lib/taprep.c

   1 /* taprep.c */
   2
   3 /*
   4  * Copyright (C) 2011-2014 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 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 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 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 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 unsigned char PREP(align_top_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 unsigned char PREP(align_top_b) [] =
 102 {
 103
 104       bci_align_top,
 105     LOOPCALL,
 106
 107 };
 108
 109 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 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 unsigned char PREP(loop_cvt_c) [] =
 153 {
 154
 155       bci_cvt_rescale_range,
 156     LOOPCALL,
 157
 158 };
 159
 160 unsigned char PREP(test_exception_b) [] =
 161 {
 162
 163   EIF,
 164
 165 };
 166
 167 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 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 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 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 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 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 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 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 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 unsigned char PREP(round_blues) [] =
 337 {
 338
 339     bci_blue_round_range,
 340   LOOPCALL,
 341
 342 };
 343
 344 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 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 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 /* this function allocates `buf', parsing `number_set' to create bytecode */
 391 /* which eventually sets CVT index `cvtl_is_element' */
 392 /* (in functions `bci_number_set_is_element' and */
 393 /* `bci_number_set_is_element2') */
 394
 395 static FT_Byte*
 396 TA_sfnt_build_number_set(SFNT* sfnt,
 397                          FT_Byte** buf,
 398                          number_range* number_set)
 399 {
 400   FT_Byte* bufp = NULL;
 401   number_range* nr;
 402
 403   FT_UInt num_singles2 = 0;
 404   FT_UInt* single2_args;
 405   FT_UInt* single2_arg;
 406   FT_UInt num_singles = 0;
 407   FT_UInt* single_args;
 408   FT_UInt* single_arg;
 409
 410   FT_UInt num_ranges2 = 0;
 411   FT_UInt* range2_args;
 412   FT_UInt* range2_arg;
 413   FT_UInt num_ranges = 0;
 414   FT_UInt* range_args;
 415   FT_UInt* range_arg;
 416
 417   FT_UInt have_single = 0;
 418   FT_UInt have_range = 0;
 419
 420   FT_UShort num_stack_elements;
 421
 422
 423   /* build up four stacks to stay as compact as possible */
 424   nr = number_set;
 425   while (nr)
 426   {
 427     if (nr->start == nr->end)
 428     {
 429       if (nr->start < 256)
 430         num_singles++;
 431       else
 432         num_singles2++;
 433     }
 434     else
 435     {
 436       if (nr->start < 256 && nr->end < 256)
 437         num_ranges++;
 438       else
 439         num_ranges2++;
 440     }
 441     nr = nr->next;
 442   }
 443
 444   /* collect all arguments temporarily in arrays (in reverse order) */
 445   /* so that we can easily split into chunks of 255 args */
 446   /* as needed by NPUSHB and friends; */
 447   /* for simplicity, always allocate an extra slot */
 448   single2_args = (FT_UInt*)malloc((num_singles2 + 1) * sizeof (FT_UInt));
 449   single_args = (FT_UInt*)malloc((num_singles + 1) * sizeof (FT_UInt));
