src/help.c

   1 /* Hypertext file browser.
   2    Copyright (C) 1994, 1995 Miguel de Icaza.
   3    Copyright (C) 1994, 1995 Janne Kukonlehto
   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 of the License, or
   8    (at your option) 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    Implements the hypertext file viewer.
  20    The hypertext file is a file that may have one or more nodes.  Each
  21    node ends with a ^D character and starts with a bracket, then the
  22    name of the node and then a closing bracket.
  23
  24    Links in the hypertext file are specified like this: the text that
  25    will be highlighted should have a leading ^A, then it comes the
  26    text, then a ^B indicating that highlighting is done, then the name
  27    of the node you want to link to and then a ^C.
  28
  29    The file must contain a ^D at the beginning and at the end of the
  30    file or the program will not be able to detect the end of file.
  31
  32    Lazyness/widgeting attack: This file does use the dialog manager
  33    and uses mainly the dialog to achieve the help work.  there is only
  34    one specialized widget and it's only used to forward the mouse messages
  35    to the appropiate routine.
  36
  37 */
  38
  39 #include <config.h>
  40 #include <stdio.h>
  41 #include <sys/types.h>
  42 #include <sys/stat.h>
  43 #include <errno.h>
  44
  45 #include "global.h"
  46 #include "tty.h"
  47 #include "color.h"
  48 #include "dialog.h"
  49 #include "win.h"
  50 #include "mouse.h"
  51 #include "key.h"        /* For mi_getch() */
  52 #include "help.h"
  53 #include "dlg.h"                /* For Dlg_head */
  54 #include "widget.h"             /* For Widget */
  55 #include "wtools.h"             /* For common_dialog_repaint() */
  56
  57 #define MAXLINKNAME 80
  58 #define HISTORY_SIZE 20
  59 #define HELP_WINDOW_WIDTH 62
  60
  61 /* "$Id$" */
  62
  63 static char *data;              /* Pointer to the loaded data file */
  64 static int help_lines;          /* Lines in help viewer */
  65 static int  history_ptr;        /* For the history queue */
  66 static char *main_node;         /* The main node */
  67 static char *last_shown = 0;    /* Last byte shown in a screen */
  68 static int end_of_node = 0;     /* Flag: the last character of the node shown? */
  69 static char *currentpoint, *startpoint;
  70 static char *selected_item;
  71
  72 /* The widget variables */
  73 static Dlg_head *whelp;
  74
  75 static struct {
  76     char *page;                 /* Pointer to the selected page */
  77     char *link;                 /* Pointer to the selected link */
  78 } history [HISTORY_SIZE];
  79
  80 /* Link areas for the mouse */
  81 typedef struct Link_Area {
  82     int x1, y1, x2, y2;
  83     char *link_name;
  84     struct Link_Area *next;
  85 } Link_Area;
  86
  87 static Link_Area *link_area = NULL;
  88 static int inside_link_area = 0;
  89
  90 static int help_callback (struct Dlg_head *h, int id, int msg);
  91
  92 #ifdef HAS_ACS_AS_PCCHARS
  93 static const struct {
  94     int acscode;
  95     int pccode;
  96 } acs2pc_table [] = {
  97     { 'q',  0xC4 },
  98     { 'x',  0xB3 },
  99     { 'l',  0xDA },
 100     { 'k',  0xBF },
 101     { 'm',  0xC0 },
 102     { 'j',  0xD9 },
 103     { 'a',  0xB0 },
 104     { 'u',  0xB4 },
 105     { 't',  0xC3 },
 106     { 'w',  0xC2 },
 107     { 'v',  0xC1 },
 108     { 'n',  0xC5 },
 109     { 0, 0 } };
 110
 111 static int acs2pc (int acscode)
 112 {
 113     int i;
 114
 115     for (i = 0; acs2pc_table[i].acscode != 0; i++)
 116         if (acscode == acs2pc_table[i].acscode) {
 117             return acs2pc_table[i].pccode;
 118         }
 119     return 0;
 120 }
 121 #endif
 122
