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 (HELP_TEXT_WIDTH + 4)
  60
  61 #define STRING_LINK_START       "\01"
  62 #define STRING_LINK_POINTER     "\02"
  63 #define STRING_LINK_END         "\03"
  64 #define STRING_NODE_END         "\04"
  65
  66 static char *data;              /* Pointer to the loaded data file */
  67 static int help_lines;          /* Lines in help viewer */
  68 static int  history_ptr;        /* For the history queue */
  69 static char *main_node;         /* The main node */
  70 static char *last_shown = 0;    /* Last byte shown in a screen */
  71 static int end_of_node = 0;     /* Flag: the last character of the node shown? */
  72 static char *currentpoint, *startpoint;
  73 static char *selected_item;
  74
  75 /* The widget variables */
  76 static Dlg_head *whelp;
  77
  78 static struct {
  79     char *page;                 /* Pointer to the selected page */
  80     char *link;                 /* Pointer to the selected link */
  81 } history [HISTORY_SIZE];
  82
  83 /* Link areas for the mouse */
  84 typedef struct Link_Area {
  85     int x1, y1, x2, y2;
  86     char *link_name;
  87     struct Link_Area *next;
  88 } Link_Area;
  89
  90 static Link_Area *link_area = NULL;
  91 static int inside_link_area = 0;
  92
  93 static int help_callback (struct Dlg_head *h, int id, int msg);
  94
  95 #ifdef HAS_ACS_AS_PCCHARS
  96 static const struct {
  97     int acscode;
  98     int pccode;
  99 } acs2pc_table [] = {
 100     { 'q',  0xC4 },
 101     { 'x',  0xB3 },
 102     { 'l',  0xDA },
 103     { 'k',  0xBF },
 104     { 'm',  0xC0 },
 105     { 'j',  0xD9 },
 106     { 'a',  0xB0 },
 107     { 'u',  0xB4 },
 108     { 't',  0xC3 },
 109     { 'w',  0xC2 },
 110     { 'v',  0xC1 },
 111     { 'n',  0xC5 },
 112     { 0, 0 } };
 113
 114 static int acs2pc (int acscode)
 115 {
 116     int i;
 117
 118     for (i = 0; acs2pc_table[i].acscode != 0; i++)
 119         if (acscode == acs2pc_table[i].acscode) {
 120             return acs2pc_table[i].pccode;
 121         }
 122     return 0;
 123 }
 124 #endif
 125
 126 /* returns the position where text was found in the start buffer */
 127 /* or 0 if not found */
 128 static char *
 129 search_string (char *start, char *text)
 130 {
 131     char *d = text;
 132     char *e = start;
 133
 134     /* fmt sometimes replaces a space with a newline in the help file */
 135     /* Replace the newlines in the link name with spaces to correct the situation */
 136     while (*d){
 137         if (*d == '\n')
 138             *d = ' ';
 139         d++;
 140     }
 141     /* Do search */
 142     for (d = text; *e; e++){
 143         if (*d == *e)
 144             d++;
 145         else
 146             d = text;
 147         if (!*d)
 148             return e+1;
 149     }
 150     return 0;
 151 }
 152
 153 /* Searches text in the buffer pointed by start.  Search ends */
 154 /* if the CHAR_NODE_END is found in the text.  Returns 0 on failure */
 155 static char *search_string_node (char *start, char *text)
 156 {
 157     char *d = text;
 158     char *e = start;
 159
 160     if (!start)
 161         return 0;
 162
 163     for (; *e && *e != CHAR_NODE_END; e++){
 164         if (*d == *e)
 165             d++;
 166         else
 167             d = text;
 168         if (!*d)
 169             return e+1;
 170     }
 171     return 0;
 172 }
 173
 174 /* Searches the_char in the buffer pointer by start and searches */
 175 /* it can search forward (direction = 1) or backward (direction = -1) */
 176 static char *search_char_node (char *start, char the_char, int direction)
 177 {
 178     char *e;
 179
 180     e = start;
 181
 182     for (; *e && (*e != CHAR_NODE_END); e += direction){
 183         if (*e == the_char)
 184             return e;