 450   range2_args = (FT_UInt*)malloc((2 * num_ranges2 + 1) * sizeof (FT_UInt));
 451   range_args = (FT_UInt*)malloc((2 * num_ranges + 1) * sizeof (FT_UInt));
 452   if (!single2_args || !single_args
 453       || !range2_args || !range_args)
 454     goto Fail;
 455
 456   /* check whether we need the extra slot for the argument to CALL */
 457   if (num_singles || num_singles2)
 458     have_single = 1;
 459   if (num_ranges || num_ranges2)
 460     have_range = 1;
 461
 462   /* set function indices outside of argument loop (using the extra slot) */
 463   if (have_single)
 464     single_args[num_singles] = bci_number_set_is_element;
 465   if (have_range)
 466     range_args[2 * num_ranges] = bci_number_set_is_element2;
 467
 468   single2_arg = single2_args + num_singles2 - 1;
 469   single_arg = single_args + num_singles - 1;
 470   range2_arg = range2_args + 2 * num_ranges2 - 1;
 471   range_arg = range_args + 2 * num_ranges - 1;
 472
 473   nr = number_set;
 474   while (nr)
 475   {
 476     if (nr->start == nr->end)
 477     {
 478       if (nr->start < 256)
 479         *(single_arg--) = nr->start;
 480       else
 481         *(single2_arg--) = nr->start;
 482     }
 483     else
 484     {
 485       if (nr->start < 256 && nr->end < 256)
 486       {
 487         *(range_arg--) = nr->start;
 488         *(range_arg--) = nr->end;
 489       }
 490       else
 491       {
 492         *(range2_arg--) = nr->start;
 493         *(range2_arg--) = nr->end;
 494       }
 495     }
 496     nr = nr->next;
 497   }
 498
 499   /* this rough estimate of the buffer size gets adjusted later on */
 500   *buf = (FT_Byte*)malloc((2 + 1) * num_singles2
 501                           + (1 + 1) * num_singles
 502                           + (4 + 1) * num_ranges2
 503                           + (2 + 1) * num_ranges
 504                           + 10);
 505   if (!*buf)
 506     goto Fail;
 507   bufp = *buf;
 508
 509   BCI(PUSHB_2);
 510     BCI(cvtl_is_element);
 511     BCI(0);
 512   BCI(WCVTP);
 513
 514   bufp = TA_build_push(bufp, single2_args, num_singles2, 1, 1);
 515   bufp = TA_build_push(bufp, single_args, num_singles + have_single, 0, 1);
 516   if (have_single)
 517     BCI(CALL);
 518
 519   bufp = TA_build_push(bufp, range2_args, 2 * num_ranges2, 1, 1);
 520   bufp = TA_build_push(bufp, range_args, 2 * num_ranges + have_range, 0, 1);
 521   if (have_range)
 522     BCI(CALL);
 523
 524   num_stack_elements = num_singles + num_singles2;
 525   if (num_stack_elements > num_ranges + num_ranges2)
 526     num_stack_elements = num_ranges + num_ranges2;
 527   num_stack_elements += ADDITIONAL_STACK_ELEMENTS;
 528   if (num_stack_elements > sfnt->max_stack_elements)
 529     sfnt->max_stack_elements = num_stack_elements;
 530
 531 Fail:
 532   free(single2_args);
 533   free(single_args);
 534   free(range2_args);
 535   free(range_args);
 536
 537   return bufp;
 538 }
 539
 540
 541 #define COPY_PREP(snippet_name) \
 542           do \
 543           { \
 544             memcpy(bufp, prep_ ## snippet_name, \
 545                    sizeof (prep_ ## snippet_name)); \
 546             bufp += sizeof (prep_ ## snippet_name); \
 547           } while (0)
 548
 549 static FT_Error
 550 TA_table_build_prep(FT_Byte** prep,
 551                     FT_ULong* prep_len,
 552                     SFNT* sfnt,
 553                     FONT* font)
 554 {
 555   SFNT_Table* glyf_table = &font->tables[sfnt->glyf_idx];
