lib/taloader.c

   1 /* taloader.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 `afloader.c' (2011-Mar-28) from FreeType */
  17
  18 /* heavily modified 2011 by Werner Lemberg <wl@gnu.org> */
  19
  20 #include <string.h>
  21
  22 #include <ft2build.h>
  23 #include FT_GLYPH_H
  24
  25 #include "ta.h"
  26 #include "tahints.h"
  27 #include "taglobal.h"
  28
  29
  30 /* from file `ftobjs.h' (2011-Mar-28) from FreeType */
  31 typedef struct FT_Slot_InternalRec_
  32 {
  33   TA_GlyphLoader loader;
  34   FT_UInt flags;
  35   FT_Bool glyph_transformed;
  36   FT_Matrix glyph_matrix;
  37   FT_Vector glyph_delta;
  38   void* glyph_hints;
  39 } FT_GlyphSlot_InternalRec;
  40
  41
  42 /* initialize glyph loader */
  43
  44 FT_Error
  45 ta_loader_init(FONT* font)
  46 {
  47   TA_Loader loader = font->loader;
  48
  49
  50   memset(loader, 0, sizeof (TA_LoaderRec));
  51
  52   ta_glyph_hints_init(&loader->hints);
  53 #ifdef TA_DEBUG
  54   _ta_debug_hints = &loader->hints;
  55 #endif
  56   return TA_GlyphLoader_New(&loader->gloader);
  57 }
  58
  59
  60 /* reset glyph loader and compute globals if necessary */
  61
  62 FT_Error
  63 ta_loader_reset(FONT* font,
  64                 FT_Face face)
  65 {
  66   FT_Error error = FT_Err_Ok;
  67   TA_Loader loader = font->loader;
  68
  69
  70   loader->face = face;
  71   loader->globals = (TA_FaceGlobals)face->autohint.data;
  72
  73   TA_GlyphLoader_Rewind(loader->gloader);
  74
  75   if (loader->globals == NULL)
  76   {
  77     error = ta_face_globals_new(face, &loader->globals, font);
  78     if (!error)
  79     {
  80       face->autohint.data = (FT_Pointer)loader->globals;
  81       face->autohint.finalizer = (FT_Generic_Finalizer)ta_face_globals_free;
  82     }
  83   }
  84
  85   return error;
  86 }
  87
  88
  89 /* finalize glyph loader */
  90
  91 void
  92 ta_loader_done(FONT* font)
  93 {
  94   TA_Loader loader = font->loader;
  95
  96
  97   ta_glyph_hints_done(&loader->hints);
  98
  99   loader->face = NULL;
 100   loader->globals = NULL;
 101
 102 #ifdef TA_DEBUG
 103   _ta_debug_hints = NULL;
 104 #endif
 105   TA_GlyphLoader_Done(loader->gloader);
 106   loader->gloader = NULL;
 107 }
 108
 109
 110 /* load a single glyph component; this routine calls itself recursively, */
 111 /* if necessary, and does the main work of `ta_loader_load_glyph' */
 112
 113 static FT_Error
 114 ta_loader_load_g(TA_Loader loader,
 115                  TA_Scaler scaler,
 116                  FT_UInt glyph_index,
 117                  FT_Int32 load_flags,
 118                  FT_UInt depth)
 119 {
 120   FT_Error error;
 121   FT_Face face = loader->face;
 122   TA_GlyphLoader gloader = loader->gloader;
 123   TA_StyleMetrics metrics = loader->metrics;
 124   TA_GlyphHints hints = &loader->hints;
 125   FT_GlyphSlot slot = face->glyph;
 126 #if 0
 127   FT_Slot_Internal internal = slot->internal;
 128 #endif
 129   FT_Int32 flags;
 130
 131
 132   flags = load_flags | FT_LOAD_LINEAR_DESIGN;
 133   error = FT_Load_Glyph(face, glyph_index, flags);
 134   if (error)
 135     goto Exit;
 136
 137 #if 0
 138   loader->transformed = internal->glyph_transformed;
 139   if (loader->transformed)
 140   {
 141     FT_Matrix inverse;
 142
 143
 144     loader->trans_matrix = internal->glyph_matrix;
 145     loader->trans_delta = internal->glyph_delta;
 146
 147     inverse = loader->trans_matrix;
 148     FT_Matrix_Invert(&inverse);
 149     FT_Vector_Transform(&loader->trans_delta, &inverse);
 150   }
 151 #endif
 152
 153   switch (slot->format)
 154   {
 155   case FT_GLYPH_FORMAT_OUTLINE:
 156     /* translate the loaded glyph when an internal transform is needed */
 157     if (loader->transformed)
 158       FT_Outline_Translate(&slot->outline,
 159                            loader->trans_delta.x,
