lib/taprep.c

   1 /* taprep.c */
   2
   3 /*
   4  * Copyright (C) 2011-2016 by Werner Lemberg.
   5  *
   6  * This file is part of the ttfautohint library, and may only be used,
   7  * modified, and distributed under the terms given in `COPYING'.  By
   8  * continuing to use, modify, or distribute this file you indicate that you
   9  * have read `COPYING' and understand and accept it fully.
  10  *
  11  * The file `COPYING' mentioned in the previous paragraph is distributed
  12  * with the ttfautohint library.
  13  */
  14
  15
  16 #include "ta.h"
  17
  18
  19 #define PREP(snippet_name) prep_ ## snippet_name
  20
  21
  22 static const unsigned char PREP(hinting_limit_a) [] =
  23 {
  24
  25   /* all our measurements are taken along the y axis, */
  26   /* including the ppem and CVT values */
  27   SVTCA_y,
  28
  29   /* first of all, check whether we do hinting at all */
  30   MPPEM,
  31   PUSHW_1,
  32
  33 };
  34
  35 /*  %d, hinting size limit */
  36
  37 static const unsigned char PREP(hinting_limit_b) [] =
  38 {
  39
  40   GT,
  41   IF,
  42     PUSHB_2,
  43       1, /* switch off hinting */
  44       1,
  45     INSTCTRL,
  46   EIF,
  47
  48 };
  49
  50 /* we store 0x10000 in CVT index `cvtl_funits_to_pixels' as a scaled value */
  51 /* to have a conversion factor from FUnits to pixels */
  52
  53 static const unsigned char PREP(store_funits_to_pixels) [] =
  54 {
  55
  56   PUSHB_1,
  57     cvtl_funits_to_pixels,
  58
  59   PUSHW_2,
  60     0x08, /* 0x800 */
  61     0x00,
  62     0x08, /* 0x800 */
  63     0x00,
  64   MUL, /* 0x10000 */
  65
  66   WCVTF, /* store value 1 in 16.16 format, scaled */
  67
  68 };
  69
  70 /* if the current ppem value is an exception, don't apply scaling */
  71
  72 static const unsigned char PREP(test_exception_a) [] =
  73 {
  74
  75   PUSHB_1,
  76     cvtl_is_element,
  77   RCVT,
  78   NOT,
  79   IF,
  80
  81 };
  82
  83 /* provide scaling factors for all styles */
  84
  85 static const unsigned char PREP(align_x_height_a) [] =
  86 {
  87
  88     PUSHB_2,
  89       sal_i,
  90       CVT_SCALING_VALUE_OFFSET(0),
  91     WS,
  92
  93 };
  94
  95 /*  PUSHB (num_used_styles + 2) */
  96 /*    ... */
  97 /*    %c, style 1's x height blue zone idx */
  98 /*    %c, style 0's x height blue zone idx */
  99 /*    %c, num_used_styles */
 100
 101 static const unsigned char PREP(align_x_height_b) [] =
 102 {
 103
 104       bci_align_x_height,
 105     LOOPCALL,
 106
 107 };
 108
 109 static const unsigned char PREP(loop_cvt_a) [] =
 110 {
 111
 112     /* loop over (almost all) vertical CVT entries of all styles, part 1 */
 113     PUSHB_2,
 114       sal_i,
 115       CVT_SCALING_VALUE_OFFSET(0),
 116     WS,
 117
 118 };
 119
 120 /*  PUSHB (2*num_used_styles + 2) */
 121 /*    ... */
 122 /*    %c, style 1's first vertical index */
 123 /*    %c, style 1's number of vertical indices */
 124 /*        (std. width, widths, flat blues zones without artifical ones) */
 125 /*    %c, style 0's first vertical index */
 126 /*    %c, style 0's number of vertical indices */
 127 /*        (std. width, widths, flat blues zones without artifical ones) */
 128 /*    %c, num_used_styles */
