Terminal control/Dimensions

Terminal control/Dimensions
You are encouraged to solve this task according to the task description, using any language you may know.

Determine the height and width of the terminal, and store this information into variables for subsequent use.

AutoHotkey

Works with: AutoHotkey_L

Translation of: C

AutoHotkey is not built for the console (it is GUI oriented) so we must call the WinAPI directly.

DllCall( "AllocConsole" ) ; create a console if not launched from one
hConsole := DllCall( "GetStdHandle", int, STDOUT := -11 )
 
MsgBox Resize the console...
 
VarSetCapacity(csbi, 22) ; CONSOLE_SCREEN_BUFFER_INFO structure
DllCall("GetConsoleScreenBufferInfo", UPtr, hConsole, UPtr, &csbi)
Left   := NumGet(csbi, 10, "short")
Top    := NumGet(csbi, 12, "short")
Right  := NumGet(csbi, 14, "short")
Bottom := NumGet(csbi, 16, "short")
 
columns	:= right - left + 1
rows	:= bottom - top + 1
MsgBox %columns% columns and %rows% rows

BBC BASIC

Works with: BBC BASIC for Windows

      dx% = @vdu.tr%[email protected]% : REM Width of text viewport in pixels
      dy% = @vdu.tb%[email protected]% : REM Height of text viewport in pixels

C

C provides no standard way to find the size of a terminal.

Library: BSD libc

BSD systems (and some other Unix clones) have TIOCGWINSZ. This ioctl(2) call gets the "window size" of a tty(4) device.

Almost all terminal devices can do NAWS (Negotiate About Window Size). A terminal emulator like xterm(1) should set the size. A network server like sshd(1) should copy the size from its client. Other devices, such as plain serial ports, might not know the window size.

Works with: BSD version 4.4

#include <sys/ioctl.h>	/* ioctl, TIOCGWINSZ */
#include <err.h>	/* err */
#include <fcntl.h>	/* open */
#include <stdio.h>	/* printf */
#include <unistd.h>	/* close */
 
int
main()
{
	struct winsize ws;
	int fd;
 
	/* Open the controlling terminal. */
	fd = open("/dev/tty", O_RDWR);
	if (fd < 0)
		err(1, "/dev/tty");
 
	/* Get window size of terminal. */ 
	if (ioctl(fd, TIOCGWINSZ, &ws) < 0)
		err(1, "/dev/tty");
 
	printf("%d rows by %d columns\n", ws.ws_row, ws.ws_col);
	printf("(%d by %d pixels)\n", ws.ws_xpixel, ws.ws_ypixel);
 
	close(fd);	
	return 0;
}

Windows

Grab a console screen handle, then call GetConsoleScreenBufferInfo() to get the information. Most consoles have a scroll bar and hold hundreds of lines, but the window shows only 25 or 50 lines. Use the window coordinates to calculate the window size.

Works with: MinGW

#include <windows.h>
#include <wchar.h>
 
int
main()
{
	HANDLE console;
	CONSOLE_SCREEN_BUFFER_INFO info;
	short rows;
	short columns;
	/* Create a handle to the console screen. */
	console = CreateFileW(L"CONOUT$", GENERIC_READ | GENERIC_WRITE,
	    FILE_SHARE_READ | FILE_SHARE_WRITE, NULL, OPEN_EXISTING,
	    0, NULL);
	if (console == INVALID_HANDLE_VALUE)
		return 1;
 
	/* Calculate the size of the console window. */
	if (GetConsoleScreenBufferInfo(console, &info) == 0)
		return 1;
	CloseHandle(console);
	columns = info.srWindow.Right - info.srWindow.Left + 1;
	rows = info.srWindow.Bottom - info.srWindow.Top + 1;
 
	wprintf(L"%d columns by %d rows\n", columns, rows);
 
	return 0;
}

Euphoria

include graphics.e
 
sequence vc
integer term_height, term_width
 
vc = video_config()
 
term_height = vc[VC_LINES]
term_width  = vc[VC_COLUMNS]
 
printf(1,"Terminal height is %d\n",term_height)
printf(1,"Terminal width is %d\n",term_width)

Forth

Works with: GNU Forth

Works with: SwiftForth

variable term-width
variable term-height
 
s" gforth" environment? [if]
  2drop form ( height width )
[else]  \ SwiftForth
  get-size ( width height ) swap
[then]
term-width ! term-height !

J

This is not well supported in J, but since the terminal window can be resized at any time and can have its font changed and so on, good design generally dictates that this kind of information be ignored.

