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 "win.h"
  49 #include "mouse.h"
  50 #include "key.h"                /* For mi_getch() */
  51 #include "help.h"
  52 #include "dialog.h"             /* For Dlg_head */
  53 #include "widget.h"             /* For Widget */
  54 #include "wtools.h"             /* For common_dialog_repaint() */
  55
  56 #define MAXLINKNAME 80
  57 #define HISTORY_SIZE 20
  58 #define HELP_WINDOW_WIDTH (HELP_TEXT_WIDTH + 4)
  59
  60 #define STRING_LINK_START       "\01"
  61 #define STRING_LINK_POINTER     "\02"
  62 #define STRING_LINK_END         "\03"
  63 #define STRING_NODE_END         "\04"
  64
  65 static char *data;              /* Pointer to the loaded data file */
  66 static int help_lines;          /* Lines in help viewer */
  67 static int  history_ptr;        /* For the history queue */
  68 static char *main_node;         /* The main node */
  69 static char *last_shown = 0;    /* Last byte shown in a screen */
  70 static int end_of_node = 0;     /* Flag: the last character of the node shown? */
  71 static char *currentpoint, *startpoint;
  72 static char *selected_item;
  73
  74 /* The widget variables */
  75 static Dlg_head *whelp;
  76
  77 static struct {
  78     char *page;                 /* Pointer to the selected page */
  79     char *link;                 /* Pointer to the selected link */
  80 } history [HISTORY_SIZE];
  81
  82 /* Link areas for the mouse */
  83 typedef struct Link_Area {
  84     int x1, y1, x2, y2;
  85     char *link_name;
  86     struct Link_Area *next;
  87 } Link_Area;
  88
  89 static Link_Area *link_area = NULL;
  90 static int inside_link_area = 0;
  91
  92 static cb_ret_t help_callback (struct Dlg_head *h, dlg_msg_t, int parm);
  93
  94 #ifdef HAS_ACS_AS_PCCHARS
  95 static const struct {
  96     int acscode;
  97     int pccode;
  98 } acs2pc_table [] = {
  99     { 'q',  0xC4 },
 100     { 'x',  0xB3 },
 101     { 'l',  0xDA },
 102     { 'k',  0xBF },
 103     { 'm',  0xC0 },
 104     { 'j',  0xD9 },
 105     { 'a',  0xB0 },
 106     { 'u',  0xB4 },
 107     { 't',  0xC3 },
 108     { 'w',  0xC2 },
 109     { 'v',  0xC1 },
 110     { 'n',  0xC5 },
 111     { 0, 0 } };
 112
 113 static int acs2pc (int acscode)
 114 {
 115     int i;
 116
 117     for (i = 0; acs2pc_table[i].acscode != 0; i++)
 118         if (acscode == acs2pc_table[i].acscode) {
 119             return acs2pc_table[i].pccode;
 120         }
 121     return 0;
 122 }
 123 #endif
 124
 125 /* returns the position where text was found in the start buffer */
 126 /* or 0 if not found */
 127 static char *
 128 search_string (char *start, char *text)
 129 {
 130     char *d = text;
 131     char *e = start;
 132
 133     /* fmt sometimes replaces a space with a newline in the help file */
 134     /* Replace the newlines in the link name with spaces to correct the situation */
 135     while (*d){
 136         if (*d == '\n')
 137             *d = ' ';
 138         d++;
 139     }
 140     /* Do search */
 141     for (d = text; *e; e++){
 142         if (*d == *e)
 143             d++;
 144         else
 145             d = text;
 146         if (!*d)
 147             return e+1;
 148     }
 149     return 0;
 150 }
 151
 152 /* Searches text in the buffer pointed by start.  Search ends */
 153 /* if the CHAR_NODE_END is found in the text.  Returns 0 on failure */
 154 static char *search_string_node (char *start, char *text)
 155 {
 156     char *d = text;
 157     char *e = start;
 158
 159     if (!start)
 160         return 0;
 161
 162     for (; *e && *e != CHAR_NODE_END; e++){
 163         if (*d == *e)
 164             d++;
 165         else
 166             d = text;
 167         if (!*d)
 168             return e+1;
 169     }
 170     return 0;
 171 }
 172
 173 /* Searches the_char in the buffer pointer by start and searches */
 174 /* it can search forward (direction = 1) or backward (direction = -1) */