 129
 130 static const unsigned char PREP(loop_cvt_b) [] =
 131 {
 132
 133       bci_cvt_rescale_range,
 134     LOOPCALL,
 135
 136     /* loop over (almost all) vertical CVT entries of all styles, part 2 */
 137     PUSHB_2,
 138       sal_i,
 139       CVT_SCALING_VALUE_OFFSET(0),
 140     WS,
 141
 142 };
 143
 144 /*  PUSHB (2*num_used_styles + 2) */
 145 /*    ... */
 146 /*    %c, style 1's first round blue zone index */
 147 /*    %c, style 1's number of round blue zones (without artificial ones) */
 148 /*    %c, style 0's first round blue zone index */
 149 /*    %c, style 0's number of round blue zones (without artificial ones) */
 150 /*    %c, num_used_styles */
 151
 152 static const unsigned char PREP(loop_cvt_c) [] =
 153 {
 154
 155       bci_cvt_rescale_range,
 156     LOOPCALL,
 157
 158 };
 159
 160 static const unsigned char PREP(test_exception_b) [] =
 161 {
 162
 163   EIF,
 164
 165 };
 166
 167 static const unsigned char PREP(store_vwidth_data_a) [] =
 168 {
 169
 170   PUSHB_2,
 171     sal_i,
 172
 173 };
 174
 175 /*  %c, offset to vertical width offset data in CVT */
 176
 177 static const unsigned char PREP(store_vwidth_data_b) [] =
 178 {
 179
 180   WS,
 181
 182 };
 183
 184 /*PUSHW (num_used_styles + 2) */
 185 /*  ... */
 186 /*  %d, style 1's first vertical width index (in multiples of 64) */
 187 /*  %d, style 0's first vertical width index (in multiples of 64) */
 188 /*  %d, num_used_styles */
 189
 190 static const unsigned char PREP(store_vwidth_data_c) [] =
 191 {
 192
 193     0x00, /* high byte */
 194     bci_vwidth_data_store, /* low byte */
 195   LOOPCALL,
 196
 197   PUSHB_2,
 198     sal_i,
 199
 200 };
 201
 202 /*  %c, offset to vertical width size data in CVT */
 203
 204 static const unsigned char PREP(store_vwidth_data_d) [] =
 205 {
 206
 207   WS,
 208
 209 };
 210
 211 /*PUSHW (num_used_styles + 2) */
 212 /*  ... */
 213 /*  %d, style 1's number of vertical widths (in multiples of 64) */
 214 /*  %d, style 0's number of vertical widths (in multiples of 64) */
 215 /*  %d, num_used_styles */
 216
 217 static const unsigned char PREP(store_vwidth_data_e) [] =
 218 {
 219
 220     0x00, /* high byte */
 221     bci_vwidth_data_store, /* low byte */
 222   LOOPCALL,
 223
 224 };
 225
 226 static const unsigned char PREP(set_smooth_or_strong_a) [] =
 227 {
 228
 229   /*
 230    * There are two ClearType flavours available on Windows: The older GDI
 231    * ClearType, introduced in 2000, and the recent DW ClearType, introduced
 232    * in 2008.  The main difference is that the older incarnation behaves
 233    * like a B/W renderer along the y axis, while the newer version does
 234    * vertical smoothing also.
 235    *
 236    * The only possibility to differentiate between GDI and DW ClearType is
 237    * testing bit 10 in the GETINFO instruction (with return value in bit 17;
 238    * this works for TrueType version >= 38), checking whether sub-pixel
 239    * positioning is available.
 240    *
 241    * If GDI ClearType is active, we use different functions for stem width
 242    * computation and blue zone rounding that snap to integer pixels as much
 243    * as possible.