Nevertheless, assuming J version 6 in its usual environment, to determine its width and height, in pixels, you can use:

_2 {.qsmsize_jijs_''

Note also that this will typically include 37 extra pixels horizontally and 79 extra pixels vertically, which are not available to display text. In other words, if the result was 700 500 you would really have 663 pixels of width and 421 pixels of height.

Locomotive Basic

Locomotive BASIC has no built-in command to get window dimensions, but there is a firmware call to &bb69 (TXT_GET_WINDOW) for this. So we have to use a snippet of Z80 machine code to call the firmware and copy the results from the DE and HL registers to RAM. It looks like this when disassembled:

4000 d5          push de
4001 e5          push hl
4002 cd 69 bb    call &bb69
4005 ed 53 20 40 ld (&4020),de
4009 22 22 40    ld (&4022),hl
400c e1          pop hl
400d d1          pop de
400e c9          ret

This routine gets POKEd into RAM (starting at address &4000) and CALLed from Locomotive BASIC, then the results are retrieved with PEEK:

10 s=&4000:SYMBOL AFTER 256:MEMORY s-1
20 FOR i=0 to 14:READ a:POKE s+i,a:NEXT
30 DATA &d5,&e5,&cd,&69,&bb,&ed,&53,&20,&40,&22,&22,&40,&e1,&d1,&c9
40 CALL s
50 h=PEEK(&4020)-PEEK(&4022)+1
60 w=PEEK(&4021)-PEEK(&4023)+1
70 PRINT "window width:"; w; ", height:"; h

In practice, one would prefer to write the machine code routine as a slightly more elaborate RSX (resident system extension) which is a freely relocatable and therefore more reusable Locomotive BASIC extension. The RSX routine might be called "getwh" and accept pointers to integers, which would simplify the BASIC code to:

10 w%=0:h%=0      ' initialize and force integer type
20 |getwh,@w%,@h% ' call RSX and pass variables as pointers
30 PRINT "window width:"; w%; ", height:"; h%

Mathematica

WIDTH=RunThrough["tput cols", ""];
HEIGHT=RunThrough["tput lines", ""];

OCaml

Using the library ANSITerminal in the interactive loop:

$ ocaml unix.cma -I +ANSITerminal ANSITerminal.cma
 
# let width, height = ANSITerminal.size () ;;
val width : int = 126
val height : int = 47

Perl

use Term::Size;
 
($cols, $rows) = Term::Size::chars;
print "The terminal has $cols columns and $rows lines\n";

Perl 6

Using stty just for the heck of it.

my $stty = qx[stty -a];
my $lines = $stty.match(/ 'rows '    <( \d+/);
my $cols  = $stty.match(/ 'columns ' <( \d+/);
say "$lines $cols";

PicoLisp

(setq
   Width (in '(tput cols) (read))
   Height (in '(tput lines) (read)) )

PureBasic

PureBasic does not have native functions for reading the size of this window, but supports API-functions that allows this.

This code is for Windows only.

Macro ConsoleHandle()
  GetStdHandle_( #STD_OUTPUT_HANDLE )
EndMacro
 
Procedure ConsoleWidth()
  Protected CBI.CONSOLE_SCREEN_BUFFER_INFO
  Protected hConsole = ConsoleHandle()
  GetConsoleScreenBufferInfo_( hConsole, @CBI )
  ProcedureReturn CBI\srWindow\right - CBI\srWindow\left + 1
EndProcedure
 
Procedure ConsoleHeight()
  Protected CBI.CONSOLE_SCREEN_BUFFER_INFO
  Protected hConsole = ConsoleHandle()
  GetConsoleScreenBufferInfo_( hConsole, @CBI )
  ProcedureReturn CBI\srWindow\bottom - CBI\srWindow\top + 1
EndProcedure
 
If OpenConsole()
  x$=Str(ConsoleWidth())
  y$=Str(ConsoleHeight())
  PrintN("This window is "+x$+"x"+y$+ " chars.")
  ;
  Print(#CRLF$+"Press ENTER to exit"):Input()
EndIf

Python

Works with: Python version 2.6

Library: ctypes

This uses the ctypes library in order to get the console dimensions on Windows. This code is a slight refactoring of an ActiveState Recipe. For Linux, the tput utility is used.

import os
 
def get_windows_terminal():
    from ctypes import windll, create_string_buffer
    h = windll.kernel32.GetStdHandle(-12)
    csbi = create_string_buffer(22)
    res = windll.kernel32.GetConsoleScreenBufferInfo(h, csbi)
 
