lib/tahints.c

   1 /* tahints.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 /* originally file `afhints.c' (2011-Mar-28) from FreeType */
  17
  18 /* heavily modified 2011 by Werner Lemberg <wl@gnu.org> */
  19
  20 #include <string.h>
  21 #include <stdlib.h>
  22 #include "tahints.h"
  23
  24
  25 /* get new segment for given axis */
  26
  27 FT_Error
  28 ta_axis_hints_new_segment(TA_AxisHints axis,
  29                           TA_Segment* asegment)
  30 {
  31   FT_Error error = FT_Err_Ok;
  32   TA_Segment segment = NULL;
  33
  34
  35   if (axis->num_segments >= axis->max_segments)
  36   {
  37     TA_Segment segments_new;
  38
  39     FT_Int old_max = axis->max_segments;
  40     FT_Int new_max = old_max;
  41     FT_Int big_max = (FT_Int)(FT_INT_MAX / sizeof (*segment));
  42
  43
  44     if (old_max >= big_max)
  45     {
  46       error = FT_Err_Out_Of_Memory;
  47       goto Exit;
  48     }
  49
  50     new_max += (new_max >> 2) + 4;
  51     if (new_max < old_max
  52         || new_max > big_max)
  53       new_max = big_max;
  54
  55     segments_new = (TA_Segment)realloc(axis->segments,
  56                                        new_max * sizeof (TA_SegmentRec));
  57     if (!segments_new)
  58       return FT_Err_Out_Of_Memory;
  59
  60     axis->segments = segments_new;
  61     axis->max_segments = new_max;
  62   }
  63
  64   segment = axis->segments + axis->num_segments++;
  65
  66 Exit:
  67   *asegment = segment;
  68   return error;
  69 }
  70
  71
  72 /* get new edge for given axis, direction, and position */
  73
  74 FT_Error
  75 ta_axis_hints_new_edge(TA_AxisHints axis,
  76                        FT_Int fpos,
  77                        TA_Direction dir,
  78                        TA_Edge* anedge)
  79 {
  80   FT_Error error = FT_Err_Ok;
  81   TA_Edge edge = NULL;
  82   TA_Edge edges;
  83
  84
  85   if (axis->num_edges >= axis->max_edges)
  86   {
  87     TA_Edge edges_new;
  88
  89     FT_Int old_max = axis->max_edges;
  90     FT_Int new_max = old_max;
  91     FT_Int big_max = (FT_Int)(FT_INT_MAX / sizeof (*edge));
  92
  93
  94     if (old_max >= big_max)
  95     {
  96       error = FT_Err_Out_Of_Memory;
  97       goto Exit;
  98     }
  99
 100     new_max += (new_max >> 2) + 4;
 101     if (new_max < old_max
 102         || new_max > big_max)
 103       new_max = big_max;
 104
 105     edges_new = (TA_Edge)realloc(axis->edges,
 106                                  new_max * sizeof (TA_EdgeRec));
 107     if (!edges_new)
 108       return FT_Err_Out_Of_Memory;
 109
 110     axis->edges = edges_new;
 111     axis->max_edges = new_max;
 112   }
 113
 114   edges = axis->edges;
 115   edge = edges + axis->num_edges;
 116
 117   while (edge > edges)
 118   {
 119     if (edge[-1].fpos < fpos)
 120       break;
 121
 122     /* we want the edge with same position and minor direction */
 123     /* to appear before those in the major one in the list */
 124     if (edge[-1].fpos == fpos
 125         && dir == axis->major_dir)
 126       break;
 127
 128     edge[0] = edge[-1];
 129     edge--;
 130   }
 131
 132   axis->num_edges++;
 133
 134   memset(edge, 0, sizeof (TA_EdgeRec));
 135   edge->fpos = (FT_Short)fpos;
 136   edge->dir = (FT_Char)dir;
 137
 138 Exit:
 139   *anedge = edge;
 140   return error;
 141 }
 142
 143
 144 #ifdef TA_DEBUG
 145
 146 #include <stdio.h>
 147 #include <stdarg.h>
 148 #include <string.h>
 149
 150
 151 void
 152 _ta_message(const char* format,
 153             ...)
