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Video display modes

From Rosetta Code
Task
Video display modes
You are encouraged to solve this task according to the task description, using any language you may know.

The task is to demonstrate how to switch video display modes within the language. A brief description of the supported video modes would be useful.

8086 Assembly[edit]

Works with: MS-DOS
mov ah,00h
mov al,videoMode
int 10h

There are quite a few valid values for videoMode, here are a few of them:

  • 03h is the standard MS-DOS command prompt that appears upon startup.
  • 04h is CGA mode, which is typically 4-color when using an RBGI cable and can be up to 16 colors when using a composite cable. The resolution is 320x200 pixels.
  • 09h is used by the Tandy 1000 computer.
  • 0Dh is EGA mode, which uses 4 bitplanes and is 16 colors, with a resolution of 320x200 pixels.
  • 13h is VGA mode, which uses one byte per pixel, 256 colors, and has a resolution of 320x200 pixels.


Some other trivia about changing video modes:

  • Using the above command to switch video modes to the same video mode you're already in will wipe the screen of all graphics, reset the text cursor, and, for VGA mode, reloads the standard VGA palette, destroying whatever user-defined palette was stored in the graphics card's memory. "Switching" to the same video mode again is a quick and easy way to clear the screen.
  • Regardless of whether you use CGA or EGA, the same text-related commands and service calls will work just as they do in MS-DOS mode. The only difference is the font which is a lot larger and supports the change of text color.
  • If you use mov ax,4C00h int 21h to return to DOS while in a different video mode, you will still be in that video mode when you return.

Action![edit]

PROC ShowMode(BYTE m,split,gr
CARD w, BYTE h,
CARD size,
CHAR ARRAY descr)
BYTE CH=$02FC
CARD i
BYTE POINTER ptr
 
Graphics(0)
PrintF("Next video mode: %B%E",m)
IF split THEN
PrintF("Split video mode%E%EUpper part:%E")
FI
 
IF gr THEN
Print("Graphics")
ELSE
Print("Text")
FI
PrintF(" mode, %Ux%B, %S%E",w,h,descr)
 
IF split THEN
PrintF("%ELower part:%EText mode 40x4, 2 luminances%E")
FI
PrintF("%EPress any key to change video mode.")
 
DO UNTIL CH#$FF OD
CH=$FF
 
Graphics(m)
ptr=PeekC(88)
 
FOR i=1 TO size
DO
ptr^=Rand(0)
ptr==+1
OD
 
DO UNTIL CH#$FF OD
CH=$FF
RETURN
 
PROC Main()
ShowMode(0,0,0,40,24,960,"2 luminances")
ShowMode(1,1,0,20,20,640,"5 colors")
ShowMode(2,1,0,20,10,400,"5 colors")
ShowMode(3,1,1,40,20,400,"4 colors")
ShowMode(4,1,1,80,40,640,"2 colors")
ShowMode(5,1,1,80,40,1120,"4 colors")
ShowMode(6,1,1,160,80,2080,"2 colors")
ShowMode(7,1,1,160,80,4000,"4 colors")
ShowMode(8,1,1,320,160,7856,"2 luminances")
ShowMode(9,0,1,80,192,7680,"16 luminances")
ShowMode(10,0,1,80,192,7680,"9 colors")
ShowMode(11,0,1,80,192,7680,"16 hues")
ShowMode(12,1,0,40,20,1120,"5 colors")
ShowMode(13,1,0,40,10,640,"5 colors")
ShowMode(14,1,1,160,160,4000,"2 colors")
ShowMode(15,1,1,160,160,7856,"4 colors")
ShowMode(17,0,0,20,24,480,"5 colors")
ShowMode(18,0,0,20,12,240,"5 colors")
ShowMode(19,0,1,40,24,240,"4 colors")
ShowMode(20,0,1,80,48,480,"2 colors")
ShowMode(21,0,1,80,48,960,"4 colors")
ShowMode(22,0,1,160,96,1920,"2 colors")
ShowMode(23,0,1,160,96,3840,"4 colors")
ShowMode(24,0,1,320,192,7680,"2 luminances")
ShowMode(28,0,0,40,24,960,"5 colors")
ShowMode(29,0,0,40,12,480,"5 colors")
ShowMode(30,0,1,160,192,3840,"2 colors")
ShowMode(31,0,1,160,192,7680,"4 colors")
RETURN
Output:

Screenshot from Atari 8-bit computer

AmigaBASIC[edit]

SCREEN 1,320,200,5,1

This command creates a new screen #1 (4 max) with 320x200 pixels and 5 bits per pixel (for a total of 2⁵=32 colors). The final parameter, 1, sets the monitor to 320x200 (NTSC Amiga) or 320x256 (PAL Amiga) non-interlaced mode. If set to 2, it would use 640*200/640*256, while 3 and 4 would result in corresponding interlaced modes with twice the vertical resolution.