 175 static char *search_char_node (char *start, char the_char, int direction)
 176 {
 177     char *e;
 178
 179     e = start;
 180
 181     for (; *e && (*e != CHAR_NODE_END); e += direction){
 182         if (*e == the_char)
 183             return e;
 184     }
 185     return 0;
 186 }
 187
 188 /* Returns the new current pointer when moved lines lines */
 189 static char *move_forward2 (char *c, int lines)
 190 {
 191     char *p;
 192     int  line;
 193
 194     currentpoint = c;
 195     for (line = 0, p = currentpoint; *p && *p != CHAR_NODE_END; p++){
 196         if (line == lines)
 197             return currentpoint = p;
 198         if (*p == '\n')
 199             line++;
 200     }
 201     return currentpoint = c;
 202 }
 203
 204 static char *move_backward2 (char *c, int lines)
 205 {
 206     char *p;
 207     int line;
 208
 209     currentpoint = c;
 210     for (line = 0, p = currentpoint; *p && p >= data; p--){
 211         if (*p == CHAR_NODE_END)
 212         {
 213             /* We reached the beginning of the node */
 214             /* Skip the node headers */
 215             while (*p != ']') p++;
 216             return currentpoint = p + 2;
 217         }
 218         if (*(p - 1) == '\n')
 219             line++;
 220         if (line == lines)
 221             return currentpoint = p;
 222     }
 223     return currentpoint = c;
 224 }
 225
 226 static void move_forward (int i)
 227 {
 228     if (end_of_node)
 229         return;
 230     currentpoint = move_forward2 (currentpoint, i);
 231 }
 232
 233 static void move_backward (int i)
 234 {
 235     currentpoint = move_backward2 (currentpoint, ++i);
 236 }
 237
 238 static void move_to_top (int dummy)
 239 {
 240     while (currentpoint > data && *currentpoint != CHAR_NODE_END)
 241         currentpoint--;
 242     while (*currentpoint != ']')
 243         currentpoint++;
 244     currentpoint = currentpoint + 1;
 245     selected_item = NULL;
 246 }
 247
 248 static void move_to_bottom (int dummy)
 249 {
 250     while (*currentpoint && *currentpoint != CHAR_NODE_END)
 251         currentpoint++;
 252     currentpoint--;
 253     move_backward (help_lines - 1);
 254 }
 255
 256 static char *help_follow_link (char *start, char *selected_item)
 257 {
 258     char link_name [MAXLINKNAME];
 259     char *p;
 260     int  i = 0;
 261
 262     if (!selected_item)
 263         return start;
 264
 265     for (p = selected_item; *p && *p != CHAR_NODE_END && *p != CHAR_LINK_POINTER; p++)
 266         ;
 267     if (*p == CHAR_LINK_POINTER){
 268         link_name [0] = '[';
 269         for (i = 1; *p != CHAR_LINK_END && *p && *p != CHAR_NODE_END && i < MAXLINKNAME-3; )
 270             link_name [i++] = *++p;
 271         link_name [i-1] = ']';
 272         link_name [i] = 0;
 273         p = search_string (data, link_name);
 274         if (p)
 275             return p;
 276     }
 277
 278     /* Create a replacement page with the error message */
 279     return _(" Help file format error\n");
 280 }
 281
 282 static char *select_next_link (char *start, char *current_link)
 283 {
 284     char *p;
 285
 286     if (!current_link)
 287         return 0;
 288
 289     p = search_string_node (current_link, STRING_LINK_END);
 290     if (!p)
 291         return NULL;
 292     p = search_string_node (p, STRING_LINK_START);
 293     if (!p)
 294         return NULL;
 295     return p - 1;
 296 }
 297
 298 static char *select_prev_link (char *start, char *current_link)
 299 {
 300     char *p;
 301
 302     if (!current_link)
 303         return 0;
 304
 305     p = current_link - 1;
 306     if (p <= start)
 307         return 0;
 308
 309     p = search_char_node (p, CHAR_LINK_START, -1);
 310     return p;
 311 }
 312
 313 static void start_link_area (int x, int y, char *link_name)
 314 {
 315     Link_Area *new;
 316
 317     if (inside_link_area)