 154 {
 155   va_list ap;
 156
 157
 158   va_start(ap, format);
 159   vfprintf(stderr, format, ap);
 160   va_end(ap);
 161 }
 162
 163
 164 static const char*
 165 ta_dir_str(TA_Direction dir)
 166 {
 167   const char* result;
 168
 169
 170   switch (dir)
 171   {
 172   case TA_DIR_UP:
 173     result = "up";
 174     break;
 175   case TA_DIR_DOWN:
 176     result = "down";
 177     break;
 178   case TA_DIR_LEFT:
 179     result = "left";
 180     break;
 181   case TA_DIR_RIGHT:
 182     result = "right";
 183     break;
 184   default:
 185     result = "none";
 186   }
 187
 188   return result;
 189 }
 190
 191
 192 #define TA_INDEX_NUM(ptr, base) \
 193           ((ptr) ? ((ptr) - (base)) \
 194                  : -1)
 195
 196
 197 void
 198 ta_glyph_hints_dump_points(TA_GlyphHints hints)
 199 {
 200   TA_Point points = hints->points;
 201   TA_Point limit = points + hints->num_points;
 202   TA_Point point;
 203
 204
 205   TA_LOG(("Table of points:\n"
 206           "  [ index |  xorg |  yorg | xscale | yscale"
 207           " |  xfit |  yfit |  flags ]\n"));
 208
 209   for (point = points; point < limit; point++)
 210     TA_LOG(("  [ %5d | %5d | %5d | %6.2f | %6.2f"
 211             " | %5.2f | %5.2f | %c%c%c%c%c%c ]\n",
 212             point - points,
 213             point->fx,
 214             point->fy,
 215             point->ox / 64.0,
 216             point->oy / 64.0,
 217             point->x / 64.0,
 218             point->y / 64.0,
 219             (point->flags & TA_FLAG_WEAK_INTERPOLATION) ? 'w' : ' ',
 220             (point->flags & TA_FLAG_INFLECTION) ? 'i' : ' ',
 221             (point->flags & TA_FLAG_EXTREMA_X) ? '<' : ' ',
 222             (point->flags & TA_FLAG_EXTREMA_Y) ? 'v' : ' ',
 223             (point->flags & TA_FLAG_ROUND_X) ? '(' : ' ',
 224             (point->flags & TA_FLAG_ROUND_Y) ? 'u' : ' '));
 225   TA_LOG(("\n"));
 226 }
 227
 228
 229 static const char*
 230 ta_edge_flags_to_string(FT_Byte flags)
 231 {
 232   static char temp[32];
 233   int pos = 0;
 234
 235
 236   if (flags & TA_EDGE_ROUND)
 237   {
 238     memcpy(temp + pos, "round", 5);
 239     pos += 5;
 240   }
 241   if (flags & TA_EDGE_SERIF)
 242   {
 243     if (pos > 0)
 244       temp[pos++] = ' ';
 245     memcpy(temp + pos, "serif", 5);
 246     pos += 5;
 247   }
 248   if (pos == 0)
 249     return "normal";
 250
 251   temp[pos] = '\0';
 252
 253   return temp;
 254 }
 255
 256
 257 /* dump the array of linked segments */
 258
 259 void
 260 ta_glyph_hints_dump_segments(TA_GlyphHints hints)
 261 {
 262   FT_Int dimension;
 263
 264
 265   for (dimension = TA_DEBUG_STARTDIM;
 266        dimension >= TA_DEBUG_ENDDIM;
 267        dimension--)
 268   {
 269     TA_AxisHints axis = &hints->axis[dimension];
 270     TA_Point points = hints->points;
 271     TA_Edge edges = axis->edges;
 272     TA_Segment segments = axis->segments;
 273     TA_Segment limit = segments + axis->num_segments;
 274     TA_Segment seg;
 275
 276
 277     TA_LOG(("Table of %s segments:\n",
 278             dimension == TA_DIMENSION_HORZ ? "vertical"
 279                                            : "horizontal"));
 280     if (axis->num_segments)
 281       TA_LOG(("  [ index |  pos  |  dir  | from"
 282               " |  to  | link | serif | edge"
 283               " | height | extra |    flags    ]\n"));
 284     else
 285       TA_LOG(("  (none)\n"));
 286
 287     for (seg = segments; seg < limit; seg++)
 288       TA_LOG(("  [ %5d | %5.2g | %5s | %4d"
 289               " | %4d | %4d | %5d | %4d"
 290               " | %6d | %5d | %11s ]\n",
 291               seg - segments,
 292               dimension == TA_DIMENSION_HORZ ? (int)seg->first->ox / 64.0
 293                                              : (int)seg->first->oy / 64.0,
 294               ta_dir_str((TA_Direction)seg->dir),
 295               TA_INDEX_NUM(seg->first, points),
 296               TA_INDEX_NUM(seg->last, points),
 297               TA_INDEX_NUM(seg->link, segments),
 298               TA_INDEX_NUM(seg->serif, segments),
 299               TA_INDEX_NUM(seg->edge, edges),
 300               seg->height,
 301               seg->height - (seg->max_coord - seg->min_coord),
 302               ta_edge_flags_to_string(seg->flags)));
 303     TA_LOG(("\n"));
 304   }
 305 }
 306
 307
 308 /* dump the array of linked edges */
 309
 310 void
 311 ta_glyph_hints_dump_edges(TA_GlyphHints hints)
 312 {
 313   FT_Int dimension;
 314
 315
 316   for (dimension = TA_DEBUG_STARTDIM;
 317        dimension >= TA_DEBUG_ENDDIM;
 318        dimension--)
 319   {
 320     TA_AxisHints axis = &hints->axis[dimension];