The screen can be closed again with

SCREEN CLOSE 1

Applesoft BASIC[edit]

There are ten possible modes:

TEXT, page 1, 40 x 24
GR, page 1, 40 x 40, 16 colors, mixed with four lines of text
HGR, page 1, 280 x 160, 6 colors, mixed with four lines of text
HGR2, page 2, 280 x 192, 6 colors, full screen
text, page 2, 40 x 24
gr, page 1, 40 x 48, 16 colors, full screen
gr, page 2, 40 x 40, 16 colors, mixed with four lines of text 
gr, page 2, 40 x 48, 16 colors, full screen
hgr, page 1, 280 x 192, 6 colors, full screen
hgr, page 2, 280 x 160, 6 colors, mixed with four lines of text
10 GR
20 FOR I = 0 TO 15 : COLOR = I : PLOT I,I : NEXT
30 HGR
40 FOR I = 1 TO 6 : HCOLOR = I : HPLOT I * 2, I TO I * 2 + 1, I : NEXT
50 TEXT
60 HOME : FOR I = 0 TO 7 : VTAB I + 1 : FOR J = 0 TO 31 : POKE PEEK(40) + PEEK(41) * 256 + 4 + J, I * 32 + J : NEXT J, I
70 HGR2
80 FOR I = 1 TO 6 : HCOLOR = I : HPLOT I * 2, I + 6 TO I * 2 + 1, I + 6 : NEXT
90 TEXT
100 GET A$
110 IF A$ = "H" THEN POKE -16297,0 : REM HI-RESOLUTION
120 IF A$ = "L" THEN POKE -16298,0 : REM LO-RESOLUTION
130 IF A$ = "2" THEN POKE -16299,0 : REM PAGE 2
140 IF A$ = "1" THEN POKE -16300,0 : REM PAGE 1
150 IF A$ = "M" THEN POKE -16301,0 : REM MIXED TEXT
160 IF A$ = "F" THEN POKE -16302,0 : REM FULL SCREEN
170 IF A$ = "T" THEN POKE -16303,0 : REM TEXT
180 IF A$ = "G" THEN POKE -16304,0 : REM GRAPHICS
190 IF A$ <> "Q" THEN 100
200 TEXT

ARM Assembly[edit]

Game Boy Advance[edit]

[Game Boy Advance Specifications]

The video display mode is a 16 bit value that is written to address 0x04000000. The lowest 3 bits control the screen mode. There are 5 to choose from. Modes 0-1 use tile graphics, Mode 2 is similar to the famous "Mode 7" on the SNES, and Modes 3, 4, and 5 are bitmap modes much like 80s home computers where individual pixels can be edited. Visibility of the background layers are controlled by bits 8 through 12 (going from right to left).

For example, to set the screen to Mode 3 with Background 2 visible:

 
MOV R1,#0x04000000
MOV R0,#0x403
STR r0,[r1] ;the game boy advance is little-endian, so I would have expected this not to work. However it does indeed work.
 

BBC BASIC[edit]

10 MODE 1: REM 320x256 4 colour graphics

Commodore BASIC[edit]

Commodore 64[edit]

Since BASIC V2 on the Commodore 64 has no specific commands to operate the graphics functions of the VIC-II, video modes must be activated by directly manipulating the various registers of the VIC-II chip. Also, no initialization is done of any user-programmable graphics memory at start up, as it is not known at startup what memory locations will be utilized for graphics. It is up to the user to decide how to utilize the memory and then make the appropriate initialization.


Summary of Video Modes[edit]

  • Standard Character Mode
    • 40 x 25 characters.
    • Single foreground color per character.
    • 16 colors available for use.
    • Font data comes from ROM.
  • Multicolor Character Mode
    • 40 x 25 characters.
    • Characters are either single colored or multi-colored.
    • Multi-color allows for 3 foreground colors per character.
    • 1 foreground color limited to first 8 colors of the palette; other 2 are global for entire screen, but may be any of 16 colors.
  • Extended Color Mode
    • Enables a total of 4 background colors which can be any of the 16 palette colors.
    • Limits character set to only first 64 characters (no PETSCII graphics or reverse characters.)
  • Programmable Character Mode
    • Works with any of the modes described above.
    • Exception is that font data comes from data in RAM.
  • Standard High Resolution Bit Mapped Mode
    • 320 x 200 pixel resolution.
    • Single foreground color per 8x8 pixel cell.
    • Single background color per 8x8 pixel cell.
    • Foreground and background color can be any of the 16 color palette.
    • Color information stored in character screen RAM, not color RAM.
  • Multicolor Hi-res Bit Mapped Mode
    • 160 x 200 pixel resolution.
    • Each 4x8 cell can have 3 foreground colors and 1 global background color.
    • Color information for foreground colors is stored in character screen RAM as well as color RAM (12 bits of color information).


