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This means it might contain formatting issues, incorrect code, conceptual problems, or other severe issues.
If you want to help to improve and eventually enable this page, please fork RosettaGit's repository and open a merge request on GitHub.
{{task}} [[File:BFCpp.png|600px||right]]
A [[wp:Barnsley_fern|Barnsley fern]] is a fractal named after British mathematician Michael Barnsley and can be created using an iterated function system (IFS).
;Task: Create this fractal fern, using the following transformations:
-
ƒ1 (chosen 1% of the time) xn + 1 = 0 yn + 1 = 0.16 yn
-
ƒ2 (chosen 85% of the time) xn + 1 = 0.85 xn + 0.04 yn yn + 1 = −0.04 xn + 0.85 yn + 1.6
-
ƒ3 (chosen 7% of the time) xn + 1 = 0.2 xn − 0.26 yn yn + 1 = 0.23 xn + 0.22 yn + 1.6
-
ƒ4 (chosen 7% of the time) xn + 1 = −0.15 xn + 0.28 yn yn + 1 = 0.26 xn + 0.24 yn + 0.44.
Starting position: x = 0, y = 0
ALGOL 68
{{works with|ALGOL 68G|any with non-standard ''establish'' routine}}
This program generates a [https://en.wikipedia.org/wiki/Netpbm_format PBM file].
BEGIN
INT iterations = 300000;
LONG REAL scale x = 40, scale y = 40;
[0:400,-200:200]CHAR canvas;
LONG REAL x := 0, y := 0;
FOR i FROM 1 LWB canvas TO 1 UPB canvas DO
FOR j FROM 2 LWB canvas TO 2 UPB canvas DO
canvas[i,j] := "0"
OD OD;
canvas[0, 0] := "1";
TO iterations DO
REAL choice := random;
LONG REAL xn = x, yn = y;
IF choice < 0.01 THEN
x := 0;
y := 0.16 * yn
ELIF (choice -:= 0.01) < 0.85 THEN
x := 0.85 * xn + 0.04 * yn;
y := -0.04 * xn + 0.85 * yn + 1.6
ELIF (choice -:= 0.85) < 0.07 THEN
x := 0.2 * xn - 0.26 * yn;
y := 0.23 * xn + 0.22 * yn + 1.6
ELSE
x := -0.15 * xn + 0.28 * yn;
y := 0.26 * xn + 0.24 * yn + 0.44
FI;
INT px = SHORTEN ROUND (x * scale x),
py = SHORTEN ROUND (y * scale y);
IF px < 2 LWB canvas OR px > 2 UPB canvas OR
py < 1 LWB canvas OR py > 1 UPB canvas
THEN
print(("resize canvas. px=", px, ", py=", py, new line));
leave
FI;
canvas[py, px] := "1"
OD;
FILE f;
IF establish(f, "fern.pbm", stand out channel) /= 0 THEN
print("error creating file!"); leave
FI;
put(f, "P1"); new line(f);
put(f, (whole((2 UPB canvas) - (2 LWB canvas) + 1, 0), " ",
whole((1 UPB canvas) - (1 LWB canvas) + 1, 0), new line));
FOR i FROM 1 UPB canvas BY -1 TO 1 LWB canvas DO
put(f, canvas[i,]); new line(f)
OD;
close(f);
leave: SKIP
END
Applesoft BASIC
100 LET YY(1) = .16
110 XX(2) = .85:XY(2) = .04
120 YX(2) = - .04:YY(2) = .85
130 LET Y(2) = 1.6
140 XX(3) = .20:XY(3) = - .26
150 YX(3) = .23:YY(3) = .22
160 LET Y(3) = 1.6
170 XX(4) = - .15:XY(4) = .28
180 YX(4) = .26:YY(4) = .24
190 LET Y(4) = .44
200 HGR :I = PEEK (49234)
210 HCOLOR= 1
220 LET X = 0:Y = 0
230 FOR I = 1 TO 100000
240 R = INT ( RND (1) * 100)
250 F = (R < 7) + (R < 14) + 2
260 F = F - (R = 99)
270 X = XX(F) * X + XY(F) * Y
280 Y = YX(F) * X + YY(F) * Y
290 Y = Y + Y(F)
300 X% = 62 + X * 27.9
320 Y% = 192 - Y * 19.1
330 HPLOT X% * 2 + 1,Y%
340 NEXT
BBC BASIC
{{works with|BBC BASIC for Windows}}
GCOL 2 : REM Green Graphics Color
X=0 : Y=0
FOR I%=1 TO 100000
R%=RND(100)
CASE TRUE OF
WHEN R% == 1 NewX= 0 : NewY= .16 * Y
WHEN R% < 9 NewX= .20 * X - .26 * Y : NewY= .23 * X + .22 * Y + 1.6
WHEN R% < 16 NewX=-.15 * X + .28 * Y : NewY= .26 * X + .24 * Y + .44
OTHERWISE NewX= .85 * X + .04 * Y : NewY=-.04 * X + .85 * Y + 1.6
ENDCASE
X=NewX : Y=NewY
PLOT 1000 + X * 130 , Y * 130
NEXT
END
C
This implementation requires the [http://www.cs.colorado.edu/~main/bgi/cs1300/ WinBGIm] library. Iteration starts from (0,0) as required by the task however before plotting the point is translated and scaled as negative co-ordinates are not supported by the graphics window, scaling is necessary as otherwise the fern is tiny even for large iterations ( > 1000000).