 321     TA_Edge edges = axis->edges;
 322     TA_Edge limit = edges + axis->num_edges;
 323     TA_Edge edge;
 324
 325
 326     /* note that TA_DIMENSION_HORZ corresponds to _vertical_ edges */
 327     /* since they have a constant X coordinate */
 328     TA_LOG(("Table of %s edges:\n",
 329             dimension == TA_DIMENSION_HORZ ? "vertical"
 330                                            : "horizontal"));
 331     if (axis->num_edges)
 332       TA_LOG(("  [ index |  pos  |  dir  | link"
 333               " | serif | blue | opos  |  pos  |    flags    ]\n"));
 334     else
 335       TA_LOG(("  (none)\n"));
 336
 337     for (edge = edges; edge < limit; edge++)
 338       TA_LOG(("  [ %5d | %5.2g | %5s | %4d"
 339               " | %5d |   %c  | %5.2f | %5.2f | %11s ]\n",
 340               edge - edges,
 341               (int)edge->opos / 64.0,
 342               ta_dir_str((TA_Direction)edge->dir),
 343               TA_INDEX_NUM(edge->link, edges),
 344               TA_INDEX_NUM(edge->serif, edges),
 345               edge->blue_edge ? 'y' : 'n',
 346               edge->opos / 64.0,
 347               edge->pos / 64.0,
 348               ta_edge_flags_to_string(edge->flags)));
 349     TA_LOG(("\n"));
 350   }
 351 }
 352
 353 #endif /* TA_DEBUG */
 354
 355
 356 /* compute the direction value of a given vector */
 357
 358 TA_Direction
 359 ta_direction_compute(FT_Pos dx,
 360                      FT_Pos dy)
 361 {
 362   FT_Pos ll, ss;  /* long and short arm lengths */
 363   TA_Direction dir; /* candidate direction */
 364
 365
 366   if (dy >= dx)
 367   {
 368     if (dy >= -dx)
 369     {
 370       dir = TA_DIR_UP;
 371       ll = dy;
 372       ss = dx;
 373     }
 374     else
 375     {
 376       dir = TA_DIR_LEFT;
 377       ll = -dx;
 378       ss = dy;
 379     }
 380   }
 381   else /* dy < dx */
 382   {
 383     if (dy >= -dx)
 384     {
 385       dir = TA_DIR_RIGHT;
 386       ll = dx;
 387       ss = dy;
 388     }
 389     else
 390     {
 391       dir = TA_DIR_DOWN;
 392       ll = dy;
 393       ss = dx;
 394     }
 395   }
 396
 397   /* return no direction if arm lengths differ too much */
 398   /* (value 14 is heuristic, corresponding to approx. 4.1 degrees) */
 399   ss *= 14;
 400   if (TA_ABS(ll) <= TA_ABS(ss))
 401     dir = TA_DIR_NONE;
 402
 403   return dir;
 404 }
 405
 406
 407 void
 408 ta_glyph_hints_init(TA_GlyphHints hints)
 409 {
 410   memset(hints, 0, sizeof (TA_GlyphHintsRec));
 411 }
 412
 413
 414 void
 415 ta_glyph_hints_done(TA_GlyphHints hints)
 416 {
 417   int dim;
 418
 419
 420   if (!hints)
 421     return;
 422
 423   /* we don't need to free the segment and edge buffers */
 424   /* since they are really within the hints->points array */
 425   for (dim = 0; dim < TA_DIMENSION_MAX; dim++)
 426   {
 427     TA_AxisHints axis = &hints->axis[dim];
 428
 429
 430     axis->num_segments = 0;
 431     axis->max_segments = 0;
 432     free(axis->segments);
 433     axis->segments = NULL;
 434
 435     axis->num_edges = 0;
 436     axis->max_edges = 0;
 437     free(axis->edges);
 438     axis->edges = NULL;
 439   }
 440
 441   free(hints->contours);
 442   hints->contours = NULL;
 443   hints->max_contours = 0;
 444   hints->num_contours = 0;
 445
 446   free(hints->points);
 447   hints->points = NULL;
 448   hints->num_points = 0;
 449   hints->max_points = 0;
 450 }
 451
 452
 453 /* reset metrics */
 454
 455 void
 456 ta_glyph_hints_rescale(TA_GlyphHints hints,
 457                        TA_StyleMetrics metrics)
 458 {
 459   hints->metrics = metrics;
 460   hints->scaler_flags = metrics->scaler.flags;
 461 }
 462
 463
 464 /* from FreeType's ftcalc.c */
 465
 466 static FT_Int
 467 ta_corner_is_flat(FT_Pos in_x,
 468                   FT_Pos in_y,
 469                   FT_Pos out_x,
 470                   FT_Pos out_y)
 471 {
 472   FT_Pos ax = in_x;
 473   FT_Pos ay = in_y;
 474
 475   FT_Pos d_in, d_out, d_corner;
 476
 477
 478   if (ax < 0)
 479     ax = -ax;
 480   if (ay < 0)
 481     ay = -ay;
 482   d_in = ax + ay;
 483
 484   ax = out_x;
 485   if (ax < 0)
 486     ax = -ax;
 487   ay = out_y;
 488   if (ay < 0)
 489     ay = -ay;
 490   d_out = ax + ay;
 491
 492   ax = out_x + in_x;
 493   if (ax < 0)
 494     ax = -ax;
 495   ay = out_y + in_y;
 496   if (ay < 0)
 497     ay = -ay;
 498   d_corner = ax + ay;
 499
 500   return (d_in + d_out - d_corner) < (d_corner >> 4);
 501 }
 502
 503
 504 /* recompute all TA_Point in TA_GlyphHints */
 505 /* from the definitions in a source outline */
 506
 507 FT_Error
 508 ta_glyph_hints_reload(TA_GlyphHints hints,
 509                       FT_Outline* outline)
 510 {
