )
 354   {
 355     FT_Error        error;
 356     FT_Stream       stream = face->root.stream;
 357     TT_HoriHeader*  header;
 358     FT_ULong        table_pos, table_size, table_end;
 359     FT_UShort       k;
 360
 361
 362     if ( vertical )
 363     {
 364       void*  v = &face->vertical;
 365
 366
 367       header     = (TT_HoriHeader*)v;
 368       table_pos  = face->vert_metrics_offset;
 369       table_size = face->vert_metrics_size;
 370     }
 371     else
 372     {
 373       header     = &face->horizontal;
 374       table_pos  = face->horz_metrics_offset;
 375       table_size = face->horz_metrics_size;
 376     }
 377
 378     table_end = table_pos + table_size;
 379
 380     k = header->number_Of_HMetrics;
 381
 382     if ( k > 0 )
 383     {
 384       if ( gindex < (FT_UInt)k )
 385       {
 386         table_pos += 4 * gindex;
 387         if ( table_pos + 4 > table_end )
 388           goto NoData;
 389
 390         if ( FT_STREAM_SEEK( table_pos ) ||
 391              FT_READ_USHORT( *aadvance ) ||
 392              FT_READ_SHORT( *abearing )  )
 393           goto NoData;
 394       }
 395       else
 396       {
 397         table_pos += 4 * ( k - 1 );
 398         if ( table_pos + 4 > table_end )
 399           goto NoData;
 400
 401         if ( FT_STREAM_SEEK( table_pos ) ||
 402              FT_READ_USHORT( *aadvance ) )
 403           goto NoData;
 404
 405         table_pos += 4 + 2 * ( gindex - k );
 406         if ( table_pos + 2 > table_end )
 407           *abearing = 0;
 408         else
 409         {
 410           if ( !FT_STREAM_SEEK( table_pos ) )
 411             (void)FT_READ_SHORT( *abearing );
 412         }
 413       }
 414     }
 415     else
 416     {
 417     NoData:
 418       *abearing = 0;
 419       *aadvance = 0;
 420     }
 421
 422     return SFNT_Err_Ok;
 423   }
 424
 425 #else /* !FT_CONFIG_OPTION_OLD_INTERNALS */
 426
 427   FT_LOCAL_DEF( FT_Error )
 428   tt_face_get_metrics( TT_Face     face,
 429                        FT_Bool     vertical,
 430                        FT_UInt     gindex,
 431                        FT_Short*   abearing,
 432                        FT_UShort*  aadvance )
 433   {
 434     void*           v = &face->vertical;
 435     void*           h = &face->horizontal;
 436     TT_HoriHeader*  header = vertical ? (TT_HoriHeader*)v
 437                                       : (TT_HoriHeader*)h;
 438     TT_LongMetrics  longs_m;
 439     FT_UShort       k = header->number_Of_HMetrics;
 440
 441
 442     if ( k == 0                                         ||
 443          !header->long_metrics                          ||
 444          gindex >= (FT_UInt)face->max_profile.numGlyphs )
 445     {
 446       *abearing = *aadvance = 0;
 447       return SFNT_Err_Ok;
 448     }
 449
 450     if ( gindex < (FT_UInt)k )
 451     {
 452       longs_m   = (TT_LongMetrics)header->long_metrics + gindex;
 453       *abearing = longs_m->bearing;
 454       *aadvance = longs_m->advance;
 455     }
 456     else
 457     {
 458       *abearing = ((TT_ShortMetrics*)header->short_metrics)[gindex - k];
 459       *aadvance = ((TT_LongMetrics)header->long_metrics)[k - 1].advance;
 460     }
 461
 462     return SFNT_Err_Ok;
 463   }
 464
 465 #endif /* !FT_CONFIG_OPTION_OLD_INTERNALS */
 466
 467
 468 /* END */