#include<graphics.h>
#include<stdlib.h>
#include<stdio.h>
#include<time.h>
void barnsleyFern(int windowWidth, unsigned long iter){
double x0=0,y0=0,x1,y1;
int diceThrow;
time_t t;
srand((unsigned)time(&t));
while(iter>0){
diceThrow = rand()%100;
if(diceThrow==0){
x1 = 0;
y1 = 0.16*y0;
}
else if(diceThrow>=1 && diceThrow<=7){
x1 = -0.15*x0 + 0.28*y0;
y1 = 0.26*x0 + 0.24*y0 + 0.44;
}
else if(diceThrow>=8 && diceThrow<=15){
x1 = 0.2*x0 - 0.26*y0;
y1 = 0.23*x0 + 0.22*y0 + 1.6;
}
else{
x1 = 0.85*x0 + 0.04*y0;
y1 = -0.04*x0 + 0.85*y0 + 1.6;
}
putpixel(30*x1 + windowWidth/2.0,30*y1,GREEN);
x0 = x1;
y0 = y1;
iter--;
}
}
int main()
{
unsigned long num;
printf("Enter number of iterations : ");
scanf("%ld",&num);
initwindow(500,500,"Barnsley Fern");
barnsleyFern(500,num);
getch();
closegraph();
return 0;
}
C++
[[File:BFCpp.png|200px|thumb|right]]
#include <windows.h>
#include <ctime>
#include <string>
const int BMP_SIZE = 600, ITERATIONS = static_cast<int>( 15e5 );
class myBitmap {
public:
myBitmap() : pen( NULL ), brush( NULL ), clr( 0 ), wid( 1 ) {}
~myBitmap() {
DeleteObject( pen ); DeleteObject( brush );
DeleteDC( hdc ); DeleteObject( bmp );
}
bool create( int w, int h ) {
BITMAPINFO bi;
ZeroMemory( &bi, sizeof( bi ) );
bi.bmiHeader.biSize = sizeof( bi.bmiHeader );
bi.bmiHeader.biBitCount = sizeof( DWORD ) * 8;
bi.bmiHeader.biCompression = BI_RGB;
bi.bmiHeader.biPlanes = 1;
bi.bmiHeader.biWidth = w;
bi.bmiHeader.biHeight = -h;
HDC dc = GetDC( GetConsoleWindow() );
bmp = CreateDIBSection( dc, &bi, DIB_RGB_COLORS, &pBits, NULL, 0 );
if( !bmp ) return false;
hdc = CreateCompatibleDC( dc );
SelectObject( hdc, bmp );
ReleaseDC( GetConsoleWindow(), dc );
width = w; height = h;
return true;
}
void clear( BYTE clr = 0 ) {
memset( pBits, clr, width * height * sizeof( DWORD ) );
}
void setBrushColor( DWORD bClr ) {
if( brush ) DeleteObject( brush );
brush = CreateSolidBrush( bClr );
SelectObject( hdc, brush );
}
void setPenColor( DWORD c ) {
clr = c; createPen();
}
void setPenWidth( int w ) {
wid = w; createPen();
}
void saveBitmap( std::string path ) {
BITMAPFILEHEADER fileheader;
BITMAPINFO infoheader;
BITMAP bitmap;
DWORD wb;
GetObject( bmp, sizeof( bitmap ), &bitmap );
DWORD* dwpBits = new DWORD[bitmap.bmWidth * bitmap.bmHeight];
ZeroMemory( dwpBits, bitmap.bmWidth * bitmap.bmHeight * sizeof( DWORD ) );
ZeroMemory( &infoheader, sizeof( BITMAPINFO ) );
ZeroMemory( &fileheader, sizeof( BITMAPFILEHEADER ) );
infoheader.bmiHeader.biBitCount = sizeof( DWORD ) * 8;
infoheader.bmiHeader.biCompression = BI_RGB;
infoheader.bmiHeader.biPlanes = 1;
infoheader.bmiHeader.biSize = sizeof( infoheader.bmiHeader );
infoheader.bmiHeader.biHeight = bitmap.bmHeight;
infoheader.bmiHeader.biWidth = bitmap.bmWidth;
infoheader.bmiHeader.biSizeImage = bitmap.bmWidth * bitmap.bmHeight * sizeof( DWORD );
fileheader.bfType = 0x4D42;
fileheader.bfOffBits = sizeof( infoheader.bmiHeader ) + sizeof( BITMAPFILEHEADER );
fileheader.bfSize = fileheader.bfOffBits + infoheader.bmiHeader.biSizeImage;
GetDIBits( hdc, bmp, 0, height, ( LPVOID )dwpBits, &infoheader, DIB_RGB_COLORS );
HANDLE file = CreateFile( path.c_str(), GENERIC_WRITE, 0, NULL, CREATE_ALWAYS,
FILE_ATTRIBUTE_NORMAL, NULL );
WriteFile( file, &fileheader, sizeof( BITMAPFILEHEADER ), &wb, NULL );
WriteFile( file, &infoheader.bmiHeader, sizeof( infoheader.bmiHeader ), &wb, NULL );
WriteFile( file, dwpBits, bitmap.bmWidth * bitmap.bmHeight * 4, &wb, NULL );
CloseHandle( file );
delete [] dwpBits;
}
HDC getDC() const { return hdc; }
