backend/djvu/djvu-document.c

   1 /* -*- Mode: C; tab-width: 8; indent-tabs-mode: t; c-basic-offset: 8; c-indent-level: 8 -*- */
   2 /*
   3  * Copyright (C) 2005, Nickolay V. Shmyrev <nshmyrev@yandex.ru>
   4  *
   5  * This program is free software; you can redistribute it and/or modify
   6  * it under the terms of the GNU General Public License as published by
   7  * the Free Software Foundation; either version 2, or (at your option)
   8  * any later version.
   9  *
  10  * This program is distributed in the hope that it will be useful,
  11  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  12  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  13  * GNU General Public License for more details.
  14  *
  15  * You should have received a copy of the GNU General Public License
  16  * along with this program; if not, write to the Free Software
  17  * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
  18  */
  19
  20 #include "djvu-document.h"
  21 #include "djvu-text.h"
  22 #include "djvu-links.h"
  23 #include "djvu-document-private.h"
  24 #include "ev-document-thumbnails.h"
  25 #include "ev-file-exporter.h"
  26 #include "ev-document-misc.h"
  27 #include "ev-document-find.h"
  28 #include "ev-document-links.h"
  29 #include "ev-selection.h"
  30
  31 #include <gdk-pixbuf/gdk-pixbuf-core.h>
  32 #include <glib/gi18n.h>
  33 #include <glib/gunicode.h>
  34 #include <string.h>
  35
  36 #define SCALE_FACTOR 0.2
  37
  38 enum {
  39         PROP_0,
  40         PROP_TITLE
  41 };
  42
  43 struct _DjvuDocumentClass
  44 {
  45         GObjectClass parent_class;
  46 };
  47
  48 typedef struct _DjvuDocumentClass DjvuDocumentClass;
  49
  50 static void djvu_document_document_iface_init (EvDocumentIface *iface);
  51 static void djvu_document_document_thumbnails_iface_init (EvDocumentThumbnailsIface *iface);
  52 static void djvu_document_file_exporter_iface_init (EvFileExporterIface *iface);
  53 static void djvu_document_find_iface_init (EvDocumentFindIface *iface);
  54 static void djvu_document_document_links_iface_init  (EvDocumentLinksIface *iface);
  55 static void djvu_selection_iface_init (EvSelectionIface *iface);
  56
  57 G_DEFINE_TYPE_WITH_CODE
  58     (DjvuDocument, djvu_document, G_TYPE_OBJECT,
  59     {
  60       G_IMPLEMENT_INTERFACE (EV_TYPE_DOCUMENT, djvu_document_document_iface_init);
  61       G_IMPLEMENT_INTERFACE (EV_TYPE_DOCUMENT_THUMBNAILS, djvu_document_document_thumbnails_iface_init);
  62       G_IMPLEMENT_INTERFACE (EV_TYPE_FILE_EXPORTER, djvu_document_file_exporter_iface_init);
  63       G_IMPLEMENT_INTERFACE (EV_TYPE_DOCUMENT_FIND, djvu_document_find_iface_init);
  64       G_IMPLEMENT_INTERFACE (EV_TYPE_DOCUMENT_LINKS, djvu_document_document_links_iface_init);
  65       G_IMPLEMENT_INTERFACE (EV_TYPE_SELECTION, djvu_selection_iface_init);
  66      });
  67
  68
  69 void
  70 djvu_handle_events (DjvuDocument *djvu_document, int wait)
  71 {
  72         ddjvu_context_t *ctx = djvu_document->d_context;
  73         const ddjvu_message_t *msg;
  74
  75         if (!ctx)
  76                 return;
  77
  78         if (wait)
  79                 msg = ddjvu_message_wait (ctx);
  80
  81         while ((msg = ddjvu_message_peek (ctx))) {
  82                 switch (msg->m_any.tag) {
  83                         case DDJVU_ERROR:
  84                                 g_warning ("DjvuLibre error: %s",
  85                                            msg->m_error.message);
  86                                 if (msg->m_error.filename)
  87                                         g_warning ("DjvuLibre error: %s:%d",
  88                                                    msg->m_error.filename,
  89                                                    msg->m_error.lineno);
  90                                 break;
  91                         default:
  92                                 break;
  93                 }
  94                 ddjvu_message_pop (ctx);
  95         }
  96 }
  97
  98 static gboolean
  99 djvu_document_load (EvDocument  *document,
 100                     const char  *uri,
 101                     GError     **error)
 102 {
