subsys/win32k/freetype/src/truetype/ttdriver.c

   1 /***************************************************************************/
   2 /*                                                                         */
   3 /*  ttdriver.c                                                             */
   4 /*                                                                         */
   5 /*    TrueType font driver implementation (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 #include <freetype/internal/ftdebug.h>
  20 #include <freetype/internal/ftstream.h>
  21 #include <freetype/internal/sfnt.h>
  22 #include <freetype/ttnameid.h>
  23
  24
  25 #ifdef FT_FLAT_COMPILE
  26
  27 #include "ttdriver.h"
  28 #include "ttgload.h"
  29
  30 #else
  31
  32 #include <freetype/src/truetype/ttdriver.h>
  33 #include <freetype/src/truetype/ttgload.h>
  34
  35 #endif
  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_ttdriver
  46
  47
  48   /*************************************************************************/
  49   /*************************************************************************/
  50   /*************************************************************************/
  51   /****                                                                 ****/
  52   /****                                                                 ****/
  53   /****                          F A C E S                              ****/
  54   /****                                                                 ****/
  55   /****                                                                 ****/
  56   /*************************************************************************/
  57   /*************************************************************************/
  58   /*************************************************************************/
  59
  60
  61 #undef  PAIR_TAG
  62 #define PAIR_TAG( left, right )  ( ( (FT_ULong)left << 16 ) | \
  63                                      (FT_ULong)right        )
  64
  65
  66   /*************************************************************************/
  67   /*                                                                       */
  68   /* <Function>                                                            */
  69   /*    Get_Kerning                                                        */
  70   /*                                                                       */
  71   /* <Description>                                                         */
  72   /*    A driver method used to return the kerning vector between two      */
  73   /*    glyphs of the same face.                                           */
  74   /*                                                                       */
  75   /* <Input>                                                               */
  76   /*    face        :: A handle to the source face object.                 */
  77   /*                                                                       */
  78   /*    left_glyph  :: The index of the left glyph in the kern pair.       */
  79   /*                                                                       */
  80   /*    right_glyph :: The index of the right glyph in the kern pair.      */
  81   /*                                                                       */
  82   /* <Output>                                                              */
  83   /*    kerning     :: The kerning vector.  This is in font units for      */
  84   /*                   scalable formats, and in pixels for fixed-sizes     */
  85   /*                   formats.                                            */
  86   /*                                                                       */
  87   /* <Return>                                                              */
  88   /*    FreeType error code.  0 means success.                             */
  89   /*                                                                       */
  90   /* <Note>                                                                */
  91   /*    Only horizontal layouts (left-to-right & right-to-left) are        */
  92   /*    supported by this function.  Other layouts, or more sophisticated  */
  93   /*    kernings, are out of scope of this method (the basic driver        */
  94   /*    interface is meant to be simple).                                  */
  95   /*                                                                       */
  96   /*    They can be implemented by format-specific interfaces.             */
  97   /*                                                                       */
  98   static
  99   FT_Error  Get_Kerning( TT_Face     face,
 100                          FT_UInt     left_glyph,
 101                          FT_UInt     right_glyph,
 102                          FT_Vector*  kerning )
 103   {
 104     TT_Kern_0_Pair*  pair;
 105
 106
 107     if ( !face )
 108       return TT_Err_Invalid_Face_Handle;
 109
 110     kerning->x = 0;
 111     kerning->y = 0;
 112
 113     if ( face->kern_pairs )
 114     {
 115       /* there are some kerning pairs in this font file! */
 116       FT_ULong  search_tag = PAIR_TAG( left_glyph, right_glyph );
 117       FT_Long   left, right;
 118
 119
 120       left  = 0;
 121       right = face->num_kern_pairs - 1;
 122
 123       while ( left <= right )
 124       {
 125         FT_Int    middle = left + ( ( right - left ) >> 1 );
 126         FT_ULong  cur_pair;
 127
 128
 129         pair     = face->kern_pairs + middle;
 130         cur_pair = PAIR_TAG( pair->left, pair->right );
 131
 132         if ( cur_pair == search_tag )
 133           goto Found;
 134
 135         if ( cur_pair < search_tag )
 136           left = middle + 1;
 137         else
 138           right = middle - 1;
 139       }
 140     }
 141
 142   Exit:
 143     return TT_Err_Ok;
 144
 145   Found:
 146     kerning->x = pair->value;
 147     goto Exit;
 148   }
 149
 150
 151 #undef PAIR_TAG
 152
 153