int getWidth() const { return width; }
int getHeight() const { return height; }
private:
void createPen() {
if( pen ) DeleteObject( pen );
pen = CreatePen( PS_SOLID, wid, clr );
SelectObject( hdc, pen );
}
HBITMAP bmp; HDC hdc;
HPEN pen; HBRUSH brush;
void *pBits; int width, height, wid;
DWORD clr;
};
class fern {
public:
void draw() {
bmp.create( BMP_SIZE, BMP_SIZE );
float x = 0, y = 0; HDC dc = bmp.getDC();
int hs = BMP_SIZE >> 1;
for( int f = 0; f < ITERATIONS; f++ ) {
SetPixel( dc, hs + static_cast<int>( x * 55.f ),
BMP_SIZE - 15 - static_cast<int>( y * 55.f ),
RGB( static_cast<int>( rnd() * 80.f ) + 20,
static_cast<int>( rnd() * 128.f ) + 128,
static_cast<int>( rnd() * 80.f ) + 30 ) );
getXY( x, y );
}
bmp.saveBitmap( "./bf.bmp" );
}
private:
void getXY( float& x, float& y ) {
float g, xl, yl;
g = rnd();
if( g < .01f ) { xl = 0; yl = .16f * y; }
else if( g < .07f ) {
xl = .2f * x - .26f * y;
yl = .23f * x + .22f * y + 1.6f;
} else if( g < .14f ) {
xl = -.15f * x + .28f * y;
yl = .26f * x + .24f * y + .44f;
} else {
xl = .85f * x + .04f * y;
yl = -.04f * x + .85f * y + 1.6f;
}
x = xl; y = yl;
}
float rnd() {
return static_cast<float>( rand() ) / static_cast<float>( RAND_MAX );
}
myBitmap bmp;
};
int main( int argc, char* argv[]) {
srand( static_cast<unsigned>( time( 0 ) ) );
fern f; f.draw(); return 0;
}
C#
using System;
using System.Diagnostics;
using System.Drawing;
namespace RosettaBarnsleyFern
{
class Program
{
static void Main(string[] args)
{
const int w = 600;
const int h = 600;
var bm = new Bitmap(w, h);
var r = new Random();
double x = 0;
double y = 0;
for (int count = 0; count < 100000; count++)
{
bm.SetPixel((int)(300 + 58 * x), (int)(58 * y), Color.ForestGreen);
int roll = r.Next(100);
double xp = x;
if (roll < 1)
{
x = 0;
y = 0.16 * y;
} else if (roll < 86)
{
x = 0.85 * x + 0.04 * y;
y = -0.04 * xp + 0.85 * y + 1.6;
} else if (roll < 93)
{
x = 0.2 * x - 0.26 * y;
y = 0.23 * xp + 0.22 * y + 1.6;
} else
{
x = -0.15 * x + 0.28 * y;
y = 0.26 * xp + 0.24 * y + 0.44;
}
}
const string filename = "Fern.png";
bm.Save(filename);
Process.Start(filename);
}
}
}
Common Lisp
This code uses the opticl package for generating an image and saving it as a PNG file.
(defpackage #:barnsley-fern
(:use #:cl
#:opticl))
(in-package #:barnsley-fern)
(defparameter *width* 800)
(defparameter *height* 800)
(defparameter *factor* (/ *height* 13))
(defparameter *x-offset* (/ *width* 2))
(defparameter *y-offset* (/ *height* 10))
(defun f1 (x y)
(declare (ignore x))
(values 0 (* 0.16 y)))
(defun f2 (x y)
(values (+ (* 0.85 x) (* 0.04 y))
(+ (* -0.04 x) (* 0.85 y) 1.6)))
(defun f3 (x y)
(values (+ (* 0.2 x) (* -0.26 y))
(+ (* 0.23 x) (* 0.22 y) 1.6)))
(defun f4 (x y)
(values (+ (* -0.15 x) (* 0.28 y))
(+ (* 0.26 x) (* 0.24 y) 0.44)))
(defun choose-transform ()
(let ((r (random 1.0)))
(cond ((< r 0.01) #'f1)
((< r 0.86) #'f2)
((< r 0.93) #'f3)
(t #'f4))))
(defun set-pixel (image x y)
(let ((%x (round (+ (* *factor* x) *x-offset*)))
(%y (round (- *height* (* *factor* y) *y-offset*))))
(setf (pixel image %y %x) (values 0 255 0))))
(defun fern (filespec &optional (iterations 10000000))
(let ((image (make-8-bit-rgb-image *height* *width* :initial-element 0))
(x 0)
(y 0))
(dotimes (i iterations)
(set-pixel image x y)
(multiple-value-setq (x y) (funcall (choose-transform) x y)))
(write-png-file filespec image)))
Delphi
{{trans|Java}} Hint: After putting a TPaintBox on the main form align it to alClient. Client width / height of the main form should be no less than 640 x 480.