 244    */
 245
 246   /* set default value */
 247   PUSHB_2,
 248     cvtl_use_strong_functions,
 249
 250 };
 251
 252 /*  %c, either 0 or 100 */
 253
 254 static const unsigned char PREP(set_smooth_or_strong_b) [] =
 255 {
 256
 257   WCVTP,
 258
 259   /* get rasterizer version (bit 0) */
 260   PUSHB_2,
 261     36,
 262     0x01,
 263   GETINFO,
 264
 265   /* `GDI ClearType': */
 266   /* version >= 36 and version < 38, ClearType enabled */
 267   LTEQ,
 268   IF,
 269     /* check whether ClearType is enabled (bit 6) */
 270     PUSHB_1,
 271       0x40,
 272     GETINFO,
 273     IF,
 274       PUSHB_2,
 275         cvtl_use_strong_functions,
 276 };
 277
 278 /*      %c, either 0 or 100 */
 279
 280 static const unsigned char PREP(set_smooth_or_strong_c) [] =
 281 {
 282
 283       WCVTP,
 284
 285       /* get rasterizer version (bit 0) */
 286       PUSHB_2,
 287         38,
 288         0x01,
 289       GETINFO,
 290
 291       /* `DW ClearType': */
 292       /* version >= 38, sub-pixel positioning is enabled */
 293       LTEQ,
 294       IF,
 295         /* check whether sub-pixel positioning is enabled (bit 10) -- */
 296         /* due to a bug in FreeType 2.5.0 and earlier, */
 297         /* bit 6 must be set also to get the correct information, */
 298         /* so we test that both return values (in bits 13 and 17) are set */
 299         PUSHW_3,
 300           0x08, /* bits 13 and 17 shifted by 6 bits */
 301           0x80,
 302           0x00, /* we do `MUL' with value 1, */
 303           0x01, /* which is essentially a division by 64 */
 304           0x04, /* bits 6 and 10 */
 305           0x40,
 306         GETINFO,
 307         MUL,
 308         EQ,
 309         IF,
 310           PUSHB_2,
 311             cvtl_use_strong_functions,
 312
 313 };
 314
 315 /*          %c, either 0 or 100 */
 316
 317 static const unsigned char PREP(set_smooth_or_strong_d) [] =
 318 {
 319
 320           WCVTP,
 321         EIF,
 322       EIF,
 323     EIF,
 324   EIF,
 325
 326 };
 327
 328 /*PUSHB (2*num_used_styles + 2) */
 329 /*  ... */
 330 /*  %c, style 1's first blue ref index */
 331 /*  %c, style 1's number of blue ref indices */
 332 /*  %c, style 0's first blue ref index */
 333 /*  %c, style 0's number of blue ref indices */
 334 /*  %c, num_used_styles */
 335
 336 static const unsigned char PREP(round_blues) [] =
 337 {
 338
 339     bci_blue_round_range,
 340   LOOPCALL,
 341
 342 };
 343
 344 static const unsigned char PREP(set_dropout_mode) [] =
 345 {
 346
 347   PUSHW_1,
 348     0x01, /* 0x01FF, activate dropout handling unconditionally */
 349     0xFF,
 350   SCANCTRL,
 351   PUSHB_1,
 352     4, /* smart dropout include stubs */
 353   SCANTYPE,
 354
 355 };
 356
 357 static const unsigned char PREP(reset_component_counter) [] =
 358 {
 359
 360   /* In case an application tries to render `.ttfautohint' */
 361   /* (which it should never do), */
 362   /* hinting of all glyphs rendered afterwards is disabled */
 363   /* because the `cvtl_is_subglyph' counter gets incremented, */
 364   /* but there is no counterpart to decrement it. */
 365   /* Font inspection tools like the FreeType demo programs */
 366   /* are an exception to that rule, however, */
 367   /* since they can directly access a font by glyph indices. */
 368   /* The following guard alleviates the problem a bit: */
 369   /* Any change of the graphics state */
 370   /* (for example, rendering at a different size or with a different mode) */