 123 /* returns the position where text was found in the start buffer */
 124 /* or 0 if not found */
 125 static char *
 126 search_string (char *start, char *text)
 127 {
 128     char *d = text;
 129     char *e = start;
 130
 131     /* fmt sometimes replaces a space with a newline in the help file */
 132     /* Replace the newlines in the link name with spaces to correct the situation */
 133     while (*d){
 134         if (*d == '\n')
 135             *d = ' ';
 136         d++;
 137     }
 138     /* Do search */
 139     for (d = text; *e; e++){
 140         if (*d == *e)
 141             d++;
 142         else
 143             d = text;
 144         if (!*d)
 145             return e+1;
 146     }
 147     return 0;
 148 }
 149
 150 /* Searches text in the buffer pointed by start.  Search ends */
 151 /* if the CHAR_NODE_END is found in the text.  Returns 0 on failure */
 152 static char *search_string_node (char *start, char *text)
 153 {
 154     char *d = text;
 155     char *e = start;
 156
 157     if (!start)
 158         return 0;
 159
 160     for (; *e && *e != CHAR_NODE_END; e++){
 161         if (*d == *e)
 162             d++;
 163         else
 164             d = text;
 165         if (!*d)
 166             return e+1;
 167     }
 168     return 0;
 169 }
 170
 171 /* Searches the_char in the buffer pointer by start and searches */
 172 /* it can search forward (direction = 1) or backward (direction = -1) */
 173 static char *search_char_node (char *start, char the_char, int direction)
 174 {
 175     char *e;
 176
 177     e = start;
 178
 179     for (; *e && (*e != CHAR_NODE_END); e += direction){
 180         if (*e == the_char)
 181             return e;
 182     }
 183     return 0;
 184 }
 185
 186 /* Returns the new current pointer when moved lines lines */
 187 static char *move_forward2 (char *c, int lines)
 188 {
 189     char *p;
 190     int  line;
 191
 192     currentpoint = c;
 193     for (line = 0, p = currentpoint; *p && *p != CHAR_NODE_END; p++){
 194         if (line == lines)
 195             return currentpoint = p;
 196         if (*p == '\n')
 197             line++;
 198     }
 199     return currentpoint = c;
 200 }
 201
 202 static char *move_backward2 (char *c, int lines)
 203 {
 204     char *p;
 205     int line;
 206
 207     currentpoint = c;
 208     for (line = 0, p = currentpoint; *p && p >= data; p--){
 209         if (*p == CHAR_NODE_END)
 210         {
 211             /* We reached the beginning of the node */
 212             /* Skip the node headers */
 213             while (*p != ']') p++;
 214             return currentpoint = p + 2;
 215         }
 216         if (*(p - 1) == '\n')
 217             line++;
 218         if (line == lines)
 219             return currentpoint = p;
 220     }
 221     return currentpoint = c;
 222 }
 223
 224 static void move_forward (int i)
 225 {
 226     if (end_of_node)
 227         return;
 228     currentpoint = move_forward2 (currentpoint, i);
 229 }
 230
 231 static void move_backward (int i)
 232 {
 233     currentpoint = move_backward2 (currentpoint, ++i);
 234 }
 235
 236 static void move_to_top (int dummy)
 237 {
 238     while (currentpoint > data && *currentpoint != CHAR_NODE_END)
 239         currentpoint--;
 240     while (*currentpoint != ']')
 241         currentpoint++;
 242     currentpoint = currentpoint + 1;
 243     selected_item = NULL;
 244 }
 245
 246 static void move_to_bottom (int dummy)
 247 {
 248     while (*currentpoint && *currentpoint != CHAR_NODE_END)
 249         currentpoint++;
 250     currentpoint--;
 251     move_backward (help_lines - 1);
 252 }
 253
 254 static char *help_follow_link (char *start, char *selected_item)
 255 {
 256     char link_name [MAXLINKNAME];
 257     char *p;
 258     int  i = 0;
 259