 103         DjvuDocument *djvu_document = DJVU_DOCUMENT (document);
 104         ddjvu_document_t *doc;
 105         gchar *filename;
 106         gboolean missing_files = FALSE;
 107
 108         /* FIXME: We could actually load uris  */
 109         filename = g_filename_from_uri (uri, NULL, error);
 110         if (!filename)
 111                 return FALSE;
 112
 113         doc = ddjvu_document_create_by_filename (djvu_document->d_context, filename, TRUE);
 114
 115         if (!doc) {
 116                 g_free (filename);
 117                 return FALSE;
 118         }
 119
 120         if (djvu_document->d_document)
 121             ddjvu_document_release (djvu_document->d_document);
 122
 123         djvu_document->d_document = doc;
 124
 125         while (!ddjvu_document_decoding_done (djvu_document->d_document))
 126                 djvu_handle_events (djvu_document, TRUE);
 127         g_free (djvu_document->uri);
 128         djvu_document->uri = g_strdup (uri);
 129
 130         if (ddjvu_document_get_type (djvu_document->d_document) == DDJVU_DOCTYPE_INDIRECT) {
 131                 gint n_files;
 132                 gint i;
 133                 gchar *base;
 134
 135                 base = g_path_get_dirname (filename);
 136
 137                 n_files = ddjvu_document_get_filenum (djvu_document->d_document);
 138                 for (i = 0; i < n_files; i++) {
 139                         struct ddjvu_fileinfo_s fileinfo;
 140                         gchar *file;
 141
 142                         ddjvu_document_get_fileinfo (djvu_document->d_document,
 143                                                      i, &fileinfo);
 144
 145                         if (fileinfo.type != 'P')
 146                                 continue;
 147
 148                         file = g_build_filename (base, fileinfo.id, NULL);
 149                         if (!g_file_test (file, G_FILE_TEST_EXISTS)) {
 150                                 missing_files = TRUE;
 151                                 g_free (file);
 152
 153                                 break;
 154                         }
 155                         g_free (file);
 156                 }
 157                 g_free (base);
 158         }
 159         g_free (filename);
 160
 161         if (missing_files) {
 162                 g_set_error (error,
 163                              G_FILE_ERROR,
 164                              G_FILE_ERROR_EXIST,
 165                              _("The document is composed by several files. "
 166                                "One or more of such files cannot be accessed."));
 167
 168                 return FALSE;
 169         }
 170
 171         return TRUE;
 172 }
 173
 174
 175 static gboolean
 176 djvu_document_save (EvDocument  *document,
 177                     const char  *uri,
 178                     GError     **error)
 179 {
 180         DjvuDocument *djvu_document = DJVU_DOCUMENT (document);
 181
 182         return ev_xfer_uri_simple (djvu_document->uri, uri, error);
 183 }
 184
 185 int
 186 djvu_document_get_n_pages (EvDocument  *document)
 187 {
 188         DjvuDocument *djvu_document = DJVU_DOCUMENT (document);
 189
 190         g_return_val_if_fail (djvu_document->d_document, 0);
 191
 192         return ddjvu_document_get_pagenum (djvu_document->d_document);
 193 }
 194
 195 static void
 196 djvu_document_get_page_size (EvDocument   *document,
 197                              int           page,
 198                              double       *width,
 199                              double       *height)
 200 {
 201         DjvuDocument *djvu_document = DJVU_DOCUMENT (document);
 202         ddjvu_pageinfo_t info;
 203         ddjvu_status_t r;
 204
 205         g_return_if_fail (djvu_document->d_document);
 206
 207         while ((r = ddjvu_document_get_pageinfo(djvu_document->d_document, page, &info)) < DDJVU_JOB_OK)
 208                 djvu_handle_events(djvu_document, TRUE);
 209
 210         if (r >= DDJVU_JOB_FAILED)
 211                 djvu_handle_events(djvu_document, TRUE);
 212
 213         *width = info.width * SCALE_FACTOR;
 214         *height = info.height * SCALE_FACTOR;