 556   glyf_Data* data = (glyf_Data*)glyf_table->data;
 557
 558   FT_Int i;
 559
 560   FT_Byte* buf = NULL;
 561   FT_Byte* buf_new;
 562   FT_UInt buf_len;
 563   FT_UInt buf_new_len;
 564
 565   FT_UInt len;
 566   FT_Byte* bufp = NULL;
 567
 568
 569   if (font->x_height_snapping_exceptions)
 570   {
 571     bufp = TA_sfnt_build_number_set(sfnt, &buf,
 572                                     font->x_height_snapping_exceptions);
 573     if (!bufp)
 574       return FT_Err_Out_Of_Memory;
 575   }
 576
 577   buf_len = bufp - buf;
 578   buf_new_len = buf_len;
 579
 580   if (font->hinting_limit)
 581     buf_new_len += sizeof (PREP(hinting_limit_a))
 582                    + 2
 583                    + sizeof (PREP(hinting_limit_b));
 584
 585   buf_new_len += sizeof (PREP(store_funits_to_pixels));
 586
 587   if (font->x_height_snapping_exceptions)
 588     buf_new_len += sizeof (PREP(test_exception_a));
 589
 590   buf_new_len += sizeof (PREP(align_top_a))
 591                  + (data->num_used_styles > 6
 592                       ? data->num_used_styles + 3
 593                       : data->num_used_styles + 2)
 594                  + sizeof (PREP(align_top_b));
 595   buf_new_len += sizeof (PREP(loop_cvt_a))
 596                  + (data->num_used_styles > 3
 597                      ? 2 * data->num_used_styles + 3
 598                      : 2 * data->num_used_styles + 2)
 599                  + sizeof (PREP(loop_cvt_b))
 600                  + (data->num_used_styles > 3
 601                      ? 2 * data->num_used_styles + 3
 602                      : 2 * data->num_used_styles + 2)
 603                  + sizeof (PREP(loop_cvt_c));
 604
 605   if (font->x_height_snapping_exceptions)
 606     buf_new_len += sizeof (PREP(test_exception_b));
 607
 608   buf_new_len += sizeof (PREP(store_vwidth_data_a))
 609                  + 1
 610                  + sizeof (PREP(store_vwidth_data_b))
 611                  + (data->num_used_styles > 6
 612                       ? 2 * (data->num_used_styles + 1) + 2
 613                       : 2 * (data->num_used_styles + 1) + 1)
 614                  + sizeof (PREP(store_vwidth_data_c))
 615                  + 1
 616                  + sizeof (PREP(store_vwidth_data_d))
 617                  + (data->num_used_styles > 6
 618                       ? 2 * (data->num_used_styles + 1) + 2
 619                       : 2 * (data->num_used_styles + 1) + 1)
 620                  + sizeof (PREP(store_vwidth_data_e));
 621   buf_new_len += sizeof (PREP(set_smooth_or_strong_a))
 622                  + 1
 623                  + sizeof (PREP(set_smooth_or_strong_b))
 624                  + 1
 625                  + sizeof (PREP(set_smooth_or_strong_c))
 626                  + 1
 627                  + sizeof (PREP(set_smooth_or_strong_d));
 628   buf_new_len += (data->num_used_styles > 3
 629                      ? 2 * data->num_used_styles + 3
 630                      : 2 * data->num_used_styles + 2)
 631                  + sizeof (PREP(round_blues));
 632   buf_new_len += sizeof (PREP(set_dropout_mode));
 633   buf_new_len += sizeof (PREP(reset_component_counter));
 634   if (font->control_data_head)
 635     buf_new_len += sizeof (PREP(adjust_delta_exceptions));
 636
 637   /* buffer length must be a multiple of four */
 638   len = (buf_new_len + 3) & ~3;
 639   buf_new = (FT_Byte*)realloc(buf, len);
 640   if (!buf_new)
 641   {
 642     free(buf);
 643     return FT_Err_Out_Of_Memory;
 644   }