 318         message (0, _("Warning"), _(" Internal bug: Double start of link area "));
 319
 320     /* Allocate memory for a new link area */
 321     new = g_new (Link_Area, 1);
 322     new->next = link_area;
 323     link_area = new;
 324
 325     /* Save the beginning coordinates of the link area */
 326     link_area->x1 = x;
 327     link_area->y1 = y;
 328
 329     /* Save the name of the destination anchor */
 330     link_area->link_name = link_name;
 331
 332     inside_link_area = 1;
 333 }
 334
 335 static void end_link_area (int x, int y)
 336 {
 337     if (inside_link_area){
 338         /* Save the end coordinates of the link area */
 339         link_area->x2 = x;
 340         link_area->y2 = y;
 341
 342         inside_link_area = 0;
 343     }
 344 }
 345
 346 static void clear_link_areas (void)
 347 {
 348     Link_Area *current;
 349
 350     while (link_area){
 351         current = link_area;
 352         link_area = current -> next;
 353         g_free (current);
 354     }
 355     inside_link_area = 0;
 356 }
 357
 358 static void help_show (Dlg_head *h, char *paint_start)
 359 {
 360     char *p;
 361     int  col, line, c;
 362     int  painting = 1;
 363     int acs;                    /* Flag: Alternate character set active? */
 364     int repeat_paint;
 365     int active_col, active_line;/* Active link position */
 366
 367     attrset (HELP_NORMAL_COLOR);
 368     do {
 369
 370         line = col = acs = active_col = active_line = repeat_paint = 0;
 371
 372         clear_link_areas ();
 373         if (selected_item < paint_start)
 374             selected_item = NULL;
 375
 376         for (p = paint_start; *p && *p != CHAR_NODE_END && line < help_lines; p++) {
 377             c = (unsigned char)*p;
 378             switch (c){
 379             case CHAR_LINK_START:
 380                 if (selected_item == NULL)
 381                     selected_item = p;
 382                 if (p == selected_item){
 383                     attrset (HELP_SLINK_COLOR);
 384
 385                     /* Store the coordinates of the link */
 386                     active_col = col + 2;
 387                     active_line = line + 2;
 388                 }
 389                 else
 390                     attrset (HELP_LINK_COLOR);
 391                 start_link_area (col, line, p);
 392                 break;
 393             case CHAR_LINK_POINTER:
 394                 painting = 0;
 395                 end_link_area (col - 1, line);
 396                 break;
 397             case CHAR_LINK_END:
 398                 painting = 1;
 399                 attrset (HELP_NORMAL_COLOR);
 400                 break;
 401             case CHAR_ALTERNATE:
 402                 acs = 1;
 403                 break;
 404             case CHAR_NORMAL:
 405                 acs = 0;
 406                 break;
 407             case CHAR_VERSION:
 408                 dlg_move (h, line+2, col+2);
 409                 addstr (VERSION);
 410                 col += strlen (VERSION);
 411                 break;
 412             case CHAR_FONT_BOLD:
 413                 attrset (HELP_BOLD_COLOR);
 414                 break;
 415             case CHAR_FONT_ITALIC:
 416                 attrset (HELP_ITALIC_COLOR);
 417                 break;
 418             case CHAR_FONT_NORMAL:
 419                 attrset (HELP_NORMAL_COLOR);
 420                 break;
 421             case '\n':
 422                 line++;
 423                 col = 0;
 424                 break;
 425             case '\t':
 426                 col = (col/8 + 1) * 8;
 427                 break;
 428             default:
 429                 if (!painting)
 430                     continue;
 431                 if (col > HELP_WINDOW_WIDTH-1)
 432                     continue;
 433
 434                 dlg_move (h, line+2, col+2);
 435                 if (acs){
 436                     if (c == ' ' || c == '.')
