libass/ass_font.c

   1 /*
   2  * Copyright (C) 2006 Evgeniy Stepanov <eugeni.stepanov@gmail.com>
   3  *
   4  * This file is part of libass.
   5  *
   6  * Permission to use, copy, modify, and distribute this software for any
   7  * purpose with or without fee is hereby granted, provided that the above
   8  * copyright notice and this permission notice appear in all copies.
   9  *
  10  * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
  11  * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
  12  * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
  13  * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
  14  * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
  15  * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
  16  * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
  17  */
  18
  19 #include "config.h"
  20
  21 #include <inttypes.h>
  22 #include <ft2build.h>
  23 #include FT_FREETYPE_H
  24 #include FT_SYNTHESIS_H
  25 #include FT_GLYPH_H
  26 #include FT_TRUETYPE_TABLES_H
  27 #include FT_OUTLINE_H
  28 #include <strings.h>
  29
  30 #include "ass.h"
  31 #include "ass_library.h"
  32 #include "ass_font.h"
  33 #include "ass_bitmap.h"
  34 #include "ass_cache.h"
  35 #include "ass_fontconfig.h"
  36 #include "ass_utils.h"
  37
  38 #define VERTICAL_LOWER_BOUND 0x02f1
  39
  40 /**
  41  * Select a good charmap, prefer Microsoft Unicode charmaps.
  42  * Otherwise, let FreeType decide.
  43  */
  44 static void charmap_magic(ASS_Library *library, FT_Face face)
  45 {
  46     int i;
  47     int ms_cmap = -1;
  48
  49     // Search for a Microsoft Unicode cmap
  50     for (i = 0; i < face->num_charmaps; ++i) {
  51         FT_CharMap cmap = face->charmaps[i];
  52         unsigned pid = cmap->platform_id;
  53         unsigned eid = cmap->encoding_id;
  54         if (pid == 3 /*microsoft */
  55             && (eid == 1 /*unicode bmp */
  56                 || eid == 10 /*full unicode */ )) {
  57             FT_Set_Charmap(face, cmap);
  58             return;
  59         } else if (pid == 3 && ms_cmap < 0)
  60             ms_cmap = i;
  61     }
  62
  63     // Try the first Microsoft cmap if no Microsoft Unicode cmap was found
  64     if (ms_cmap >= 0) {
  65         FT_CharMap cmap = face->charmaps[ms_cmap];
  66         FT_Set_Charmap(face, cmap);
  67         return;
  68     }
  69
  70     if (!face->charmap) {
  71         if (face->num_charmaps == 0) {
  72             ass_msg(library, MSGL_WARN, "Font face with no charmaps");
  73             return;
  74         }
  75         ass_msg(library, MSGL_WARN,
  76                 "No charmap autodetected, trying the first one");
  77         FT_Set_Charmap(face, face->charmaps[0]);
  78         return;
  79     }
  80 }
  81
  82 /**
  83  * \brief find a memory font by name
  84  */
  85 static int find_font(ASS_Library *library, char *name)
  86 {
  87     int i;
  88     for (i = 0; i < library->num_fontdata; ++i)
  89         if (strcasecmp(name, library->fontdata[i].name) == 0)
  90             return i;
  91     return -1;
  92 }
  93
  94 static void face_set_size(FT_Face face, double size);
  95
  96 static void buggy_font_workaround(FT_Face face)
  97 {
  98     // Some fonts have zero Ascender/Descender fields in 'hhea' table.
  99     // In this case, get the information from 'os2' table or, as
 100     // a last resort, from face.bbox.