 511   FT_Error error = FT_Err_Ok;
 512   TA_Point points;
 513   FT_UInt old_max, new_max;
 514
 515   FT_Fixed x_scale = hints->x_scale;
 516   FT_Fixed y_scale = hints->y_scale;
 517   FT_Pos x_delta = hints->x_delta;
 518   FT_Pos y_delta = hints->y_delta;
 519
 520
 521   hints->num_points = 0;
 522   hints->num_contours = 0;
 523
 524   hints->axis[0].num_segments = 0;
 525   hints->axis[0].num_edges = 0;
 526   hints->axis[1].num_segments = 0;
 527   hints->axis[1].num_edges = 0;
 528
 529   /* first of all, reallocate the contours array if necessary */
 530   new_max = (FT_UInt)outline->n_contours;
 531   old_max = hints->max_contours;
 532   if (new_max > old_max)
 533   {
 534     TA_Point* contours_new;
 535
 536
 537     new_max = (new_max + 3) & ~3; /* round up to a multiple of 4 */
 538
 539     contours_new = (TA_Point*)realloc(hints->contours,
 540                                       new_max * sizeof (TA_Point));
 541     if (!contours_new)
 542       return FT_Err_Out_Of_Memory;
 543
 544     hints->contours = contours_new;
 545     hints->max_contours = new_max;
 546   }
 547
 548   /* reallocate the points arrays if necessary -- we reserve */
 549   /* two additional point positions, used to hint metrics appropriately */
 550   new_max = (FT_UInt)(outline->n_points + 2);
 551   old_max = hints->max_points;
 552   if (new_max > old_max)
 553   {
 554     TA_Point  points_new;
 555
 556
 557     new_max = (new_max + 2 + 7) & ~7; /* round up to a multiple of 8 */
 558
 559     points_new = (TA_Point)realloc(hints->points,
 560                                    new_max * sizeof (TA_PointRec));
 561     if (!points_new)
 562       return FT_Err_Out_Of_Memory;
 563
 564     hints->points = points_new;
 565     hints->max_points = new_max;
 566   }
 567
 568   hints->num_points = outline->n_points;
 569   hints->num_contours = outline->n_contours;
 570
 571   /* we can't rely on the value of `FT_Outline.flags' to know the fill */
 572   /* direction used for a glyph, given that some fonts are broken */
 573   /* (e.g. the Arphic ones); we thus recompute it each time we need to */
 574
 575   hints->axis[TA_DIMENSION_HORZ].major_dir = TA_DIR_UP;
 576   hints->axis[TA_DIMENSION_VERT].major_dir = TA_DIR_LEFT;
 577
 578   if (FT_Outline_Get_Orientation(outline) == FT_ORIENTATION_POSTSCRIPT)
 579   {
 580     hints->axis[TA_DIMENSION_HORZ].major_dir = TA_DIR_DOWN;
 581     hints->axis[TA_DIMENSION_VERT].major_dir = TA_DIR_RIGHT;
 582   }
 583
 584   hints->x_scale = x_scale;
 585   hints->y_scale = y_scale;
 586   hints->x_delta = x_delta;
 587   hints->y_delta = y_delta;
 588
 589   hints->xmin_delta = 0;
 590   hints->xmax_delta = 0;
 591
 592   points = hints->points;
 593   if (hints->num_points == 0)
 594     goto Exit;
 595
 596   {
 597     TA_Point point;
 598     TA_Point point_limit = points + hints->num_points;
 599
 600
 601     /* compute coordinates & Bezier flags, next and prev */
 602     {
 603       FT_Vector* vec = outline->points;
 604       char* tag = outline->tags;
 605
 606       TA_Point end = points + outline->contours[0];
 607       TA_Point prev = end;
 608
 609       FT_Int contour_index = 0;
 610
 611
 612       for (point = points; point < point_limit; point++, vec++, tag++)
 613       {
 614         point->fx = (FT_Short)vec->x;
 615         point->fy = (FT_Short)vec->y;
 616         point->ox = point->x = FT_MulFix(vec->x, x_scale) + x_delta;
 617         point->oy = point->y = FT_MulFix(vec->y, y_scale) + y_delta;
 618
 619         switch (FT_CURVE_TAG(*tag))
 620         {
 621         case FT_CURVE_TAG_CONIC:
 622           point->flags = TA_FLAG_CONIC;
 623           break;
 624         case FT_CURVE_TAG_CUBIC:
 625           point->flags = TA_FLAG_CUBIC;
 626           break;
 627         default:
 628           point->flags = TA_FLAG_NONE;
 629         }
 630
 631         point->prev = prev;
 632         prev->next = point;
 633         prev = point;
 634
 635         if (point == end)
 636         {
 637           if (++contour_index < outline->n_contours)
 638           {
 639             end = points + outline->contours[contour_index];
 640             prev = end;
 641           }
 642         }
 643       }
 644     }
 645
 646     /* set up the contours array */
 647     {
 648       TA_Point* contour = hints->contours;
 649       TA_Point* contour_limit = contour + hints->num_contours;
 650
 651       short* end = outline->contours;
 652       short idx = 0;
 653
 654
 655       for (; contour < contour_limit; contour++, end++)
 656       {
 657         contour[0] = points + idx;
 658         idx = (short)(end[0] + 1);
 659       }