 260     if (!selected_item)
 261         return start;
 262
 263     for (p = selected_item; *p && *p != CHAR_NODE_END && *p != CHAR_LINK_POINTER; p++)
 264         ;
 265     if (*p == CHAR_LINK_POINTER){
 266         link_name [0] = '[';
 267         for (i = 1; *p != CHAR_LINK_END && *p && *p != CHAR_NODE_END && i < MAXLINKNAME-3; )
 268             link_name [i++] = *++p;
 269         link_name [i-1] = ']';
 270         link_name [i] = 0;
 271         p = search_string (data, link_name);
 272         if (p)
 273             return p;
 274     }
 275     return _(" Help file format error\n\x4");   /*  */
 276 }
 277
 278 static char *select_next_link (char *start, char *current_link)
 279 {
 280     char *p;
 281
 282     if (!current_link)
 283         return 0;
 284
 285     p = search_string_node (current_link, STRING_LINK_END);
 286     if (!p)
 287         return NULL;
 288     p = search_string_node (p, STRING_LINK_START);
 289     if (!p)
 290         return NULL;
 291     return p - 1;
 292 }
 293
 294 static char *select_prev_link (char *start, char *current_link)
 295 {
 296     char *p;
 297
 298     if (!current_link)
 299         return 0;
 300
 301     p = current_link - 1;
 302     if (p <= start)
 303         return 0;
 304
 305     p = search_char_node (p, CHAR_LINK_START, -1);
 306     return p;
 307 }
 308
 309 static void start_link_area (int x, int y, char *link_name)
 310 {
 311     Link_Area *new;
 312
 313     if (inside_link_area)
 314         message (0, _(" Warning "), _(" Internal bug: Double start of link area "));
 315
 316     /* Allocate memory for a new link area */
 317     new = g_new (Link_Area, 1);
 318     new->next = link_area;
 319     link_area = new;
 320
 321     /* Save the beginning coordinates of the link area */
 322     link_area->x1 = x;
 323     link_area->y1 = y;
 324
 325     /* Save the name of the destination anchor */
 326     link_area->link_name = link_name;
 327
 328     inside_link_area = 1;
 329 }
 330
 331 static void end_link_area (int x, int y)
 332 {
 333     if (inside_link_area){
 334         /* Save the end coordinates of the link area */
 335         link_area->x2 = x;
 336         link_area->y2 = y;
 337
 338         inside_link_area = 0;
 339     }
 340 }
 341
 342 static void clear_link_areas (void)
 343 {
 344     Link_Area *current;
 345
 346     while (link_area){
 347         current = link_area;
 348         link_area = current -> next;
 349         g_free (current);
 350     }
 351     inside_link_area = 0;
 352 }
 353
 354 static void show (Dlg_head *h, char *paint_start)
 355 {
 356     char *p;
 357     int  col, line, c;
 358     int  painting = 1;
 359     int acs;                    /* Flag: Alternate character set active? */
 360     int repeat_paint;
 361     int active_col, active_line;/* Active link position */
 362
 363     attrset (HELP_NORMAL_COLOR);
 364     do {
 365
 366         line = col = acs = active_col = active_line = repeat_paint = 0;
 367
 368         clear_link_areas ();
 369         if (selected_item < paint_start)
 370             selected_item = NULL;
 371
 372         for (p = paint_start; *p && *p != CHAR_NODE_END && line < help_lines; p++) {
 373             c = (unsigned char)*p;
 374             switch (c){
 375             case CHAR_LINK_START:
 376                 if (selected_item == NULL)
 377                     selected_item = p;
 378                 if (p == selected_item){
 379                     attrset (HELP_SLINK_COLOR);
 380
 381                     /* Store the coordinates of the link */
 382                     active_col = col + 2;
 383                     active_line = line + 2;
 384                 }
 385                 else
 386                     attrset (HELP_LINK_COLOR);
 387                 start_link_area (col, line, p);
