# Pseudorandom number generator image

Pseudorandom number generator image is a draft programming task. It is not yet considered ready to be promoted as a complete task, for reasons that should be found in its talk page.

Write a program that creates an image from a Pseudorandom Number Generator (PRNG) algorithm's output. The image can have the following dimensions:

1. 250px by 250px : If the algorithm requires the use of prime numbers, use 8-15 bit primes.
2. 500px by 500px : If the algorithm requires the use of prime numbers, use 8-15 bit primes.
3. 1000px by 1000px : If the algorithm requires the use of prime numbers, use 8-32 bit primes.
4. 1500px by 1500px : If the algorithm requires the use of prime numbers, use 16-64 bit primes.
Possible Output
•   Blum Blum Shub [1].
•   Blum-Micali Algorithm: [2].
•   Linear congruential generator [3].

## 6502 Assembly

### 6502js/easy6502

The "hardware" gives us a memory-mapped port at address \$00FE which contains a different random number every clock cycle. We can use this to write to video memory (there are only 16 colors so the top 4 bits of the random value are ignored.)

```define vramPtr \$00
define vramPtrHi \$01
main:
;we're guaranteed to start off with all registers zeroed.
STA vramPtr
LDA #\$02
STA vramPtrHi
LDX #4

loop:
LDA \$FE	;read a random byte from the port
STA (vramPtr),y
INY
BNE loop
INC vramPtrHi
DEX
bne loop

brk    ;end program```

Output can be seen by copying/pasting the above code here.

```-- Generate a (pseudo)random image
-- J. Carter     2023 Apr

procedure Random_Image is

Gen   : Color_Random.Generator;

begin -- Random_Image
Color_Random.Reset (Gen => Gen);
Image := Ada_GUI.New_Graphic_Area (Width => 250, Height => 250);

All_X : for X in 0 .. 249 loop
All_Y : for Y in 0 .. 249 loop
Image.Set_Pixel (X => X, Y => Y, Color => (Red   => Color_Random.Random (Gen),
Green => Color_Random.Random (Gen),
Blue  => Color_Random.Random (Gen),
Alpha => 1.0) );
end loop All_Y;
end loop All_X;

Wait : loop

exit Wait when not Event.Timed_Out and then Event.Event.Kind = Ada_GUI.Window_Closed;
end loop Wait;

end Random_Image;
end.
```
Output:

## Delphi

```program Pseudorandom_number_generator_image;

{\$APPTYPE CONSOLE}

uses
System.SysUtils,
vcl.Graphics,
Vcl.Imaging.PngImage;

type
TRGBTriple = packed record
b: Byte;
g: Byte;
r: Byte;
end;

PRGBTripleArray = ^TRGBTripleArray;

TRGBTripleArray = array[0..999] of TRGBTriple;

function Noise(cWidth, cHeight: Integer; Color: boolean = True): TBitmap;
const
Seed = 2147483647;
var
Pixels: PRGBTripleArray;
begin
RandSeed := Seed;
Result := TBitmap.Create;
with Result do
begin
SetSize(cWidth, cHeight);
PixelFormat := pf24bit;
for var row := 0 to cHeight - 1 do
begin
Pixels := ScanLine[row];
for var col := 0 to cWidth - 1 do
begin
if Color then
begin
Pixels[col].r := random(255);
Pixels[col].g := random(255);
Pixels[col].b := random(255);
end
else
begin
var Gray := Round((0.299 * random(255)) + (0.587 * random(255)) + (0.114
* random(255)));
Pixels[col].r := Gray;
Pixels[col].g := Gray;
Pixels[col].b := Gray;
end;
end;
end;
end;
end;

const
cWidth = 1000;
cHeight = 1000;

begin
// Color noise
var bmp := Noise(cWidth, cHeight);
bmp.SaveToFile('randbitmap-rdo.bmp');

// to Png
with TPngImage.create do
begin
Assign(bmp);
SaveToFile('randbitmap-rdo.png');
free;
end;
bmp.Free;

// Gray noise
bmp := Noise(cWidth, cHeight, False);
bmp.SaveToFile('randbitmap-rdo_g.bmp');

// to Png
with TPngImage.create do
begin
Assign(bmp);
SaveToFile('randbitmap-rdo_g.png');
free;
end;
bmp.Free;

end.
```
Output:

## Factor

Factor's default PRNG is Mersenne Twister, but it can be easily swapped out for others like Drand, Xoroshiro, Blum Blum Shub, lagged Fibonnaci, system RNGs, and more.

Works with: Factor version 0.99 2021-02-05
```USING: accessors images.testing images.viewer literals math
random sequences ;

CONSTANT: size 500

<rgb-image>
\${ size size } >>dim
size sq 3 * [ 256 random ] B{ } replicate-as >>bitmap
image-window
```

## Forth

Works with: gforth version 0.7.3

Uses gforth random generator to create PBM portable pixmap image file.