 160                            loader->trans_delta.y);
 161
 162     /* copy the outline points in the loader's current extra points */
 163     /* which are used to keep original glyph coordinates */
 164     error = TA_GLYPHLOADER_CHECK_POINTS(gloader,
 165                                         slot->outline.n_points + 4,
 166                                         slot->outline.n_contours);
 167     if (error)
 168       goto Exit;
 169
 170     memcpy(gloader->current.outline.points,
 171            slot->outline.points,
 172            slot->outline.n_points * sizeof (FT_Vector));
 173     memcpy(gloader->current.outline.contours,
 174            slot->outline.contours,
 175            slot->outline.n_contours * sizeof (short));
 176     memcpy(gloader->current.outline.tags,
 177            slot->outline.tags,
 178            slot->outline.n_points * sizeof (char));
 179
 180     gloader->current.outline.n_points = slot->outline.n_points;
 181     gloader->current.outline.n_contours = slot->outline.n_contours;
 182
 183     /* compute original horizontal phantom points */
 184     /* (and ignore vertical ones) */
 185     loader->pp1.x = hints->x_delta;
 186     loader->pp1.y = hints->y_delta;
 187     loader->pp2.x = FT_MulFix(slot->metrics.horiAdvance,
 188                               hints->x_scale) + hints->x_delta;
 189     loader->pp2.y = hints->y_delta;
 190
 191     /* be sure to check for spacing glyphs */
 192     if (slot->outline.n_points == 0)
 193       goto Hint_Metrics;
 194
 195     /* now load the slot image into the auto-outline */
 196     /* and run the automatic hinting process */
 197     {
 198       TA_StyleClass style_class = metrics->style_class;
 199       TA_WritingSystemClass writing_system_class =
 200         ta_writing_system_classes[style_class->writing_system];
 201
 202
 203       if (writing_system_class->style_hints_apply)
 204         writing_system_class->style_hints_apply(hints,
 205                                                 &gloader->current.outline,
 206                                                 metrics);
 207     }
 208
 209     /* we now need to adjust the metrics according to the change in */
 210     /* width/positioning that occurred during the hinting process */
 211     if (scaler->render_mode != FT_RENDER_MODE_LIGHT)
 212     {
 213       FT_Pos old_rsb, old_lsb, new_lsb;
 214       FT_Pos pp1x_uh, pp2x_uh;
 215       TA_AxisHints axis = &hints->axis[TA_DIMENSION_HORZ];
 216
 217       TA_Edge edge1 = axis->edges; /* leftmost edge */
 218       TA_Edge edge2 = edge1 + axis->num_edges - 1; /* rightmost edge */
 219
 220
 221       if (axis->num_edges > 1 && TA_HINTS_DO_ADVANCE(hints))
 222       {
 223         old_rsb = loader->pp2.x - edge2->opos;
 224         old_lsb = edge1->opos;
 225         new_lsb = edge1->pos;
 226
 227         /* remember unhinted values to later account */
 228         /* for rounding errors */
 229         pp1x_uh = new_lsb - old_lsb;
 230         pp2x_uh = edge2->pos + old_rsb;
 231
 232         /* prefer too much space over too little space */
 233         /* for very small sizes */
 234         if (old_lsb < 24)
 235           pp1x_uh -= 8;
 236         if (old_rsb < 24)
 237           pp2x_uh += 8;
 238
 239         loader->pp1.x = TA_PIX_ROUND(pp1x_uh);
 240         loader->pp2.x = TA_PIX_ROUND(pp2x_uh);
 241
 242         if (loader->pp1.x >= new_lsb
 243             && old_lsb > 0)
 244           loader->pp1.x -= 64;
 245         if (loader->pp2.x <= edge2->pos
 246             && old_rsb > 0)
 247           loader->pp2.x += 64;
 248
 249         slot->lsb_delta = loader->pp1.x - pp1x_uh;
 250         slot->rsb_delta = loader->pp2.x - pp2x_uh;
 251       }
 252       else
 253       {
 254         FT_Pos pp1x = loader->pp1.x;
 255         FT_Pos pp2x = loader->pp2.x;
 256
 257