 154   /*************************************************************************/
 155   /*************************************************************************/
 156   /*************************************************************************/
 157   /****                                                                 ****/
 158   /****                                                                 ****/
 159   /****                           S I Z E S                             ****/
 160   /****                                                                 ****/
 161   /****                                                                 ****/
 162   /*************************************************************************/
 163   /*************************************************************************/
 164   /*************************************************************************/
 165
 166
 167   /*************************************************************************/
 168   /*                                                                       */
 169   /* <Function>                                                            */
 170   /*    Set_Char_Sizes                                                     */
 171   /*                                                                       */
 172   /* <Description>                                                         */
 173   /*    A driver method used to reset a size's character sizes (horizontal */
 174   /*    and vertical) expressed in fractional points.                      */
 175   /*                                                                       */
 176   /* <Input>                                                               */
 177   /*    char_width      :: The character width expressed in 26.6           */
 178   /*                       fractional points.                              */
 179   /*                                                                       */
 180   /*    char_height     :: The character height expressed in 26.6          */
 181   /*                       fractional points.                              */
 182   /*                                                                       */
 183   /*    horz_resolution :: The horizontal resolution of the output device. */
 184   /*                                                                       */
 185   /*    vert_resolution :: The vertical resolution of the output device.   */
 186   /*                                                                       */
 187   /* <InOut>                                                               */
 188   /*    size            :: A handle to the target size object.             */
 189   /*                                                                       */
 190   /* <Return>                                                              */
 191   /*    FreeType error code.  0 means success.                             */
 192   /*                                                                       */
 193   static
 194   FT_Error  Set_Char_Sizes( TT_Size     size,
 195                             FT_F26Dot6  char_width,
 196                             FT_F26Dot6  char_height,
 197                             FT_UInt     horz_resolution,
 198                             FT_UInt     vert_resolution )
 199   {
 200     FT_Size_Metrics*  metrics = &size->root.metrics;
 201     TT_Face           face    = (TT_Face)size->root.face;
 202     FT_Long           dim_x, dim_y;
 203
 204
 205     /* This bit flag, when set, indicates that the pixel size must be */
 206     /* truncated to an integer.  Nearly all TrueType fonts have this  */
 207     /* bit set, as hinting won't work really well otherwise.          */
 208     /*                                                                */
 209     /* However, for those rare fonts who do not set it, we override   */
 210     /* the default computations performed by the base layer.  I       */
 211     /* really don't know whether this is useful, but hey, that's the  */
 212     /* spec :-)                                                       */
 213     /*                                                                */
 214     if ( ( face->header.Flags & 8 ) == 0 )
 215     {
 216       /* Compute pixel sizes in 26.6 units */
 217       dim_x = ( char_width  * horz_resolution ) / 72;
 218       dim_y = ( char_height * vert_resolution ) / 72;
 219
 220       metrics->x_scale = FT_DivFix( dim_x, face->root.units_per_EM );
 221       metrics->y_scale = FT_DivFix( dim_y, face->root.units_per_EM );
 222
 223       metrics->x_ppem  = (FT_UShort)( dim_x >> 6 );
 224       metrics->y_ppem  = (FT_UShort)( dim_y >> 6 );
 225     }
 226
 227     size->ttmetrics.valid = FALSE;
 228
 229     return TT_Reset_Size( size );
 230   }
 231
 232
 233   /*************************************************************************/
 234   /*                                                                       */
 235   /* <Function>                                                            */
 236   /*    Set_Pixel_Sizes                                                    */
 237   /*                                                                       */
 238   /* <Description>                                                         */
 239   /*    A driver method used to reset a size's character sizes (horizontal */
 240   /*    and vertical) expressed in integer pixels.                         */
 241   /*                                                                       */
 242   /* <Input>                                                               */
 243   /*    pixel_width  :: The character width expressed in integer pixels.   */
 244   /*                                                                       */
 245   /*    pixel_height :: The character height expressed in integer pixels.  */
 246   /*                                                                       */
 247   /* <InOut>                                                               */