 371   /* resets the counter to zero. */
 372   PUSHB_2,
 373     cvtl_is_subglyph,
 374     0,
 375   WCVTP,
 376
 377 };
 378
 379 static const unsigned char PREP(adjust_delta_exceptions) [] =
 380 {
 381
 382   /* set delta base */
 383   PUSHB_1,
 384     CONTROL_DELTA_PPEM_MIN,
 385   SDB,
 386
 387 };
 388
 389
 390 static const unsigned char PREP(set_default_cvs_values) [] =
 391 {
 392
 393   /* We set a default value for `cvtl_do_iup_y'. */
 394   /* If we have delta exceptions before IUP_y, */
 395   /* the glyph's bytecode sets this CVT value temporarily to zero */
 396   /* and manually inserts IUP_y afterwards. */
 397
 398   /* We set a default value for `cvtl_ignore_std_width'. */
 399   /* As the name implies, the stem width computation routines */
 400   /* ignore the standard width(s) if this flag gets set. */
 401
 402   /* It would be more elegant to use storage area locations instead, */
 403   /* however, it is not possible to have default values for them */
 404   /* since storage area locations might be reset on a per-glyph basis */
 405   /* (this is dependent on the bytecode interpreter implementation). */
 406
 407   PUSHB_4,
 408     cvtl_do_iup_y,
 409     100,
 410     cvtl_ignore_std_width,
 411     0,
 412   WCVTP,
 413   WCVTP,
 414
 415 };
 416
 417
 418 /* this function allocates `buf', parsing `number_set' to create bytecode */
 419 /* which eventually sets CVT index `cvtl_is_element' */
 420 /* (in functions `bci_number_set_is_element' and */
 421 /* `bci_number_set_is_element2') */
 422
 423 static FT_Byte*
 424 TA_sfnt_build_number_set(SFNT* sfnt,
 425                          FT_Byte** buf,
 426                          number_range* number_set)
 427 {
 428   FT_Byte* bufp = NULL;
 429   number_range* nr;
 430
 431   FT_UInt num_singles2 = 0;
 432   FT_UInt* single2_args;
 433   FT_UInt* single2_arg;
 434   FT_UInt num_singles = 0;
 435   FT_UInt* single_args;
 436   FT_UInt* single_arg;
 437
 438   FT_UInt num_ranges2 = 0;
 439   FT_UInt* range2_args;
 440   FT_UInt* range2_arg;
 441   FT_UInt num_ranges = 0;
 442   FT_UInt* range_args;
 443   FT_UInt* range_arg;
 444
 445   FT_UInt have_single = 0;
 446   FT_UInt have_range = 0;
 447
 448   FT_UShort num_stack_elements;
 449
 450
 451   /* build up four stacks to stay as compact as possible */
 452   nr = number_set;
 453   while (nr)
 454   {
 455     if (nr->start == nr->end)
 456     {
 457       if (nr->start < 256)
 458         num_singles++;
 459       else
 460         num_singles2++;
 461     }
 462     else
 463     {
 464       if (nr->start < 256 && nr->end < 256)
 465         num_ranges++;
 466       else
 467         num_ranges2++;
 468     }
 469     nr = nr->next;
 470   }
 471
 472   /* collect all arguments temporarily in arrays (in reverse order) */
 473   /* so that we can easily split into chunks of 255 args */
 474   /* as needed by NPUSHB and friends; */
 475   /* for simplicity, always allocate an extra slot */
 476   single2_args = (FT_UInt*)malloc((num_singles2 + 1) * sizeof (FT_UInt));
 477   single_args = (FT_UInt*)malloc((num_singles + 1) * sizeof (FT_UInt));
 478   range2_args = (FT_UInt*)malloc((2 * num_ranges2 + 1) * sizeof (FT_UInt));
 479   range_args = (FT_UInt*)malloc((2 * num_ranges + 1) * sizeof (FT_UInt));
 480   if (!single2_args || !single_args
 481       || !range2_args || !range_args)
 482     goto Fail;
 483
 484   /* check whether we need the extra slot for the argument to CALL */