 660     }
 661
 662     /* compute directions of in & out vectors */
 663     {
 664       TA_Point first = points;
 665       TA_Point prev = NULL;
 666
 667       FT_Pos in_x = 0;
 668       FT_Pos in_y = 0;
 669
 670       TA_Direction in_dir = TA_DIR_NONE;
 671
 672       FT_Pos last_good_in_x = 0;
 673       FT_Pos last_good_in_y = 0;
 674
 675       FT_UInt units_per_em = hints->metrics->scaler.face->units_per_EM;
 676       FT_Int near_limit = 20 * units_per_em / 2048;
 677
 678
 679       for (point = points; point < point_limit; point++)
 680       {
 681         TA_Point next;
 682         FT_Pos out_x, out_y;
 683
 684
 685         if (point == first)
 686         {
 687           prev = first->prev;
 688
 689           in_x = first->fx - prev->fx;
 690           in_y = first->fy - prev->fy;
 691
 692           last_good_in_x = in_x;
 693           last_good_in_y = in_y;
 694
 695           if (TA_ABS(in_x) + TA_ABS(in_y) < near_limit)
 696           {
 697             /* search first non-near point to get a good `in_dir' value */
 698
 699             TA_Point point_ = prev;
 700
 701
 702             while (point_ != first)
 703             {
 704               TA_Point prev_ = point_->prev;
 705
 706               FT_Pos in_x_ = point_->fx - prev_->fx;
 707               FT_Pos in_y_ = point_->fy - prev_->fy;
 708
 709
 710               if (TA_ABS(in_x_) + TA_ABS(in_y_) >= near_limit)
 711               {
 712                 last_good_in_x = in_x_;
 713                 last_good_in_y = in_y_;
 714
 715                 break;
 716               }
 717
 718               point_ = prev_;
 719             }
 720           }
 721
 722           in_dir = ta_direction_compute(in_x, in_y);
 723           first = prev + 1;
 724         }
 725
 726         point->in_dir = (FT_Char)in_dir;
 727
 728         /* check whether the current point is near to the previous one */
 729         /* (value 20 in `near_limit' is heuristic; we use Taxicab */
 730         /* metrics for the test) */
 731
 732         if (TA_ABS(in_x) + TA_ABS(in_y) < near_limit)
 733           point->flags |= TA_FLAG_NEAR;
 734         else
 735         {
 736           last_good_in_x = in_x;
 737           last_good_in_y = in_y;
 738         }
 739
 740         next = point->next;
 741         out_x = next->fx - point->fx;
 742         out_y = next->fy - point->fy;
 743
 744         in_dir = ta_direction_compute(out_x, out_y);
 745         point->out_dir = (FT_Char)in_dir;
 746
 747         /* Check for weak points.  The remaining points not collected */
 748         /* in edges are then implicitly classified as strong points. */
 749
 750         if (point->flags & TA_FLAG_CONTROL)
 751         {
 752           /* control points are always weak */
 753         Is_Weak_Point:
 754           point->flags |= TA_FLAG_WEAK_INTERPOLATION;
 755         }
 756         else if (point->out_dir == point->in_dir)
 757         {
 758           if (point->out_dir != TA_DIR_NONE)
 759           {
 760             /* current point lies on a horizontal or          */
 761             /* vertical segment (but doesn't start or end it) */
 762             goto Is_Weak_Point;
 763           }
 764
 765           /* test whether `in' and `out' direction is approximately */
 766           /* the same (and use the last good `in' vector in case    */
 767           /* the current point is near to the previous one)         */
 768           if (ta_corner_is_flat(point->flags & TA_FLAG_NEAR ? last_good_in_x
 769                                                             : in_x,
 770                                 point->flags & TA_FLAG_NEAR ? last_good_in_y
 771                                                             : in_y,
 772                                 out_x,
 773                                 out_y))
 774           {
 775             /* current point lies on a straight, diagonal line */
 776             /* (more or less)                                  */
 777             goto Is_Weak_Point;
 778           }
 779         }
 780         else if (point->in_dir == -point->out_dir)
 781         {
 782           /* current point forms a spike */
 783           goto Is_Weak_Point;
 784         }
 785
 786         in_x = out_x;
 787         in_y = out_y;
 788       }
 789     }
 790   }
 791
 792 Exit:
 793   return error;
 794 }
 795
 796
 797 /* store the hinted outline in an FT_Outline structure */
 798
 799 void
 800 ta_glyph_hints_save(TA_GlyphHints hints,
 801                     FT_Outline* outline)
 802 {
 803   TA_Point point = hints->points;
 804   TA_Point limit = point + hints->num_points;
 805