 437                         addch (c);
 438                     else
 439 #ifndef HAVE_SLANG
 440                         addch (acs_map [c]);
 441 #else
 442                         SLsmg_draw_object (h->y + line + 2, h->x + col + 2, c);
 443 #endif
 444                 } else
 445                     addch (c);
 446                 col++;
 447                 break;
 448             }
 449         }
 450         last_shown = p;
 451         end_of_node = line < help_lines;
 452         attrset (HELP_NORMAL_COLOR);
 453         if (selected_item >= last_shown){
 454             if (link_area != NULL){
 455                 selected_item = link_area->link_name;
 456                 repeat_paint = 1;
 457             }
 458             else
 459                 selected_item = NULL;
 460         }
 461     } while (repeat_paint);
 462
 463     /* Position the cursor over a nice link */
 464     if (active_col)
 465         dlg_move (h, active_line, active_col);
 466 }
 467
 468 static int help_event (Gpm_Event *event, Widget *w)
 469 {
 470     Link_Area *current_area;
 471
 472     if (! (event->type & GPM_UP))
 473         return 0;
 474
 475     /* The event is relative to the dialog window, adjust it: */
 476     event->y -= 2;
 477
 478     if (event->buttons & GPM_B_RIGHT){
 479         currentpoint = startpoint = history [history_ptr].page;
 480         selected_item = history [history_ptr].link;
 481         history_ptr--;
 482         if (history_ptr < 0)
 483             history_ptr = HISTORY_SIZE-1;
 484
 485         help_callback (w->parent, DLG_DRAW, 0);
 486         return 0;
 487     }
 488
 489     /* Test whether the mouse click is inside one of the link areas */
 490     current_area = link_area;
 491     while (current_area)
 492     {
 493         /* Test one line link area */
 494         if (event->y == current_area->y1 && event->x >= current_area->x1 &&
 495             event->y == current_area->y2 && event->x <= current_area->x2)
 496             break;
 497         /* Test two line link area */
 498         if (current_area->y1 + 1 == current_area->y2){
 499             /* The first line */
 500             if (event->y == current_area->y1 && event->x >= current_area->x1)
 501                 break;
 502             /* The second line */
 503             if (event->y == current_area->y2 && event->x <= current_area->x2)
 504                 break;
 505         }
 506         /* Mouse will not work with link areas of more than two lines */
 507
 508         current_area = current_area -> next;
 509     }
 510
 511     /* Test whether a link area was found */
 512     if (current_area){
 513         /* The click was inside a link area -> follow the link */
 514         history_ptr = (history_ptr+1) % HISTORY_SIZE;
 515         history [history_ptr].page = currentpoint;
 516         history [history_ptr].link = current_area->link_name;
 517         currentpoint = startpoint = help_follow_link (currentpoint, current_area->link_name);
 518         selected_item = NULL;
 519     } else{
 520         if (event->y < 0)
 521             move_backward (help_lines - 1);
 522         else if (event->y >= help_lines)
 523             move_forward (help_lines - 1);
 524         else if (event->y < help_lines/2)
 525             move_backward (1);
 526         else
 527             move_forward (1);
 528     }
 529
 530     /* Show the new node */
 531     help_callback (w->parent, DLG_DRAW, 0);
 532
 533     return 0;
 534 }
 535
 536 /* show help */
 537 static void
 538 help_help_cmd (Dlg_head *h)
 539 {
 540     history_ptr = (history_ptr+1) % HISTORY_SIZE;
 541     history [history_ptr].page = currentpoint;
 542     history [history_ptr].link = selected_item;
 543     currentpoint = startpoint = search_string (data, "[How to use help]") + 1;
 544     selected_item = NULL;
 545     help_callback (h, DLG_DRAW, 0);
 546 }
 547
 548 static void
 549 help_index_cmd (Dlg_head * h)
 550 {
 551     char *new_item;
 552
 553     if (!(new_item = search_string (data, "[Contents]"))) {
 554         message (1, MSG_ERROR, _(" Cannot find node %s in help file "),
 555                  "[Contents]");
 556         return;
 557     }
 558
 559     history_ptr = (history_ptr + 1) % HISTORY_SIZE;
 560     history[history_ptr].page = currentpoint;