 485   if (num_singles || num_singles2)
 486     have_single = 1;
 487   if (num_ranges || num_ranges2)
 488     have_range = 1;
 489
 490   /* set function indices outside of argument loop (using the extra slot) */
 491   if (have_single)
 492     single_args[num_singles] = bci_number_set_is_element;
 493   if (have_range)
 494     range_args[2 * num_ranges] = bci_number_set_is_element2;
 495
 496   single2_arg = single2_args + num_singles2 - 1;
 497   single_arg = single_args + num_singles - 1;
 498   range2_arg = range2_args + 2 * num_ranges2 - 1;
 499   range_arg = range_args + 2 * num_ranges - 1;
 500
 501   nr = number_set;
 502   while (nr)
 503   {
 504     FT_UInt start = (FT_UInt)nr->start;
 505     FT_UInt end = (FT_UInt)nr->end;
 506
 507
 508     if (start == end)
 509     {
 510       if (start < 256)
 511         *(single_arg--) = start;
 512       else
 513         *(single2_arg--) = start;
 514     }
 515     else
 516     {
 517       if (start < 256 && end < 256)
 518       {
 519         *(range_arg--) = start;
 520         *(range_arg--) = end;
 521       }
 522       else
 523       {
 524         *(range2_arg--) = start;
 525         *(range2_arg--) = end;
 526       }
 527     }
 528     nr = nr->next;
 529   }
 530
 531   /* this rough estimate of the buffer size gets adjusted later on */
 532   *buf = (FT_Byte*)malloc((2 + 1) * num_singles2
 533                           + (1 + 1) * num_singles
 534                           + (4 + 1) * num_ranges2
 535                           + (2 + 1) * num_ranges
 536                           + 10);
 537   if (!*buf)
 538     goto Fail;
 539   bufp = *buf;
 540
 541   BCI(PUSHB_2);
 542     BCI(cvtl_is_element);
 543     BCI(0);
 544   BCI(WCVTP);
 545
 546   bufp = TA_build_push(bufp, single2_args, num_singles2, 1, 1);
 547   bufp = TA_build_push(bufp, single_args, num_singles + have_single, 0, 1);
 548   if (have_single)
 549     BCI(CALL);
 550
 551   bufp = TA_build_push(bufp, range2_args, 2 * num_ranges2, 1, 1);
 552   bufp = TA_build_push(bufp, range_args, 2 * num_ranges + have_range, 0, 1);
 553   if (have_range)
 554     BCI(CALL);
 555
 556   num_stack_elements = (FT_UShort)(num_singles + num_singles2);
 557   if (num_stack_elements > num_ranges + num_ranges2)
 558     num_stack_elements = (FT_UShort)(num_ranges + num_ranges2);
 559   num_stack_elements += ADDITIONAL_STACK_ELEMENTS;
 560   if (num_stack_elements > sfnt->max_stack_elements)
 561     sfnt->max_stack_elements = num_stack_elements;
 562
 563 Fail:
 564   free(single2_args);
 565   free(single_args);
 566   free(range2_args);
 567   free(range_args);
 568
 569   return bufp;
 570 }
 571
 572
 573 #define COPY_PREP(snippet_name) \
 574           do \
 575           { \
 576             memcpy(bufp, prep_ ## snippet_name, \
 577                    sizeof (prep_ ## snippet_name)); \
 578             bufp += sizeof (prep_ ## snippet_name); \
 579           } while (0)
 580
 581 static FT_Error
 582 TA_table_build_prep(FT_Byte** prep,
 583                     FT_ULong* prep_len,
 584                     SFNT* sfnt,
 585                     FONT* font)
 586 {
 587   SFNT_Table* glyf_table = &font->tables[sfnt->glyf_idx];
 588   glyf_Data* data = (glyf_Data*)glyf_table->data;
 589   /* XXX: make this work for more than 256 styles */
 590   FT_Byte num_used_styles = (FT_Byte)data->num_used_styles;
 591
 592   FT_Int i;
 593
 594   FT_Byte* buf = NULL;
 595   FT_Byte* buf_new;