 388                 break;
 389             case CHAR_LINK_POINTER:
 390                 painting = 0;
 391                 end_link_area (col - 1, line);
 392                 break;
 393             case CHAR_LINK_END:
 394                 painting = 1;
 395                 attrset (HELP_NORMAL_COLOR);
 396                 break;
 397             case CHAR_ALTERNATE:
 398                 acs = 1;
 399                 break;
 400             case CHAR_NORMAL:
 401                 acs = 0;
 402                 break;
 403             case CHAR_VERSION:
 404                 dlg_move (h, line+2, col+2);
 405                 addstr (VERSION);
 406                 col += strlen (VERSION);
 407                 break;
 408             case CHAR_BOLD_ON:
 409                 attrset (HELP_BOLD_COLOR);
 410                 break;
 411             case CHAR_ITALIC_ON:
 412                 attrset (HELP_ITALIC_COLOR);
 413                 break;
 414             case CHAR_BOLD_OFF:
 415                 attrset (HELP_NORMAL_COLOR);
 416                 break;
 417             case '\n':
 418                 line++;
 419                 col = 0;
 420                 break;
 421             case '\t':
 422                 col = (col/8 + 1) * 8;
 423                 break;
 424             case CHAR_MCLOGO:
 425             case CHAR_TEXTONLY_START:
 426             case CHAR_TEXTONLY_END:
 427                 break;
 428             case CHAR_XONLY_START:
 429                 while (*p && *p != CHAR_NODE_END && *p != CHAR_XONLY_END)
 430                     p++;
 431                 if (*p == CHAR_NODE_END || !*p)
 432                     p--;
 433                 break;
 434             default:
 435                 if (!painting)
 436                     continue;
 437                 if (col > HELP_WINDOW_WIDTH-1)
 438                     continue;
 439
 440                 dlg_move (h, line+2, col+2);
 441                 if (acs){
 442                     if (c == ' ' || c == '.')
 443                         addch (c);
 444                     else
 445 #ifndef OS2_NT
 446 #ifndef HAVE_SLANG
 447                         addch (acs_map [c]);
 448 #else
 449                         SLsmg_draw_object (h->y + line + 2, h->x + col + 2, c);
 450 #endif
 451 #else
 452                         addch (acs2pc (c));
 453 #endif /* OS2_NT */
 454                 } else
 455                     addch (c);
 456                 col++;
 457                 break;
 458             }
 459         }
 460         last_shown = p;
 461         end_of_node = line < help_lines;
 462         attrset (HELP_NORMAL_COLOR);
 463         if (selected_item >= last_shown){
 464             if (link_area != NULL){
 465                 selected_item = link_area->link_name;
 466                 repeat_paint = 1;
 467             }
 468             else
 469                 selected_item = NULL;
 470         }
 471     } while (repeat_paint);
 472
 473     /* Position the cursor over a nice link */
 474     if (active_col)
 475         dlg_move (h, active_line, active_col);
 476 }
 477
 478 static int help_event (Gpm_Event *event, Widget *w)
 479 {
 480     Link_Area *current_area;
 481
 482     if (! (event->type & GPM_UP))
 483         return 0;
 484
 485     /* The event is relative to the dialog window, adjust it: */
 486     event->y -= 2;
 487
 488     if (event->buttons & GPM_B_RIGHT){
 489         currentpoint = startpoint = history [history_ptr].page;
 490         selected_item = history [history_ptr].link;
 491         history_ptr--;
 492         if (history_ptr < 0)
 493             history_ptr = HISTORY_SIZE-1;
 494
 495         help_callback (w->parent, 0, DLG_DRAW);
 496         return 0;
 497     }
 498