unit Unit1;
interface
uses
Windows, SysUtils, Graphics, Forms, Controls, Classes, ExtCtrls;
type
TForm1 = class(TForm)
PaintBox1: TPaintBox;
procedure FormPaint(Sender: TObject);
private
{ Private declarations }
public
{ Public declarations }
end;
var
Form1: TForm1;
implementation
{$R *.dfm}
procedure CreateFern(const w, h: integer);
var r, x, y: double;
tmpx, tmpy: double;
i: integer;
begin
x := 0;
y := 0;
randomize();
for i := 0 to 200000 do begin
r := random(100000000) / 99999989;
if r <= 0.01 then begin
tmpx := 0;
tmpy := 0.16 * y;
end
else if r <= 0.08 then begin
tmpx := 0.2 * x - 0.26 * y;
tmpy := 0.23 * x + 0.22 * y + 1.6;
end
else if r <= 0.15 then begin
tmpx := -0.15 * x + 0.28 * y;
tmpy := 0.26 * x + 0.24 * y + 0.44;
end
else begin
tmpx := 0.85 * x + 0.04 * y;
tmpy := -0.04 * x + 0.85 * y + 1.6;
end;
x := tmpx;
y := tmpy;
Form1.PaintBox1.Canvas.Pixels[round(w / 2 + x * w / 11), round(h - y * h / 11)] := clGreen;
end;
end;
procedure TForm1.FormPaint(Sender: TObject);
begin
CreateFern(Form1.ClientWidth, Form1.ClientHeight);
end;
end.
EasyLang
[https://easylang.online/apps/barnsley-fern.html Run it]
=={{header|Fōrmulæ}}==
In [https://wiki.formulae.org/Barnsley_fern this] page you can see the solution of this task.
Fōrmulæ programs are not textual, visualization/edition of programs is done showing/manipulating structures but not text ([http://wiki.formulae.org/Editing_F%C5%8Drmul%C3%A6_expressions more info]). Moreover, there can be multiple visual representations of the same program. Even though it is possible to have textual representation —i.e. XML, JSON— they are intended for transportation effects more than visualization and edition.
The option to show Fōrmulæ programs and their results is showing images. Unfortunately images cannot be uploaded in Rosetta Code.
## Fortran
```fortran
!Generates an output file "plot.dat" that contains the x and y coordinates
!for a scatter plot that can be visualized with say, GNUPlot
program BarnsleyFern
implicit none
double precision :: p(4), a(4), b(4), c(4), d(4), e(4), f(4), trx, try, prob
integer :: itermax, i
!The probabilites and coefficients can be modified to generate other
!fractal ferns, e.g. http://www.home.aone.net.au/~byzantium/ferns/fractal.html
!probabilities
p(1) = 0.01; p(2) = 0.85; p(3) = 0.07; p(4) = 0.07
!coefficients
a(1) = 0.00; a(2) = 0.85; a(3) = 0.20; a(4) = -0.15
b(1) = 0.00; b(2) = 0.04; b(3) = -0.26; b(4) = 0.28
c(1) = 0.00; c(2) = -0.04; c(3) = 0.23; c(4) = 0.26
d(1) = 0.16; d(2) = 0.85; d(3) = 0.22; d(4) = 0.24
e(1) = 0.00; e(2) = 0.00; e(3) = 0.00; e(4) = 0.00
f(1) = 0.00; f(2) = 1.60; f(3) = 1.60; f(4) = 0.44
itermax = 100000
trx = 0.0D0
try = 0.0D0
open(1, file="plot.dat")
write(1,*) "#X #Y"
write(1,'(2F10.5)') trx, try
do i = 1, itermax
call random_number(prob)
if (prob < p(1)) then
trx = a(1) * trx + b(1) * try + e(1)
try = c(1) * trx + d(1) * try + f(1)
else if(prob < (p(1) + p(2))) then
trx = a(2) * trx + b(2) * try + e(2)
try = c(2) * trx + d(2) * try + f(2)
else if ( prob < (p(1) + p(2) + p(3))) then
trx = a(3) * trx + b(3) * try + e(3)
try = c(3) * trx + d(3) * try + f(3)
else
trx = a(4) * trx + b(4) * try + e(4)
try = c(4) * trx + d(4) * try + f(4)
end if
write(1,'(2F10.5)') trx, try
end do
close(1)
end program BarnsleyFern
FreeBASIC
' version 10-10-2016
' compile with: fbc -s console
Sub barnsley(height As UInteger)
Dim As Double x, y, xn, yn
Dim As Double f = height / 10.6
Dim As UInteger offset_x = height \ 4 - height \ 40
Dim As UInteger n, r
ScreenRes height \ 2, height, 32
For n = 1 To height * 50
r = Int(Rnd * 100) ' f from 0 to 99
Select Case As Const r
Case 0 To 84
xn = 0.85 * x + 0.04 * y
yn = -0.04 * x + 0.85 * y + 1.6
Case 85 To 91
xn = 0.2 * x - 0.26 * y
yn = 0.23 * x + 0.22 * y + 1.6
Case 92 To 98
xn = -0.15 * x + 0.28 * y
yn = 0.26 * x + 0.24 * y + 0.44
Case Else
xn = 0
yn = 0.16 * y
End Select
x = xn : y = yn
PSet( offset_x + x * f, height - y * f), RGB(0, 255, 0)
Next