 596   FT_UInt buf_len;
 597   FT_UInt buf_new_len;
 598
 599   FT_UInt len;
 600   FT_Byte* bufp = NULL;
 601
 602
 603   if (font->x_height_snapping_exceptions)
 604   {
 605     bufp = TA_sfnt_build_number_set(sfnt, &buf,
 606                                     font->x_height_snapping_exceptions);
 607     if (!bufp)
 608       return FT_Err_Out_Of_Memory;
 609   }
 610
 611   buf_len = (FT_UInt)(bufp - buf);
 612   buf_new_len = buf_len;
 613
 614   if (font->hinting_limit)
 615     buf_new_len += sizeof (PREP(hinting_limit_a))
 616                    + 2
 617                    + sizeof (PREP(hinting_limit_b));
 618
 619   buf_new_len += sizeof (PREP(store_funits_to_pixels));
 620
 621   if (font->x_height_snapping_exceptions)
 622     buf_new_len += sizeof (PREP(test_exception_a));
 623
 624   buf_new_len += sizeof (PREP(align_x_height_a))
 625                  + (num_used_styles > 6 ? num_used_styles + 3
 626                                         : num_used_styles + 2)
 627                  + sizeof (PREP(align_x_height_b));
 628   buf_new_len += sizeof (PREP(loop_cvt_a))
 629                  + (num_used_styles > 3 ? 2 * num_used_styles + 3
 630                                         : 2 * num_used_styles + 2)
 631                  + sizeof (PREP(loop_cvt_b))
 632                  + (num_used_styles > 3 ? 2 * num_used_styles + 3
 633                                         : 2 * num_used_styles + 2)
 634                  + sizeof (PREP(loop_cvt_c));
 635
 636   if (font->x_height_snapping_exceptions)
 637     buf_new_len += sizeof (PREP(test_exception_b));
 638
 639   buf_new_len += sizeof (PREP(store_vwidth_data_a))
 640                  + 1
 641                  + sizeof (PREP(store_vwidth_data_b))
 642                  + (num_used_styles > 6 ? 2 * (num_used_styles + 1) + 2
 643                                         : 2 * (num_used_styles + 1) + 1)
 644                  + sizeof (PREP(store_vwidth_data_c))
 645                  + 1
 646                  + sizeof (PREP(store_vwidth_data_d))
 647                  + (num_used_styles > 6 ? 2 * (num_used_styles + 1) + 2
 648                                         : 2 * (num_used_styles + 1) + 1)
 649                  + sizeof (PREP(store_vwidth_data_e));
 650   buf_new_len += sizeof (PREP(set_smooth_or_strong_a))
 651                  + 1
 652                  + sizeof (PREP(set_smooth_or_strong_b))
 653                  + 1
 654                  + sizeof (PREP(set_smooth_or_strong_c))
 655                  + 1
 656                  + sizeof (PREP(set_smooth_or_strong_d));
 657   buf_new_len += (num_used_styles > 3 ? 2 * num_used_styles + 3
 658                                       : 2 * num_used_styles + 2)
 659                  + sizeof (PREP(round_blues));
 660   buf_new_len += sizeof (PREP(set_dropout_mode));
 661   buf_new_len += sizeof (PREP(reset_component_counter));
 662   if (font->control_data_head)
 663     buf_new_len += sizeof (PREP(adjust_delta_exceptions));
 664   buf_new_len += sizeof (PREP(set_default_cvs_values));
 665
 666   /* buffer length must be a multiple of four */
 667   len = (buf_new_len + 3) & ~3U;
 668   buf_new = (FT_Byte*)realloc(buf, len);
 669   if (!buf_new)
 670   {
 671     free(buf);
 672     return FT_Err_Out_Of_Memory;
 673   }
 674   buf = buf_new;
 675
 676   /* pad end of buffer with zeros */
 677   buf[len - 1] = 0x00;
 678   buf[len - 2] = 0x00;
 679   buf[len - 3] = 0x00;
 680
 681   /* copy remaining cvt program into buffer */