 185     }
 186     return 0;
 187 }
 188
 189 /* Returns the new current pointer when moved lines lines */
 190 static char *move_forward2 (char *c, int lines)
 191 {
 192     char *p;
 193     int  line;
 194
 195     currentpoint = c;
 196     for (line = 0, p = currentpoint; *p && *p != CHAR_NODE_END; p++){
 197         if (line == lines)
 198             return currentpoint = p;
 199         if (*p == '\n')
 200             line++;
 201     }
 202     return currentpoint = c;
 203 }
 204
 205 static char *move_backward2 (char *c, int lines)
 206 {
 207     char *p;
 208     int line;
 209
 210     currentpoint = c;
 211     for (line = 0, p = currentpoint; *p && p >= data; p--){
 212         if (*p == CHAR_NODE_END)
 213         {
 214             /* We reached the beginning of the node */
 215             /* Skip the node headers */
 216             while (*p != ']') p++;
 217             return currentpoint = p + 2;
 218         }
 219         if (*(p - 1) == '\n')
 220             line++;
 221         if (line == lines)
 222             return currentpoint = p;
 223     }
 224     return currentpoint = c;
 225 }
 226
 227 static void move_forward (int i)
 228 {
 229     if (end_of_node)
 230         return;
 231     currentpoint = move_forward2 (currentpoint, i);
 232 }
 233
 234 static void move_backward (int i)
 235 {
 236     currentpoint = move_backward2 (currentpoint, ++i);
 237 }
 238
 239 static void move_to_top (int dummy)
 240 {
 241     while (currentpoint > data && *currentpoint != CHAR_NODE_END)
 242         currentpoint--;
 243     while (*currentpoint != ']')
 244         currentpoint++;
 245     currentpoint = currentpoint + 1;
 246     selected_item = NULL;
 247 }
 248
 249 static void move_to_bottom (int dummy)
 250 {
 251     while (*currentpoint && *currentpoint != CHAR_NODE_END)
 252         currentpoint++;
 253     currentpoint--;
 254     move_backward (help_lines - 1);
 255 }
 256
 257 static char *help_follow_link (char *start, char *selected_item)
 258 {
 259     char link_name [MAXLINKNAME];
 260     char *p;
 261     int  i = 0;
 262
 263     if (!selected_item)
 264         return start;
 265
 266     for (p = selected_item; *p && *p != CHAR_NODE_END && *p != CHAR_LINK_POINTER; p++)
 267         ;
 268     if (*p == CHAR_LINK_POINTER){
 269         link_name [0] = '[';
 270         for (i = 1; *p != CHAR_LINK_END && *p && *p != CHAR_NODE_END && i < MAXLINKNAME-3; )
 271             link_name [i++] = *++p;
 272         link_name [i-1] = ']';
 273         link_name [i] = 0;
 274         p = search_string (data, link_name);
 275         if (p)
 276             return p;
 277     }
 278
 279     /* Create a replacement page with the error message */
 280     return _(" Help file format error\n");
 281 }
 282
 283 static char *select_next_link (char *start, char *current_link)
 284 {
 285     char *p;
 286
 287     if (!current_link)
 288         return 0;
 289
 290     p = search_string_node (current_link, STRING_LINK_END);
 291     if (!p)
 292         return NULL;
 293     p = search_string_node (p, STRING_LINK_START);
 294     if (!p)
 295         return NULL;
 296     return p - 1;
 297 }
 298
 299 static char *select_prev_link (char *start, char *current_link)
 300 {
 301     char *p;
 302
 303     if (!current_link)
 304         return 0;
 305
 306     p = current_link - 1;
 307     if (p <= start)
 308         return 0;
 309
 310     p = search_char_node (p, CHAR_LINK_START, -1);
 311     return p;
 312 }
 313
 314 static void start_link_area (int x, int y, char *link_name)
 315 {
 316     Link_Area *new;
 317
 318     if (inside_link_area)
 319         message (0, _("Warning"), _(" Internal bug: Double start of link area "));
 320
 321     /* Allocate memory for a new link area */