' remove comment (') in next line to save window as .bmp file
' BSave "barnsley_fern_" + Str(height) + ".bmp", 0
End Sub
' ------=< MAIN >=------
' adjustable window height
' call the subroutine with the height you want
' it's possible to have a window that's large than your display
barnsley(800)
' empty keyboard buffer
While Inkey <> "" : Wend
Windowtitle "hit any key to end program"
Sleep
End
=={{header|G'MIC}}==
# Put this into a new file 'fern.gmic' and invoke it from the command line, like this:
# $ gmic fern.gmic -barnsley_fern
barnsley_fern :
1024,2048
-skip {"
f1 = [ 0,0,0,0.16 ]; g1 = [ 0,0 ];
f2 = [ 0.2,-0.26,0.23,0.22 ]; g2 = [ 0,1.6 ];
f3 = [ -0.15,0.28,0.26,0.24 ]; g3 = [ 0,0.44 ];
f4 = [ 0.85,0.04,-0.04,0.85 ]; g4 = [ 0,1.6 ];
xy = [ 0,0 ];
for (n = 0, n<2e6, ++n,
r = u(100);
xy = r<=1?((f1**xy)+=g1):
r<=8?((f2**xy)+=g2):
r<=15?((f3**xy)+=g3):
((f4**xy)+=g4);
uv = xy*200 + [ 480,0 ];
uv[1] = h - uv[1];
I(uv) = 0.7*I(uv) + 0.3*255;
)"}
-r 40%,40%,1,1,2
gnuplot
{{trans|PARI/GP}} {{Works with|gnuplot|5.0 (patchlevel 3) and above}} [[File:BarnsleyFernGnu.png|right|thumb|Output BarnsleyFernGnu.png]]
## Barnsley fern fractal 2/17/17 aev
reset
fn="BarnsleyFernGnu"; clr='"green"';
ttl="Barnsley fern fractal"
dfn=fn.".dat"; ofn=fn.".png";
set terminal png font arial 12 size 640,640
set print dfn append
set output ofn
unset border; unset xtics; unset ytics; unset key;
set size square
set title ttl font "Arial:Bold,12"
n=100000; max=100; x=y=xw=yw=p=0;
randgp(top) = floor(rand(0)*top)
do for [i=1:n] {
p=randgp(max);
if (p==1) {xw=0;yw=0.16*y;}
if (1<p&&p<=8) {xw=0.2*x-0.26*y;yw=0.23*x+0.22*y+1.6;}
if (8<p&&p<=15) {xw=-0.15*x+0.28*y;yw=0.26*x+0.24*y+0.44;}
if (p>15) {xw=0.85*x+0.04*y;yw=-0.04*x+0.85*y+1.6;}
x=xw;y=yw; print x," ",y;
}
plot dfn using 1:2 with points pt 7 ps 0.5 lc @clr
set output
unset print
{{Output}}
File: BarnsleyFernGnu.png
(also BarnsleyFernGnu.dat)
Go
package main
import (
"image"
"image/color"
"image/draw"
"image/png"
"log"
"math/rand"
"os"
)
// values from WP
const (
xMin = -2.1820
xMax = 2.6558
yMin = 0.
yMax = 9.9983
)
// parameters
var (
width = 200
n = int(1e6)
c = color.RGBA{34, 139, 34, 255} // forest green
)
func main() {
dx := xMax - xMin
dy := yMax - yMin
fw := float64(width)
fh := fw * dy / dx
height := int(fh)
r := image.Rect(0, 0, width, height)
img := image.NewRGBA(r)
draw.Draw(img, r, &image.Uniform{color.White}, image.ZP, draw.Src)
var x, y float64
plot := func() {
// transform computed float x, y to integer image coordinates
ix := int(fw * (x - xMin) / dx)
iy := int(fh * (yMax - y) / dy)
img.SetRGBA(ix, iy, c)
}
plot()
for i := 0; i < n; i++ {
switch s := rand.Intn(100); {
case s < 85:
x, y =
.85*x+.04*y,
-.04*x+.85*y+1.6
case s < 85+7:
x, y =
.2*x-.26*y,
.23*x+.22*y+1.6
case s < 85+7+7:
x, y =
-.15*x+.28*y,
.26*x+.24*y+.44
default:
x, y = 0, .16*y
}
plot()
}
// write img to png file
f, err := os.Create("bf.png")
if err != nil {
log.Fatal(err)
}
if err := png.Encode(f, img); err != nil {
log.Fatal(err)
}
}
Haskell
import Data.List (scanl')
import Diagrams.Backend.Rasterific.CmdLine
import Diagrams.Prelude
import System.Random
type Pt = (Double, Double)
-- Four affine transformations used to produce a Barnsley fern.
f1, f2, f3, f4 :: Pt -> Pt
f1 (x, y) = ( 0, 0.16 * y)
f2 (x, y) = ( 0.85 * x + 0.04 * y , -0.04 * x + 0.85 * y + 1.60)
f3 (x, y) = ( 0.20 * x - 0.26 * y , 0.23 * x + 0.22 * y + 1.60)
f4 (x, y) = (-0.15 * x + 0.28 * y , 0.26 * x + 0.24 * y + 0.44)
-- Given a random number in [0, 1) transform an initial point by a randomly
-- chosen function.
func :: Pt -> Double -> Pt
func p r | r < 0.01 = f1 p
| r < 0.86 = f2 p
| r < 0.93 = f3 p
| otherwise = f4 p
-- Using a sequence of uniformly distributed random numbers in [0, 1) return
-- the same number of points in the fern.
fern :: [Double] -> [Pt]
fern = scanl' func (0, 0)
-- Given a supply of random values and a count, generate a diagram of a fern
-- composed of that number of points.