Explanation of Program[edit]

Lines Description
10-25 Clear the screen, switch to lower-case mode, set the basic border, background, and foreground colors, including the extended and multicolors.
30 Check to see if we've run this routine before by examining the first two bytes of our reserved graphics area. If we have, skip it. (It does take some time to complete.)
35 Tell BASIC to limit its RAM usage to a new top-end of 8K. The following 8K (8192 to 16384) will be reserved for graphics data to be used by the VIC-II.
40 Let the user know we're initializing.
45 The contents of the character ROM are not normally visible to the CPU and must be switched through the I/O port of the CPU. However, this will also make certain interrupt functions running in the background fail, so interrupts must be turned off by stopping the interrupt timer on CIA 2 (first POKE in line 45) before switching the ROM in (second POKE in line 45).
50 Initialize part of the graphics area by copying all 4K of character ROM into the reserved graphics area.
55 Switch out the ROM since we are done with it, and restart the interrupt timer.
60-115 Modify a few characters to be custom designed (defined in DATA statements), and then define the rest of the reserved graphics memory with high-resolution lines (line 65), as well as a specific bit pattern that will help illustrate the high resolution multi-color mode (line 70).
480-810 This section goes through each of the modes. Activation of the modes is called as a subroutine, and some video modes are actually a combination of discrete video modes.
1000-1020 A subroutine to print some demonstration text to the screen to illustrate the variety of the various text modes. On lines 1011 and 1013, chr$(160) is the same as SHIFT-SPACE for the spaces between letters, which is distinctly different from a regular SPACE character (CHR$(32)).
1050-1065 A subroutine to put a variety of color definition into the high-resolution bit map modes.
1100-1430 These subroutines are the methods for switching certain discrete video modes on and off. This is done by specifically modifying the various registers in the VIC-II chip. Most of these are then combined to achieve other video modes.
9000-9020 Finally, a generic "wait for keypress" routine.


Program Listing[edit]

10 rem video modes - c64
15 rem rosetta code
20 print chr$(147);chr$(14):poke 53280,0:poke 53281,0:poke 646,1
25 poke 53282,2:poke 53283,11:poke 53284,9:rem set extended and multi colors
30 if peek(12288)=60 and peek(12289)=102 then goto 100
35 poke 52,32:poke 56,32:clr
40 print "Initializing - Please wait..."
45 poke 56334,peek(56334) and 254:poke1,peek(1) and 251
50 for i=0 to 4096:poke i+12288,peek(i+53248):next
55 poke1,peek(1) or 4:poke56334,peek(56334) or 1
60 for i=0 to 31:read d:poke 15368+i,d:next i
65 x=0:for i=8192 to 10239:poke i,2^x:x=(x+1) and 7:next
70 for i=10240 to 12287:poke i,228:next
100 data 60,66,165,129,165,153,66,60
105 data 60,66,165,129,153,165,66,60
110 data 245,245,245,245,10,10,10,10
115 data 10,10,10,10,245,245,245,245
480 print chr$(147);"Demonstration of Video Modes"
485 print
490 print "The video modes described at Rosetta "
495 print "Code will be demonstrated in order. "
500 print "Simply press a key to advance to the"
505 print "next video mode."
510 print
515 print "See rosettacode.org for description."
516 print
517 print "http://www.rosettacode.org/wiki/";
518 print "Video";chr$(164);"display";chr$(164);"modes#";
519 print "Commodore";chr$(164);"BASIC"
520 print
525 print "Press any key to begin."
530 gosub 9010
600 print chr$(147);"Standard Character Mode"
605 print " - ROM Characters"
610 print:gosub 1000:print:gosub 9000:print chr$(147)
615 gosub 1210
620 print chr$(147);"Multicolor Character Mode"
625 print " - ROM Characters"
630 print:gosub 1000:print:gosub 9000:print chr$(147)
635 gosub 1220
640 gosub 1310
645 print chr$(147);"Extended Color Character Mode"
650 print " - ROM Characters"
655 print:gosub 1000:print:gosub 9000:print chr$(147)
660 gosub 1320
665 gosub 1100
670 print chr$(147);"Standard Character Mode"
675 print " - Programmed Characters"
680 print:gosub 1000:print:gosub 9000:print chr$(147)
685 gosub 1210
690 print chr$(147);"Multicolor Character Mode"
695 print " - Programmed Characters"
700 print:gosub 1000:print:gosub 9000:print chr$(147)
705 gosub 1220
710 gosub 1310
715 print chr$(147);"Extended Color Character Mode"
720 print " - Programmed Characters"
725 print:gosub 1000:print:gosub 9000:print chr$(147)
730 gosub 1320
735 print chr$(147);"The next screen will be the"
740 print "High Resolution Bit Map Mode"
745 print
750 gosub 9000
755 gosub 1430:gosub 1410
760 print:gosub 1050:print:gosub 9010:print chr$(147)
765 gosub 1420:gosub 1120
770 print chr$(147);"The next screen will be the"
775 print "Multicolor High Resolution Bit Map Mode"
780 print
785 gosub 9000
790 gosub 1430:gosub 1410:gosub 1210
795 print:gosub 1050:print:gosub 9010:print chr$(147)
800 gosub 1420:gosub 1220:gosub 1120
805 print chr$(147);"End of demonstration."
810 end
1000 rem put some characters up for demo
1005 for i=0 to 15:poke 646,i
1010 print" a b c d ";
1011 print chr$(160);"A";chr$(160);"B";chr$(160);"C";chr$(160);"D";chr$(160);
1012 print chr$(18);" a b c d ";
1013 print chr$(160);"A";chr$(160);"B";chr$(160);"C";chr$(160);"D";chr$(160);
1014 print chr$(146)
1015 next i:poke 646,1
1020 return
1050 rem show color variety for hi-res modes
1051 print chr$(147)
1055 for i=0 to 255:poke 1024+i,i:poke 55296+i,1:next
1060 for i=0 to 255:poke 1280+i,i:poke 55552+i,int(rnd(1)*16):next
1065 return
1100 rem programmable character mode
1110 poke 53272,(peek(53272) and 240)+14:return:rem on
1120 poke 53272,(peek(53272) and 240)+6:return:rem off
1200 rem multicolor mode
1210 poke 53270,peek(53270) or 16:return:rem on
1220 poke 53270,peek(53270) and 239:return:rem off
1300 rem extended color mode
1310 poke 53265,peek(53265) or 64:return:rem on
1320 poke 53265,peek(53265) and 191:return:rem off
1400 rem hi res mode
1410 poke 53265,(peek(53265) or 32):return:rem on
1420 poke 53265,(peek(53265) and 223):return:rem off
1430 poke 53272,peek(53272) or 8:return:rem place bitmap at 8192
9000 print "Press any key for next screen.";
9010 get k$:if k$="" then 9010
9020 return