 248   /*    size         :: A handle to the target size object.                */
 249   /*                                                                       */
 250   /* <Return>                                                              */
 251   /*    FreeType error code.  0 means success.                             */
 252   /*                                                                       */
 253   static
 254   FT_Error  Set_Pixel_Sizes( TT_Size  size,
 255                              FT_UInt  pixel_width,
 256                              FT_UInt  pixel_height )
 257   {
 258     FT_UNUSED( pixel_width );
 259     FT_UNUSED( pixel_height );
 260
 261     /* many things have been pre-computed by the base layer */
 262
 263     size->ttmetrics.valid = FALSE;
 264
 265     return TT_Reset_Size( size );
 266   }
 267
 268
 269   /*************************************************************************/
 270   /*                                                                       */
 271   /* <Function>                                                            */
 272   /*    Load_Glyph                                                         */
 273   /*                                                                       */
 274   /* <Description>                                                         */
 275   /*    A driver method used to load a glyph within a given glyph slot.    */
 276   /*                                                                       */
 277   /* <Input>                                                               */
 278   /*    slot        :: A handle to the target slot object where the glyph  */
 279   /*                   will be loaded.                                     */
 280   /*                                                                       */
 281   /*    size        :: A handle to the source face size at which the glyph */
 282   /*                   must be scaled, loaded, etc.                        */
 283   /*                                                                       */
 284   /*    glyph_index :: The index of the glyph in the font file.            */
 285   /*                                                                       */
 286   /*    load_flags  :: A flag indicating what to load for this glyph.  The */
 287   /*                   FTLOAD_??? constants can be used to control the     */
 288   /*                   glyph loading process (e.g., whether the outline    */
 289   /*                   should be scaled, whether to load bitmaps or not,   */
 290   /*                   whether to hint the outline, etc).                  */
 291   /*                                                                       */
 292   /* <Return>                                                              */
 293   /*    FreeType error code.  0 means success.                             */
 294   /*                                                                       */
 295   static
 296   FT_Error  Load_Glyph( TT_GlyphSlot  slot,
 297                         TT_Size       size,
 298                         FT_UShort     glyph_index,
 299                         FT_UInt       load_flags )
 300   {
 301     FT_Error  error;
 302
 303
 304     if ( !slot )
 305       return TT_Err_Invalid_Glyph_Handle;
 306
 307     /* check whether we want a scaled outline or bitmap */
 308     if ( !size )
 309       load_flags |= FT_LOAD_NO_SCALE | FT_LOAD_NO_HINTING;
 310
 311     if ( load_flags & FT_LOAD_NO_SCALE )
 312       size = NULL;
 313
 314     /* reset the size object if necessary */
 315     if ( size )
 316     {
 317       /* these two object must have the same parent */
 318       if ( size->root.face != slot->face )
 319         return TT_Err_Invalid_Face_Handle;
 320
 321       if ( !size->ttmetrics.valid )
 322       {
 323         if ( FT_SET_ERROR( TT_Reset_Size( size ) ) )
 324           return error;
 325       }
 326     }
 327
 328     /* now load the glyph outline if necessary */
 329     error = TT_Load_Glyph( size, slot, glyph_index, load_flags );
 330
 331     /* force drop-out mode to 2 - irrelevant now */
 332     /* slot->outline.dropout_mode = 2; */
 333
 334     return error;
 335   }
 336
 337
 338   /*************************************************************************/
 339   /*************************************************************************/
 340   /*************************************************************************/
 341   /****                                                                 ****/
 342   /****                                                                 ****/
 343   /****             C H A R A C T E R   M A P P I N G S                 ****/
 344   /****                                                                 ****/
 345   /****                                                                 ****/
 346   /*************************************************************************/
 347   /*************************************************************************/
 348   /*************************************************************************/
 349
 350   /*************************************************************************/
 351   /*                                                                       */
 352   /* <Function>                                                            */
 353   /*    Get_Char_Index                                                     */
 354   /*                                                                       */
 355   /* <Description>                                                         */
 356   /*    Uses a charmap to return a given character code's glyph index.     */
 357   /*                                                                       */
 358   /* <Input>                                                               */
 359   /*    charmap  :: A handle to the source charmap object.                 */
 360   /*    charcode :: The character code.                                    */
