src/taloader.c

   1 /* taloader.c */
   2
   3 /* originally file `afloader.c' (2011-Mar-28) from FreeType */
   4
   5 /* heavily modified 2011 by Werner Lemberg <wl@gnu.org> */
   6
   7 #include <string.h>
   8
   9 #include <ft2build.h>
  10 #include FT_GLYPH_H
  11
  12 #include "taloader.h"
  13 #include "tahints.h"
  14 #include "taglobal.h"
  15
  16
  17 /* from file `ftobjs.h' (2011-Mar-28) from FreeType */
  18 typedef struct FT_Slot_InternalRec_
  19 {
  20   TA_GlyphLoader loader;
  21   FT_UInt flags;
  22   FT_Bool glyph_transformed;
  23   FT_Matrix glyph_matrix;
  24   FT_Vector glyph_delta;
  25   void* glyph_hints;
  26 } FT_GlyphSlot_InternalRec;
  27
  28
  29 /* initialize glyph loader */
  30
  31 FT_Error
  32 ta_loader_init(TA_Loader loader)
  33 {
  34   memset(loader, 0, sizeof (TA_LoaderRec));
  35
  36   ta_glyph_hints_init(&loader->hints);
  37 #ifdef TA_DEBUG
  38   _ta_debug_hints = &loader->hints;
  39 #endif
  40   return TA_GlyphLoader_New(&loader->gloader);
  41 }
  42
  43
  44 /* reset glyph loader and compute globals if necessary */
  45
  46 FT_Error
  47 ta_loader_reset(TA_Loader loader,
  48                 FT_Face face)
  49 {
  50   FT_Error error = FT_Err_Ok;
  51
  52
  53   loader->face = face;
  54   loader->globals = (TA_FaceGlobals)face->autohint.data;
  55
  56   TA_GlyphLoader_Rewind(loader->gloader);
  57
  58   if (loader->globals == NULL)
  59   {
  60     error = ta_face_globals_new(face, &loader->globals);
  61     if (!error)
  62     {
  63       face->autohint.data = (FT_Pointer)loader->globals;
  64       face->autohint.finalizer = (FT_Generic_Finalizer)ta_face_globals_free;
  65     }
  66   }
  67
  68   return error;
  69 }
  70
  71
  72 /* finalize glyph loader */
  73
  74 void
  75 ta_loader_done(TA_Loader loader)
  76 {
  77   ta_glyph_hints_done(&loader->hints);
  78
  79   loader->face = NULL;
  80   loader->globals = NULL;
  81
  82 #ifdef TA_DEBUG
  83   _ta_debug_hints = NULL;
  84 #endif
  85   TA_GlyphLoader_Done(loader->gloader);
  86   loader->gloader = NULL;
  87 }
  88
  89
  90 /* load a single glyph component; this routine calls itself recursively, */
  91 /* if necessary, and does the main work of `ta_loader_load_glyph' */
  92
  93 static FT_Error
  94 ta_loader_load_g(TA_Loader loader,
  95                  TA_Scaler scaler,
  96                  FT_UInt glyph_index,
  97                  FT_Int32 load_flags,
  98                  FT_UInt depth)
  99 {
 100   FT_Error error;
 101   FT_Face face = loader->face;
 102   TA_GlyphLoader gloader = loader->gloader;
 103   TA_ScriptMetrics metrics = loader->metrics;
 104   TA_GlyphHints hints = &loader->hints;
 105   FT_GlyphSlot slot = face->glyph;
 106   FT_Slot_Internal internal = slot->internal;
 107
 108
 109   error = FT_Load_Glyph(face, glyph_index, load_flags);
 110   if (error)
 111     goto Exit;
 112
 113   loader->transformed = internal->glyph_transformed;
 114   if (loader->transformed)
 115   {
 116     FT_Matrix inverse;
 117
 118
 119     loader->trans_matrix = internal->glyph_matrix;
 120     loader->trans_delta = internal->glyph_delta;
 121
 122     inverse = loader->trans_matrix;
 123     FT_Matrix_Invert(&inverse);
 124     FT_Vector_Transform(&loader->trans_delta, &inverse);
 125   }
 126
 127   /* set linear metrics */
 128   slot->linearHoriAdvance = slot->metrics.horiAdvance;
 129   slot->linearVertAdvance = slot->metrics.vertAdvance;
 130
 131   switch (slot->format)
 132   {
 133   case FT_GLYPH_FORMAT_OUTLINE:
 134     /* translate the loaded glyph when an internal transform is needed */
 135     if (loader->transformed)
 136       FT_Outline_Translate(&slot->outline,
 137                            loader->trans_delta.x,
 138                            loader->trans_delta.y);
 139
 140     /* copy the outline points in the loader's current extra points */
 141     /* which are used to keep original glyph coordinates */
 142     error = TA_GLYPHLOADER_CHECK_POINTS(gloader,
 143                                         slot->outline.n_points + 4,
 144                                         slot->outline.n_contours);
 145     if (error)
 146       goto Exit;
 147
 148     memcpy(gloader->current.outline.points,
 149            slot->outline.points,
 150            slot->outline.n_points * sizeof (FT_Vector));
 151     memcpy(gloader->current.outline.contours,
 152            slot->outline.contours,
 153            slot->outline.n_contours * sizeof (short));
 154     memcpy(gloader->current.outline.tags,
 155            slot->outline.tags,
 156            slot->outline.n_points * sizeof (char));
 157
 158     gloader->current.outline.n_points = slot->outline.n_points;
 159     gloader->current.outline.n_contours = slot->outline.n_contours;
 160
 161     /* compute original horizontal phantom points */
 162     /* (and ignore vertical ones) */
 163     loader->pp1.x = hints->x_delta;
 164     loader->pp1.y = hints->y_delta;
 165     loader->pp2.x = FT_MulFix(slot->metrics.horiAdvance,
 166                               hints->x_scale) + hints->x_delta;
 167     loader->pp2.y = hints->y_delta;
 168
 169     /* be sure to check for spacing glyphs */
 170     if (slot->outline.n_points == 0)
 171       goto Hint_Metrics;
 172
 173     /* now load the slot image into the auto-outline */
 174     /* and run the automatic hinting process */
 175     if (metrics->clazz->script_hints_apply)
 176       metrics->clazz->script_hints_apply(hints,
 177                                          &gloader->current.outline,
 178                                          metrics);
 179
 180     /* we now need to adjust the metrics according to the change in */
 181     /* width/positioning that occurred during the hinting process */
 182     if (scaler->render_mode != FT_RENDER_MODE_LIGHT)
 183     {
 184       FT_Pos old_rsb, old_lsb, new_lsb;
 185       FT_Pos pp1x_uh, pp2x_uh;
 186       TA_AxisHints axis = &hints->axis[TA_DIMENSION_HORZ];
 187
 188       TA_Edge edge1 = axis->edges; /* leftmost edge */
 189       TA_Edge edge2 = edge1 + axis->num_edges - 1; /* rightmost edge */
 190
 191
 192       if (axis->num_edges > 1 && TA_HINTS_DO_ADVANCE(hints))
 193       {
 194         old_rsb = loader->pp2.x - edge2->opos;
 195         old_lsb = edge1->opos;
 196         new_lsb = edge1->pos;
 197
 198         /* remember unhinted values to later account */
 199         /* for rounding errors */
 200         pp1x_uh = new_lsb - old_lsb;
 201         pp2x_uh = edge2->pos + old_rsb;
 202
 203         /* prefer too much space over too little space */
 204         /* for very small sizes */
 205         if (old_lsb < 24)
 206           pp1x_uh -= 8;
 207         if (old_rsb < 24)
 208           pp2x_uh += 8;
 209
 210         loader->pp1.x = TA_PIX_ROUND(pp1x_uh);
 211         loader->pp2.x = TA_PIX_ROUND(pp2x_uh);
 212
 213         if (loader->pp1.x >= new_lsb
 214             && old_lsb > 0)
 215           loader->pp1.x -= 64;
 216         if (loader->pp2.x <= edge2->pos
 217             && old_rsb > 0)
 218           loader->pp2.x += 64;