ERRE[edit]

ERRE language (for PC) supports these modes (accessible with SCREEN procedure of PC.LIB library):

  • SCREEN(0) => text 80x25 or 40x25 -- standard
  • SCREEN(1) => 320x200 4 colors
  • SCREEN(2) => 640x200 2 colors
  • SCREEN(7) => 320x200 16 colors
  • SCREEN(8) => 640x200 16 colors
  • SCREEN(9) => 640x350 16 colors
  • SCREEN(10) => 640x350 for MDA monitors (if you have one .....)

It's possible to activate all VGA and SVGA modes using DOS interrupts. On the distribution disk there is an example to activate 320x200 - 256 colors.

ERRE language (for C-64) support high resolution graphic (320x200) using HGR.LIB library.

Go[edit]

Translation of: UNIX Shell
Works with: Ubuntu 16.04
package main
 
import (
"fmt"
"log"
"os/exec"
"time"
)
 
func main() {
// query supported display modes
out, err := exec.Command("xrandr", "-q").Output()
if err != nil {
log.Fatal(err)
}
fmt.Println(string(out))
time.Sleep(3 * time.Second)
 
// change display mode to 1024x768 say (no text output)
err = exec.Command("xrandr", "-s", "1024x768").Run()
if err != nil {
log.Fatal(err)
}
time.Sleep(3 * time.Second)
 
// change it back again to 1366x768 (or whatever is optimal for your system)
err = exec.Command("xrandr", "-s", "1366x768").Run()
if err != nil {
log.Fatal(err)
}
}
Output:
Screen 0: minimum 8 x 8, current 1366 x 768, maximum 32767 x 32767
eDP1 connected primary 1366x768+0+0 (normal left inverted right x axis y axis) 344mm x 193mm
   1366x768      60.00*+  48.01  
   1360x768      59.80    59.96  
   1280x720      60.00  
   1024x768      60.00  
   1024x576      60.00  
   960x540       60.00  
   800x600       60.32    56.25  
   864x486       60.00  
   640x480       59.94  
   720x405       60.00  
   680x384       60.00  
   640x360       60.00  
DP1 disconnected (normal left inverted right x axis y axis)
DP2 disconnected (normal left inverted right x axis y axis)
HDMI1 disconnected (normal left inverted right x axis y axis)
HDMI2 disconnected (normal left inverted right x axis y axis)
VIRTUAL1 disconnected (normal left inverted right x axis y axis)

Groovy[edit]

Translation of: Kotlin
Works with: Ubuntu 14.04
def invoke(String cmd) { println(cmd.execute().text) }
 
invoke("xrandr -q")
Thread.sleep(3000)
 
invoke("xrandr -s 1024x768")
Thread.sleep(3000)
 
invoke("xrandr -s 1366x768")
Output:
Screen 0: minimum 640 x 480, current 5080 x 1898, maximum 5080 x 1920
default connected 5080x1898+0+0 0mm x 0mm
   2880x1800     60.00  
   1440x900      60.00  
   2560x1600     60.00  
   2048x1280     60.00  
   1024x768      60.00  
   800x600       60.00  
   640x480       60.00  
   1680x1050     60.00  
   1280x800      60.00  
   5080x1898      1.00* 
   5080x1920      2.00  

GW-BASIC[edit]

This example is wrong! GWBASIC can use ONLY EGA-Graphic until SCREEN 9 (640 x 350 - 16 colors) with color monitor or SCREEN 10 (640 x 350 - 2 "colors") for monochrome monitor. GWBASIC version used: 3.23