 682   /* and fill in the missing variables */
 683   bufp = buf + buf_len;
 684
 685   if (font->hinting_limit)
 686   {
 687     COPY_PREP(hinting_limit_a);
 688     *(bufp++) = HIGH(font->hinting_limit);
 689     *(bufp++) = LOW(font->hinting_limit);
 690     COPY_PREP(hinting_limit_b);
 691   }
 692
 693   COPY_PREP(store_funits_to_pixels);
 694
 695   if (font->x_height_snapping_exceptions)
 696     COPY_PREP(test_exception_a);
 697
 698   COPY_PREP(align_x_height_a);
 699   if (num_used_styles > 6)
 700   {
 701     BCI(NPUSHB);
 702     BCI(num_used_styles + 2);
 703   }
 704   else
 705     BCI(PUSHB_1 - 1 + num_used_styles + 2);
 706   /* XXX: make this work for offsets > 255 */
 707   for (i = TA_STYLE_MAX - 1; i >= 0; i--)
 708   {
 709     if (data->style_ids[i] == 0xFFFFU)
 710       continue;
 711
 712     *(bufp++) = CVT_X_HEIGHT_BLUE_OFFSET(i) >= 0xFFFFU
 713                   ? 0
 714                   : (unsigned char)CVT_X_HEIGHT_BLUE_OFFSET(i);
 715   }
 716   *(bufp++) = num_used_styles;
 717   COPY_PREP(align_x_height_b);
 718
 719   COPY_PREP(loop_cvt_a);
 720   if (num_used_styles > 3)
 721   {
 722     BCI(NPUSHB);
 723     BCI(2 * num_used_styles + 2);
 724   }
 725   else
 726     BCI(PUSHB_1 - 1 + 2 * num_used_styles + 2);
 727   /* XXX: make this work for offsets > 255 */
 728   for (i = TA_STYLE_MAX - 1; i >= 0; i--)
 729   {
 730     if (data->style_ids[i] == 0xFFFFU)
 731       continue;
 732
 733     /* don't loop over artificial blue zones */
 734     *(bufp++) = (unsigned char)CVT_VERT_STANDARD_WIDTH_OFFSET(i);
 735     *(bufp++) = (unsigned char)(
 736                   1
 737                   + CVT_VERT_WIDTHS_SIZE(i)
 738                   + (CVT_BLUES_SIZE(i) > 1
 739                      ? CVT_BLUES_SIZE(i) - (font->windows_compatibility ? 2
 740                                                                         : 0)
 741                      : 0));
 742   }
 743   *(bufp++) = num_used_styles;
 744   COPY_PREP(loop_cvt_b);
 745   if (num_used_styles > 3)
 746   {
 747     BCI(NPUSHB);
 748     BCI(2 * num_used_styles + 2);
 749   }
 750   else
 751     BCI(PUSHB_1 - 1 + 2 * num_used_styles + 2);
 752   /* XXX: make this work for offsets > 255 */
 753   for (i = TA_STYLE_MAX - 1; i >= 0; i--)
 754   {
 755     if (data->style_ids[i] == 0xFFFFU)
 756       continue;
 757
 758     /* don't loop over artificial blue zones */
 759     *(bufp++) = (unsigned char)CVT_BLUE_SHOOTS_OFFSET(i);
 760     *(bufp++) = (unsigned char)(
 761                   CVT_BLUES_SIZE(i) > 1
 762                   ? CVT_BLUES_SIZE(i) - (font->windows_compatibility ? 2
 763                                                                      : 0)
 764                   : 0);
 765   }
 766   *(bufp++) = num_used_styles;
 767   COPY_PREP(loop_cvt_c);
 768
 769   if (font->x_height_snapping_exceptions)
 770     COPY_PREP(test_exception_b);
 771
 772   COPY_PREP(store_vwidth_data_a);
 773   *(bufp++) = (unsigned char)CVT_VWIDTH_OFFSET_DATA(0);
 774   COPY_PREP(store_vwidth_data_b);
 775   if (num_used_styles > 6)
 776   {
 777     BCI(NPUSHW);
 778     BCI(num_used_styles + 2);
 779   }
 780   else
 781     BCI(PUSHW_1 - 1 + num_used_styles + 2);
 782   for (i = TA_STYLE_MAX - 1; i >= 0; i--)
 783   {
 784     if (data->style_ids[i] == 0xFFFFU)
 785       continue;
 786
 787     *(bufp++) = HIGH(CVT_VERT_WIDTHS_OFFSET(i) * 64);
 788     *(bufp++) = LOW(CVT_VERT_WIDTHS_OFFSET(i) * 64);
 789   }