 499     /* Test whether the mouse click is inside one of the link areas */
 500     current_area = link_area;
 501     while (current_area)
 502     {
 503         /* Test one line link area */
 504         if (event->y == current_area->y1 && event->x >= current_area->x1 &&
 505             event->y == current_area->y2 && event->x <= current_area->x2)
 506             break;
 507         /* Test two line link area */
 508         if (current_area->y1 + 1 == current_area->y2){
 509             /* The first line */
 510             if (event->y == current_area->y1 && event->x >= current_area->x1)
 511                 break;
 512             /* The second line */
 513             if (event->y == current_area->y2 && event->x <= current_area->x2)
 514                 break;
 515         }
 516         /* Mouse will not work with link areas of more than two lines */
 517
 518         current_area = current_area -> next;
 519     }
 520
 521     /* Test whether a link area was found */
 522     if (current_area){
 523         /* The click was inside a link area -> follow the link */
 524         history_ptr = (history_ptr+1) % HISTORY_SIZE;
 525         history [history_ptr].page = currentpoint;
 526         history [history_ptr].link = current_area->link_name;
 527         currentpoint = startpoint = help_follow_link (currentpoint, current_area->link_name);
 528         selected_item = NULL;
 529     } else{
 530         if (event->y < 0)
 531             move_backward (help_lines - 1);
 532         else if (event->y >= help_lines)
 533             move_forward (help_lines - 1);
 534         else if (event->y < help_lines/2)
 535             move_backward (1);
 536         else
 537             move_forward (1);
 538     }
 539
 540     /* Show the new node */
 541     help_callback (w->parent, 0, DLG_DRAW);
 542
 543     return 0;
 544 }
 545
 546 /* show help */
 547 static void
 548 help_help_cmd (Dlg_head *h)
 549 {
 550     history_ptr = (history_ptr+1) % HISTORY_SIZE;
 551     history [history_ptr].page = currentpoint;
 552     history [history_ptr].link = selected_item;
 553     currentpoint = startpoint = search_string (data, "[How to use help]") + 1;
 554     selected_item = NULL;
 555     help_callback (h, 0, DLG_DRAW);
 556 }
 557
 558 static void
 559 help_index_cmd (Dlg_head * h)
 560 {
 561     char *new_item;
 562
 563     if (!(new_item = search_string (data, "[Contents]"))) {
 564         message (1, MSG_ERROR, _(" Cannot find node %s in help file "),
 565                  "[Contents]");
 566         return;
 567     }
 568
 569     history_ptr = (history_ptr + 1) % HISTORY_SIZE;
 570     history[history_ptr].page = currentpoint;
 571     history[history_ptr].link = selected_item;
 572
 573     currentpoint = startpoint = new_item + 1;
 574     selected_item = NULL;
 575     help_callback (h, 0, DLG_DRAW);
 576 }
 577
 578 static void quit_cmd (void *x)
 579 {
 580     dlg_stop ((Dlg_head *)x);
 581 }
 582
 583 static void prev_node_cmd (Dlg_head *h)
 584 {
 585     currentpoint = startpoint = history [history_ptr].page;
 586     selected_item = history [history_ptr].link;
 587     history_ptr--;
 588     if (history_ptr < 0)
 589         history_ptr = HISTORY_SIZE-1;
 590
 591     help_callback (h, 0, DLG_DRAW);
 592 }
 593
 594 static int md_callback (Dlg_head *h, Widget *w, int msg, int par)
 595 {
 596     return default_proc (h, msg, par);
 597 }
 598
 599 static Widget *mousedispatch_new (int y, int x, int yl, int xl)
 600 {
 601     Widget *w = g_new (Widget, 1);
 602
 603     init_widget (w, y, x, yl, xl,
 604                  (callback_fn) md_callback, 0, (mouse_h)  help_event, NULL);
 605
 606     return w;
 607 }
 608
 609 static int help_handle_key (struct Dlg_head *h, int c)
 610 {
 611     char *new_item;
 612