10 REM GW Basic can switch VGA modes
20 SCREEN 18: REM Mode 12h 640x480 16 colour graphics

Icon and Unicon[edit]

The following works in both languages on X-windows based systems and assume xrandr is installed:

Translation of: UNIX Shell
procedure main(A)
mode := A[1]
if \mode then system("xrandr -s " || \mode || " >/dev/null")
else system("xrandr -q") # Display available modes
end

Output with no arguments:

->vdm
Screen 0: minimum 8 x 8, current 3840 x 1200, maximum 8192 x 8192
DVI-I-0 disconnected (normal left inverted right x axis y axis)
VGA-0 connected 1920x1200+0+0 (normal left inverted right x axis y axis) 518mm x 324mm
   1920x1200      60.0*+
   1600x1200      75.0     70.0     65.0     60.0  
   1280x1024      75.0     60.0  
   1280x960       60.0  
   1152x864       75.0  
   1024x768       75.0     70.1     60.0  
   800x600        75.0     72.2     60.3     56.2  
   640x480        75.0     72.8     59.9  
TV-0 disconnected (normal left inverted right x axis y axis)
DVI-I-1 connected 1920x1200+1920+0 (normal left inverted right x axis y axis) 518mm x 324mm
   1920x1200      60.0*+
   1680x1050      60.0  
   1600x1200      60.0  
   1280x1024      75.0     60.0  
   1280x960       75.0  
   1024x768       75.0     60.0  
   800x600        75.0     60.3  
   640x480        75.0     59.9  
->

Julia[edit]

Translation of: Phix
 
if Base.Sys.islinux()
run(`xrandr -s 640x480`)
sleep(3)
run(`xrandr -s 1280x960`)
else # windows
run(`mode CON: COLS=40 LINES=100`)
sleep(3)
run(`mode CON: COLS=100 LINES=50`)
end
 

Kotlin[edit]

Translation of: UNIX Shell
Works with: Ubuntu 14.04
// version 1.1.51
 
import java.util.Scanner
 
fun runSystemCommand(command: String) {
val proc = Runtime.getRuntime().exec(command)
Scanner(proc.inputStream).use {
while (it.hasNextLine()) println(it.nextLine())
}
proc.waitFor()
println()
}
 
fun main(args: Array<String>) {
// query supported display modes
runSystemCommand("xrandr -q")
Thread.sleep(3000)
 
// change display mode to 1024x768 say (no text output)
runSystemCommand("xrandr -s 1024x768")
Thread.sleep(3000)
 
// change it back again to 1366x768 (or whatever is optimal for your system)
runSystemCommand("xrandr -s 1366x768")
}
Output:
Screen 0: minimum 320 x 200, current 1366 x 768, maximum 32767 x 32767
eDP1 connected primary 1366x768+0+0 (normal left inverted right x axis y axis) 344mm x 193mm
   1366x768       60.0*+   48.0  
   1360x768       59.8     60.0  
   1024x768       60.0  
   800x600        60.3     56.2  
   640x480        59.9  
HDMI1 disconnected (normal left inverted right x axis y axis)
DP1 disconnected (normal left inverted right x axis y axis)
HDMI2 disconnected (normal left inverted right x axis y axis)
HDMI3 disconnected (normal left inverted right x axis y axis)
DP2 disconnected (normal left inverted right x axis y axis)
VIRTUAL1 disconnected (normal left inverted right x axis y axis)

Locomotive Basic[edit]

The Amstrad CPC464 supports three video modes:

  • Mode 0 - Graphics: 160x200 Text: 20x25 Colours: 16
  • Mode 1 - Graphics: 320x200 Text: 40x25 Colours: 4
  • Mode 2 - Graphics: 640x200 Text: 80x25 Colours: 2

Note that text can be displayed using conventional means in all display modes.

10 MODE 0: REM switch to mode 0


Nim[edit]

Works with: Linux

Using the command "xrandr" on Linux systems.

import os, osproc, strformat, strscans
 
# Retrieve video modes.
let p = startProcess("xrandr", "", ["-q"], nil, {poUsePath})
var currWidth, currHeight = 0 # Current video mode.
var width, height = 0 # Some other video mode.
for line in p.lines:
echo line
# Find current display mode, marked by an asterisk.
var f: float
if currWidth == 0:
# Find current width and height.
discard line.scanf(" $s$ix$i $s$f*", currWidth, currHeight, f)
elif width == 0:
# Find another width and height.
discard line.scanf(" $s$ix$i $s$f", width, height, f)
p.close()
 
# Change video mode.
let newMode = &"{width}x{height}"
sleep 1000
echo "\nSwitching to ", newMode
sleep 2000
discard execProcess("xrandr", "", ["-s", newMode], nil, {poUsePath})
 
# Restore previous video mode.
let prevMode = &"{currWidth}x{currHeight}"
sleep 1000
echo "\nSwitching back to ", prevMode
sleep 2000
discard execProcess("xrandr", "", ["-s", prevMode], nil, {poUsePath})
Output:

Some possible output:

Screen 0: minimum 8 x 8, current 1920 x 1080, maximum 32767 x 32767
eDP1 connected primary 1920x1080+0+0 (normal left inverted right x axis y axis) 310mm x 170mm
   1920x1080     60.01*+  59.93  
   1680x1050     59.95    59.88  
   1400x1050     59.98  
   1600x900      60.00    59.95    59.82  
   1280x1024     60.02  
   1400x900      59.96    59.88  
   1280x960      60.00  
   1368x768      60.00    59.88    59.85  
   1280x800      59.81    59.91  
   1280x720      59.86    60.00    59.74  
   1024x768      60.00  
   1024x576      60.00    59.90    59.82  
   960x540       60.00    59.63    59.82  
   800x600       60.32    56.25  
   864x486       60.00    59.92    59.57  
   640x480       59.94  
   720x405       59.51    60.00    58.99  
   640x360       59.84    59.32    60.00  
HDMI1 disconnected (normal left inverted right x axis y axis)
VIRTUAL1 disconnected (normal left inverted right x axis y axis)

Switching to 1680x1050

Switching back to 1920x1080

Perl[edit]

Same caveats as with Raku.

Translation of: Raku
$| = 1;
 
my @info = `xrandr -q`;
$info[0] =~ /current (\d+) x (\d+)/;
my $current = "$1x$2";
 
my @resolutions;
for (@info) {
push @resolutions, $1 if /^\s+(\d+x\d+)/
}
 
system("xrandr -s $resolutions[-1]");
print "Current resolution $resolutions[-1].\n";
for (reverse 1 .. 9) {
print "\rChanging back in $_ seconds...";
sleep 1;
}
system("xrandr -s $current");
print "\rResolution returned to $current.\n";

Phix[edit]

if platform()=LINUX then
{} = system_exec("xrandr -s 640x480")
sleep(3)
{} = system_exec("xrandr -s 1280x960")
else -- WINDOWS
puts(1,"") -- (ensure console exists)
system("mode CON: COLS=40 LINES=25")
sleep(3)
system("mode CON: COLS=80 LINES=25")
end if

Obviously running xrandr -q or mode -? will tell you more.

Python[edit]

Library: win32api
Library: win32con

This program changes the resolution the screen is running at to 640x480.

import win32api
import win32con
import pywintypes
devmode=pywintypes.DEVMODEType()
devmode.PelsWidth=640
devmode.PelsHeight=480
devmode.Fields=win32con.DM_PELSWIDTH | win32con.DM_PELSHEIGHT
win32api.ChangeDisplaySettings(devmode,0)

QBasic[edit]

This example is wrong! QBASIC can use EGA/VGA Graphics until SCREEN 13 (320x200 - 256 colors) or SCREEN 12 (640x480 - 16 colors).QBASIC version used: 1.1

'QBasic can switch VGA modes
SCREEN 18 'Mode 12h 640x480 16 colour graphics

Raku[edit]

(formerly Perl 6) Raku runs on several different operating systems over many different architectures so can not easily assume direct control over hardware. Instead, like most modern programming languages, it relies on the current OS and windowing system to provide APIs.

Here is an example which will work for most Debian based Linuxs (and probably others) running some variant of X11 with a single active monitor.

Works with: Rakudo version 2018.05
my @info = QX('xrandr -q').lines;
 
@info[0] ~~ /<?after 'current '>(\d+) ' x ' (\d+)/;
my $current = "$0x$1";
 
my @resolutions;
@resolutions.push: $0 if $_ ~~ /^\s+(\d+'x'\d+)/ for @info;
 
QX("xrandr -s @resolutions[*-1]");
say "Current resolution {@resolutions[*-1]}.";
for 9 ... 1 {
print "\rChanging back in $_ seconds...";
sleep 1;
}
QX("xrandr -s $current");
say "\rResolution returned to {$current}. ";

REXX[edit]

This method only works in DOS prompt either under (native) DOS or Microsoft WINDOWS.

DOS (under Microsoft Windows) will support:

  • columns   of   11 ──> 32,766   (inclusive)
  • lines         of   1 ──> 32,766   (inclusive)

version 1: no checking for which OS[edit]

/*REXX program to switch video display modes based on columns and lines.*/
 
parse arg cols lines .
'MODE' "CON: COLS="cols 'LINES='lines
/*stick a fork in it, we're done.*/

version 2: checks for which OS[edit]

The prologue code (at the bottom of the program) is a collection of some general-purpose subroutines which determine:

  • which environment (operating system) the REXX interpreter is running under
  • if Windows/NT/XP/Vista/7/8 (the NT family) is running
  • which REXX is being executed
  • what literal to use to obtain the environmental variables (for the value bif)
  • what the fileName, fileType/fileExt, fileMode/path is of the REXX program
  • which command to use to clear the terminal screen
  • invokes $H to show general documentation (1st and only arg = ?)
  • invokes $H to show a flow diagram (1st and only arg = ?FLOW)
  • invokes $H to show sample uses (1st and only arg = ?SAMPLE)
  • invokes $H to show the author & contact info (1st and only arg = ?AUTHOR)

All the prologue was left intact to give a general feel of the scope of the boilerplate code. The prologue code is in many REXX programs and it's easier to keep them on one line for copying purposes and sorting.