 219
 220         slot->lsb_delta = loader->pp1.x - pp1x_uh;
 221         slot->rsb_delta = loader->pp2.x - pp2x_uh;
 222       }
 223       else
 224       {
 225         FT_Pos pp1x = loader->pp1.x;
 226         FT_Pos pp2x = loader->pp2.x;
 227
 228
 229         loader->pp1.x = TA_PIX_ROUND(pp1x);
 230         loader->pp2.x = TA_PIX_ROUND(pp2x);
 231
 232         slot->lsb_delta = loader->pp1.x - pp1x;
 233         slot->rsb_delta = loader->pp2.x - pp2x;
 234       }
 235     }
 236     else
 237     {
 238       FT_Pos pp1x = loader->pp1.x;
 239       FT_Pos pp2x = loader->pp2.x;
 240
 241
 242       loader->pp1.x = TA_PIX_ROUND(pp1x + hints->xmin_delta);
 243       loader->pp2.x = TA_PIX_ROUND(pp2x + hints->xmax_delta);
 244
 245       slot->lsb_delta = loader->pp1.x - pp1x;
 246       slot->rsb_delta = loader->pp2.x - pp2x;
 247     }
 248
 249     /* good, we simply add the glyph to our loader's base */
 250     TA_GlyphLoader_Add(gloader);
 251     break;
 252
 253   case FT_GLYPH_FORMAT_COMPOSITE:
 254     {
 255       FT_UInt nn, num_subglyphs = slot->num_subglyphs;
 256       FT_UInt num_base_subgs, start_point;
 257       TA_SubGlyph subglyph;
 258
 259
 260       start_point = gloader->base.outline.n_points;
 261
 262       /* first of all, copy the subglyph descriptors in the glyph loader */
 263       error = TA_GlyphLoader_CheckSubGlyphs(gloader, num_subglyphs);
 264       if (error)
 265         goto Exit;
 266
 267       memcpy(gloader->current.subglyphs,
 268              slot->subglyphs,
 269              num_subglyphs * sizeof (TA_SubGlyphRec));
 270
 271       gloader->current.num_subglyphs = num_subglyphs;
 272       num_base_subgs = gloader->base.num_subglyphs;
 273
 274       /* now read each subglyph independently */
 275       for (nn = 0; nn < num_subglyphs; nn++)
 276       {
 277         FT_Vector pp1, pp2;
 278         FT_Pos x, y;
 279         FT_UInt num_points, num_new_points, num_base_points;
 280
 281
 282         /* gloader.current.subglyphs can change during glyph loading due */
 283         /* to re-allocation -- we must recompute the current subglyph on */
 284         /* each iteration */
 285         subglyph = gloader->base.subglyphs + num_base_subgs + nn;
 286
 287         pp1 = loader->pp1;
 288         pp2 = loader->pp2;
 289
 290         num_base_points = gloader->base.outline.n_points;
 291
 292         error = ta_loader_load_g(loader, scaler, subglyph->index,
 293                                  load_flags, depth + 1);
 294         if (error)
 295           goto Exit;
 296
 297         /* recompute subglyph pointer */
 298         subglyph = gloader->base.subglyphs + num_base_subgs + nn;
 299
 300         if (subglyph->flags & FT_SUBGLYPH_FLAG_USE_MY_METRICS)
 301         {
 302           pp1 = loader->pp1;
 303           pp2 = loader->pp2;
 304         }
 305         else
 306         {
 307           loader->pp1 = pp1;
 308           loader->pp2 = pp2;
 309         }
 310
 311         num_points = gloader->base.outline.n_points;
 312         num_new_points = num_points - num_base_points;
 313
 314         /* now perform the transformation required for this subglyph */
 315         if (subglyph->flags & (FT_SUBGLYPH_FLAG_SCALE
 316                                | FT_SUBGLYPH_FLAG_XY_SCALE
 317                                | FT_SUBGLYPH_FLAG_2X2))
 318         {
 319           FT_Vector* cur = gloader->base.outline.points + num_base_points;
 320           FT_Vector* limit = cur + num_new_points;
 321
 322