 101     if (face->ascender + face->descender == 0 || face->height == 0) {
 102         TT_OS2 *os2 = FT_Get_Sfnt_Table(face, ft_sfnt_os2);
 103         if (os2) {
 104             face->ascender = os2->sTypoAscender;
 105             face->descender = os2->sTypoDescender;
 106             face->height = face->ascender - face->descender;
 107         } else {
 108             face->ascender = face->bbox.yMax;
 109             face->descender = face->bbox.yMin;
 110             face->height = face->ascender - face->descender;
 111         }
 112     }
 113 }
 114
 115 /**
 116  * \brief Select a face with the given charcode and add it to ASS_Font
 117  * \return index of the new face in font->faces, -1 if failed
 118  */
 119 static int add_face(void *fc_priv, ASS_Font *font, uint32_t ch)
 120 {
 121     char *path;
 122     int index;
 123     FT_Face face;
 124     int error;
 125     int mem_idx;
 126
 127     if (font->n_faces == ASS_FONT_MAX_FACES)
 128         return -1;
 129
 130     path =
 131         fontconfig_select(font->library, fc_priv, font->desc.family,
 132                           font->desc.treat_family_as_pattern,
 133                           font->desc.bold, font->desc.italic, &index, ch);
 134     if (!path)
 135         return -1;
 136
 137     mem_idx = find_font(font->library, path);
 138     if (mem_idx >= 0) {
 139         error =
 140             FT_New_Memory_Face(font->ftlibrary,
 141                                (unsigned char *) font->library->
 142                                fontdata[mem_idx].data,
 143                                font->library->fontdata[mem_idx].size, index,
 144                                &face);
 145         if (error) {
 146             ass_msg(font->library, MSGL_WARN,
 147                     "Error opening memory font: '%s'", path);
 148             free(path);
 149             return -1;
 150         }
 151     } else {
 152         error = FT_New_Face(font->ftlibrary, path, index, &face);
 153         if (error) {
 154             ass_msg(font->library, MSGL_WARN,
 155                     "Error opening font: '%s', %d", path, index);
 156             free(path);
 157             return -1;
 158         }
 159     }
 160     charmap_magic(font->library, face);
 161     buggy_font_workaround(face);
 162
 163     font->faces[font->n_faces++] = face;
 164     face_set_size(face, font->size);
 165     free(path);
 166     return font->n_faces - 1;
 167 }
 168
 169 /**
 170  * \brief Create a new ASS_Font according to "desc" argument
 171  */
 172 ASS_Font *ass_font_new(void *font_cache, ASS_Library *library,
 173                        FT_Library ftlibrary, void *fc_priv,
 174                        ASS_FontDesc *desc)
 175 {
 176     int error;
 177     ASS_Font *fontp;
 178     ASS_Font font;
 179
 180     fontp = ass_font_cache_find((Hashmap *) font_cache, desc);
 181     if (fontp)
 182         return fontp;
 183
 184     font.library = library;
 185     font.ftlibrary = ftlibrary;
 186     font.n_faces = 0;
 187     font.desc.family = strdup(desc->family);
 188     font.desc.treat_family_as_pattern = desc->treat_family_as_pattern;
 189     font.desc.bold = desc->bold;
 190     font.desc.italic = desc->italic;
 191     font.desc.vertical = desc->vertical;
 192
 193     font.scale_x = font.scale_y = 1.;
 194     font.v.x = font.v.y = 0;
 195     font.size = 0.;
 196
 197     error = add_face(fc_priv, &font, 0);
 198     if (error == -1) {
 199         free(font.desc.family);
 200         return 0;
 201     } else
 202         return ass_font_cache_add((Hashmap *) font_cache, &font);
 203 }
 204
 205 /**
 206  * \brief Set font transformation matrix and shift vector
 207  **/
 208 void ass_font_set_transform(ASS_Font *font, double scale_x,
 209                             double scale_y, FT_Vector *v)
 210 {
 211     font->scale_x = scale_x;
 212     font->scale_y = scale_y;
 213     if (v) {
 214         font->v.x = v->x;
 215         font->v.y = v->y;
 216     }
 217 }
 218
 219 static void face_set_size(FT_Face face, double size)
 220 {
 221     TT_HoriHeader *hori = FT_Get_Sfnt_Table(face, ft_sfnt_hhea);
 222     TT_OS2 *os2 = FT_Get_Sfnt_Table(face, ft_sfnt_os2);
 223     double mscale = 1.;
 224     FT_Size_RequestRec rq;
 225     FT_Size_Metrics *m = &face->size->metrics;
 226     // VSFilter uses metrics from TrueType OS/2 table
 227     // The idea was borrowed from asa (http://asa.diac24.net)
 228     if (hori && os2) {
 229         int hori_height = hori->Ascender - hori->Descender;
 230         int os2_height = os2->usWinAscent + os2->usWinDescent;
 231         if (hori_height && os2_height)
 232             mscale = (double) hori_height / os2_height;
 233     }
 234     memset(&rq, 0, sizeof(rq));
 235     rq.type = FT_SIZE_REQUEST_TYPE_REAL_DIM;
 236     rq.width = 0;
 237     rq.height = double_to_d6(size * mscale);
 238     rq.horiResolution = rq.vertResolution = 0;
 239     FT_Request_Size(face, &rq);
 240     m->ascender /= mscale;
 241     m->descender /= mscale;
 242     m->height /= mscale;
 243 }
 244
 245 /**
 246  * \brief Set font size
 247  **/
 248 void ass_font_set_size(ASS_Font *font, double size)
 249 {
 250     int i;
 251     if (font->size != size) {
 252         font->size = size;
 253         for (i = 0; i < font->n_faces; ++i)
 254             face_set_size(font->faces[i], size);
 255     }
 256 }
 257
 258 /**
 259  * \brief Get maximal font ascender and descender.