 215 }
 216
 217 static cairo_surface_t *
 218 djvu_document_render (EvDocument      *document,
 219                       EvRenderContext *rc)
 220 {
 221         DjvuDocument *djvu_document = DJVU_DOCUMENT (document);
 222         cairo_surface_t *surface;
 223         gchar *pixels;
 224         gint   rowstride;
 225         ddjvu_rect_t rrect;
 226         ddjvu_rect_t prect;
 227         ddjvu_page_t *d_page;
 228         ddjvu_page_rotation_t rotation;
 229         double page_width, page_height, tmp;
 230         static const cairo_user_data_key_t key;
 231
 232         d_page = ddjvu_page_create_by_pageno (djvu_document->d_document, rc->page);
 233
 234         while (!ddjvu_page_decoding_done (d_page))
 235                 djvu_handle_events(djvu_document, TRUE);
 236
 237         page_width = ddjvu_page_get_width (d_page) * rc->scale * SCALE_FACTOR + 0.5;
 238         page_height = ddjvu_page_get_height (d_page) * rc->scale * SCALE_FACTOR + 0.5;
 239
 240         switch (rc->rotation) {
 241                 case 90:
 242                         rotation = DDJVU_ROTATE_90;
 243                         tmp = page_height;
 244                         page_height = page_width;
 245                         page_width = tmp;
 246
 247                         break;
 248                 case 180:
 249                         rotation = DDJVU_ROTATE_180;
 250
 251                         break;
 252                 case 270:
 253                         rotation = DDJVU_ROTATE_270;
 254                         tmp = page_height;
 255                         page_height = page_width;
 256                         page_width = tmp;
 257
 258                         break;
 259                 default:
 260                         rotation = DDJVU_ROTATE_0;
 261         }
 262
 263         rowstride = page_width * 4;
 264         pixels = (gchar *) g_malloc (page_height * rowstride);
 265         surface = cairo_image_surface_create_for_data (pixels,
 266                                                        CAIRO_FORMAT_RGB24,
 267                                                        page_width,
 268                                                        page_height,
 269                                                        rowstride);
 270         cairo_surface_set_user_data (surface, &key,
 271                                      pixels, (cairo_destroy_func_t)g_free);
 272         prect.x = 0;
 273         prect.y = 0;
 274         prect.w = page_width;
 275         prect.h = page_height;
 276         rrect = prect;
 277
 278         ddjvu_page_set_rotation (d_page, rotation);
 279
 280         ddjvu_page_render (d_page, DDJVU_RENDER_COLOR,
 281                            &prect,
 282                            &rrect,
 283                            djvu_document->d_format,
 284                            rowstride,
 285                            pixels);
 286
 287         return surface;
 288 }
 289
 290 static void
 291 djvu_document_finalize (GObject *object)
 292 {
 293         DjvuDocument *djvu_document = DJVU_DOCUMENT (object);
 294
 295         if (djvu_document->search)
 296             djvu_text_free (djvu_document->search);
 297
 298         if (djvu_document->d_document)
 299             ddjvu_document_release (djvu_document->d_document);
 300
 301         if (djvu_document->opts)
 302             g_string_free (djvu_document->opts, TRUE);
 303
 304         if (djvu_document->ps_filename)
 305             g_free (djvu_document->ps_filename);
 306
 307         ddjvu_context_release (djvu_document->d_context);
 308         ddjvu_format_release (djvu_document->d_format);
 309         ddjvu_format_release (djvu_document->thumbs_format);
 310         g_free (djvu_document->uri);
 311
 312         G_OBJECT_CLASS (djvu_document_parent_class)->finalize (object);
 313 }
 314
 315 static void
 316 djvu_document_class_init (DjvuDocumentClass *klass)
 317 {
 318         GObjectClass *gobject_class = G_OBJECT_CLASS (klass);
 319
 320         gobject_class->finalize = djvu_document_finalize;
 321 }
 322
 323 static EvDocumentInfo *
 324 djvu_document_get_info (EvDocument *document)
 325 {