 645   buf = buf_new;
 646
 647   /* pad end of buffer with zeros */
 648   buf[len - 1] = 0x00;
 649   buf[len - 2] = 0x00;
 650   buf[len - 3] = 0x00;
 651
 652   /* copy remaining cvt program into buffer */
 653   /* and fill in the missing variables */
 654   bufp = buf + buf_len;
 655
 656   if (font->hinting_limit)
 657   {
 658     COPY_PREP(hinting_limit_a);
 659     *(bufp++) = HIGH(font->hinting_limit);
 660     *(bufp++) = LOW(font->hinting_limit);
 661     COPY_PREP(hinting_limit_b);
 662   }
 663
 664   COPY_PREP(store_funits_to_pixels);
 665
 666   if (font->x_height_snapping_exceptions)
 667     COPY_PREP(test_exception_a);
 668
 669   COPY_PREP(align_top_a);
 670   if (data->num_used_styles > 6)
 671   {
 672     BCI(NPUSHB);
 673     BCI(data->num_used_styles + 2);
 674   }
 675   else
 676     BCI(PUSHB_1 - 1 + data->num_used_styles + 2);
 677   /* XXX: make this work for offsets > 255 */
 678   for (i = TA_STYLE_MAX - 1; i >= 0; i--)
 679   {
 680     if (data->style_ids[i] == 0xFFFFU)
 681       continue;
 682
 683     *(bufp++) = CVT_X_HEIGHT_BLUE_OFFSET(i) >= 0xFFFFU
 684                   ? 0
 685                   : (unsigned char)CVT_X_HEIGHT_BLUE_OFFSET(i);
 686   }
 687   *(bufp++) = data->num_used_styles;
 688   COPY_PREP(align_top_b);
 689
 690   COPY_PREP(loop_cvt_a);
 691   if (data->num_used_styles > 3)
 692   {
 693     BCI(NPUSHB);
 694     BCI(2 * data->num_used_styles + 2);
 695   }
 696   else
 697     BCI(PUSHB_1 - 1 + 2 * data->num_used_styles + 2);
 698   /* XXX: make this work for offsets > 255 */
 699   for (i = TA_STYLE_MAX - 1; i >= 0; i--)
 700   {
 701     if (data->style_ids[i] == 0xFFFFU)
 702       continue;
 703
 704     /* don't loop over artificial blue zones */
 705     *(bufp++) = (unsigned char)CVT_VERT_STANDARD_WIDTH_OFFSET(i);
 706     *(bufp++) = (unsigned char)(
 707                   1
 708                   + CVT_VERT_WIDTHS_SIZE(i)
 709                   + (CVT_BLUES_SIZE(i) > 1 ? CVT_BLUES_SIZE(i) - 2 : 0));
 710   }
 711   *(bufp++) = data->num_used_styles;
 712   COPY_PREP(loop_cvt_b);
 713   if (data->num_used_styles > 3)
 714   {
 715     BCI(NPUSHB);
 716     BCI(2 * data->num_used_styles + 2);
 717   }
 718   else
 719     BCI(PUSHB_1 - 1 + 2 * data->num_used_styles + 2);
 720   /* XXX: make this work for offsets > 255 */
 721   for (i = TA_STYLE_MAX - 1; i >= 0; i--)
 722   {
 723     if (data->style_ids[i] == 0xFFFFU)
 724       continue;
 725
 726     /* don't loop over artificial blue zones */
 727     *(bufp++) = (unsigned char)CVT_BLUE_SHOOTS_OFFSET(i);
 728     *(bufp++) = (unsigned char)(
 729                   CVT_BLUES_SIZE(i) > 1 ? CVT_BLUES_SIZE(i) - 2 : 0);
 730   }
 731   *(bufp++) = data->num_used_styles;
 732   COPY_PREP(loop_cvt_c);
 733
 734   if (font->x_height_snapping_exceptions)
 735     COPY_PREP(test_exception_b);
 736
 737   COPY_PREP(store_vwidth_data_a);
 738   *(bufp++) = (unsigned char)CVT_VWIDTH_OFFSET_DATA(0);
 739   COPY_PREP(store_vwidth_data_b);
 740   if (data->num_used_styles > 6)
 741   {
 742     BCI(NPUSHW);
 743     BCI(data->num_used_styles + 2);
 744   }
 745   else
 746     BCI(PUSHW_1 - 1 + data->num_used_styles + 2);
 747   for (i = TA_STYLE_MAX - 1; i >= 0; i--)
 748   {
 749     if (data->style_ids[i] == 0xFFFFU)
 750       continue;
 751
 752     *(bufp++) = HIGH(CVT_VERT_WIDTHS_OFFSET(i) * 64);
 753     *(bufp++) = LOW(CVT_VERT_WIDTHS_OFFSET(i) * 64);
 754   }
 755   *(bufp++) = HIGH(data->num_used_styles);