 260  * \param ch character code
 261  * The values are extracted from the font face that provides glyphs for the given character
 262  **/
 263 void ass_font_get_asc_desc(ASS_Font *font, uint32_t ch, int *asc,
 264                            int *desc)
 265 {
 266     int i;
 267     for (i = 0; i < font->n_faces; ++i) {
 268         FT_Face face = font->faces[i];
 269         TT_OS2 *os2 = FT_Get_Sfnt_Table(face, ft_sfnt_os2);
 270         if (FT_Get_Char_Index(face, ch)) {
 271             int y_scale = face->size->metrics.y_scale;
 272             if (os2) {
 273                 *asc = FT_MulFix(os2->usWinAscent, y_scale);
 274                 *desc = FT_MulFix(os2->usWinDescent, y_scale);
 275             } else {
 276                 *asc = FT_MulFix(face->ascender, y_scale);
 277                 *desc = FT_MulFix(-face->descender, y_scale);
 278             }
 279             if (font->desc.vertical && ch >= VERTICAL_LOWER_BOUND) {
 280                 *asc = FT_MulFix(face->max_advance_width, y_scale);
 281             }
 282             return;
 283         }
 284     }
 285
 286     *asc = *desc = 0;
 287 }
 288
 289 /*
 290  * Strike a glyph with a horizontal line; it's possible to underline it
 291  * and/or strike through it.  For the line's position and size, truetype
 292  * tables are consulted.  Obviously this relies on the data in the tables
 293  * being accurate.
 294  *
 295  */
 296 static int ass_strike_outline_glyph(FT_Face face, ASS_Font *font,
 297                                     FT_Glyph glyph, int under, int through)
 298 {
 299     TT_OS2 *os2 = FT_Get_Sfnt_Table(face, ft_sfnt_os2);
 300     TT_Postscript *ps = FT_Get_Sfnt_Table(face, ft_sfnt_post);
 301     FT_Outline *ol = &((FT_OutlineGlyph) glyph)->outline;
 302     int bear, advance, y_scale, i, dir;
 303
 304     if (!under && !through)
 305         return 0;
 306
 307     // Grow outline
 308     i = (under ? 4 : 0) + (through ? 4 : 0);
 309     ol->points = realloc(ol->points, sizeof(FT_Vector) *
 310                          (ol->n_points + i));
 311     ol->tags = realloc(ol->tags, ol->n_points + i);
 312     i = !!under + !!through;
 313     ol->contours = realloc(ol->contours, sizeof(short) *
 314                            (ol->n_contours + i));
 315
 316     // If the bearing is negative, the glyph starts left of the current
 317     // pen position
 318     bear = FFMIN(face->glyph->metrics.horiBearingX, 0);
 319     // We're adding half a pixel to avoid small gaps
 320     advance = d16_to_d6(glyph->advance.x) + 32;
 321     y_scale = face->size->metrics.y_scale;
 322
 323     // Reverse drawing direction for non-truetype fonts
 324     dir = FT_Outline_Get_Orientation(ol);
 325
 326     // Add points to the outline
 327     if (under && ps) {
 328         int pos, size;
 329         pos = FT_MulFix(ps->underlinePosition, y_scale * font->scale_y);
 330         size = FT_MulFix(ps->underlineThickness,
 331                          y_scale * font->scale_y / 2);
 332
 333         if (pos > 0 || size <= 0)
 334             return 1;
 335
 336         FT_Vector points[4] = {
 337             {.x = bear,      .y = pos + size},
 338             {.x = advance,   .y = pos + size},
 339             {.x = advance,   .y = pos - size},
 340             {.x = bear,      .y = pos - size},
 341         };
 342
 343         if (dir == FT_ORIENTATION_TRUETYPE) {
 344             for (i = 0; i < 4; i++) {
 345                 ol->points[ol->n_points] = points[i];
 346                 ol->tags[ol->n_points++] = 1;
 347             }
 348         } else {
 349             for (i = 3; i >= 0; i--) {
 350                 ol->points[ol->n_points] = points[i];
 351                 ol->tags[ol->n_points++] = 1;
 352             }
 353         }
 354
 355         ol->contours[ol->n_contours++] = ol->n_points - 1;
 356     }
 357
 358     if (through && os2) {
 359         int pos, size;
 360         pos = FT_MulFix(os2->yStrikeoutPosition, y_scale * font->scale_y);