 258         loader->pp1.x = TA_PIX_ROUND(pp1x);
 259         loader->pp2.x = TA_PIX_ROUND(pp2x);
 260
 261         slot->lsb_delta = loader->pp1.x - pp1x;
 262         slot->rsb_delta = loader->pp2.x - pp2x;
 263       }
 264     }
 265     else
 266     {
 267       FT_Pos pp1x = loader->pp1.x;
 268       FT_Pos pp2x = loader->pp2.x;
 269
 270
 271       loader->pp1.x = TA_PIX_ROUND(pp1x + hints->xmin_delta);
 272       loader->pp2.x = TA_PIX_ROUND(pp2x + hints->xmax_delta);
 273
 274       slot->lsb_delta = loader->pp1.x - pp1x;
 275       slot->rsb_delta = loader->pp2.x - pp2x;
 276     }
 277
 278     /* good, we simply add the glyph to our loader's base */
 279     TA_GlyphLoader_Add(gloader);
 280     break;
 281
 282   case FT_GLYPH_FORMAT_COMPOSITE:
 283     {
 284       FT_UInt nn, num_subglyphs = slot->num_subglyphs;
 285       FT_UInt num_base_subgs, start_point;
 286       TA_SubGlyph subglyph;
 287
 288
 289       start_point = gloader->base.outline.n_points;
 290
 291       /* first of all, copy the subglyph descriptors in the glyph loader */
 292       error = TA_GlyphLoader_CheckSubGlyphs(gloader, num_subglyphs);
 293       if (error)
 294         goto Exit;
 295
 296       memcpy(gloader->current.subglyphs,
 297              slot->subglyphs,
 298              num_subglyphs * sizeof (TA_SubGlyphRec));
 299
 300       gloader->current.num_subglyphs = num_subglyphs;
 301       num_base_subgs = gloader->base.num_subglyphs;
 302
 303       /* now read each subglyph independently */
 304       for (nn = 0; nn < num_subglyphs; nn++)
 305       {
 306         FT_Vector pp1, pp2;
 307         FT_Pos x, y;
 308         FT_UInt num_points, num_new_points, num_base_points;
 309
 310
 311         /* gloader.current.subglyphs can change during glyph loading due */
 312         /* to re-allocation -- we must recompute the current subglyph on */
 313         /* each iteration */
 314         subglyph = gloader->base.subglyphs + num_base_subgs + nn;
 315
 316         pp1 = loader->pp1;
 317         pp2 = loader->pp2;
 318
 319         num_base_points = gloader->base.outline.n_points;
 320
 321         error = ta_loader_load_g(loader, scaler, subglyph->index,
 322                                  load_flags, depth + 1);
 323         if (error)
 324           goto Exit;
 325
 326         /* recompute subglyph pointer */
 327         subglyph = gloader->base.subglyphs + num_base_subgs + nn;
 328
 329         if (!(subglyph->flags & FT_SUBGLYPH_FLAG_USE_MY_METRICS))
 330         {
 331           loader->pp1 = pp1;
 332           loader->pp2 = pp2;
 333         }
 334
 335         num_points = gloader->base.outline.n_points;
 336         num_new_points = num_points - num_base_points;
 337
 338         /* now perform the transformation required for this subglyph */
 339         if (subglyph->flags & (FT_SUBGLYPH_FLAG_SCALE
 340                                | FT_SUBGLYPH_FLAG_XY_SCALE
 341                                | FT_SUBGLYPH_FLAG_2X2))
 342         {
 343           FT_Vector* cur = gloader->base.outline.points + num_base_points;
 344           FT_Vector* limit = cur + num_new_points;
 345
 346
 347           for (; cur < limit; cur++)
 348             FT_Vector_Transform(cur, &subglyph->transform);
 349         }
 350
 351         /* apply offset */
 352         if (!(subglyph->flags & FT_SUBGLYPH_FLAG_ARGS_ARE_XY_VALUES))
 353         {
 354           FT_Int k = subglyph->arg1;
 355           FT_UInt l = subglyph->arg2;
 356           FT_Vector* p1;
 357           FT_Vector* p2;
 358
 359
 360           if (start_point + k >= num_base_points
 361               || l >= (FT_UInt)num_new_points)
 362           {
 363             error = FT_Err_Invalid_Composite;
 364             goto Exit;
 365           }
 366
 367           l += num_base_points;
 368
 369           /* for now, only use the current point coordinates; */