 326         EvDocumentInfo *info;
 327
 328         info = g_new0 (EvDocumentInfo, 1);
 329
 330         return info;
 331 }
 332
 333 static void
 334 djvu_document_document_iface_init (EvDocumentIface *iface)
 335 {
 336         iface->load = djvu_document_load;
 337         iface->save = djvu_document_save;
 338         iface->get_n_pages = djvu_document_get_n_pages;
 339         iface->get_page_size = djvu_document_get_page_size;
 340         iface->render = djvu_document_render;
 341         iface->get_info = djvu_document_get_info;
 342 }
 343
 344 static gchar *
 345 djvu_selection_get_selected_text (EvSelection     *selection,
 346                                   EvRenderContext *rc,
 347                                   EvSelectionStyle style,
 348                                   EvRectangle     *points)
 349 {
 350         DjvuDocument *djvu_document = DJVU_DOCUMENT (selection);
 351         double width, height;
 352         EvRectangle rectangle;
 353         gchar *text;
 354
 355         djvu_document_get_page_size (EV_DOCUMENT (djvu_document),
 356                                      rc->page, &width, &height);
 357         rectangle.x1 = points->x1 / SCALE_FACTOR;
 358         rectangle.y1 = (height - points->y2) / SCALE_FACTOR;
 359         rectangle.x2 = points->x2 / SCALE_FACTOR;
 360         rectangle.y2 = (height - points->y1) / SCALE_FACTOR;
 361
 362         text = djvu_text_copy (djvu_document, rc->page, &rectangle);
 363
 364         if (text == NULL)
 365                 text = g_strdup ("");
 366
 367         return text;
 368 }
 369
 370 static void
 371 djvu_selection_iface_init (EvSelectionIface *iface)
 372 {
 373         iface->get_selected_text = djvu_selection_get_selected_text;
 374 }
 375
 376 static void
 377 djvu_document_thumbnails_get_dimensions (EvDocumentThumbnails *document,
 378                                          EvRenderContext      *rc,
 379                                          gint                 *width,
 380                                          gint                 *height)
 381 {
 382         DjvuDocument *djvu_document = DJVU_DOCUMENT (document);
 383         gdouble page_width, page_height;
 384
 385         djvu_document_get_page_size (EV_DOCUMENT(djvu_document), rc->page,
 386                                      &page_width, &page_height);
 387
 388         if (rc->rotation == 90 || rc->rotation == 270) {
 389                 *width = (gint) (page_height * rc->scale);
 390                 *height = (gint) (page_width * rc->scale);
 391         } else {
 392                 *width = (gint) (page_width * rc->scale);
 393                 *height = (gint) (page_height * rc->scale);
 394         }
 395 }
 396
 397 static GdkPixbuf *
 398 djvu_document_thumbnails_get_thumbnail (EvDocumentThumbnails *document,
 399                                         EvRenderContext      *rc,
 400                                         gboolean              border)
 401 {
 402         DjvuDocument *djvu_document = DJVU_DOCUMENT (document);
 403         GdkPixbuf *pixbuf, *rotated_pixbuf;
 404         gdouble page_width, page_height;
 405         gint thumb_width, thumb_height;
 406         guchar *pixels;
 407
 408         g_return_val_if_fail (djvu_document->d_document, NULL);
 409
 410         djvu_document_get_page_size (EV_DOCUMENT(djvu_document), rc->page,
 411                                      &page_width, &page_height);
 412
 413         thumb_width = (gint) (page_width * rc->scale);
 414         thumb_height = (gint) (page_height * rc->scale);
 415
 416         pixbuf = gdk_pixbuf_new (GDK_COLORSPACE_RGB, FALSE, 8,
 417                                  thumb_width, thumb_height);
 418         gdk_pixbuf_fill (pixbuf, 0xffffffff);
 419         pixels = gdk_pixbuf_get_pixels (pixbuf);
 420
 421         while (ddjvu_thumbnail_status (djvu_document->d_document, rc->page, 1) < DDJVU_JOB_OK)
 422                 djvu_handle_events(djvu_document, TRUE);
 423
 424         ddjvu_thumbnail_render (djvu_document->d_document, rc->page,
 425                                 &thumb_width, &thumb_height,
 426                                 djvu_document->thumbs_format,