 361         size = FT_MulFix(os2->yStrikeoutSize, y_scale * font->scale_y / 2);
 362
 363         if (pos < 0 || size <= 0)
 364             return 1;
 365
 366         FT_Vector points[4] = {
 367             {.x = bear,      .y = pos + size},
 368             {.x = advance,   .y = pos + size},
 369             {.x = advance,   .y = pos - size},
 370             {.x = bear,      .y = pos - size},
 371         };
 372
 373         if (dir == FT_ORIENTATION_TRUETYPE) {
 374             for (i = 0; i < 4; i++) {
 375                 ol->points[ol->n_points] = points[i];
 376                 ol->tags[ol->n_points++] = 1;
 377             }
 378         } else {
 379             for (i = 3; i >= 0; i--) {
 380                 ol->points[ol->n_points] = points[i];
 381                 ol->tags[ol->n_points++] = 1;
 382             }
 383         }
 384
 385         ol->contours[ol->n_contours++] = ol->n_points - 1;
 386     }
 387
 388     return 0;
 389 }
 390
 391 /**
 392  * Slightly embold a glyph without touching its metrics
 393  */
 394 static void ass_glyph_embolden(FT_GlyphSlot slot)
 395 {
 396     int str;
 397
 398     if (slot->format != FT_GLYPH_FORMAT_OUTLINE)
 399         return;
 400
 401     str = FT_MulFix(slot->face->units_per_EM,
 402                     slot->face->size->metrics.y_scale) / 64;
 403
 404     FT_Outline_Embolden(&slot->outline, str);
 405 }
 406
 407 /**
 408  * \brief Get a glyph
 409  * \param ch character code
 410  **/
 411 FT_Glyph ass_font_get_glyph(void *fontconfig_priv, ASS_Font *font,
 412                             uint32_t ch, ASS_Hinting hinting, int deco)
 413 {
 414     int error;
 415     int index = 0;
 416     int i;
 417     FT_Glyph glyph;
 418     FT_Face face = 0;
 419     int flags = 0;
 420     int vertical = font->desc.vertical;
 421
 422     if (ch < 0x20)
 423         return 0;
 424     // Handle NBSP like a regular space when rendering the glyph
 425     if (ch == 0xa0)
 426         ch = ' ';
 427     if (font->n_faces == 0)
 428         return 0;
 429
 430     for (i = 0; i < font->n_faces; ++i) {
 431         face = font->faces[i];
 432         index = FT_Get_Char_Index(face, ch);
 433         if (index)
 434             break;
 435     }
 436
 437 #ifdef CONFIG_FONTCONFIG
 438     if (index == 0) {
 439         int face_idx;
 440         ass_msg(font->library, MSGL_INFO,
 441                 "Glyph 0x%X not found, selecting one more "
 442                 "font for (%s, %d, %d)", ch, font->desc.family,
 443                 font->desc.bold, font->desc.italic);
 444         face_idx = add_face(fontconfig_priv, font, ch);
 445         if (face_idx >= 0) {
 446             face = font->faces[face_idx];
 447             index = FT_Get_Char_Index(face, ch);
 448             if (index == 0 && face->num_charmaps > 0) {
 449                 ass_msg(font->library, MSGL_WARN,
 450                     "Glyph 0x%X not found, falling back to first charmap", ch);
 451                 FT_CharMap cur = face->charmap;
 452                 FT_Set_Charmap(face, face->charmaps[0]);
 453                 index = FT_Get_Char_Index(face, ch);
 454                 FT_Set_Charmap(face, cur);
 455             }
 456             if (index == 0) {
 457                 ass_msg(font->library, MSGL_ERR,
 458                         "Glyph 0x%X not found in font for (%s, %d, %d)",
 459                         ch, font->desc.family, font->desc.bold,
 460                         font->desc.italic);
 461             }
 462         }
 463     }
 464 #endif
 465
 466     flags = FT_LOAD_NO_BITMAP | FT_LOAD_IGNORE_GLOBAL_ADVANCE_WIDTH
 467             | FT_LOAD_IGNORE_TRANSFORM;
 468     switch (hinting) {
 469     case ASS_HINTING_NONE:
 470         flags |= FT_LOAD_NO_HINTING;
 471         break;
 472     case ASS_HINTING_LIGHT:
 473         flags |= FT_LOAD_FORCE_AUTOHINT | FT_LOAD_TARGET_LIGHT;
 474         break;
 475     case ASS_HINTING_NORMAL:
 476         flags |= FT_LOAD_FORCE_AUTOHINT;
 477         break;
 478     case ASS_HINTING_NATIVE:
 479         break;
 480     }
 481
 482     error = FT_Load_Glyph(face, index, flags);
 483     if (error) {
 484         ass_msg(font->library, MSGL_WARN, "Error loading glyph, index %d",
 485                 index);
 486         return 0;
 487     }
 488     if (!(face->style_flags & FT_STYLE_FLAG_ITALIC) &&
 489         (font->desc.italic > 55)) {
 490         FT_GlyphSlot_Oblique(face->glyph);
 491     }
 492
 493     if (!(face->style_flags & FT_STYLE_FLAG_BOLD) &&
 494         (font->desc.bold > 80)) {
 495         ass_glyph_embolden(face->glyph);
 496     }
 497     error = FT_Get_Glyph(face->glyph, &glyph);
 498     if (error) {
 499         ass_msg(font->library, MSGL_WARN, "Error loading glyph, index %d",
 500                 index);
 501         return 0;
 502     }
 503
 504     // Rotate glyph, if needed
 505     if (vertical && ch >= VERTICAL_LOWER_BOUND) {
 506         FT_Matrix m = { 0, double_to_d16(-1.0), double_to_d16(1.0), 0 };
 507         FT_Outline_Transform(&((FT_OutlineGlyph) glyph)->outline, &m);
 508         FT_Outline_Translate(&((FT_OutlineGlyph) glyph)->outline,
 509                              face->glyph->metrics.vertAdvance,
 510                              0);
 511         glyph->advance.x = face->glyph->linearVertAdvance;
 512     }
 513
 514     // Apply scaling and shift
 515     FT_Matrix scale = { double_to_d16(font->scale_x), 0, 0,
 516                         double_to_d16(font->scale_y) };
 517     FT_Outline *outl = &((FT_OutlineGlyph) glyph)->outline;
 518     FT_Outline_Transform(outl, &scale);
 519     FT_Outline_Translate(outl, font->v.x, font->v.y);
 520     glyph->advance.x *= font->scale_x;
 521
 522     ass_strike_outline_glyph(face, font, glyph, deco & DECO_UNDERLINE,
 523                              deco & DECO_STRIKETHROUGH);
 524
 525     return glyph;
 526 }
 527
 528 /**
 529  * \brief Get kerning for the pair of glyphs.
 530  **/
 531 FT_Vector ass_font_get_kerning(ASS_Font *font, uint32_t c1, uint32_t c2)
 532 {
 533     FT_Vector v = { 0, 0 };
 534     int i;
 535
 536     if (font->desc.vertical)
 537         return v;
 538
 539     for (i = 0; i < font->n_faces; ++i) {
 540         FT_Face face = font->faces[i];
 541         int i1 = FT_Get_Char_Index(face, c1);
 542         int i2 = FT_Get_Char_Index(face, c2);
 543         if (i1 && i2) {
 544             if (FT_HAS_KERNING(face))
 545                 FT_Get_Kerning(face, i1, i2, FT_KERNING_DEFAULT, &v);
 546             return v;
 547         }
 548         if (i1 || i2)           // these glyphs are from different font faces, no kerning information
 549             return v;
 550     }
 551     return v;
 552 }
 553
 554 /**
 555  * \brief Deallocate ASS_Font
 556  **/
 557 void ass_font_free(ASS_Font *font)
 558 {
 559     int i;
 560     for (i = 0; i < font->n_faces; ++i)
 561         if (font->faces[i])
 562             FT_Done_Face(font->faces[i]);
 563     free(font->desc.family);
 564     free(font);
 565 }
 566
 567 /**
 568  * \brief Calculate the cbox of a series of points
 569  */
 570 static void
 571 get_contour_cbox(FT_BBox *box, FT_Vector *points, int start, int end)
 572 {
 573     box->xMin = box->yMin = INT_MAX;
 574     box->xMax = box->yMax = INT_MIN;
 575     int i;
 576
 577     for (i = start; i <= end; i++) {
 578         box->xMin = (points[i].x < box->xMin) ? points[i].x : box->xMin;
 579         box->xMax = (points[i].x > box->xMax) ? points[i].x : box->xMax;
 580         box->yMin = (points[i].y < box->yMin) ? points[i].y : box->yMin;
 581         box->yMax = (points[i].y > box->yMax) ? points[i].y : box->yMax;
 582     }
 583 }
 584
 585 /**
 586  * \brief Determine winding direction of a contour
 587  * \return direction; 0 = clockwise
 588  */
 589 static int get_contour_direction(FT_Vector *points, int start, int end)
 590 {
 591     int i;