 756   *(bufp++) = LOW(data->num_used_styles);
 757   COPY_PREP(store_vwidth_data_c);
 758   *(bufp++) = (unsigned char)CVT_VWIDTH_SIZE_DATA(0);
 759   COPY_PREP(store_vwidth_data_d);
 760   if (data->num_used_styles > 6)
 761   {
 762     BCI(NPUSHW);
 763     BCI(data->num_used_styles + 2);
 764   }
 765   else
 766     BCI(PUSHW_1 - 1 + data->num_used_styles + 2);
 767   for (i = TA_STYLE_MAX - 1; i >= 0; i--)
 768   {
 769     if (data->style_ids[i] == 0xFFFFU)
 770       continue;
 771
 772     *(bufp++) = HIGH(CVT_VERT_WIDTHS_SIZE(i) * 64);
 773     *(bufp++) = LOW(CVT_VERT_WIDTHS_SIZE(i) * 64);
 774   }
 775   *(bufp++) = HIGH(data->num_used_styles);
 776   *(bufp++) = LOW(data->num_used_styles);
 777   COPY_PREP(store_vwidth_data_e);
 778
 779   COPY_PREP(set_smooth_or_strong_a);
 780   *(bufp++) = font->gray_strong_stem_width ? 100 : 0;
 781   COPY_PREP(set_smooth_or_strong_b);
 782   *(bufp++) = font->gdi_cleartype_strong_stem_width ? 100 : 0;
 783   COPY_PREP(set_smooth_or_strong_c);
 784   *(bufp++) = font->dw_cleartype_strong_stem_width ? 100 : 0;
 785   COPY_PREP(set_smooth_or_strong_d);
 786
 787   if (data->num_used_styles > 3)
 788   {
 789     BCI(NPUSHB);
 790     BCI(2 * data->num_used_styles + 2);
 791   }
 792   else
 793     BCI(PUSHB_1 - 1 + 2 * data->num_used_styles + 2);
 794   /* XXX: make this work for offsets > 255 */
 795   for (i = TA_STYLE_MAX - 1; i >= 0; i--)
 796   {
 797     if (data->style_ids[i] == 0xFFFFU)
 798       continue;
 799
 800     *(bufp++) = (unsigned char)CVT_BLUE_REFS_OFFSET(i);
 801     *(bufp++) = (unsigned char)CVT_BLUES_SIZE(i);
 802   }
 803   *(bufp++) = data->num_used_styles;
 804   COPY_PREP(round_blues);
 805
 806   COPY_PREP(set_dropout_mode);
 807   COPY_PREP(reset_component_counter);
 808   if (font->control_data_head)
 809     COPY_PREP(adjust_delta_exceptions);
 810
 811   *prep = buf;
 812   *prep_len = buf_new_len;
 813
 814   return FT_Err_Ok;
 815 }
 816
 817
 818 FT_Error
 819 TA_sfnt_build_prep_table(SFNT* sfnt,
 820                          FONT* font)
 821 {
 822   FT_Error error;
 823
 824   SFNT_Table* glyf_table = &font->tables[sfnt->glyf_idx];
 825   glyf_Data* data = (glyf_Data*)glyf_table->data;
 826
 827   FT_Byte* prep_buf;
 828   FT_ULong prep_len;
 829
 830
 831   error = TA_sfnt_add_table_info(sfnt);
 832   if (error)
 833     goto Exit;
 834
 835   /* `glyf', `cvt', `fpgm', and `prep' are always used in parallel */
 836   if (glyf_table->processed)
 837   {
 838     sfnt->table_infos[sfnt->num_table_infos - 1] = data->prep_idx;
 839     goto Exit;
 840   }
 841
 842   error = TA_table_build_prep(&prep_buf, &prep_len, sfnt, font);
 843   if (error)
 844     goto Exit;
 845
 846 #if 0
 847   /* ttfautohint's bytecode in `fpgm' is larger */
 848   /* than the bytecode in `prep'; */
 849   /* this commented out code here is just for completeness */
 850   if (prep_len > sfnt->max_instructions)
 851     sfnt->max_instructions = prep_len;
 852 #endif
 853
 854   /* in case of success, `prep_buf' gets linked */
 855   /* and is eventually freed in `TA_font_unload' */
 856   error = TA_font_add_table(font,
 857                             &sfnt->table_infos[sfnt->num_table_infos - 1],
 858                             TTAG_prep, prep_len, prep_buf);
 859   if (error)
 860     free(prep_buf);
 861   else
 862     data->prep_idx = sfnt->table_infos[sfnt->num_table_infos - 1];
 863
 864 Exit:
 865   return error;
 866 }
 867
 868 /* end of taprep.c */