 361   /*                                                                       */
 362   /* <Return>                                                              */
 363   /*    Glyph index.  0 means `undefined character code'.                  */
 364   /*                                                                       */
 365   static
 366   FT_UInt  Get_Char_Index( TT_CharMap  charmap,
 367                            FT_Long     charcode )
 368   {
 369     FT_Error       error;
 370     TT_Face        face;
 371     TT_CMapTable*  cmap;
 372
 373
 374     cmap = &charmap->cmap;
 375     face = (TT_Face)charmap->root.face;
 376
 377     /* Load table if needed */
 378     if ( !cmap->loaded )
 379     {
 380       SFNT_Interface*  sfnt = (SFNT_Interface*)face->sfnt;
 381
 382
 383       error = sfnt->load_charmap( face, cmap, face->root.stream );
 384       if ( error )
 385         return 0;
 386
 387       cmap->loaded = TRUE;
 388     }
 389
 390     if ( cmap->get_index )
 391       return cmap->get_index( cmap, charcode );
 392     else
 393       return 0;
 394   }
 395
 396
 397   /*************************************************************************/
 398   /*************************************************************************/
 399   /*************************************************************************/
 400   /****                                                                 ****/
 401   /****                                                                 ****/
 402   /****                D R I V E R  I N T E R F A C E                   ****/
 403   /****                                                                 ****/
 404   /****                                                                 ****/
 405   /*************************************************************************/
 406   /*************************************************************************/
 407   /*************************************************************************/
 408
 409
 410   static
 411   FT_Module_Interface  tt_get_interface( TT_Driver    driver,
 412                                          const char*  interface )
 413   {
 414     FT_Module        sfntd = FT_Get_Module( driver->root.root.library,
 415                                             "sfnt" );
 416     SFNT_Interface*  sfnt;
 417
 418
 419     /* only return the default interface from the SFNT module */
 420     if ( sfntd )
 421     {
 422       sfnt = (SFNT_Interface*)( sfntd->clazz->module_interface );
 423       if ( sfnt )
 424         return sfnt->get_interface( FT_MODULE( driver ), interface );
 425     }
 426
 427     return 0;
 428   }
 429
 430
 431   /* The FT_DriverInterface structure is defined in ftdriver.h. */
 432
 433   const FT_Driver_Class  tt_driver_class =
 434   {
 435     {
 436       ft_module_font_driver     |
 437       ft_module_driver_scalable |
 438 #ifdef TT_CONFIG_OPTION_BYTECODE_INTERPRETER
 439       ft_module_driver_has_hinter,
 440 #else
 441       0,
 442 #endif
 443
 444       sizeof ( TT_DriverRec ),
 445
 446       "truetype",      /* driver name                           */
 447       0x10000L,        /* driver version == 1.0                 */
 448       0x20000L,        /* driver requires FreeType 2.0 or above */
 449
 450       (void*)0,        /* driver specific interface */
 451
 452       (FT_Module_Constructor)TT_Init_Driver,
 453       (FT_Module_Destructor) TT_Done_Driver,
 454       (FT_Module_Requester)  tt_get_interface,
 455     },
 456
 457     sizeof ( TT_FaceRec ),
 458     sizeof ( TT_SizeRec ),
 459     sizeof ( FT_GlyphSlotRec ),
 460
 461
 462     (FTDriver_initFace)     TT_Init_Face,
 463     (FTDriver_doneFace)     TT_Done_Face,
 464     (FTDriver_initSize)     TT_Init_Size,
 465     (FTDriver_doneSize)     TT_Done_Size,
 466     (FTDriver_initGlyphSlot)0,
 467     (FTDriver_doneGlyphSlot)0,
 468
 469     (FTDriver_setCharSizes) Set_Char_Sizes,
 470     (FTDriver_setPixelSizes)Set_Pixel_Sizes,
 471     (FTDriver_loadGlyph)    Load_Glyph,
 472     (FTDriver_getCharIndex) Get_Char_Index,
 473
 474     (FTDriver_getKerning)   Get_Kerning,
 475     (FTDriver_attachFile)   0,
 476     (FTDriver_getAdvances)  0
 477   };
 478
 479
 480 #ifdef FT_CONFIG_OPTION_DYNAMIC_DRIVERS
 481
 482
 483   /*************************************************************************/
 484   /*                                                                       */
 485   /* <Function>                                                            */
 486   /*    getDriverInterface                                                 */
 487   /*                                                                       */
 488   /* <Description>                                                         */
 489   /*    This function is used when compiling the TrueType driver as a      */
 490   /*    shared library (`.DLL' or `.so').  It will be used by the          */
 491   /*    high-level library of FreeType to retrieve the address of the      */
 492   /*    driver's generic interface.                                        */
 493   /*                                                                       */
 494   /*    It shouldn't be implemented in a static build, as each driver must */
 495   /*    have the same function as an exported entry point.                 */
 496   /*                                                                       */
 497   /* <Return>                                                              */
 498   /*    The address of the TrueType's driver generic interface.  The       */
 499   /*    format-specific interface can then be retrieved through the method */
 500   /*    interface->get_format_interface.                                   */
 501   /*                                                                       */
 502   EXPORT_FUNC( const FT_Driver_Class* )  getDriverClass( void )
 503   {
 504     return &tt_driver_class;
 505   }
 506
 507
 508 #endif /* CONFIG_OPTION_DYNAMIC_DRIVERS */
 509
 510
 511 /* END */