drawFern :: [Double] -> Int -> Diagram B
drawFern rs n = frame 0.5 . diagramFrom . take n $ fern rs
where diagramFrom = flip atPoints (repeat dot) . map p2
dot = circle 0.005 # lc green
-- To generate a PNG image of a fern, call this program like:
--
-- fern -o fern.png -w 640 -h 640 50000
--
-- where the arguments specify the width, height and number of points in the
-- image.
main :: IO ()
main = do
rand <- getStdGen
mainWith $ drawFern (randomRs (0, 1) rand)
J
[[File:jfern.png|200px|thumb|right]]
require 'plot'
f=: |: 0 ". ];._2 noun define
0 0 0 0.16 0 0 0.01
0.85 -0.04 0.04 0.85 0 1.60 0.85
0.20 0.23 -0.26 0.22 0 1.60 0.07
-0.15 0.26 0.28 0.24 0 0.44 0.07
)
fm=: {&(|: 2 2 $ f)
fa=: {&(|: 4 5 { f)
prob=: (+/\ 6 { f) I. ?@0:
ifs=: (fa@] + fm@] +/ .* [) prob
getPoints=: ifs^:(<200000)
plotFern=: 'dot;grids 0 0;tics 0 0;labels 0 0;color green' plot ;/@|:
plotFern getPoints 0 0
Java
[[File:barnsley_fern.png|200px|thumb|right]] {{works with|Java|8}}
import java.awt.*;
import java.awt.image.BufferedImage;
import javax.swing.*;
public class BarnsleyFern extends JPanel {
BufferedImage img;
public BarnsleyFern() {
final int dim = 640;
setPreferredSize(new Dimension(dim, dim));
setBackground(Color.white);
img = new BufferedImage(dim, dim, BufferedImage.TYPE_INT_ARGB);
createFern(dim, dim);
}
void createFern(int w, int h) {
double x = 0;
double y = 0;
for (int i = 0; i < 200_000; i++) {
double tmpx, tmpy;
double r = Math.random();
if (r <= 0.01) {
tmpx = 0;
tmpy = 0.16 * y;
} else if (r <= 0.08) {
tmpx = 0.2 * x - 0.26 * y;
tmpy = 0.23 * x + 0.22 * y + 1.6;
} else if (r <= 0.15) {
tmpx = -0.15 * x + 0.28 * y;
tmpy = 0.26 * x + 0.24 * y + 0.44;
} else {
tmpx = 0.85 * x + 0.04 * y;
tmpy = -0.04 * x + 0.85 * y + 1.6;
}
x = tmpx;
y = tmpy;
img.setRGB((int) Math.round(w / 2 + x * w / 11),
(int) Math.round(h - y * h / 11), 0xFF32CD32);
}
}
@Override
public void paintComponent(Graphics gg) {
super.paintComponent(gg);
Graphics2D g = (Graphics2D) gg;
g.setRenderingHint(RenderingHints.KEY_ANTIALIASING,
RenderingHints.VALUE_ANTIALIAS_ON);
g.drawImage(img, 0, 0, null);
}
public static void main(String[] args) {
SwingUtilities.invokeLater(() -> {
JFrame f = new JFrame();
f.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
f.setTitle("Barnsley Fern");
f.setResizable(false);
f.add(new BarnsleyFern(), BorderLayout.CENTER);
f.pack();
f.setLocationRelativeTo(null);
f.setVisible(true);
});
}
}
JavaScript
{{trans|PARI/GP}} [[File:BarnsleyFernjs.png|right|thumb|Output BarnsleyFernjs.png]]
// Barnsley fern fractal
//6/17/16 aev
function pBarnsleyFern(canvasId,lim) {
// DCLs
var canvas = document.getElementById(canvasId);
var ctx = canvas.getContext("2d");
var w = canvas.width;
var h = canvas.height;
var x=0.,y=0.,xw=0.,yw=0.,r;
// Like in PARI/GP: return random number 0..max-1
function randgp(max) {return Math.floor(Math.random()*max)}
// Clean canvas
ctx.fillStyle="white"; ctx.fillRect(0,0,w,h);
// MAIN LOOP
for(var i=0; i<lim; i++) {
r=randgp(100);
if (r<=1) {xw=0;yw=0.16*y;}
else if (r<=8) {xw=0.2*x-0.26*y;yw=0.23*x+0.22*y+1.6;}
else if (r<=15) {xw=-0.15*x+0.28*y;yw=0.26*x+0.24*y+0.44;}
else {xw=0.85*x+0.04*y;yw=-0.04*x+0.85*y+1.6;}
x=xw;y=yw; ctx.fillStyle="green"; ctx.fillRect(x*50+260,-y*50+540,1,1);
}//fend i
}
'''Executing:'''
<html>
<head><script src="BarnsleyFern.js"></script></head>
<body onload="pBarnsleyFern('canvas', 100000)">
<br /> <h3>Barnsley fern fractal</h3>
<canvas id="canvas" width="540" height="540" style="border: 2px inset;"></canvas>
</body>
</html>
{{Output}}
Page with BarnsleyFernjs.png
Julia
{{works with|Julia|0.6}}