 613     if (c != KEY_UP && c != KEY_DOWN &&
 614         check_movement_keys (c, 1, help_lines, currentpoint,
 615                              (movefn) move_backward2,
 616                              (movefn) move_forward2,
 617                              (movefn) move_to_top,
 618                              (movefn) move_to_bottom))
 619         /* Nothing */;
 620     else switch (c){
 621     case 'l':
 622     case KEY_LEFT:
 623         prev_node_cmd (h);
 624         break;
 625
 626     case '\n':
 627     case KEY_RIGHT:
 628         /* follow link */
 629         if (!selected_item){
 630 #ifdef WE_WANT_TO_GO_BACKWARD_ON_KEY_RIGHT
 631             /* Is there any reason why the right key would take us
 632              * backward if there are no links selected?, I agree
 633              * with Torben than doing nothing in this case is better
 634              */
 635             /* If there are no links, go backward in history */
 636             history_ptr--;
 637             if (history_ptr < 0)
 638                 history_ptr = HISTORY_SIZE-1;
 639
 640             currentpoint = startpoint = history [history_ptr].page;
 641             selected_item   = history [history_ptr].link;
 642 #endif
 643         } else {
 644             history_ptr = (history_ptr+1) % HISTORY_SIZE;
 645             history [history_ptr].page = currentpoint;
 646             history [history_ptr].link = selected_item;
 647             currentpoint = startpoint = help_follow_link (currentpoint, selected_item) + 1;
 648         }
 649         selected_item = NULL;
 650         break;
 651
 652     case KEY_DOWN:
 653     case '\t':
 654         /* select next link */
 655         new_item = select_next_link (startpoint, selected_item);
 656         if (new_item){
 657             selected_item = new_item;
 658             if (selected_item >= last_shown){
 659                 if (c == KEY_DOWN)
 660                     move_forward (1);
 661                 else
 662                     selected_item = NULL;
 663             }
 664         } else if (c == KEY_DOWN)
 665             move_forward (1);
 666         else
 667             selected_item = NULL;
 668         break;
 669
 670     case KEY_UP:
 671     case ALT ('\t'):
 672         /* select previous link */
 673         new_item = select_prev_link (startpoint, selected_item);
 674         selected_item = new_item;
 675         if (selected_item < currentpoint || selected_item >= last_shown){
 676             if (c == KEY_UP)
 677                 move_backward (1);
 678             else{
 679                 if (link_area != NULL)
 680                     selected_item = link_area->link_name;
 681                 else
 682                     selected_item = NULL;
 683             }
 684         }
 685         break;
 686
 687     case 'n':
 688         /* Next node */
 689         new_item = currentpoint;
 690         while (*new_item && *new_item != CHAR_NODE_END)
 691             new_item++;
 692         if (*++new_item == '['){
 693             while (*++new_item) {
 694                 if (*new_item == ']' && *++new_item && *++new_item) {
 695                     currentpoint = new_item;
 696                     selected_item = NULL;
 697                     break;
 698                 }
 699             }
 700         }
 701         break;
 702
 703     case 'p':
 704         /* Previous node */
 705         new_item = currentpoint;
 706         while (new_item > data + 1 && *new_item != CHAR_NODE_END)
 707             new_item--;
 708         new_item--;
 709         while (new_item > data && *new_item != CHAR_NODE_END)
 710             new_item--;
 711         while (*new_item != ']')
 712             new_item++;
 713         currentpoint = new_item + 2;
 714         selected_item = NULL;