```require random.fs
: prngimage
outfile-id >r
s" prngimage.pbm" w/o create-file throw to outfile-id
s\" P1\n500 500\n" type
500 0 do
500 0 do
2 random 48 + emit
loop  #lf emit
loop
outfile-id close-file throw
r> to outfile-id ;

prngimage
```

## FreeBASIC

```Windowtitle "Pseudorandom number generator image"
Dim As Integer w = 500, h = w, x, y
Screenres w, h, 16

For x = 0 To w-1
For y = 0 To h-1
Pset(x, y), Rgb(Rnd * 255, Rnd * 255, Rnd * 255)
Next y
Next x

Bsave "Pseudo-Random-Algorithm.bmp",0```

image500.png (sample image, offsite)

## Go

The math/rand package uses a custom algorithm attributed to D.P.Mitchell and J.A.Reeds. It doesn't need to be seeded by a prime number. Typically (as here) the seed is generated from the current time.

The image is saved to a .png file which can then be viewed with a utility such as EOG.

```package main

import (
"image"
"image/color"
"image/png"
"log"
"math/rand"
"os"
"time"
)

func main() {
rand.Seed(time.Now().UnixNano())
img := image.NewNRGBA(image.Rect(0, 0, 1000, 1000))
for x := 0; x < 1000; x++ {
for y := 0; y < 1000; y++ {
col := color.RGBA{uint8(rand.Intn(256)), uint8(rand.Intn(256)), uint8(rand.Intn(256)), 255}
img.Set(x, y, col)
}
}
fileName := "pseudorandom_number_generator.png"
imgFile, err := os.Create(fileName)
if err != nil {
log.Fatal(err)
}
defer imgFile.Close()

if err := png.Encode(imgFile, img); err != nil {
imgFile.Close()
log.Fatal(err)
}
}
```

## Java

Following implementation generates images from java.util.Random(uses linear congruential generator [4].) and Blum Blum Shub Algorithm with least significant bit method and even bit parity method[5].

```import javax.imageio.ImageIO;
import java.awt.*;
import java.awt.image.BufferedImage;
import java.io.File;
import java.io.IOException;
import java.math.BigInteger;
import java.security.SecureRandom;
import java.util.Random;
import java.util.Scanner;
/*
* Numbers to try:
* p = 11 or BigInteger.probablePrime(BIT1_LENGTH, rand)
* q = 23 or BigInteger.probablePrime(BIT_LENGTH, rand)
* seed = 3 or BigInteger.probablePrime(BIT_LENGTH,rand)
* */

public class csprngBBS {
public static Scanner input = new Scanner(System.in);
private static final String fileformat = "png";
private static String bitsStri = "";
private static String parityEven = "";
private static String leastSig = "";
private static String randomJavaUtil = "";
private static int width = 0;
private static int BIT_LENGTH = 0;
private static final Random rand = new SecureRandom();
private static BigInteger p = null; // 11
private static BigInteger q = null; // 23
private static BigInteger m = null;
private static BigInteger seed = null; // 3
private static BigInteger seedFinal = null;
private static final Random randMathUtil = new SecureRandom();
public static void main(String[] args) throws IOException {
System.out.print("Width: ");
width = input.nextInt();
System.out.print("Bit-Length: ");
BIT_LENGTH = input.nextInt();
System.out.print("Generator format: ");
String useGenerator = input.next();
p = BigInteger.probablePrime(BIT_LENGTH, rand);
q = BigInteger.probablePrime(BIT_LENGTH, rand);
m = p.multiply(q);
seed = BigInteger.probablePrime(BIT_LENGTH,rand);
if(useGenerator.contains("parity") && useGenerator.contains("significant")) {
findLeastSignificant();
findBitParityEven();
createImage(parityEven, "parityEven");
createImage(leastSig, "significant");
}

if(useGenerator.contains("parity") && !useGenerator.contains("significant")){
findBitParityEven();
}

if(useGenerator.contains("significant") && !useGenerator.contains("parity")){
findLeastSignificant();
createImage(leastSig, "significant");
}

if(useGenerator.contains("util")){
findRandomJava(randMathUtil);
createImage(randomJavaUtil, "randomUtilJava");
}
}
public static void findRandomJava(Random random){
for(int x = 1; x <= Math.pow(width, 2); x++){
randomJavaUtil += random.nextInt(2);
}
}

public static void findBitParityEven(){
for(int x = 1; x <= Math.pow(width, 2); x++) {
seed = seed.pow(2).mod(m);
bitsStri = convertBinary(seed);
char[] bits = bitsStri.toCharArray();
int counter = 0;
for (char bit : bits) {
if (bit == '1') {
counter++;
}
}
if (counter % 2 != 0) {
parityEven += "1";
} else {
parityEven += "0";
}
}
}

public static void findLeastSignificant(){
seed = seedFinal;
for(int x = 1; x <= Math.pow(width, 2); x++){
seed = seed.pow(2).mod(m);
leastSig += bitsStri.substring(bitsStri.length() - 1);
}
}

public static String convertBinary(BigInteger value){
StringBuilder total = new StringBuilder();
BigInteger two = BigInteger.TWO;
while(value.compareTo(BigInteger.ZERO) > 0){
total.append(value.mod(two));
value = value.divide(two);
}
}

public static void createImage(String useThis, String fileName) throws IOException {
int length = csprngBBS.width;
// Constructs a BufferedImage of one of the predefined image types.
BufferedImage bufferedImage = new BufferedImage(length, length, 1/*BufferedImage.TYPE_INT_RGB*/);
// Create a graphics which can be used to draw into the buffered image
Graphics2D g2d = bufferedImage.createGraphics();
for (int y = 1; y <= length; y++) {
for (int x = 1; x <= length; x++) {
if (useThis.startsWith("1")) {
useThis = useThis.substring(1);
g2d.setColor(Color.BLACK);
g2d.fillRect(x, y, 1, 1);
} else if (useThis.startsWith("0")) {
useThis = useThis.substring(1);
g2d.setColor(Color.WHITE);
g2d.fillRect(x, y, 1, 1);
}
}
System.out.print(y + "\t");
}
// Disposes of this graphics context and releases any system resources that it is using.
g2d.dispose();
// Save as file
File file = new File("REPLACEFILEPATHHERE" + fileName + "." + fileformat);
ImageIO.write(bufferedImage, fileformat, file);
}
}
```