function barnsleyfern(n::Integer)
funs = (
(x, y) -> (0, 0.16y),
(x, y) -> (0.85x + 0.04y, -0.04x + 0.85y + 1.6),
(x, y) -> (0.2x - 0.26y, 0.23x + 0.22y + 1.6),
(x, y) -> (-0.15x + 0,28y, 0.26x + 0.24y + 0.44))
rst = Matrix{Float64}(n, 2)
rst[1, :] = 0.0
for row in 2:n
r = rand(0:99)
if r < 1; f = 1;
elseif r < 86; f = 2;
elseif r < 93; f = 3;
else f = 4; end
rst[row, 1], rst[row, 2] = funs[f](rst[row-1, 1], rst[row-1, 2])
end
return rst
end
Kotlin
{{trans|Java}}
// version 1.1.0
import java.awt.*
import java.awt.image.BufferedImage
import javax.swing.*
class BarnsleyFern(private val dim: Int) : JPanel() {
private val img: BufferedImage
init {
preferredSize = Dimension(dim, dim)
background = Color.black
img = BufferedImage(dim, dim, BufferedImage.TYPE_INT_ARGB)
createFern(dim, dim)
}
private fun createFern(w: Int, h: Int) {
var x = 0.0
var y = 0.0
for (i in 0 until 200_000) {
var tmpx: Double
var tmpy: Double
val r = Math.random()
if (r <= 0.01) {
tmpx = 0.0
tmpy = 0.16 * y
}
else if (r <= 0.86) {
tmpx = 0.85 * x + 0.04 * y
tmpy = -0.04 * x + 0.85 * y + 1.6
}
else if (r <= 0.93) {
tmpx = 0.2 * x - 0.26 * y
tmpy = 0.23 * x + 0.22 * y + 1.6
}
else {
tmpx = -0.15 * x + 0.28 * y
tmpy = 0.26 * x + 0.24 * y + 0.44
}
x = tmpx
y = tmpy
img.setRGB(Math.round(w / 2.0 + x * w / 11.0).toInt(),
Math.round(h - y * h / 11.0).toInt(), 0xFF32CD32.toInt())
}
}
override protected fun paintComponent(gg: Graphics) {
super.paintComponent(gg)
val g = gg as Graphics2D
g.setRenderingHint(RenderingHints.KEY_ANTIALIASING, RenderingHints.VALUE_ANTIALIAS_ON)
g.drawImage(img, 0, 0, null)
}
}
fun main(args: Array<String>) {
SwingUtilities.invokeLater {
val f = JFrame()
f.defaultCloseOperation = JFrame.EXIT_ON_CLOSE
f.title = "Barnsley Fern"
f.setResizable(false)
f.add(BarnsleyFern(640), BorderLayout.CENTER)
f.pack()
f.setLocationRelativeTo(null)
f.setVisible(true)
}
}
Lua
Needs LÖVE 2D Engine
g = love.graphics
wid, hei = g.getWidth(), g.getHeight()
function choose( i, j )
local r = math.random()
if r < .01 then return 0, .16 * j
elseif r < .07 then return .2 * i - .26 * j, .23 * i + .22 * j + 1.6
elseif r < .14 then return -.15 * i + .28 * j, .26 * i + .24 * j + .44
else return .85 * i + .04 * j, -.04 * i + .85 * j + 1.6
end
end
function createFern( iterations )
local hw, x, y, scale = wid / 2, 0, 0, 45
local pts = {}
for k = 1, iterations do
pts[1] = { hw + x * scale, hei - 15 - y * scale,
20 + math.random( 80 ),
128 + math.random( 128 ),
20 + math.random( 80 ), 150 }
g.points( pts )
x, y = choose( x, y )
end
end
function love.load()
math.randomseed( os.time() )
canvas = g.newCanvas( wid, hei )
g.setCanvas( canvas )
createFern( 15e4 )
g.setCanvas()
end
function love.draw()
g.draw( canvas )
end
=={{header|Mathematica}} / {{header|Wolfram Language}}==
BarnsleyFern[{x_, y_}] := Module[{},
i = RandomInteger[{1, 100}];
If[i <= 1, {xt = 0, yt = 0.16*y},
If[i <= 8, {xt = 0.2*x - 0.26*y, yt = 0.23*x + 0.22*y + 1.6},
If[i <= 15, {xt = -0.15*x + 0.28*y, yt = 0.26*x + 0.24*y + 0.44},
{xt = 0.85*x + 0.04*y, yt = -0.04*x + 0.85*y + 1.6}]]];
{xt, yt}];
points = NestList[BarnsleyFern, {0,0}, 100000];
Show[Graphics[{Hue[.35, 1, .7], PointSize[.001], Point[#] & /@ points}]]
Nim
import nimPNG, random
randomize()
const
width = 640
height = 640
minX = -2.1815
maxX = 2.6556
minY = 0.0
maxY = 9.9982
iterations = 1_000_000
var img: array[width * height * 3, char]
proc floatToPixel(x,y:float): tuple[a:int,b:int] =
var px = abs(x - minX) / abs(maxX - minX)
var py = abs(y - minY) / abs(maxY - minY)
var a:int = (int)(width * px)
var b:int = (int)(height * py)