 790   *(bufp++) = HIGH(num_used_styles);
 791   *(bufp++) = LOW(num_used_styles);
 792   COPY_PREP(store_vwidth_data_c);
 793   *(bufp++) = (unsigned char)CVT_VWIDTH_SIZE_DATA(0);
 794   COPY_PREP(store_vwidth_data_d);
 795   if (num_used_styles > 6)
 796   {
 797     BCI(NPUSHW);
 798     BCI(num_used_styles + 2);
 799   }
 800   else
 801     BCI(PUSHW_1 - 1 + num_used_styles + 2);
 802   for (i = TA_STYLE_MAX - 1; i >= 0; i--)
 803   {
 804     if (data->style_ids[i] == 0xFFFFU)
 805       continue;
 806
 807     *(bufp++) = HIGH(CVT_VERT_WIDTHS_SIZE(i) * 64);
 808     *(bufp++) = LOW(CVT_VERT_WIDTHS_SIZE(i) * 64);
 809   }
 810   *(bufp++) = HIGH(num_used_styles);
 811   *(bufp++) = LOW(num_used_styles);
 812   COPY_PREP(store_vwidth_data_e);
 813
 814   COPY_PREP(set_smooth_or_strong_a);
 815   *(bufp++) = font->gray_strong_stem_width ? 100 : 0;
 816   COPY_PREP(set_smooth_or_strong_b);
 817   *(bufp++) = font->gdi_cleartype_strong_stem_width ? 100 : 0;
 818   COPY_PREP(set_smooth_or_strong_c);
 819   *(bufp++) = font->dw_cleartype_strong_stem_width ? 100 : 0;
 820   COPY_PREP(set_smooth_or_strong_d);
 821
 822   if (num_used_styles > 3)
 823   {
 824     BCI(NPUSHB);
 825     BCI(2 * num_used_styles + 2);
 826   }
 827   else
 828     BCI(PUSHB_1 - 1 + 2 * num_used_styles + 2);
 829   /* XXX: make this work for offsets > 255 */
 830   for (i = TA_STYLE_MAX - 1; i >= 0; i--)
 831   {
 832     if (data->style_ids[i] == 0xFFFFU)
 833       continue;
 834
 835     *(bufp++) = (unsigned char)CVT_BLUE_REFS_OFFSET(i);
 836     *(bufp++) = (unsigned char)CVT_BLUES_SIZE(i);
 837   }
 838   *(bufp++) = num_used_styles;
 839   COPY_PREP(round_blues);
 840
 841   COPY_PREP(set_dropout_mode);
 842   COPY_PREP(reset_component_counter);
 843   if (font->control_data_head)
 844     COPY_PREP(adjust_delta_exceptions);
 845   COPY_PREP(set_default_cvs_values);
 846
 847   *prep = buf;
 848   *prep_len = buf_new_len;
 849
 850   return FT_Err_Ok;
 851 }
 852
 853
 854 FT_Error
 855 TA_sfnt_build_prep_table(SFNT* sfnt,
 856                          FONT* font)
 857 {
 858   FT_Error error;
 859
 860   SFNT_Table* glyf_table = &font->tables[sfnt->glyf_idx];
 861   glyf_Data* data = (glyf_Data*)glyf_table->data;
 862
 863   FT_Byte* prep_buf;
 864   FT_ULong prep_len;
 865
 866
 867   error = TA_sfnt_add_table_info(sfnt);
 868   if (error)
 869     goto Exit;
 870
 871   /* `glyf', `cvt', `fpgm', and `prep' are always used in parallel */
 872   if (glyf_table->processed)
 873   {
 874     sfnt->table_infos[sfnt->num_table_infos - 1] = data->prep_idx;
 875     goto Exit;
 876   }
 877
 878   error = TA_table_build_prep(&prep_buf, &prep_len, sfnt, font);
 879   if (error)
 880     goto Exit;
 881
 882 #if 0
 883   /* ttfautohint's bytecode in `fpgm' is larger */
 884   /* than the bytecode in `prep'; */
 885   /* this commented out code here is just for completeness */
 886   if (prep_len > sfnt->max_instructions)
 887     sfnt->max_instructions = prep_len;
 888 #endif
 889
 890   /* in case of success, `prep_buf' gets linked */
 891   /* and is eventually freed in `TA_font_unload' */
 892   error = TA_font_add_table(font,
 893                             &sfnt->table_infos[sfnt->num_table_infos - 1],
 894                             TTAG_prep, prep_len, prep_buf);
 895   if (error)
 896     free(prep_buf);
 897   else
 898     data->prep_idx = sfnt->table_infos[sfnt->num_table_infos - 1];
 899
 900 Exit:
 901   return error;
 902 }
 903
 904 /* end of taprep.c */