## jq

Works with jq and gojq, the C and Go implementations of jq

It has been claimed that the elementary cellular automaton with "Rule 30" can be used as a PRNG, (see e.g. Elementary_cellular_automaton/Random_number_generator), so this entry generates a set of (x,y,color) co-ordinates so that this hypothesis might be visually evaluated e.g. using the gnuplot program.

To keep things brief, the jq filter definitions at Elementary_cellular_automaton#jq are used but not repeated here.

```include "elementary-cellular-automaton" {search : "."};  # the defs at [[Elementary_cellular_automaton#jq]]

def binary2number:
reduce (.[]|tonumber) as \$x ({p:1}; .n += .p * \$x | .p *= 2) | .n;

# Emit a stream of \$n PRNGs in range(0;255)
def prng(\$n):
# 30 is 11110
("1" + 100 * "0" )
| [automaton(30; 8 * \$n) | .[0:1]]
| _nwise(8) | binary2number ;

foreach prng(99*99) as \$color ({x:0, y:1};
.color = \$color
| .x += 1
| if .x == 100 then .x = 1 | .y += 1 else . end )
| "\(.x) \(.y) \(.color)"```

Invocation:

```jq -nrf program.jq > prng.txt
gnuplot
plot("prng.txt") with image pixels
```

## Julia

Julia uses the Mersenne Twister algorithm for its default rand() function. That algorithm uses over 600 32-bit ints to represent its internal state, rather than just a product of two or three primes.

```using FileIO, ImageIO

save("randombw.png", rand(Float16, 1000, 1000))
```

## Lua

Lua uses the `xoroshiro256**` algorithm.

```size = 500
math.randomseed(os.time())

-- Writes a 256-bit grayscale PGM image file:
function writePgm(data, fn, comment)
local rows = #data
local cols = #data[1]
local file = io.open(fn, "wb")

file:write("P5", "\n")
if comment ~= nil then
file:write("# ", comment, "\n")
end
file:write(cols, " ", rows, "\n")
file:write("255", "\n")
-- Write data in raw bytes
for _, r in ipairs(data) do
file:write(string.char(unpack(r)))
end
file:close()
end

img = {}
for r = 1, size do
img[r] = {}
for c = 1, size do
img[r][c] = math.random(0,255)
end
end

writePgm(img, "prng_img.pgm", string.format("PRNG Image (%d x %d)", size, size))
```

## Maxima

```genmatrix(lambda([i,j],random(1000)),1000,1000)\$
wxdraw2d(image(%,0,0,30,30));
```

## Nim

Nim standard PRNG is an implementation of the `xoroshiro128+` (xor/rotate/shift/rotate) algorithm which is extremely fast. The standard library provides a Mersenne Twister implementation too. For this task, we used the first one.