 322     new = g_new (Link_Area, 1);
 323     new->next = link_area;
 324     link_area = new;
 325
 326     /* Save the beginning coordinates of the link area */
 327     link_area->x1 = x;
 328     link_area->y1 = y;
 329
 330     /* Save the name of the destination anchor */
 331     link_area->link_name = link_name;
 332
 333     inside_link_area = 1;
 334 }
 335
 336 static void end_link_area (int x, int y)
 337 {
 338     if (inside_link_area){
 339         /* Save the end coordinates of the link area */
 340         link_area->x2 = x;
 341         link_area->y2 = y;
 342
 343         inside_link_area = 0;
 344     }
 345 }
 346
 347 static void clear_link_areas (void)
 348 {
 349     Link_Area *current;
 350
 351     while (link_area){
 352         current = link_area;
 353         link_area = current -> next;
 354         g_free (current);
 355     }
 356     inside_link_area = 0;
 357 }
 358
 359 static void help_show (Dlg_head *h, char *paint_start)
 360 {
 361     char *p;
 362     int  col, line, c;
 363     int  painting = 1;
 364     int acs;                    /* Flag: Alternate character set active? */
 365     int repeat_paint;
 366     int active_col, active_line;/* Active link position */
 367
 368     attrset (HELP_NORMAL_COLOR);
 369     do {
 370
 371         line = col = acs = active_col = active_line = repeat_paint = 0;
 372
 373         clear_link_areas ();
 374         if (selected_item < paint_start)
 375             selected_item = NULL;
 376
 377         for (p = paint_start; *p && *p != CHAR_NODE_END && line < help_lines; p++) {
 378             c = (unsigned char)*p;
 379             switch (c){
 380             case CHAR_LINK_START:
 381                 if (selected_item == NULL)
 382                     selected_item = p;
 383                 if (p == selected_item){
 384                     attrset (HELP_SLINK_COLOR);
 385
 386                     /* Store the coordinates of the link */
 387                     active_col = col + 2;
 388                     active_line = line + 2;
 389                 }
 390                 else
 391                     attrset (HELP_LINK_COLOR);
 392                 start_link_area (col, line, p);
 393                 break;
 394             case CHAR_LINK_POINTER:
 395                 painting = 0;
 396                 end_link_area (col - 1, line);
 397                 break;
 398             case CHAR_LINK_END:
 399                 painting = 1;
 400                 attrset (HELP_NORMAL_COLOR);
 401                 break;
 402             case CHAR_ALTERNATE:
 403                 acs = 1;
 404                 break;
 405             case CHAR_NORMAL:
 406                 acs = 0;
 407                 break;
 408             case CHAR_VERSION:
 409                 dlg_move (h, line+2, col+2);
 410                 addstr (VERSION);
 411                 col += strlen (VERSION);
 412                 break;
 413             case CHAR_FONT_BOLD:
 414                 attrset (HELP_BOLD_COLOR);
 415                 break;
 416             case CHAR_FONT_ITALIC:
 417                 attrset (HELP_ITALIC_COLOR);
 418                 break;
 419             case CHAR_FONT_NORMAL:
 420                 attrset (HELP_NORMAL_COLOR);
 421                 break;
 422             case '\n':
 423                 line++;
 424                 col = 0;
 425                 break;
 426             case '\t':
 427                 col = (col/8 + 1) * 8;
 428                 break;
 429             default:
 430                 if (!painting)
 431                     continue;
 432                 if (col > HELP_WINDOW_WIDTH-1)
 433                     continue;
 434
 435                 dlg_move (h, line+2, col+2);
 436                 if (acs){
 437                     if (c == ' ' || c == '.')