 323           for (; cur < limit; cur++)
 324             FT_Vector_Transform(cur, &subglyph->transform);
 325         }
 326
 327         /* apply offset */
 328         if (!(subglyph->flags & FT_SUBGLYPH_FLAG_ARGS_ARE_XY_VALUES))
 329         {
 330           FT_Int k = subglyph->arg1;
 331           FT_UInt l = subglyph->arg2;
 332           FT_Vector* p1;
 333           FT_Vector* p2;
 334
 335
 336           if (start_point + k >= num_base_points
 337               || l >= (FT_UInt)num_new_points)
 338           {
 339             error = FT_Err_Invalid_Composite;
 340             goto Exit;
 341           }
 342
 343           l += num_base_points;
 344
 345           /* for now, only use the current point coordinates; */
 346           /* we eventually may consider another approach */
 347           p1 = gloader->base.outline.points + start_point + k;
 348           p2 = gloader->base.outline.points + start_point + l;
 349
 350           x = p1->x - p2->x;
 351           y = p1->y - p2->y;
 352         }
 353         else
 354         {
 355           x = FT_MulFix(subglyph->arg1, hints->x_scale) + hints->x_delta;
 356           y = FT_MulFix(subglyph->arg2, hints->y_scale) + hints->y_delta;
 357
 358           x = TA_PIX_ROUND(x);
 359           y = TA_PIX_ROUND(y);
 360         }
 361
 362         {
 363           FT_Outline dummy = gloader->base.outline;
 364
 365
 366           dummy.points += num_base_points;
 367           dummy.n_points = (short)num_new_points;
 368
 369           FT_Outline_Translate(&dummy, x, y);
 370         }
 371       }
 372     }
 373     break;
 374
 375   default:
 376     /* we don't support other formats (yet?) */
 377     error = FT_Err_Unimplemented_Feature;
 378   }
 379
 380 Hint_Metrics:
 381   if (depth == 0)
 382   {
 383     FT_BBox bbox;
 384     FT_Vector vvector;
 385
 386
 387     vvector.x = slot->metrics.vertBearingX - slot->metrics.horiBearingX;
 388     vvector.y = slot->metrics.vertBearingY - slot->metrics.horiBearingY;
 389     vvector.x = FT_MulFix(vvector.x, metrics->scaler.x_scale);
 390     vvector.y = FT_MulFix(vvector.y, metrics->scaler.y_scale);
 391
 392     /* transform the hinted outline if needed */
 393     if (loader->transformed)
 394     {
 395       FT_Outline_Transform(&gloader->base.outline, &loader->trans_matrix);
 396       FT_Vector_Transform(&vvector, &loader->trans_matrix);
 397     }
 398 #if 1
 399     /* we must translate our final outline by -pp1.x */
 400     /* and compute the new metrics */
 401     if (loader->pp1.x)
 402       FT_Outline_Translate(&gloader->base.outline, -loader->pp1.x, 0);
 403 #endif
 404     FT_Outline_Get_CBox(&gloader->base.outline, &bbox);
 405
 406     bbox.xMin = TA_PIX_FLOOR(bbox.xMin);
 407     bbox.yMin = TA_PIX_FLOOR(bbox.yMin);
 408     bbox.xMax = TA_PIX_CEIL(bbox.xMax);
 409     bbox.yMax = TA_PIX_CEIL(bbox.yMax);
 410
 411     slot->metrics.width = bbox.xMax - bbox.xMin;
 412     slot->metrics.height = bbox.yMax - bbox.yMin;
 413     slot->metrics.horiBearingX = bbox.xMin;
 414     slot->metrics.horiBearingY = bbox.yMax;
 415
 416     slot->metrics.vertBearingX = TA_PIX_FLOOR(bbox.xMin + vvector.x);
 417     slot->metrics.vertBearingY = TA_PIX_FLOOR(bbox.yMax + vvector.y);
 418
 419     /* for mono-width fonts (like Andale, Courier, etc.) we need */
 420     /* to keep the original rounded advance width; ditto for */
 421     /* digits if all have the same advance width */
 422     if (FT_IS_FIXED_WIDTH(slot->face)
 423         || (ta_face_globals_is_digit(loader->globals, glyph_index)