```import random
import imageman

const Size = 500

randomize()
var image = initImage[ColorRGBU](Size, Size)
for x in 0..<Size:
for y in 0..<Size:
let color = ColorRGBU([rand(255).byte, rand(255).byte, rand(255).byte])
image[x, y] = color

image.savePNG("prng_image.png", compression = 9)
```

## Perl

Perl unified the PRNG with its own internal drand48() implementation on all platforms since v5.20.0. Without a manual srand, Perl by default source the seed from "/dev/urandom" if it is available so there shouldn't be any prime prerequisite.

```use strict;
use warnings;
use GD;

my \$img = GD::Image->new(500, 500, 1);

for my \$y (0..500) {
for my \$x (0..500) {
my \$color = \$img->colorAllocate(rand 256, rand 256, rand 256);
\$img->setPixel(\$x, \$y, \$color);
}
}

open  F, "image500.png";
print F  \$img->png;
```

image500.png (sample image, offsite)

## Phix

Library: Phix/pGUI
```-- demo\rosetta\Pseudorandom_number_generator_image.exw
without js -- IupSaveImage(), not possible from within a browser (though a "save" button might be?)
include pGUI.e

IupOpen()
integer w=250, h=w
sequence bw = repeat(0,w*h)
for x=0 to w-1 do
for y=0 to h-1 do
if rand(2)=2 then bw[x*h+y+1] = 255 end if
end for
end for
Ihandle image = IupImage(w,h,bw)
object res = IupSaveImage(image,"bw.png","PNG")
IupClose()
```

## PicoLisp

```(seed (in "/dev/urandom" (rd 8)))
(out "image.pbm"
(prinl "P1")
(prinl 500 " " 500)
(do 500
(do 500
(prin (if (rand T) 1 0)) )
(prinl) ) )```

## Python

Libraries: Pillow, random
```# pseudorandom number image generator by Xing216
from random import randbytes
from PIL import Image

size = 1500
x = bytes.fromhex(" ".join([randbytes(3).hex() for x in range(size*size)]))
img = Image.frombuffer('RGB', (size, size), x, 'raw', 'RGB', 0, 1)
img.show()
```
Output: rcXing216.png (transfer.sh)

## Raku

MoarVM uses Mersenne Twister as its PRNG but a prime seeder is not mandatory.

```# 20200818 Raku programming solution

use Image::PNG::Portable;

srand 2⁶³ - 25; # greatest prime smaller than 2⁶³ and the max my system can take

my @data = < 250 500 1000 1500 >;

@data.map: {
my \$o = Image::PNG::Portable.new: :width(\$_), :height(\$_);
for ^\$_ X ^\$_ -> @pixel { # about 40% slower if split to (\$x,\$y) or (\x,\y)
\$o.set: @pixel[0], @pixel[1], 256.rand.Int, 256.rand.Int, 256.rand.Int
}
\$o.write: "image\$_.png" or die;
}
```
Output:
```file image*.png
image1000.png: PNG image data, 1000 x 1000, 8-bit/color RGBA, non-interlaced
image1500.png: PNG image data, 1500 x 1500, 8-bit/color RGBA, non-interlaced
image250.png:  PNG image data, 250 x 250, 8-bit/color RGBA, non-interlaced
image500.png:  PNG image data, 500 x 500, 8-bit/color RGBA, non-interlaced
```

image500.png (sample image, offsite)

## Sidef

Translation of: Perl
```require('GD')

var img = %O<GD::Image>.new(500, 500, 1)

for y in (0..500), x in (0..500) {
var color = img.colorAllocate(255.irand, 255.irand, 255.irand)
img.setPixel(x, y, color)
}

File("image500.png").write(img.png, :raw)
```

## Wren

Library: DOME

Wren's 'random' module uses the 'Well equidistributed long-period linear' (WELL512a) PRNG which doesn't need to be seeded with a prime number. It is in fact seeded from a sequence of 16 numbers but, if less are provided, the others are generated automatically. Typically (as here) the seed is generated from the current time.

```import "dome" for Window
import "graphics" for Canvas, Color
import "random" for Random

class Game {
static init() {
Window.title = "Pseudorandom Number Generator Image"
Window.resize(1000, 1000)
Canvas.resize(1000, 1000)
var r = Random.new() // generates seed from current time
for (x in 0...1000) {
for (y in 0...1000) {
var c = Color.rgb(r.int(256), r.int(256), r.int(256))
Canvas.pset(x, y, c)
}
}
}

static update() {}

static draw(dt) {}
}```

## XPL0

The PRNG is linear congruential and is built-in. It's seeded with the time-of-day.

```int X, Y;
[SetVid(\$11B);  \VESA 1280x1024x24
for Y:= 0 to 1000-1 do
for X:= 0 to 1000-1 do
Point(X, Y, Ran(\$100_0000));
]```
Output:
```Essentially the same as Delphi's image.
```