 806   FT_Vector* vec = outline->points;
 807   char* tag = outline->tags;
 808
 809
 810   for (; point < limit; point++, vec++, tag++)
 811   {
 812     vec->x = point->x;
 813     vec->y = point->y;
 814
 815     if (point->flags & TA_FLAG_CONIC)
 816       tag[0] = FT_CURVE_TAG_CONIC;
 817     else if (point->flags & TA_FLAG_CUBIC)
 818       tag[0] = FT_CURVE_TAG_CUBIC;
 819     else
 820       tag[0] = FT_CURVE_TAG_ON;
 821   }
 822 }
 823
 824
 825 /****************************************************************
 826  *
 827  *                     EDGE POINT GRID-FITTING
 828  *
 829  ****************************************************************/
 830
 831
 832 /* align all points of an edge to the same coordinate value, */
 833 /* either horizontally or vertically */
 834
 835 void
 836 ta_glyph_hints_align_edge_points(TA_GlyphHints hints,
 837                                  TA_Dimension dim)
 838 {
 839   TA_AxisHints axis = &hints->axis[dim];
 840   TA_Segment segments = axis->segments;
 841   TA_Segment segment_limit = segments + axis->num_segments;
 842   TA_Segment seg;
 843
 844
 845   if (dim == TA_DIMENSION_HORZ)
 846   {
 847     for (seg = segments; seg < segment_limit; seg++)
 848     {
 849       TA_Edge edge = seg->edge;
 850       TA_Point point, first, last;
 851
 852
 853       if (edge == NULL)
 854         continue;
 855
 856       first = seg->first;
 857       last = seg->last;
 858       point = first;
 859       for (;;)
 860       {
 861         point->x = edge->pos;
 862         point->flags |= TA_FLAG_TOUCH_X;
 863
 864         if (point == last)
 865           break;
 866
 867         point = point->next;
 868       }
 869     }
 870   }
 871   else
 872   {
 873     for (seg = segments; seg < segment_limit; seg++)
 874     {
 875       TA_Edge edge = seg->edge;
 876       TA_Point point, first, last;
 877
 878
 879       if (edge == NULL)
 880         continue;
 881
 882       first = seg->first;
 883       last = seg->last;
 884       point = first;
 885       for (;;)
 886       {
 887         point->y = edge->pos;
 888         point->flags |= TA_FLAG_TOUCH_Y;
 889
 890         if (point == last)
 891           break;
 892
 893         point = point->next;
 894       }
 895     }
 896   }
 897 }
 898
 899
 900 /****************************************************************
 901  *
 902  *                    STRONG POINT INTERPOLATION
 903  *
 904  ****************************************************************/
 905
 906
 907 /* hint the strong points -- */
 908 /* this is equivalent to the TrueType `IP' hinting instruction */
 909
 910 void
 911 ta_glyph_hints_align_strong_points(TA_GlyphHints hints,
 912                                    TA_Dimension dim)
 913 {
 914   TA_Point points = hints->points;
 915   TA_Point point_limit = points + hints->num_points;
 916
 917   TA_AxisHints axis = &hints->axis[dim];
 918
 919   TA_Edge edges = axis->edges;
 920   TA_Edge edge_limit = edges + axis->num_edges;
 921
 922   FT_UShort touch_flag;
 923
 924
 925   if (dim == TA_DIMENSION_HORZ)
 926     touch_flag = TA_FLAG_TOUCH_X;
 927   else
 928     touch_flag = TA_FLAG_TOUCH_Y;
 929
 930   if (edges < edge_limit)
 931   {
 932     TA_Point point;
 933     TA_Edge edge;
 934
 935
 936     for (point = points; point < point_limit; point++)
 937     {
 938       FT_Pos u, ou, fu;  /* point position */
 939       FT_Pos delta;
 940
 941
 942       if (point->flags & touch_flag)
 943         continue;
 944
 945       /* if this point is candidate to weak interpolation, we */
 946       /* interpolate it after all strong points have been processed */
 947
 948       if ((point->flags & TA_FLAG_WEAK_INTERPOLATION)
 949           && !(point->flags & TA_FLAG_INFLECTION))
 950         continue;
 951
 952       if (dim == TA_DIMENSION_VERT)
 953       {
 954         u = point->fy;
 955         ou = point->oy;
 956       }
 957       else
 958       {
 959         u = point->fx;
 960         ou = point->ox;
 961       }
 962
 963       fu = u;
 964
 965       /* is the point before the first edge? */
 966       edge = edges;
 967       delta = edge->fpos - u;
 968       if (delta >= 0)
 969       {
 970         u = edge->pos - (edge->opos - ou);
 971
 972         if (hints->recorder)
 973           hints->recorder(ta_ip_before, hints, dim,
 974                           point, NULL, NULL, NULL, NULL);
 975
 976         goto Store_Point;
 977       }
 978
 979       /* is the point after the last edge? */
 980       edge = edge_limit - 1;
 981       delta = u - edge->fpos;
 982       if (delta >= 0)
 983       {
 984         u = edge->pos + (ou - edge->opos);
 985