 427                                 gdk_pixbuf_get_rowstride (pixbuf),
 428                                 (gchar *)pixels);
 429
 430         rotated_pixbuf = gdk_pixbuf_rotate_simple (pixbuf, 360 - rc->rotation);
 431         g_object_unref (pixbuf);
 432
 433         if (border) {
 434               GdkPixbuf *tmp_pixbuf = rotated_pixbuf;
 435
 436               rotated_pixbuf = ev_document_misc_get_thumbnail_frame (-1, -1, tmp_pixbuf);
 437               g_object_unref (tmp_pixbuf);
 438         }
 439
 440         return rotated_pixbuf;
 441 }
 442
 443 static void
 444 djvu_document_document_thumbnails_iface_init (EvDocumentThumbnailsIface *iface)
 445 {
 446         iface->get_thumbnail = djvu_document_thumbnails_get_thumbnail;
 447         iface->get_dimensions = djvu_document_thumbnails_get_dimensions;
 448 }
 449
 450 /* EvFileExporterIface */
 451 static void
 452 djvu_document_file_exporter_begin (EvFileExporter        *exporter,
 453                                    EvFileExporterContext *fc)
 454 {
 455         DjvuDocument *djvu_document = DJVU_DOCUMENT (exporter);
 456
 457         if (djvu_document->ps_filename)
 458                 g_free (djvu_document->ps_filename);
 459         djvu_document->ps_filename = g_strdup (fc->filename);
 460
 461         g_string_assign (djvu_document->opts, "-page=");
 462 }
 463
 464 static void
 465 djvu_document_file_exporter_do_page (EvFileExporter  *exporter,
 466                                      EvRenderContext *rc)
 467 {
 468         DjvuDocument *djvu_document = DJVU_DOCUMENT (exporter);
 469
 470         g_string_append_printf (djvu_document->opts, "%d,", (rc->page) + 1);
 471 }
 472
 473 static void
 474 djvu_document_file_exporter_end (EvFileExporter *exporter)
 475 {
 476         int d_optc = 1;
 477         const char *d_optv[d_optc];
 478
 479         DjvuDocument *djvu_document = DJVU_DOCUMENT (exporter);
 480
 481         FILE *fn = fopen (djvu_document->ps_filename, "w");
 482         if (fn == NULL) {
 483                 g_warning ("Cannot open file “%s”.", djvu_document->ps_filename);
 484                 return;
 485         }
 486
 487         d_optv[0] = djvu_document->opts->str;
 488
 489         ddjvu_job_t * job = ddjvu_document_print(djvu_document->d_document, fn, d_optc, d_optv);
 490         while (!ddjvu_job_done(job)) {
 491                 djvu_handle_events (djvu_document, TRUE);
 492         }
 493
 494         fclose(fn);
 495 }
 496
 497 static EvFileExporterCapabilities
 498 djvu_document_file_exporter_get_capabilities (EvFileExporter *exporter)
 499 {
 500         return  EV_FILE_EXPORTER_CAN_PAGE_SET |
 501                 EV_FILE_EXPORTER_CAN_COPIES |
 502                 EV_FILE_EXPORTER_CAN_COLLATE |
 503                 EV_FILE_EXPORTER_CAN_REVERSE |
 504                 EV_FILE_EXPORTER_CAN_GENERATE_PS;
 505 }
 506
 507 static void
 508 djvu_document_file_exporter_iface_init (EvFileExporterIface *iface)
 509 {
 510         iface->begin = djvu_document_file_exporter_begin;
 511         iface->do_page = djvu_document_file_exporter_do_page;
 512         iface->end = djvu_document_file_exporter_end;
 513         iface->get_capabilities = djvu_document_file_exporter_get_capabilities;
 514 }
 515
 516 static void
 517 djvu_document_init (DjvuDocument *djvu_document)
 518 {
 519         guint masks[4] = { 0xff0000, 0xff00, 0xff, 0xff000000 };
 520
 521         djvu_document->d_context = ddjvu_context_create ("Evince");
 522         djvu_document->d_format = ddjvu_format_create (DDJVU_FORMAT_RGBMASK32, 4, masks);
 523         ddjvu_format_set_row_order (djvu_document->d_format, 1);
 524
 525         djvu_document->thumbs_format = ddjvu_format_create (DDJVU_FORMAT_RGB24, 0, 0);
 526         ddjvu_format_set_row_order (djvu_document->thumbs_format, 1);
 527
 528         djvu_document->ps_filename = NULL;
 529         djvu_document->opts = g_string_new ("");
 530
 531         djvu_document->d_document = NULL;
 532 }
 533
 534 static void
 535 djvu_document_find_begin (EvDocumentFind   *document,
 536                           int               page,
 537                           const char       *search_string,