    #return default size if actual size can't be determined
    if not res: return 80, 25 
 
    import struct
    (bufx, bufy, curx, cury, wattr, left, top, right, bottom, maxx, maxy)\
    = struct.unpack("hhhhHhhhhhh", csbi.raw)
    width = right - left + 1
    height = bottom - top + 1
 
    return width, height
 
def get_linux_terminal():
    width = os.popen('tput cols', 'r').readline()
    height = os.popen('tput lines', 'r').readline()
 
    return int(width), int(height)
 
print get_linux_terminal() if os.name == 'posix' else get_windows_terminal()
 

Racket

 
#lang racket
(require (planet neil/charterm:3:0))
(with-charterm
 (charterm-screen-size))
 

Retro

This information is provided by Retro in the ch (height) and cw (width) variables. You can manually obtain it using the io ports.

-3 5 out wait 5 in !cw
-4 5 out wait 5 in !ch

REXX

using TPUT under Linux/Unix

Works with: brexx

Works with: regina

Works with: rexximc

Some Rexx interpreters don't provide basic terminal control as part of the language.
However, it's possible to determine the size of the terminal window by using external system commands:

 
width = 'tput'( 'cols' )
height = 'tput'( 'lines' )
 
say 'The terminal is' width 'characters wide'
say 'and has' height 'lines'
 

using LINESIZE bif

Most (classic) REXX interpreters (and some others) such as

• CMS REXX
• TSO REXX
• VSE REXX
• IBM REXX compiler
• PC/REXX
• Personal REXX
• REXX/imc
• R4
• ROO

support the   LINESIZE   built-in function which returns the (terminal) screen's width.

A sample usage of the   LINESIZE   bif is:

width=linesize()

using SCRSIZE bif

A few classic REXX interpretors support the   SCRSIZE   bif:

• PC/REXX
• Personal REXX
• R4
• ROO

The   SCRSIZE   bif returns two integers:

• the screen depth
• the screen width

 parse value scrsize() with sd sw

Ruby

def winsize
  # Ruby 1.9.3 added 'io/console' to the standard library.
  require 'io/console'
  IO.console.winsize
rescue LoadError
  # This works with older Ruby, but only with systems
  # that have a tput(1) command, such as Unix clones.
  [Integer(`tput li`), Integer(`tput co`)]
end
 
rows, cols = winsize
printf "%d rows by %d columns\n", rows, cols

Library: curses

Curses.lines and Curses.cols return the size of the terminal. The program must call Curses.init_screen, because without this call, Curses might report 0 lines and 0 columns. Beware that Curses.init_screen also switches the terminal to screen-oriented mode, and fails on those terminals that cannot support curses.

require 'curses'
 
begin
  Curses.init_screen
 
  r, c = Curses.lines, Curses.cols
 
  Curses.setpos r / 2, 0
  Curses.addstr "#{r} rows by #{c} columns".center(c)
  Curses.getch
ensure
  Curses.close_screen
end

Seed7

The functions height and width are portable and determine the dimensions of the console window. Height and width are based on terminfo respectively the Windows console API.

$ include "seed7_05.s7i";
  include "console.s7i";
 
const proc: main is func
  local
    var text: console is STD_NULL;
  begin
    console := open(CONSOLE);
    writeln(console, "height: " <& height(console) lpad 3);
    writeln(console, "width:  " <& width(console) lpad 3);
    # Terminal windows often restore the previous
    # content, when a program is terminated. Therefore
    # the program waits until Return/Enter is pressed.
    readln;
  end func;

Tcl

Translation of: UNIX Shell

set width [exec tput cols]
set height [exec tput lines]
puts "The terminal is $width characters wide and has $height lines"

UNIX Shell

Works with: Bourne Shell

#!/bin/sh
WIDTH=`tput cols`
HEIGHT=`tput lines`
echo "The terminal is $WIDTH characters wide and has $HEIGHT lines."

Library: termcap

termcap is obsolete.

#!/bin/sh
WIDTH=`tput co`
HEIGHT=`tput li`
echo "The terminal is $WIDTH characters wide and has $HEIGHT lines."

C Shell

#!/bin/csh -f
set WIDTH=`tput cols`
set HEIGHT=`tput lines`
echo "The terminal is $WIDTH characters wide and has $HEIGHT lines."

XPL0

include c:\cxpl\codes;
int W, H;
[W:= Peek($40, $4A);            \IBM-PC BIOS data
 H:= Peek($40, $84) + 1;
Text(0, "Terminal width and height = ");
IntOut(0, W);  ChOut(0, ^x);  IntOut(0, H);
]

Output:

80x25