Very Computer

in the old DOS time it was no problem to draw frames
by using the "ASCII" characters 128-255.
(btw. i am aware that ASCII is only 7bit ;-)

Recently i tried this on my Linux box, and i found
that i am using the ISO 8859-1 character set. So my
question is how can I use the same table like
DOS inside my c program?

(I do not understand if this has something to do
with the terminal settings. On my box i have
TERM=xterm).

TIA, Oliver
--
Wer Druckfehler findet, darf die behalten.

Most probably on your DOS box you used Windows code page 850 (?),
which contained the box-frame-characters in character positions above
127.  ISO8859-1 contains various Umlauts and other symbols instead in
these positions, so there are no box-building characters in that
encoding.  Check your manpages for `code page' and/or `font encoding'.

Good luck...
R'

 Oliver> Hi,
 Oliver> in the old DOS time it was no problem to draw frames by using
 Oliver> the "ASCII" characters 128-255.  (btw. i am aware that ASCII
 Oliver> is only 7bit ;-)

 Oliver> Recently i tried this on my Linux box, and i found that i am
 Oliver> using the ISO 8859-1 character set. So my question is how can
 Oliver> I use the same table like DOS inside my c program?

 Oliver> (I do not understand if this has something to do with the
 Oliver> terminal settings. On my box i have TERM=xterm).

It does indeed depend on the terminal settings. Most terminal descriptions
contain a table of linedraw characters and the necessary escape sequences
needed to tell the terminal to use them.

The simplest way to do this, as usual, is to use the curses library,
which allows you to write full-screen character-mode programs which
take advantage of most terminal features and which work on almost any
terminal type for which a working description exists. A simple example,
which should use line-drawing characters if available but fall back to
using '+', '-' and '|' if not:

#include <ncurses.h>

int main(void)
{
    WINDOW *win;

    initscr();   /* curses initialisation */
    cbreak();
    noecho();
    curs_set(0); /* turn cursor off if possible */

    clear();
    leaveok(stdscr, TRUE);

    /* draw a "window" pattern two-thirds of the way down the screen */    
    move((2*LINES/3)-2, COLS/2-2);
    addch(ACS_ULCORNER);
    addch(ACS_HLINE);
    addch(ACS_TTEE);
    addch(ACS_HLINE);
    addch(ACS_URCORNER);
    move((2*LINES/3)-1, COLS/2-2);
    addch(ACS_VLINE);
    addch(' ');
    addch(ACS_VLINE);
    addch(' ');
    addch(ACS_VLINE);
    move((2*LINES/3), COLS/2-2);
    addch(ACS_LTEE);
    addch(ACS_HLINE);
    addch(ACS_PLUS);
    addch(ACS_HLINE);
    addch(ACS_RTEE);
    move((2*LINES/3)+1, COLS/2-2);
    addch(ACS_VLINE);
    addch(' ');
    addch(ACS_VLINE);
    addch(' ');
    addch(ACS_VLINE);
    move((2*LINES/3)+2, COLS/2-2);
    addch(ACS_LLCORNER);
    addch(ACS_HLINE);
    addch(ACS_BTEE);
    addch(ACS_HLINE);
    addch(ACS_LRCORNER);

    /* update the virtual screen (no actual output yet) */
    wnoutrefresh(stdscr);

    /* create a new window one-third of the way down the screen,
     * draw a border box in it (goes _inside_ the window),
     * and display a message
     */
    win = newwin(5, 24, (LINES/3)-2, (COLS-24)/2);
    box(win,0,0);
    mvwaddstr(win, 2, 6, "Hello World!");
    leaveok(win, TRUE);

    /* update the new window to the virtual screen */
    wnoutrefresh(win);

    /* finally, actually display everything */
    doupdate();

    /* wait for a keystroke */
    getch();

    /* restore terminal modes */
    endwin();

    return 0;

Quote:}

comp.unix.programmer FAQ: see <URL: http://www.erlenstar.demon.co.uk/unix/>

I was thinking of changeing the character set,
and i used to think this was the way curses does it.
Now i hear i have to change the terminal and use
escape sequences, so how would i do this?

TIA, Oliver

I do not remember how you determine the character you need
to send (when in ACS mode) to get it translated to line-drawing
graphics, but there is a list somewhere. RTFineM "terminfo".
IMHO, most of this stuff is modeled after the old "VT 100"
terminals, so any description of these might also help.
As a start, try   http://www.cs.utk.edu/~shuford/terminal/dec.html

HTH,
Joerg Bruehe

--
Joerg Bruehe, SQL Datenbanksysteme GmbH, Berlin, Germany
     (speaking only for himself)

 Joerg> AFAIR, this may be implemented by terminals (either hardware,
 Joerg> or emulators in software) as "alternate character set", and
 Joerg> the terminal can be switched into / out of that set.  The
 Joerg> escape sequences to do that switching are called "smacs" ("Set
 Joerg> Mode Alternate Character Set") and "rmacs" ("Reset ...") in
 Joerg> the "terminfo" stuff, see the "ACS..."  character names in
 Joerg> Andrew's post. AIUI, in the ACS mode you have no Umlauts or
 Joerg> other ISO characters beyond ASCII.

 Joerg> I do not remember how you determine the character you need to
 Joerg> send (when in ACS mode) to get it translated to line-drawing
 Joerg> graphics, but there is a list somewhere.

the 'acsc' string capability ('ac' in termcap) contains pairs of
characters, where the first character in each pair is the character you
have to send to a vt100 to get the specific graphic, and the second is
the character you have to send for the type of terminal being described.
(Of course, for vt100-emulators like xterm, these are the same.)

--
Andrew.

comp.unix.programmer FAQ: see <URL: http://www.erlenstar.demon.co.uk/unix/>

Any ideas what i am doing wrong here?

#include <stdio.h>
int main(void)
{
  char esc=27;

  printf("%c[2J",esc);         /* clear screen */
  printf("%c[%d;%dH",esc,5,5); /* set cursor to positon */

  printf("%c[12m",esc);        /* switch to alternate charset */
  printf("jjkkllmm");          /* try some... */
  printf("%c[10m",esc);        /* reset from alt. chars */
  printf("\n");

  return 0;

Quote:}

 Oliver> Unfortunately i still don't get it. Therefore here's my testprog.
 Oliver> I tried TERM=xterm and TERM=vt100. And after a look at /etc/termcap
 Oliver> some ways to switch to the alternate characterset, which won't work.
 Oliver> (clearing the screen and setting the cursor is no problem however).

 Oliver> Any ideas what i am doing wrong here?

 Oliver> #include <stdio.h>
 Oliver> int main(void)
 Oliver> {
 Oliver>   char esc=27;

 Oliver>   printf("%c[2J",esc);         /* clear screen */
 Oliver>   printf("%c[%d;%dH",esc,5,5); /* set cursor to positon */

 Oliver>   printf("%c[12m",esc);        /* switch to alternate charset */

for a vt100 or xterm that needs to be "%c(0" to set the alternate charset
and "%c(B" to reset it to normal. You should, ideally, get these strings
from the termcap 'as' and 'ae' capabilities (smacs and rmacs in terminfo).
With that change, your program works as expected.

 Oliver>   printf("jjkkllmm");          /* try some... */
 Oliver>   printf("%c[10m",esc);        /* reset from alt. chars */
 Oliver>   printf("\n");

 Oliver>   return 0;
 Oliver> }

--
Andrew.

comp.unix.programmer FAQ: see <URL: http://www.erlenstar.demon.co.uk/unix/>

Thanks for all the help!

Oliver
--
Wer Druckfehler findet, darf die behalten.