 538                           gboolean          case_sensitive)
 539 {
 540         DjvuDocument *djvu_document = DJVU_DOCUMENT (document);
 541
 542         if (djvu_document->search &&
 543             strcmp (search_string, djvu_text_get_text (djvu_document->search)) == 0)
 544                 return;
 545
 546         if (djvu_document->search)
 547                 djvu_text_free (djvu_document->search);
 548
 549         djvu_document->search = djvu_text_new (djvu_document,
 550                                                           page,
 551                                                           case_sensitive,
 552                                                           search_string);
 553 }
 554
 555 static int
 556 djvu_document_find_get_n_results (EvDocumentFind *document_find, int page)
 557 {
 558         DjvuText *search = DJVU_DOCUMENT (document_find)->search;
 559
 560         if (search) {
 561                 return djvu_text_n_results (search, page);
 562         } else {
 563                 return 0;
 564         }
 565 }
 566
 567 static gboolean
 568 djvu_document_find_get_result (EvDocumentFind *document_find,
 569                                int             page,
 570                                int             n_result,
 571                                EvRectangle    *rectangle)
 572 {
 573         DjvuDocument *djvu_document = DJVU_DOCUMENT (document_find);
 574         DjvuText *search = djvu_document->search;
 575         EvRectangle *r;
 576         double width, height;
 577
 578         if (search == NULL)
 579                 return FALSE;
 580
 581         r = djvu_text_get_result (search, page, n_result);
 582         if (r == NULL)
 583                 return FALSE;
 584
 585         djvu_document_get_page_size (EV_DOCUMENT (djvu_document),
 586                 page, &width, &height);
 587         rectangle->x1 = r->x1 * SCALE_FACTOR;
 588         rectangle->y1 = height - r->y2 * SCALE_FACTOR;
 589         rectangle->x2 = r->x2 * SCALE_FACTOR;
 590         rectangle->y2 = height - r->y1 * SCALE_FACTOR;
 591
 592         return TRUE;
 593 }
 594
 595 static int
 596 djvu_document_find_page_has_results (EvDocumentFind *document_find,
 597                                     int             page)
 598 {
 599         DjvuText *search = DJVU_DOCUMENT (document_find)->search;
 600
 601         return search && djvu_text_has_results (search, page);
 602 }
 603
 604 static double
 605 djvu_document_find_get_progress (EvDocumentFind *document_find)
 606 {
 607         DjvuText *search = DJVU_DOCUMENT (document_find)->search;
 608
 609         if (search == NULL) {
 610                 return 0;
 611         }
 612
 613         return djvu_text_get_progress (search);
 614 }
 615
 616 static void
 617 djvu_document_find_cancel (EvDocumentFind *document)
 618 {
 619         DjvuDocument *djvu_document = DJVU_DOCUMENT (document);
 620
 621         if (djvu_document->search) {
 622                 djvu_text_free (djvu_document->search);
 623                 djvu_document->search = NULL;
 624         }
 625 }
 626
 627 static void
 628 djvu_document_find_iface_init (EvDocumentFindIface *iface)
 629 {
 630         iface->begin = djvu_document_find_begin;
 631         iface->get_n_results = djvu_document_find_get_n_results;
 632         iface->get_result = djvu_document_find_get_result;
 633         iface->page_has_results = djvu_document_find_page_has_results;
 634         iface->get_progress = djvu_document_find_get_progress;
 635         iface->cancel = djvu_document_find_cancel;
 636 }
 637
 638 static GList *
 639 djvu_document_links_get_links (EvDocumentLinks *document_links,
 640                                gint             page)
 641 {
 642         return djvu_links_get_links (document_links, page, SCALE_FACTOR);
 643 }
 644
 645 static void
 646 djvu_document_document_links_iface_init  (EvDocumentLinksIface *iface)
 647 {
 648         iface->has_document_links = djvu_links_has_document_links;
 649         iface->get_links_model = djvu_links_get_links_model;
 650         iface->get_links = djvu_document_links_get_links;
 651         iface->find_link_dest = djvu_links_find_link_dest;
 652 }