 561     history[history_ptr].link = selected_item;
 562
 563     currentpoint = startpoint = new_item + 1;
 564     selected_item = NULL;
 565     help_callback (h, DLG_DRAW, 0);
 566 }
 567
 568 static void help_quit_cmd (void *x)
 569 {
 570     dlg_stop ((Dlg_head *)x);
 571 }
 572
 573 static void prev_node_cmd (Dlg_head *h)
 574 {
 575     currentpoint = startpoint = history [history_ptr].page;
 576     selected_item = history [history_ptr].link;
 577     history_ptr--;
 578     if (history_ptr < 0)
 579         history_ptr = HISTORY_SIZE-1;
 580
 581     help_callback (h, DLG_DRAW, 0);
 582 }
 583
 584 static cb_ret_t
 585 md_callback (Widget *w, widget_msg_t msg, int parm)
 586 {
 587     return default_proc (msg, parm);
 588 }
 589
 590 static Widget *
 591 mousedispatch_new (int y, int x, int yl, int xl)
 592 {
 593     Widget *w = g_new (Widget, 1);
 594
 595     init_widget (w, y, x, yl, xl, (callback_fn) md_callback,
 596                  (mouse_h) help_event);
 597
 598     return w;
 599 }
 600
 601 static cb_ret_t
 602 help_handle_key (struct Dlg_head *h, int c)
 603 {
 604     char *new_item;
 605
 606     if (c != KEY_UP && c != KEY_DOWN &&
 607         check_movement_keys (c, help_lines, currentpoint,
 608                              (movefn) move_backward2,
 609                              (movefn) move_forward2,
 610                              (movefn) move_to_top,
 611                              (movefn) move_to_bottom))
 612         /* Nothing */;
 613     else switch (c){
 614     case 'l':
 615     case KEY_LEFT:
 616         prev_node_cmd (h);
 617         break;
 618
 619     case '\n':
 620     case KEY_RIGHT:
 621         /* follow link */
 622         if (!selected_item){
 623 #ifdef WE_WANT_TO_GO_BACKWARD_ON_KEY_RIGHT
 624             /* Is there any reason why the right key would take us
 625              * backward if there are no links selected?, I agree
 626              * with Torben than doing nothing in this case is better
 627              */
 628             /* If there are no links, go backward in history */
 629             history_ptr--;
 630             if (history_ptr < 0)
 631                 history_ptr = HISTORY_SIZE-1;
 632
 633             currentpoint = startpoint = history [history_ptr].page;
 634             selected_item   = history [history_ptr].link;
 635 #endif
 636         } else {
 637             history_ptr = (history_ptr+1) % HISTORY_SIZE;
 638             history [history_ptr].page = currentpoint;
 639             history [history_ptr].link = selected_item;
 640             currentpoint = startpoint = help_follow_link (currentpoint, selected_item) + 1;
 641         }
 642         selected_item = NULL;
 643         break;
 644
 645     case KEY_DOWN:
 646     case '\t':
 647         /* select next link */
 648         new_item = select_next_link (startpoint, selected_item);
 649         if (new_item){
 650             selected_item = new_item;
 651             if (selected_item >= last_shown){
 652                 if (c == KEY_DOWN)
 653                     move_forward (1);
 654                 else
 655                     selected_item = NULL;
 656             }
 657         } else if (c == KEY_DOWN)
 658             move_forward (1);
 659         else
 660             selected_item = NULL;
 661         break;
 662
 663     case KEY_UP:
 664     case ALT ('\t'):
 665         /* select previous link */
 666         new_item = select_prev_link (startpoint, selected_item);
 667         selected_item = new_item;
 668         if (selected_item < currentpoint || selected_item >= last_shown){
 669             if (c == KEY_UP)
 670                 move_backward (1);
 671             else{
 672                 if (link_area != NULL)
 673                     selected_item = link_area->link_name;
 674                 else
 675                     selected_item = NULL;
 676             }
 677         }
 678         break;
 679
 680     case 'n':
 681         /* Next node */
 682         new_item = currentpoint;
 683         while (*new_item && *new_item != CHAR_NODE_END)
 684             new_item++;
 685         if (*++new_item == '['){
 686             while (*++new_item) {
 687                 if (*new_item == ']' && *++new_item && *++new_item) {
 688                     currentpoint = new_item;