 986         if (hints->recorder)
 987           hints->recorder(ta_ip_after, hints, dim,
 988                           point, NULL, NULL, NULL, NULL);
 989
 990         goto Store_Point;
 991       }
 992
 993       {
 994         FT_PtrDist min, max, mid;
 995         FT_Pos fpos;
 996
 997
 998         /* find enclosing edges */
 999         min = 0;
1000         max = edge_limit - edges;
1001
1002         /* for a small number of edges, a linear search is better */
1003         if (max <= 8)
1004         {
1005           FT_PtrDist nn;
1006
1007
1008           for (nn = 0; nn < max; nn++)
1009             if (edges[nn].fpos >= u)
1010               break;
1011
1012           if (edges[nn].fpos == u)
1013           {
1014             u = edges[nn].pos;
1015
1016             if (hints->recorder)
1017               hints->recorder(ta_ip_on, hints, dim,
1018                               point, &edges[nn], NULL, NULL, NULL);
1019
1020             goto Store_Point;
1021           }
1022           min = nn;
1023         }
1024         else
1025           while (min < max)
1026           {
1027             mid = (max + min) >> 1;
1028             edge = edges + mid;
1029             fpos = edge->fpos;
1030
1031             if (u < fpos)
1032               max = mid;
1033             else if (u > fpos)
1034               min = mid + 1;
1035             else
1036             {
1037               /* we are on the edge */
1038               u = edge->pos;
1039
1040               if (hints->recorder)
1041                 hints->recorder(ta_ip_on, hints, dim,
1042                                 point, edge, NULL, NULL, NULL);
1043
1044               goto Store_Point;
1045             }
1046           }
1047
1048         /* point is not on an edge */
1049         {
1050           TA_Edge before = edges + min - 1;
1051           TA_Edge after = edges + min + 0;
1052
1053
1054           /* assert(before && after && before != after) */
1055           if (before->scale == 0)
1056             before->scale = FT_DivFix(after->pos - before->pos,
1057                                       after->fpos - before->fpos);
1058
1059           u = before->pos + FT_MulFix(fu - before->fpos,
1060                                       before->scale);
1061
1062           if (hints->recorder)
1063             hints->recorder(ta_ip_between, hints, dim,
1064                             point, before, after, NULL, NULL);
1065         }
1066       }
1067
1068     Store_Point:
1069       /* save the point position */
1070       if (dim == TA_DIMENSION_HORZ)
1071         point->x = u;
1072       else
1073         point->y = u;
1074
1075       point->flags |= touch_flag;
1076     }
1077   }
1078 }
1079
1080
1081 /****************************************************************
1082  *
1083  *                    WEAK POINT INTERPOLATION
1084  *
1085  ****************************************************************/
1086
1087
1088 /* shift the original coordinates of all points between `p1' and */
1089 /* `p2' to get hinted coordinates, using the same difference as */
1090 /* given by `ref' */
1091
1092 static void
1093 ta_iup_shift(TA_Point p1,
1094              TA_Point p2,
1095              TA_Point ref)
1096 {
1097   TA_Point p;
1098   FT_Pos delta = ref->u - ref->v;
1099
1100
1101   if (delta == 0)
1102     return;
1103
1104   for (p = p1; p < ref; p++)
1105     p->u = p->v + delta;
1106
1107   for (p = ref + 1; p <= p2; p++)
1108     p->u = p->v + delta;
1109 }
1110
1111
1112 /* interpolate the original coordinates of all points between `p1' and */
1113 /* `p2' to get hinted coordinates, using `ref1' and `ref2' as the */
1114 /* reference points;  the `u' and `v' members are the current and */
1115 /* original coordinate values, respectively. */
1116
1117 /* details can be found in the TrueType bytecode specification */
1118
1119 static void
1120 ta_iup_interp(TA_Point p1,
1121               TA_Point p2,
1122               TA_Point ref1,
1123               TA_Point ref2)
1124 {
1125   TA_Point p;
1126   FT_Pos u;
1127   FT_Pos v1 = ref1->v;
1128   FT_Pos v2 = ref2->v;
1129   FT_Pos d1 = ref1->u - v1;
1130   FT_Pos d2 = ref2->u - v2;
1131
1132
1133   if (p1 > p2)
1134     return;
1135
1136   if (v1 == v2)
1137   {
1138     for (p = p1; p <= p2; p++)
1139     {
1140       u = p->v;
1141
1142       if (u <= v1)
1143         u += d1;
1144       else
1145         u += d2;
1146
1147       p->u = u;
1148     }
1149     return;
1150   }
1151
1152   if (v1 < v2)
1153   {
1154     for (p = p1; p <= p2; p++)
1155     {
1156       u = p->v;
1157
1158       if (u <= v1)
1159         u += d1;
1160       else if (u >= v2)
1161         u += d2;