 370           /* we eventually may consider another approach */
 371           p1 = gloader->base.outline.points + start_point + k;
 372           p2 = gloader->base.outline.points + start_point + l;
 373
 374           x = p1->x - p2->x;
 375           y = p1->y - p2->y;
 376         }
 377         else
 378         {
 379           x = FT_MulFix(subglyph->arg1, hints->x_scale) + hints->x_delta;
 380           y = FT_MulFix(subglyph->arg2, hints->y_scale) + hints->y_delta;
 381
 382           x = TA_PIX_ROUND(x);
 383           y = TA_PIX_ROUND(y);
 384         }
 385
 386         {
 387           FT_Outline dummy = gloader->base.outline;
 388
 389
 390           dummy.points += num_base_points;
 391           dummy.n_points = (short)num_new_points;
 392
 393           FT_Outline_Translate(&dummy, x, y);
 394         }
 395       }
 396     }
 397     break;
 398
 399   default:
 400     /* we don't support other formats (yet?) */
 401     error = FT_Err_Unimplemented_Feature;
 402   }
 403
 404 Hint_Metrics:
 405   if (depth == 0)
 406   {
 407     FT_BBox bbox;
 408     FT_Vector vvector;
 409
 410
 411     vvector.x = slot->metrics.vertBearingX - slot->metrics.horiBearingX;
 412     vvector.y = slot->metrics.vertBearingY - slot->metrics.horiBearingY;
 413     vvector.x = FT_MulFix(vvector.x, metrics->scaler.x_scale);
 414     vvector.y = FT_MulFix(vvector.y, metrics->scaler.y_scale);
 415
 416     /* transform the hinted outline if needed */
 417     if (loader->transformed)
 418     {
 419       FT_Outline_Transform(&gloader->base.outline, &loader->trans_matrix);
 420       FT_Vector_Transform(&vvector, &loader->trans_matrix);
 421     }
 422 #if 1
 423     /* we must translate our final outline by -pp1.x */
 424     /* and compute the new metrics */
 425     if (loader->pp1.x)
 426       FT_Outline_Translate(&gloader->base.outline, -loader->pp1.x, 0);
 427 #endif
 428     FT_Outline_Get_CBox(&gloader->base.outline, &bbox);
 429
 430     bbox.xMin = TA_PIX_FLOOR(bbox.xMin);
 431     bbox.yMin = TA_PIX_FLOOR(bbox.yMin);
 432     bbox.xMax = TA_PIX_CEIL(bbox.xMax);
 433     bbox.yMax = TA_PIX_CEIL(bbox.yMax);
 434
 435     slot->metrics.width = bbox.xMax - bbox.xMin;
 436     slot->metrics.height = bbox.yMax - bbox.yMin;
 437     slot->metrics.horiBearingX = bbox.xMin;
 438     slot->metrics.horiBearingY = bbox.yMax;
 439
 440     slot->metrics.vertBearingX = TA_PIX_FLOOR(bbox.xMin + vvector.x);
 441     slot->metrics.vertBearingY = TA_PIX_FLOOR(bbox.yMax + vvector.y);
 442
 443     /* for mono-width fonts (like Andale, Courier, etc.) we need */
 444     /* to keep the original rounded advance width; ditto for */
 445     /* digits if all have the same advance width */
 446     if (scaler->render_mode != FT_RENDER_MODE_LIGHT
 447         && (FT_IS_FIXED_WIDTH(slot->face)
 448             || (ta_face_globals_is_digit(loader->globals, glyph_index)
 449                 && metrics->digits_have_same_width)))
 450     {
 451       slot->metrics.horiAdvance = FT_MulFix(slot->metrics.horiAdvance,
 452                                             metrics->scaler.x_scale);
 453
 454       /* set delta values to 0, otherwise code that uses them */
 455       /* is going to ruin the fixed advance width */
 456       slot->lsb_delta = 0;
 457       slot->rsb_delta = 0;
 458     }
 459     else
 460     {
 461       /* non-spacing glyphs must stay as-is */
 462       if (slot->metrics.horiAdvance)
 463         slot->metrics.horiAdvance = loader->pp2.x - loader->pp1.x;
 464     }
 465
 466     slot->metrics.vertAdvance = FT_MulFix(slot->metrics.vertAdvance,
 467                                           metrics->scaler.y_scale);
 468
 469     slot->metrics.horiAdvance = TA_PIX_ROUND(slot->metrics.horiAdvance);
 470     slot->metrics.vertAdvance = TA_PIX_ROUND(slot->metrics.vertAdvance);