/*REXX program to switch video display modes based on columns and lines.*/
parse arg !; if !all() then exit /*exit if documentation specified*/
if \!dos & \!os2 then exit /*if this isn't DOS, then exit. */
 
parse arg cols lines .
'MODE' "CON: COLS="cols 'LINES='lines
 
exit /*stick a fork in it, we're done.*/
/*══════════════════════════════════general 1-line subs═════════════════*/
!all:!!=!;!=space(!);upper !;call !fid;!nt=right(!var('OS'),2)=='NT';!cls=word('CLS VMFCLEAR CLRSCREEN',1+!cms+!tso*2);if arg(1)\==1 then return 0;if wordpos(!,'? ?SAMPLES ?AUTHOR ?FLOW')==0 then return 0;!call=']$H';call '$H' !fn !;!call=;return 1
!cal:if symbol('!CALL')\=="VAR" then !call=;return !call
!env:!env='ENVIRONMENT';if !sys=='MSDOS'|!brexx|!r4|!roo then !env='SYSTEM';if !os2 then !env='OS2'!env;!ebcdic=1=='f0'x;return
!fid:parse upper source !sys !fun !fid . 1 . . !fn !ft !fm .;call !sys;if !dos then do;_=lastpos('\',!fn);!fm=left(!fn,_);!fn=substr(!fn,_+1);parse var !fn !fn '.' !ft;end;return word(0 !fn !ft !fm,1+('0'arg(1)))
!rex:parse upper version !ver !vernum !verdate .;!brexx='BY'==!vernum;!kexx='KEXX'==!ver;!pcrexx='REXX/PERSONAL'==!ver|'REXX/PC'==!ver;!r4='REXX-R4'==!ver;!regina='REXX-REGINA'==left(!ver,11);!roo='REXX-ROO'==!ver;call !env;return
!sys:!cms=!sys=='CMS';!os2=!sys=='OS2';!tso=!sys=='TSO'|!sys=='MVS';!vse=!sys=='VSE';!dos=pos('DOS',!sys)\==0|pos('WIN',!sys)\==0|!sys=='CMD';call !rex;return
!var:call !fid;if !kexx then return space(dosenv(arg(1)));return space(value(arg(1),,!env))

Ring[edit]

 
system("mode 40, 25")
 

Scala[edit]

Translation of: UNIX Shell
Works with: Ubuntu 14.04
object VideoDisplayModes extends App {
 
import java.util.Scanner
 
def runSystemCommand(command: String) {
val proc = Runtime.getRuntime.exec(command)
 
val a: Unit = {
val a = new Scanner(proc.getInputStream)
while (a.hasNextLine) println(a.nextLine())
}
proc.waitFor()
println()
}
 
// query supported display modes
runSystemCommand("xrandr -q")
Thread.sleep(3000)
 
// change display mode to 1024x768 say (no text output)
runSystemCommand("xrandr -s 1024x768")
Thread.sleep(3000)
 
// change it back again to 1366x768 (or whatever is optimal for your system)
runSystemCommand("xrandr -s 1366x768")
 
}

smart BASIC[edit]

GRAPHICS switches to graphics view (as opposed to text view).

GRAPHICS MODE X sets graphics commands compositing mode to X, where X is one of the following modes:

CLEAR, COLOR, COLORBURN, COLORDODGE, COPY, DARKEN, DESTATOP, DESTIN, DESTOUT, DESTOVER, DIFFERENCE, EXCLUSION, HARDLIGHT, HUE, LIGHTEN, LUMINOSITY, MULTIPLY, NORMAL (default), OVERLAY, PLUSDARKER, PLUSLIGHTER, SATURATION, SCREEN, SOFTLIGHT, SOURCEATOP, SOURCEIN, SOURCEOUT, XOR.

EXAMPLE:

GRAPHICS
FILL RECT 50,50 SIZE 50
GRAPHICS MODE CLEAR
FILL RECT 50,50 SIZE 25

UNIX Shell[edit]

If the system runs X11 and supports XRANDR, then

$ xrandr -q

lists the available modes, and

$ xrandr -s 1024x768

sets the screen to the given size.

With modern LCD monitors, this feature is not very useful. These monitors have a single best mode, and the X server discovers and uses that mode by default. Smaller screen modes might work, but make a blurry picture.

Wren[edit]

The ability to call external processes such as xrandr is expected to be added to Wren-cli in the next release. In the meantime, we embed the following Wren script in a minimal C host (no error checking) to complete this task.