1162       else
1163         u = ref1->u + FT_MulDiv(u - v1, ref2->u - ref1->u, v2 - v1);
1164
1165       p->u = u;
1166     }
1167   }
1168   else
1169   {
1170     for (p = p1; p <= p2; p++)
1171     {
1172       u = p->v;
1173
1174       if (u <= v2)
1175         u += d2;
1176       else if (u >= v1)
1177         u += d1;
1178       else
1179         u = ref1->u + FT_MulDiv(u - v1, ref2->u - ref1->u, v2 - v1);
1180
1181       p->u = u;
1182     }
1183   }
1184 }
1185
1186
1187 /* hint the weak points -- */
1188 /* this is equivalent to the TrueType `IUP' hinting instruction */
1189
1190 void
1191 ta_glyph_hints_align_weak_points(TA_GlyphHints hints,
1192                                  TA_Dimension dim)
1193 {
1194   TA_Point points = hints->points;
1195   TA_Point point_limit = points + hints->num_points;
1196
1197   TA_Point* contour = hints->contours;
1198   TA_Point* contour_limit = contour + hints->num_contours;
1199
1200   FT_UShort touch_flag;
1201   TA_Point point;
1202   TA_Point end_point;
1203   TA_Point first_point;
1204
1205
1206   /* pass 1: move segment points to edge positions */
1207
1208   if (dim == TA_DIMENSION_HORZ)
1209   {
1210     touch_flag = TA_FLAG_TOUCH_X;
1211
1212     for (point = points; point < point_limit; point++)
1213     {
1214       point->u = point->x;
1215       point->v = point->ox;
1216     }
1217   }
1218   else
1219   {
1220     touch_flag = TA_FLAG_TOUCH_Y;
1221
1222     for (point = points; point < point_limit; point++)
1223     {
1224       point->u = point->y;
1225       point->v = point->oy;
1226     }
1227   }
1228
1229   for (; contour < contour_limit; contour++)
1230   {
1231     TA_Point first_touched, last_touched;
1232
1233
1234     point = *contour;
1235     end_point = point->prev;
1236     first_point = point;
1237
1238     /* find first touched point */
1239     for (;;)
1240     {
1241       if (point > end_point) /* no touched point in contour */
1242         goto NextContour;
1243
1244       if (point->flags & touch_flag)
1245         break;
1246
1247       point++;
1248     }
1249
1250     first_touched = point;
1251
1252     for (;;)
1253     {
1254       /* skip any touched neighbours */
1255       while (point < end_point
1256              && (point[1].flags & touch_flag) != 0)
1257         point++;
1258
1259       last_touched = point;
1260
1261       /* find the next touched point, if any */
1262       point++;
1263       for (;;)
1264       {
1265         if (point > end_point)
1266           goto EndContour;
1267
1268         if ((point->flags & touch_flag) != 0)
1269           break;
1270
1271         point++;
1272       }
1273
1274       /* interpolate between last_touched and point */
1275       ta_iup_interp(last_touched + 1, point - 1,
1276                     last_touched, point);
1277     }
1278
1279   EndContour:
1280     /* special case: only one point was touched */
1281     if (last_touched == first_touched)
1282       ta_iup_shift(first_point, end_point, first_touched);
1283
1284     else /* interpolate the last part */
1285     {
1286       if (last_touched < end_point)
1287         ta_iup_interp(last_touched + 1, end_point,
1288                       last_touched, first_touched);
1289
1290       if (first_touched > points)
1291         ta_iup_interp(first_point, first_touched - 1,
1292                       last_touched, first_touched);
1293     }
1294
1295   NextContour:
1296     ;
1297   }
1298
1299   /* now save the interpolated values back to x/y */
1300   if (dim == TA_DIMENSION_HORZ)
1301   {
1302     for (point = points; point < point_limit; point++)
1303       point->x = point->u;
1304   }
1305   else
1306   {
1307     for (point = points; point < point_limit; point++)
1308       point->y = point->u;
1309   }
1310 }
1311
1312
1313 #ifdef TA_CONFIG_OPTION_USE_WARPER
1314
1315 /* apply (small) warp scale and warp delta for given dimension */
1316
1317 static void
1318 ta_glyph_hints_scale_dim(TA_GlyphHints hints,
1319                          TA_Dimension dim,
1320                          FT_Fixed scale,
1321                          FT_Pos delta)
1322 {
1323   TA_Point points = hints->points;
1324   TA_Point points_limit = points + hints->num_points;
1325   TA_Point point;
1326
1327
1328   if (dim == TA_DIMENSION_HORZ)
1329   {
1330     for (point = points; point < points_limit; point++)
1331       point->x = FT_MulFix(point->fx, scale) + delta;
1332   }
1333   else
1334   {
1335     for (point = points; point < points_limit; point++)
1336       point->y = FT_MulFix(point->fy, scale) + delta;
1337   }
1338 }
1339
1340 #endif /* TA_CONFIG_OPTION_USE_WARPER */
1341
1342 /* end of tahints.c */