 438                         addch (c);
 439                     else
 440 #ifndef NATIVE_WIN32
 441 #ifndef HAVE_SLANG
 442                         addch (acs_map [c]);
 443 #else
 444                         SLsmg_draw_object (h->y + line + 2, h->x + col + 2, c);
 445 #endif
 446 #else
 447                         addch (acs2pc (c));
 448 #endif /* NATIVE_WIN32 */
 449                 } else
 450                     addch (c);
 451                 col++;
 452                 break;
 453             }
 454         }
 455         last_shown = p;
 456         end_of_node = line < help_lines;
 457         attrset (HELP_NORMAL_COLOR);
 458         if (selected_item >= last_shown){
 459             if (link_area != NULL){
 460                 selected_item = link_area->link_name;
 461                 repeat_paint = 1;
 462             }
 463             else
 464                 selected_item = NULL;
 465         }
 466     } while (repeat_paint);
 467
 468     /* Position the cursor over a nice link */
 469     if (active_col)
 470         dlg_move (h, active_line, active_col);
 471 }
 472
 473 static int help_event (Gpm_Event *event, Widget *w)
 474 {
 475     Link_Area *current_area;
 476
 477     if (! (event->type & GPM_UP))
 478         return 0;
 479
 480     /* The event is relative to the dialog window, adjust it: */
 481     event->y -= 2;
 482
 483     if (event->buttons & GPM_B_RIGHT){
 484         currentpoint = startpoint = history [history_ptr].page;
 485         selected_item = history [history_ptr].link;
 486         history_ptr--;
 487         if (history_ptr < 0)
 488             history_ptr = HISTORY_SIZE-1;
 489
 490         help_callback (w->parent, 0, DLG_DRAW);
 491         return 0;
 492     }
 493
 494     /* Test whether the mouse click is inside one of the link areas */
 495     current_area = link_area;
 496     while (current_area)
 497     {
 498         /* Test one line link area */
 499         if (event->y == current_area->y1 && event->x >= current_area->x1 &&
 500             event->y == current_area->y2 && event->x <= current_area->x2)
 501             break;
 502         /* Test two line link area */
 503         if (current_area->y1 + 1 == current_area->y2){
 504             /* The first line */
 505             if (event->y == current_area->y1 && event->x >= current_area->x1)
 506                 break;
 507             /* The second line */
 508             if (event->y == current_area->y2 && event->x <= current_area->x2)
 509                 break;
 510         }
 511         /* Mouse will not work with link areas of more than two lines */
 512
 513         current_area = current_area -> next;
 514     }
 515
 516     /* Test whether a link area was found */
 517     if (current_area){
 518         /* The click was inside a link area -> follow the link */
 519         history_ptr = (history_ptr+1) % HISTORY_SIZE;
 520         history [history_ptr].page = currentpoint;
 521         history [history_ptr].link = current_area->link_name;
 522         currentpoint = startpoint = help_follow_link (currentpoint, current_area->link_name);
 523         selected_item = NULL;
 524     } else{
 525         if (event->y < 0)
 526             move_backward (help_lines - 1);
 527         else if (event->y >= help_lines)
 528             move_forward (help_lines - 1);
 529         else if (event->y < help_lines/2)
 530             move_backward (1);
 531         else
 532             move_forward (1);
 533     }
 534
 535     /* Show the new node */
 536     help_callback (w->parent, 0, DLG_DRAW);
 537
 538     return 0;
 539 }
 540
 541 /* show help */
 542 static void
 543 help_help_cmd (Dlg_head *h)
 544 {
 545     history_ptr = (history_ptr+1) % HISTORY_SIZE;
 546     history [history_ptr].page = currentpoint;
 547     history [history_ptr].link = selected_item;
 548     currentpoint = startpoint = search_string (data, "[How to use help]") + 1;
 549     selected_item = NULL;
 550     help_callback (h, 0, DLG_DRAW);
 551 }
 552
 553 static void
 554 help_index_cmd (Dlg_head * h)
 555 {
 556     char *new_item;
 557
 558     if (!(new_item = search_string (data, "[Contents]"))) {
 559         message (1, MSG_ERROR, _(" Cannot find node %s in help file "),
 560                  "[Contents]");
 561         return;
 562     }