/* video_display_modes.wren */
 
class C {
foreign static xrandr(args)
 
foreign static usleep(usec)
}
 
// query supported display modes
C.xrandr("-q")
 
C.usleep(3000)
 
// change display mode to 1368x768
System.print("\nChanging to 1368 x 768 mode.")
C.xrandr("-s 1368x768")
 
C.usleep(3000)
 
// change it back again to 1920x1080
System.print("\nReverting to 1920 x 1080 mode.")
C.xrandr("-s 1920x1080")


We now embed this in the following C program, compile and run it.

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include "wren.h"
 
void C_xrandr(WrenVM* vm) {
const char *arg = wrenGetSlotString(vm, 1);
char command[strlen(arg) + 8];
strcpy(command, "xrandr ");
strcat(command, arg);
system(command);
}
 
void C_usleep(WrenVM* vm) {
useconds_t usec = (useconds_t)wrenGetSlotDouble(vm, 1);
usleep(usec);
}
 
WrenForeignMethodFn bindForeignMethod(
WrenVM* vm,
const char* module,
const char* className,
bool isStatic,
const char* signature) {
if (strcmp(module, "main") == 0) {
if (strcmp(className, "C") == 0) {
if (isStatic && strcmp(signature, "xrandr(_)") == 0) return C_xrandr;
if (isStatic && strcmp(signature, "usleep(_)") == 0) return C_usleep;
}
}
return NULL;
}
 
static void writeFn(WrenVM* vm, const char* text) {
printf("%s", text);
}
 
char *readFile(const char *fileName) {
FILE *f = fopen(fileName, "r");
fseek(f, 0, SEEK_END);
long fsize = ftell(f);
rewind(f);
char *script = malloc(fsize + 1);
fread(script, 1, fsize, f);
fclose(f);
script[fsize] = 0;
return script;
}
 
int main(int argc, char **argv) {
WrenConfiguration config;
wrenInitConfiguration(&config);
config.writeFn = &writeFn;
config.bindForeignMethodFn = &bindForeignMethod;
WrenVM* vm = wrenNewVM(&config);
const char* module = "main";
const char* fileName = "video_display_modes.wren";
char *script = readFile(fileName);
wrenInterpret(vm, module, script);
wrenFreeVM(vm);
free(script);
return 0;
}
Output:
Screen 0: minimum 320 x 200, current 1920 x 1080, maximum 16384 x 16384
eDP-1 connected primary 1920x1080+0+0 (normal left inverted right x axis y axis) 344mm x 193mm
   1920x1080     60.01*+  60.01    59.97    59.96    59.93  
   1680x1050     59.95    59.88  
   1600x1024     60.17  
   1400x1050     59.98  
   1600x900      59.99    59.94    59.95    59.82  
   1280x1024     60.02  
   1440x900      59.89  
   1400x900      59.96    59.88  
   1280x960      60.00  
   1440x810      60.00    59.97  
   1368x768      59.88    59.85  
   1360x768      59.80    59.96  
   1280x800      59.99    59.97    59.81    59.91  
   1152x864      60.00  
   1280x720      60.00    59.99    59.86    59.74  
   1024x768      60.04    60.00  
   960x720       60.00  
   928x696       60.05  
   896x672       60.01  
   1024x576      59.95    59.96    59.90    59.82  
   960x600       59.93    60.00  
   960x540       59.96    59.99    59.63    59.82  
   800x600       60.00    60.32    56.25  
   840x525       60.01    59.88  
   864x486       59.92    59.57  
   800x512       60.17  
   700x525       59.98  
   800x450       59.95    59.82  
   640x512       60.02  
   720x450       59.89  
   700x450       59.96    59.88  
   640x480       60.00    59.94  
   720x405       59.51    58.99  
   684x384       59.88    59.85  
   680x384       59.80    59.96  
   640x400       59.88    59.98  
   576x432       60.06  
   640x360       59.86    59.83    59.84    59.32  
   512x384       60.00  
   512x288       60.00    59.92  
   480x270       59.63    59.82  
   400x300       60.32    56.34  
   432x243       59.92    59.57  
   320x240       60.05  
   360x202       59.51    59.13  
   320x180       59.84    59.32  
DP-1 disconnected (normal left inverted right x axis y axis)
HDMI-1 disconnected (normal left inverted right x axis y axis)
HDMI-2 disconnected (normal left inverted right x axis y axis)

Changing to 1368 x 768 mode.

Reverting to 1920 x 1080 mode.

XPL0[edit]

code SetVid=45;
SetVid(Mode)

Any display mode supported by the IBM-PC-compatible hardware and by the VGA or VESA standards can be enabled by calling the SetVid intrinsic routine. This works without problem on computers booted into DOS and under versions of Windows up until XP. DOSBox[1] gets around most of the incompatibilities introduced by WinXP and later versions.

Example display modes:

$03 - CGA 80x25 text in 16 colors (x4)
$12 - VGA 640x480x4 graphics
$13 - VGA 320x200x8
$101 - VESA 640x480x8
$118 - VESA 1024x768x24

On modern LCD displays (as opposed to older CRT monitors) images can look terrible if the selected mode does not match the native resolution of the LCD.