 471
 472 #if 0
 473     /* now copy outline into glyph slot */
 474     TA_GlyphLoader_Rewind(internal->loader);
 475     error = TA_GlyphLoader_CopyPoints(internal->loader, gloader);
 476     if (error)
 477       goto Exit;
 478
 479     /* reassign all outline fields except flags to protect them */
 480     slot->outline.n_contours = internal->loader->base.outline.n_contours;
 481     slot->outline.n_points = internal->loader->base.outline.n_points;
 482     slot->outline.points = internal->loader->base.outline.points;
 483     slot->outline.tags = internal->loader->base.outline.tags;
 484     slot->outline.contours = internal->loader->base.outline.contours;
 485
 486     slot->format = FT_GLYPH_FORMAT_OUTLINE;
 487 #endif
 488   }
 489
 490 Exit:
 491   return error;
 492 }
 493
 494
 495 /* load a glyph */
 496
 497 FT_Error
 498 ta_loader_load_glyph(FONT* font,
 499                      FT_Face face,
 500                      FT_UInt gindex,
 501                      FT_Int32 load_flags)
 502 {
 503   FT_Error error;
 504   FT_Size size = face->size;
 505   TA_Loader loader = font->loader;
 506   TA_ScalerRec scaler;
 507
 508
 509   if (!size)
 510     return FT_Err_Invalid_Argument;
 511
 512   memset(&scaler, 0, sizeof (TA_ScalerRec));
 513
 514   scaler.face = face;
 515   scaler.x_scale = size->metrics.x_scale;
 516   scaler.x_delta = 0; /* XXX: TODO: add support for sub-pixel hinting */
 517   scaler.y_scale = size->metrics.y_scale;
 518   scaler.y_delta = 0; /* XXX: TODO: add support for sub-pixel hinting */
 519
 520   scaler.render_mode = FT_LOAD_TARGET_MODE(load_flags);
 521   scaler.flags = 0; /* XXX: fix this */
 522
 523   /* XXX this is an ugly hack of ttfautohint: */
 524   /* bit 29 triggers vertical hinting only */
 525   if (load_flags & (1 << 29))
 526     scaler.flags |= TA_SCALER_FLAG_NO_HORIZONTAL;
 527
 528   /* note that the fallback style can't be changed anymore */
 529   /* after the first call of `ta_loader_load_glyph' */
 530   error = ta_loader_reset(font, face);
 531   if (!error)
 532   {
 533     TA_StyleMetrics metrics;
 534     FT_UInt options = TA_STYLE_NONE_DFLT;
 535
 536
 537 #ifdef FT_OPTION_AUTOFIT2
 538     /* XXX: undocumented hook to activate the latin2 hinter */
 539     if (load_flags & (1UL << 20))
 540       options = TA_STYLE_LTN2_DFLT;
 541 #endif
 542
 543     error = ta_face_globals_get_metrics(loader->globals, gindex,
 544                                         options, &metrics);
 545     if (!error)
 546     {
 547       TA_StyleClass style_class = metrics->style_class;
 548       TA_WritingSystemClass writing_system_class =
 549         ta_writing_system_classes[style_class->writing_system];
 550
 551
 552       loader->metrics = metrics;
 553
 554       if (writing_system_class->style_metrics_scale)
 555         writing_system_class->style_metrics_scale(metrics, &scaler);
 556       else
 557         metrics->scaler = scaler;
 558
 559       load_flags |= FT_LOAD_NO_SCALE
 560                     | FT_LOAD_IGNORE_TRANSFORM;
 561       load_flags &= ~FT_LOAD_RENDER;
 562
 563       if (writing_system_class->style_hints_init)
 564       {
 565         error = writing_system_class->style_hints_init(&loader->hints,
 566                                                        metrics);
 567         if (error)
 568           goto Exit;
 569       }
 570
 571       error = ta_loader_load_g(loader, &scaler, gindex, load_flags, 0);
 572     }
 573   }
 574 Exit:
 575   return error;
 576 }
 577
 578
 579 void
 580 ta_loader_register_hints_recorder(TA_Loader loader,
 581                                   TA_Hints_Recorder hints_recorder,
 582                                   void* user)
 583 {
 584   loader->hints.recorder = hints_recorder;
 585   loader->hints.user = user;
 586 }
 587
 588 /* end of taloader.c */