 563
 564     history_ptr = (history_ptr + 1) % HISTORY_SIZE;
 565     history[history_ptr].page = currentpoint;
 566     history[history_ptr].link = selected_item;
 567
 568     currentpoint = startpoint = new_item + 1;
 569     selected_item = NULL;
 570     help_callback (h, 0, DLG_DRAW);
 571 }
 572
 573 static void help_quit_cmd (void *x)
 574 {
 575     dlg_stop ((Dlg_head *)x);
 576 }
 577
 578 static void prev_node_cmd (Dlg_head *h)
 579 {
 580     currentpoint = startpoint = history [history_ptr].page;
 581     selected_item = history [history_ptr].link;
 582     history_ptr--;
 583     if (history_ptr < 0)
 584         history_ptr = HISTORY_SIZE-1;
 585
 586     help_callback (h, 0, DLG_DRAW);
 587 }
 588
 589 static int md_callback (Widget *w, int msg, int par)
 590 {
 591     return default_proc (msg, par);
 592 }
 593
 594 static Widget *mousedispatch_new (int y, int x, int yl, int xl)
 595 {
 596     Widget *w = g_new (Widget, 1);
 597
 598     init_widget (w, y, x, yl, xl,
 599                  (callback_fn) md_callback, 0, (mouse_h)  help_event, NULL);
 600
 601     return w;
 602 }
 603
 604 static int help_handle_key (struct Dlg_head *h, int c)
 605 {
 606     char *new_item;
 607
 608     if (c != KEY_UP && c != KEY_DOWN &&
 609         check_movement_keys (c, 1, help_lines, currentpoint,
 610                              (movefn) move_backward2,
 611                              (movefn) move_forward2,
 612                              (movefn) move_to_top,
 613                              (movefn) move_to_bottom))
 614         /* Nothing */;
 615     else switch (c){
 616     case 'l':
 617     case KEY_LEFT:
 618         prev_node_cmd (h);
 619         break;
 620
 621     case '\n':
 622     case KEY_RIGHT:
 623         /* follow link */
 624         if (!selected_item){
 625 #ifdef WE_WANT_TO_GO_BACKWARD_ON_KEY_RIGHT
 626             /* Is there any reason why the right key would take us
 627              * backward if there are no links selected?, I agree
 628              * with Torben than doing nothing in this case is better
 629              */
 630             /* If there are no links, go backward in history */
 631             history_ptr--;
 632             if (history_ptr < 0)
 633                 history_ptr = HISTORY_SIZE-1;
 634
 635             currentpoint = startpoint = history [history_ptr].page;
 636             selected_item   = history [history_ptr].link;
 637 #endif
 638         } else {
 639             history_ptr = (history_ptr+1) % HISTORY_SIZE;
 640             history [history_ptr].page = currentpoint;
 641             history [history_ptr].link = selected_item;
 642             currentpoint = startpoint = help_follow_link (currentpoint, selected_item) + 1;
 643         }
 644         selected_item = NULL;
 645         break;
 646
 647     case KEY_DOWN:
 648     case '\t':
 649         /* select next link */
 650         new_item = select_next_link (startpoint, selected_item);
 651         if (new_item){
 652             selected_item = new_item;
 653             if (selected_item >= last_shown){
 654                 if (c == KEY_DOWN)
 655                     move_forward (1);
 656                 else
 657                     selected_item = NULL;
 658             }
 659         } else if (c == KEY_DOWN)
 660             move_forward (1);
 661         else
 662             selected_item = NULL;
 663         break;
 664
 665     case KEY_UP:
 666     case ALT ('\t'):
 667         /* select previous link */
 668         new_item = select_prev_link (startpoint, selected_item);
 669         selected_item = new_item;
 670         if (selected_item < currentpoint || selected_item >= last_shown){
 671             if (c == KEY_UP)
 672                 move_backward (1);
 673             else{
 674                 if (link_area != NULL)
 675                     selected_item = link_area->link_name;
 676                 else
 677                     selected_item = NULL;
 678             }
 679         }
 680         break;
 681
 682     case 'n':
 683         /* Next node */
 684         new_item = currentpoint;
 685         while (*new_item && *new_item != CHAR_NODE_END)
 686             new_item++;
 687         if (*++new_item == '['){
 688             while (*++new_item) {