 715         break;
 716
 717     case 'c':
 718         help_index_cmd (h);
 719         break;
 720
 721     case ESC_CHAR:
 722     case XCTRL('g'):
 723         dlg_stop (h);
 724         break;
 725
 726     default:
 727         return 0;
 728
 729     }
 730     help_callback (h, 0, DLG_DRAW);
 731     return 1;
 732 }
 733
 734 static int help_callback (struct Dlg_head *h, int id, int msg)
 735 {
 736     switch (msg){
 737     case DLG_DRAW:
 738         common_dialog_repaint (h);
 739         show (h, currentpoint);
 740         break;
 741
 742     case DLG_KEY:
 743         return help_handle_key (h, id);
 744     }
 745     return 0;
 746 }
 747
 748 static void
 749 interactive_display_finish (void)
 750 {
 751     clear_link_areas ();
 752     g_free (data);
 753 }
 754
 755 void
 756 interactive_display (char *filename, char *node)
 757 {
 758     WButtonBar *help_bar;
 759     Widget *md;
 760     char *hlpfile = filename;
 761
 762     if (filename)
 763         data = load_file (filename);
 764     else
 765         data = load_mc_home_file ("mc.hlp", &hlpfile);
 766
 767     if (data == NULL) {
 768         message (1, MSG_ERROR, _(" Cannot open file %s \n %s "), hlpfile,
 769                  unix_error_string (errno));
 770     }
 771
 772     if (!filename)
 773         g_free (hlpfile);
 774
 775     if (!data)
 776         return;
 777
 778     if (!node || !*node)
 779         node = "[main]";
 780
 781     if (!(main_node = search_string (data, node))) {
 782         message (1, MSG_ERROR, _(" Cannot find node %s in help file "),
 783                  node);
 784
 785         /* Fallback to [main], return if it also cannot be found */
 786         main_node = search_string (data, "[main]");
 787         if (!main_node) {
 788             interactive_display_finish ();
 789             return;
 790         }
 791     }
 792
 793     help_lines = min (LINES - 4, max (2 * LINES / 3, 18));
 794
 795     whelp =
 796         create_dlg (0, 0, help_lines + 4, HELP_WINDOW_WIDTH + 4,
 797                     dialog_colors, help_callback, "[Help]", _("Help"),
 798                     DLG_TRYUP | DLG_CENTER | DLG_WANT_TAB);
 799
 800     selected_item = search_string_node (main_node, STRING_LINK_START) - 1;
 801     currentpoint = startpoint = main_node + 1;
 802
 803     for (history_ptr = HISTORY_SIZE; history_ptr;) {
 804         history_ptr--;
 805         history[history_ptr].page = currentpoint;
 806         history[history_ptr].link = selected_item;
 807     }
 808
 809     help_bar = buttonbar_new (1);
 810     help_bar->widget.y -= whelp->y;
 811     help_bar->widget.x -= whelp->x;
 812
 813     md = mousedispatch_new (1, 1, help_lines, HELP_WINDOW_WIDTH - 2);
 814
 815     add_widget (whelp, help_bar);
 816     add_widget (whelp, md);
 817
 818     define_label_data (whelp, (Widget *) NULL, 1, _("Help"),
 819                        (buttonbarfn) help_help_cmd, whelp);
 820     define_label_data (whelp, (Widget *) NULL, 2, _("Index"),
 821                        (buttonbarfn) help_index_cmd, whelp);
 822     define_label_data (whelp, (Widget *) NULL, 3, _("Prev"),
 823                        (buttonbarfn) prev_node_cmd, whelp);
 824     define_label (whelp, (Widget *) NULL, 4, "", 0);
 825     define_label (whelp, (Widget *) NULL, 5, "", 0);
 826     define_label (whelp, (Widget *) NULL, 6, "", 0);
 827     define_label (whelp, (Widget *) NULL, 7, "", 0);
 828     define_label (whelp, (Widget *) NULL, 8, "", 0);
 829     define_label (whelp, (Widget *) NULL, 9, "", 0);
 830     define_label_data (whelp, (Widget *) NULL, 10, _("Quit"), quit_cmd,
 831                        whelp);
 832
 833     run_dlg (whelp);
 834     interactive_display_finish ();
 835     destroy_dlg (whelp);
 836 }
 837