 689                     selected_item = NULL;
 690                     break;
 691                 }
 692             }
 693         }
 694         break;
 695
 696     case 'p':
 697         /* Previous node */
 698         new_item = currentpoint;
 699         while (new_item > data + 1 && *new_item != CHAR_NODE_END)
 700             new_item--;
 701         new_item--;
 702         while (new_item > data && *new_item != CHAR_NODE_END)
 703             new_item--;
 704         while (*new_item != ']')
 705             new_item++;
 706         currentpoint = new_item + 2;
 707         selected_item = NULL;
 708         break;
 709
 710     case 'c':
 711         help_index_cmd (h);
 712         break;
 713
 714     case ESC_CHAR:
 715     case XCTRL('g'):
 716         dlg_stop (h);
 717         break;
 718
 719     default:
 720         return MSG_NOT_HANDLED;
 721
 722     }
 723     help_callback (h, DLG_DRAW, 0);
 724     return MSG_HANDLED;
 725 }
 726
 727 static cb_ret_t
 728 help_callback (struct Dlg_head *h, dlg_msg_t msg, int parm)
 729 {
 730     switch (msg) {
 731     case DLG_DRAW:
 732         common_dialog_repaint (h);
 733         help_show (h, currentpoint);
 734         return MSG_HANDLED;
 735
 736     case DLG_KEY:
 737         return help_handle_key (h, parm);
 738
 739     default:
 740         return default_dlg_callback (h, msg, parm);
 741     }
 742 }
 743
 744 static void
 745 interactive_display_finish (void)
 746 {
 747     clear_link_areas ();
 748     g_free (data);
 749 }
 750
 751 void
 752 interactive_display (char *filename, char *node)
 753 {
 754     WButtonBar *help_bar;
 755     Widget *md;
 756     char *hlpfile = filename;
 757
 758     if (filename)
 759         data = load_file (filename);
 760     else
 761         data = load_mc_home_file ("mc.hlp", &hlpfile);
 762
 763     if (data == NULL) {
 764         message (1, MSG_ERROR, _(" Cannot open file %s \n %s "), hlpfile,
 765                  unix_error_string (errno));
 766     }
 767
 768     if (!filename)
 769         g_free (hlpfile);
 770
 771     if (!data)
 772         return;
 773
 774     if (!node || !*node)
 775         node = "[main]";
 776
 777     if (!(main_node = search_string (data, node))) {
 778         message (1, MSG_ERROR, _(" Cannot find node %s in help file "),
 779                  node);
 780
 781         /* Fallback to [main], return if it also cannot be found */
 782         main_node = search_string (data, "[main]");
 783         if (!main_node) {
 784             interactive_display_finish ();
 785             return;
 786         }
 787     }
 788
 789     help_lines = min (LINES - 4, max (2 * LINES / 3, 18));
 790
 791     whelp =
 792         create_dlg (0, 0, help_lines + 4, HELP_WINDOW_WIDTH + 4,
 793                     dialog_colors, help_callback, "[Help]", _("Help"),
 794                     DLG_TRYUP | DLG_CENTER | DLG_WANT_TAB);
 795
 796     selected_item = search_string_node (main_node, STRING_LINK_START) - 1;
 797     currentpoint = startpoint = main_node + 1;
 798
 799     for (history_ptr = HISTORY_SIZE; history_ptr;) {
 800         history_ptr--;
 801         history[history_ptr].page = currentpoint;
 802         history[history_ptr].link = selected_item;
 803     }
 804
 805     help_bar = buttonbar_new (1);
 806     help_bar->widget.y -= whelp->y;
 807     help_bar->widget.x -= whelp->x;
 808
 809     md = mousedispatch_new (1, 1, help_lines, HELP_WINDOW_WIDTH - 2);
 810
 811     add_widget (whelp, md);
 812     add_widget (whelp, help_bar);
 813
 814     define_label_data (whelp, 1, _("Help"), (buttonbarfn) help_help_cmd,
 815                        whelp);
 816     define_label_data (whelp, 2, _("Index"), (buttonbarfn) help_index_cmd,
 817                        whelp);
 818     define_label_data (whelp, 3, _("Prev"), (buttonbarfn) prev_node_cmd,
 819                        whelp);
 820     define_label (whelp, 4, "", 0);
 821     define_label (whelp, 5, "", 0);
 822     define_label (whelp, 6, "", 0);
 823     define_label (whelp, 7, "", 0);
 824     define_label (whelp, 8, "", 0);
 825     define_label (whelp, 9, "", 0);
 826     define_label_data (whelp, 10, _("Quit"), help_quit_cmd, whelp);
 827
 828     run_dlg (whelp);
 829     interactive_display_finish ();
 830     destroy_dlg (whelp);
 831 }
 832