 689                 if (*new_item == ']' && *++new_item && *++new_item) {
 690                     currentpoint = new_item;
 691                     selected_item = NULL;
 692                     break;
 693                 }
 694             }
 695         }
 696         break;
 697
 698     case 'p':
 699         /* Previous node */
 700         new_item = currentpoint;
 701         while (new_item > data + 1 && *new_item != CHAR_NODE_END)
 702             new_item--;
 703         new_item--;
 704         while (new_item > data && *new_item != CHAR_NODE_END)
 705             new_item--;
 706         while (*new_item != ']')
 707             new_item++;
 708         currentpoint = new_item + 2;
 709         selected_item = NULL;
 710         break;
 711
 712     case 'c':
 713         help_index_cmd (h);
 714         break;
 715
 716     case ESC_CHAR:
 717     case XCTRL('g'):
 718         dlg_stop (h);
 719         break;
 720
 721     default:
 722         return 0;
 723
 724     }
 725     help_callback (h, 0, DLG_DRAW);
 726     return 1;
 727 }
 728
 729 static int help_callback (struct Dlg_head *h, int id, int msg)
 730 {
 731     switch (msg){
 732     case DLG_DRAW:
 733         common_dialog_repaint (h);
 734         help_show (h, currentpoint);
 735         break;
 736
 737     case DLG_KEY:
 738         return help_handle_key (h, id);
 739     }
 740     return 0;
 741 }
 742
 743 static void
 744 interactive_display_finish (void)
 745 {
 746     clear_link_areas ();
 747     g_free (data);
 748 }
 749
 750 void
 751 interactive_display (char *filename, char *node)
 752 {
 753     WButtonBar *help_bar;
 754     Widget *md;
 755     char *hlpfile = filename;
 756
 757     if (filename)
 758         data = load_file (filename);
 759     else
 760         data = load_mc_home_file ("mc.hlp", &hlpfile);
 761
 762     if (data == NULL) {
 763         message (1, MSG_ERROR, _(" Cannot open file %s \n %s "), hlpfile,
 764                  unix_error_string (errno));
 765     }
 766
 767     if (!filename)
 768         g_free (hlpfile);
 769
 770     if (!data)
 771         return;
 772
 773     if (!node || !*node)
 774         node = "[main]";
 775
 776     if (!(main_node = search_string (data, node))) {
 777         message (1, MSG_ERROR, _(" Cannot find node %s in help file "),
 778                  node);
 779
 780         /* Fallback to [main], return if it also cannot be found */
 781         main_node = search_string (data, "[main]");
 782         if (!main_node) {
 783             interactive_display_finish ();
 784             return;
 785         }
 786     }
 787
 788     help_lines = min (LINES - 4, max (2 * LINES / 3, 18));
 789
 790     whelp =
 791         create_dlg (0, 0, help_lines + 4, HELP_WINDOW_WIDTH + 4,
 792                     dialog_colors, help_callback, "[Help]", _("Help"),
 793                     DLG_TRYUP | DLG_CENTER | DLG_WANT_TAB);
 794
 795     selected_item = search_string_node (main_node, STRING_LINK_START) - 1;
 796     currentpoint = startpoint = main_node + 1;
 797
 798     for (history_ptr = HISTORY_SIZE; history_ptr;) {
 799         history_ptr--;
 800         history[history_ptr].page = currentpoint;
 801         history[history_ptr].link = selected_item;
 802     }
 803
 804     help_bar = buttonbar_new (1);
 805     help_bar->widget.y -= whelp->y;
 806     help_bar->widget.x -= whelp->x;
 807
 808     md = mousedispatch_new (1, 1, help_lines, HELP_WINDOW_WIDTH - 2);
 809
 810     add_widget (whelp, help_bar);
 811     add_widget (whelp, md);
 812
 813     define_label_data (whelp, 1, _("Help"), (buttonbarfn) help_help_cmd,
 814                        whelp);
 815     define_label_data (whelp, 2, _("Index"), (buttonbarfn) help_index_cmd,
 816                        whelp);
 817     define_label_data (whelp, 3, _("Prev"), (buttonbarfn) prev_node_cmd,
 818                        whelp);
 819     define_label (whelp, 4, "", 0);
 820     define_label (whelp, 5, "", 0);
 821     define_label (whelp, 6, "", 0);
 822     define_label (whelp, 7, "", 0);
 823     define_label (whelp, 8, "", 0);
 824     define_label (whelp, 9, "", 0);
 825     define_label_data (whelp, 10, _("Quit"), help_quit_cmd, whelp);
 826
 827     run_dlg (whelp);
 828     interactive_display_finish ();
 829     destroy_dlg (whelp);
 830 }
 831