Terminal control/Preserve screen: Difference between revisions

There is no requirement to change the font or kerning in this task, however character decorations and attributes are expected to be preserved.   If the implementer decides to change the font or kerning during the display of the temporary screen, then these settings need to be restored prior to exit.

<br><br>

 

=={{header|Applesoft BASIC}}==

Restores 40 x 24 TEXT screen, cursor position, display mode, and speed. Adjusts HIMEM to make room to store 1024 bytes aligned to the 256 byte page boundary. POKEs a machine language "copy 4 pages of memory" routine into page 3.

11 LET FD = 253:FC = FD - 1

12 POKE FC, 0 : POKE FE, 0

61 CALL R : POKE 241, S

62 VTAB V + 1 : HTAB C + 1

 

=={{header|BBC BASIC}}==

{{works with|BBC BASIC for Windows}}

The screen is saved as a bitmap:

OSCLI "GSAVE """ + @tmp$ + "bbcsave"""

WAIT 200

PRINT "This is the new screen, following a CLS"

WAIT 200

 

=={{header|Befunge}}==

Assuming a terminal with support for Xterm's [http://invisible-island.net/xterm/ctlseqs/ctlseqs.html#h2-The-Alternate-Screen-Buffer ''alternate screen buffer''] escape sequences (which I believe is fairly standard these days), this example will switch to the alternate screen buffer, output "Press <Enter> to restore..." in the top left corner, and then restore the original screen.

 

 

=={{header|C}}==

#include <unistd.h>

 

 

return 0;

 

=={{header|Common Lisp}}==

{{trans|C}}

(format t "~C[?1049h~C[H" (code-char #O33) (code-char #O33))

(format t "Alternate screen buffer~%")

))

(format t "~C[?1049l" (code-char #O33))

 

==={{header|ncurses}}===

When the ncurses terminal library is used, characters are displayed on an alternate screen of the terminal. Leaving ncurses returns to the original screen buffer with the previous content preserved. To interface ncurses from Lisp, the ''croatoan'' library is used.

;; starting a ncurses screen enters the alternate screen buffer of the terminal

(with-screen (scr :input-echoing nil :input-blocking t)

(refresh scr)

(get-char scr)))

 

=={{header|Emacs Lisp}}==

 

;; -*- lexical-binding: t; -*-

 

 

;; "ESC [ ? 1049 l" - Disable alternative screen buffer

 

=={{header|Forth}}==

{{trans|C}}

{{works with|gforth|0.7.3}}

." Press any key to return" ekey drop

 

=={{header|Go}}==

{{trans|C}}

{{works with|Ubuntu 16.04}}

 

import (

}

fmt.Print("\033[?1049l")

 

=={{header|Java}}==

{{trans|C}}

{{works with|Ubuntu 16.04}}

{

public static void main(String[] args) throws InterruptedException {

System.out.print("\033[?1049l");

}

 

=={{header|JavaScript}}==

var orig= document.body.innerHTML

document.body.innerHTML= '';

}, 1000);

}, 1000);

 

This implementation assumes that Javascript is running in the browser.

=={{header|Julia}}==

{{trans|C}}

 

print("$ESC[?1049h$ESC[H")

print("$ESC[?1049l\n\n\n")

 

 

=={{header|Kotlin}}==

{{trans|C}}

{{Works with|Ubuntu|14.04}}

 

const val ESC = "\u001B"

}

print("$ESC[?1049l")

 

=={{header|M2000 Interpreter}}==

If we change Mode (size of font), or Window size (console witdh/height), or use a Form statement to set character resolution (number characters in a row by row number) which automatic calculate size and line spacing, then saved consoled bitmap erased. To preserve screen from this situation we have to preserve last form's arguments, or window's arguments or mode's argument.

 

Module PreserveScreen {

Bold 1

PreserveScreen

 

 

=={{header|Mathematica}}/{{header|Wolfram Language}}==

Run["echo Hello"]

Pause[5] (* Wait five seconds *)

 

=={{header|Nim}}==

{{trans|Python}}

 

echo "\e[?1049h\e[H"

sleep 1000

 

 

=={{header|Perl}}==

{{trans|C}}

print "Alternate screen buffer\n";

 

}

 

 

=={{header|Phix}}==

 

=={{header|PicoLisp}}==

 

(call 'tput "smcup")

(call 'tput "rmcup")

 

 

=={{header|Python}}==

Similar to the C example above:

 

 

import time

time.sleep(1)

 

 

=={{header|R}}==

{{trans|C}}

cat("Alternate screen buffer\n")

for (i in 5:1) {

cat("\33[2J")

}

 

=={{header|Racket}}==

#lang racket

 

 

(flash "Hello world.")

 

=={{header|Raku}}==

(formerly Perl 6)

say "Alternate buffer!";

 

}

 

 

=={{header|REXX}}==

 

The &nbsp; '''CLS''' &nbsp; (DOS) command is used to clear the terminal screen.

/*──── screen, writes a half screen of ~~~ lines, and then restores the original screen.*/

 

end /*restore*/ /* [↑] writes (restores) SD lines. */

/*stick a fork in it, we're all done. */

This REXX program makes use of &nbsp; '''scrsize''' &nbsp; BIF which is used to determine the screen size of the terminal (console).

 

For those REXXes that don't have the &nbsp; '''scrsize''' &nbsp; BIF, the &nbsp; '''SCRSIZE.REX''' &nbsp; REXX program is included here &nbsp; ──► &nbsp; [[SCRSIZE.REX]]. <br><br>

 

=={{header|Scala}}==

Similar to the C example above:

 

println("Alternate buffer!")

 

}

 

 

=={{header|Sidef}}==

{{trans|Raku}}

say "Alternate buffer!";

 

}

 

 

=={{header|Swift}}==

{{trans|C}}

public let CSI = ESC+"[" // Control Sequence Introducer

func write(_ text: String...) {

}

write(CSI,"?1049l") // close alternate screen

 

=={{header|Tcl}}==

On Unix terminals only, with the help of <tt>tput</tt>:

proc terminal {args} {

exec /usr/bin/tput {*}$args >/dev/tty

gets stdin

# Restore the screen with the "exit_ca_mode" capability, a.k.a. 'rmcup'

 

=={{header|UNIX Shell}}==

{{works with|Bourne Shell}} {{works with|bash}}

 

tput smcup # Save the display

echo 'Hello'

sleep 5 # Wait five seconds

 

=={{header|Wren}}==

{{trans|C}}

import "timer" for Timer

 

Timer.sleep(1000)

}

 

=={{header|XPL0}}==

 

proc SetPage(P); \Select active display page for video screen

if ChIn(1) then []; \wait for keystroke

SetPage(0); \restore original, default text screen, page 0

 

=={{header|Z80 Assembly}}==

Using the Amstrad CPC firmware:

 

 

txt_output: equ $bb5a

ret

 

 

=={{header|zkl}}==

{{trans|C}}

Works in a Mint Linux terminal, switching to the alternate screen buffer, printing a count down message and then switching back.

println("Alternate screen buffer");

foreach i in ([5..1,-1]){

Atomic.sleep(1);

}