 592     long long sum = 0;
 593     int x = points[start].x;
 594     int y = points[start].y;
 595     for (i = start + 1; i <= end; i++) {
 596         sum += x * (points[i].y - y) - y * (points[i].x - x);
 597         x = points[i].x;
 598         y = points[i].y;
 599     }
 600     sum += x * (points[start].y - y) - y * (points[start].x - x);
 601     return sum > 0;
 602 }
 603
 604 /**
 605  * \brief Fix-up stroker result for huge borders by removing inside contours
 606  * that would reverse in size
 607  */
 608 void fix_freetype_stroker(FT_OutlineGlyph glyph, int border_x, int border_y)
 609 {
 610     int nc = glyph->outline.n_contours;
 611     int begin, stop;
 612     char modified = 0;
 613     char *valid_cont = malloc(nc);
 614     int start = 0;
 615     int end = -1;
 616     FT_BBox *boxes = malloc(nc * sizeof(FT_BBox));
 617     int i, j;
 618     int inside_direction;
 619
 620     inside_direction = FT_Outline_Get_Orientation(&glyph->outline) ==
 621         FT_ORIENTATION_TRUETYPE;
 622
 623     // create a list of cboxes of the contours
 624     for (i = 0; i < nc; i++) {
 625         start = end + 1;
 626         end = glyph->outline.contours[i];
 627         get_contour_cbox(&boxes[i], glyph->outline.points, start, end);
 628     }
 629
 630     // for each contour, check direction and whether it's "outside"
 631     // or contained in another contour
 632     end = -1;
 633     for (i = 0; i < nc; i++) {
 634         start = end + 1;
 635         end = glyph->outline.contours[i];
 636         int dir = get_contour_direction(glyph->outline.points, start, end);
 637         valid_cont[i] = 1;
 638         if (dir == inside_direction) {
 639             for (j = 0; j < nc; j++) {
 640                 if (i == j)
 641                     continue;
 642                 if (boxes[i].xMin >= boxes[j].xMin &&
 643                     boxes[i].xMax <= boxes[j].xMax &&
 644                     boxes[i].yMin >= boxes[j].yMin &&
 645                     boxes[i].yMax <= boxes[j].yMax)
 646                     goto check_inside;
 647             }
 648             /* "inside" contour but we can't find anything it could be
 649              * inside of - assume the font is buggy and it should be
 650              * an "outside" contour, and reverse it */
 651             for (j = 0; j < (end + 1 - start) / 2; j++) {
 652                 FT_Vector temp = glyph->outline.points[start + j];
 653                 char temp2 = glyph->outline.tags[start + j];
 654                 glyph->outline.points[start + j] = glyph->outline.points[end - j];
 655                 glyph->outline.points[end - j] = temp;
 656                 glyph->outline.tags[start + j] = glyph->outline.tags[end - j];
 657                 glyph->outline.tags[end - j] = temp2;
 658             }
 659             dir ^= 1;
 660         }
 661         check_inside:
 662         if (dir == inside_direction) {
 663             FT_BBox box;
 664             get_contour_cbox(&box, glyph->outline.points, start, end);
 665             int width = box.xMax - box.xMin;
 666             int height = box.yMax - box.yMin;
 667             if (width < border_x * 2 || height < border_y * 2) {
 668                 valid_cont[i] = 0;
 669                 modified = 1;
 670             }
 671         }
 672     }
 673
 674     // zero-out contours that can be removed; much simpler than copying
 675     if (modified) {
 676         for (i = 0; i < nc; i++) {
 677             if (valid_cont[i])
 678                 continue;
 679             begin = (i == 0) ? 0 : glyph->outline.contours[i - 1] + 1;
 680             stop = glyph->outline.contours[i];
 681             for (j = begin; j <= stop; j++) {
 682                 glyph->outline.points[j].x = 0;
 683                 glyph->outline.points[j].y = 0;
 684                 glyph->outline.tags[j] = 0;
 685             }
 686         }
 687     }
 688
 689     free(boxes);
 690     free(valid_cont);
 691 }
 692