 424             && metrics->digits_have_same_width))
 425     {
 426       slot->metrics.horiAdvance = FT_MulFix(slot->metrics.horiAdvance,
 427                                             metrics->scaler.x_scale);
 428
 429       /* set delta values to 0, otherwise code that uses them */
 430       /* is going to ruin the fixed advance width */
 431       slot->lsb_delta = 0;
 432       slot->rsb_delta = 0;
 433     }
 434     else
 435     {
 436       /* non-spacing glyphs must stay as-is */
 437       if (slot->metrics.horiAdvance)
 438         slot->metrics.horiAdvance = loader->pp2.x - loader->pp1.x;
 439     }
 440
 441     slot->metrics.vertAdvance = FT_MulFix(slot->metrics.vertAdvance,
 442                                           metrics->scaler.y_scale);
 443
 444     slot->metrics.horiAdvance = TA_PIX_ROUND(slot->metrics.horiAdvance);
 445     slot->metrics.vertAdvance = TA_PIX_ROUND(slot->metrics.vertAdvance);
 446
 447     /* now copy outline into glyph slot */
 448     TA_GlyphLoader_Rewind(internal->loader);
 449     error = TA_GlyphLoader_CopyPoints(internal->loader, gloader);
 450     if (error)
 451       goto Exit;
 452
 453     slot->outline = internal->loader->base.outline;
 454     slot->format = FT_GLYPH_FORMAT_OUTLINE;
 455   }
 456
 457 #ifdef DEBUG_HINTER
 458   ta_debug_hinter = hinter;
 459 #endif
 460
 461 Exit:
 462   return error;
 463 }
 464
 465
 466 /* load a glyph */
 467
 468 FT_Error
 469 ta_loader_load_glyph(TA_Loader loader,
 470                      FT_Face face,
 471                      FT_UInt gindex,
 472                      FT_UInt32 load_flags)
 473 {
 474   FT_Error error;
 475   FT_Size size = face->size;
 476   TA_ScalerRec scaler;
 477
 478
 479   if (!size)
 480     return FT_Err_Invalid_Argument;
 481
 482   memset(&scaler, 0, sizeof (TA_ScalerRec));
 483
 484   scaler.face = face;
 485   scaler.x_scale = size->metrics.x_scale;
 486   scaler.x_delta = 0; /* XXX: TODO: add support for sub-pixel hinting */
 487   scaler.y_scale = size->metrics.y_scale;
 488   scaler.y_delta = 0; /* XXX: TODO: add support for sub-pixel hinting */
 489
 490   scaler.render_mode = FT_LOAD_TARGET_MODE(load_flags);
 491   scaler.flags = 0; /* XXX: fix this */
 492
 493   error = ta_loader_reset(loader, face);
 494   if (!error)
 495   {
 496     TA_ScriptMetrics metrics;
 497     FT_UInt options = 0;
 498
 499
 500 #ifdef FT_OPTION_AUTOFIT2
 501     /* XXX: undocumented hook to activate the latin2 hinter */
 502     if (load_flags & (1UL << 20))
 503       options = 2;
 504 #endif
 505
 506     error = ta_face_globals_get_metrics(loader->globals, gindex,
 507                                         options, &metrics);
 508     if (!error)
 509     {
 510       loader->metrics = metrics;
 511
 512       if (metrics->clazz->script_metrics_scale)
 513         metrics->clazz->script_metrics_scale(metrics, &scaler);
 514       else
 515         metrics->scaler = scaler;
 516
 517       load_flags |= FT_LOAD_NO_SCALE
 518                     | FT_LOAD_IGNORE_TRANSFORM;
 519       load_flags &= ~FT_LOAD_RENDER;
 520
 521       if (metrics->clazz->script_hints_init)
 522       {
 523         error = metrics->clazz->script_hints_init(&loader->hints,
 524                                                   metrics);
 525         if (error)
 526           goto Exit;
 527       }
 528
 529       error = ta_loader_load_g(loader, &scaler, gindex, load_flags, 0);
 530     }
 531   }
 532 Exit:
 533   return error;
 534 }
 535
 536 /* end of taloader.c */