a = a.clamp(0, width-1)
b = b.clamp(0, height-1)
# flip the y axis
(a:a,b:height-b-1)
proc pixelToOffset(a,b: int): int =
b * width * 3 + a * 3
proc toString(a: openArray[char]): string =
result = newStringOfCap(a.len)
for ch in items(a):
result.add(ch)
proc drawPixel(x,y:float) =
var (a,b) = floatToPixel(x,y)
var offset = pixelToOffset(a,b)
#img[offset] = 0 # red channel
img[offset+1] = char(250) # green channel
#img[offset+2] = 0 # blue channel
# main
var x, y: float = 0.0
for i in 1..iterations:
var r = random(101)
var nx, ny: float
if r <= 85:
nx = 0.85 * x + 0.04 * y
ny = -0.04 * x + 0.85 * y + 1.6
elif r <= 85 + 7:
nx = 0.2 * x - 0.26 * y
ny = 0.23 * x + 0.22 * y + 1.6
elif r <= 85 + 7 + 7:
nx = -0.15 * x + 0.28 * y
ny = 0.26 * x + 0.24 * y + 0.44
else:
nx = 0
ny = 0.16 * y
x = nx
y = ny
drawPixel(x,y)
discard savePNG24("fern.png",img.toString, width, height)
=={{header|Oberon-2}}== [[File:Barnsleyfern-oberon2.png|250px|thumb|right]]
MODULE BarnsleyFern;
(**
Oxford Oberon-2
**)
IMPORT Random, XYplane;
VAR
a1, b1, c1, d1, e1, f1, p1: REAL;
a2, b2, c2, d2, e2, f2, p2: REAL;
a3, b3, c3, d3, e3, f3, p3: REAL;
a4, b4, c4, d4, e4, f4, p4: REAL;
X, Y: REAL;
x0, y0, e: INTEGER;
PROCEDURE Draw;
VAR x, y: REAL; xi, eta: INTEGER; rn: REAL;
BEGIN
REPEAT
rn := Random.Uniform();
IF rn < p1 THEN
x := a1 * X + b1 * Y + e1; y := c1 * X + d1 * Y + f1
ELSIF rn < (p1 + p2) THEN
x := a2 *X + b2 * Y + e2; y := c2 * X + d2 * Y + f2
ELSIF rn < (p1 + p2 + p3) THEN
x := a3 * X + b3 * Y + e3; y := c3 * X + d3 * Y + f3
ELSE
x := a4 * X + b4 * Y + e4; y := c4 * X + d4 * Y + f4
END;
X := x; xi := x0 + SHORT(ENTIER(X * e));
Y := y; eta := y0 + SHORT(ENTIER(Y * e));
XYplane.Dot(xi, eta, XYplane.draw)
UNTIL "s" = XYplane.Key()
END Draw;
PROCEDURE Init;
BEGIN
X := 0; Y := 0;
x0 := 120; y0 := 0; e := 25;
a1 := 0.00; a2 := 0.85; a3 := 0.20; a4 := -0.15;
b1 := 0.00; b2 := 0.04; b3 := -0.26; b4 := 0.28;
c1 := 0.00; c2 := -0.04; c3 := 0.23; c4 := 0.26;
d1 := 0.16; d2 := 0.85; d3 := 0.22; d4 := 0.24;
e1 := 0.00; e2 := 0.00; e3 := 0.00; e4 := 0.00;
f1 := 0.00; f2 := 1.60; f3 := 1.60; f4 := 0.44;
p1 := 0.01; p2 := 0.85; p3 := 0.07; p4 := 0.07;
XYplane.Open;
END Init;
BEGIN
Init;Draw
END BarnsleyFern.
PARI/GP
{{trans|zkl}} {{Works with|PARI/GP|2.7.4 and above}} [[File:BarnsleyFern.png|right|thumb|Output BarnsleyFern.png]]
\\ Barnsley fern fractal
\\ 6/17/16 aev
pBarnsleyFern(size,lim)={
my(X=List(),Y=X,x=y=xw=yw=0.0,r);
print(" *** Barnsley Fern, size=",size," lim=",lim);
plotinit(0); plotcolor(0,6); \\green
plotscale(0, -3,3, 0,10); plotmove(0, 0,0);
for(i=1, lim,
r=random(100);
if(r<=1, xw=0;yw=0.16*y,
if(r<=8, xw=0.2*x-0.26*y;yw=0.23*x+0.22*y+1.6,
if(r<=15, xw=-0.15*x+0.28*y;yw=0.26*x+0.24*y+0.44,
xw=0.85*x+0.04*y;yw=-0.04*x+0.85*y+1.6)));
x=xw;y=yw; listput(X,x); listput(Y,y);
);\\fend i
plotpoints(0,Vec(X),Vec(Y));
plotdraw([0,-3,-0]);
}
{\\ Executing:
pBarnsleyFern(530,100000); \\ BarnsleyFern.png
}
{{Output}}
> pBarnsleyFern(530,100000); \\ BarnsleyFern.png
*** Barnsley Fern, size=530 lim=100000
Perl
[[File:BarnsleyFernPerl.png|250px|thumb|right]]
use Imager;
my $w = 640;
my $h = 640;
my $img = Imager->new(xsize => $w, ysize => $h, channels => 3);
my $green = Imager::Color->new('#00FF00');
my ($x, $y) = (0, 0);
foreach (1 .. 2e5) {
my $r = rand(100);
($x, $y) = do {
if ($r <= 1) { ( 0.00 * $x - 0.00 * $y, 0.00 * $x + 0.16 * $y + 0.00) }
elsif ($r <= 8) { ( 0.20 * $x - 0.26 * $y, 0.23 * $x + 0.22 * $y + 1.60) }
elsif ($r <= 15) { (-0.15 * $x + 0.28 * $y, 0.26 * $x + 0.24 * $y + 0.44) }
else { ( 0.85 * $x + 0.04 * $y, -0.04 * $x + 0.85 * $y + 1.60) }
};
$img->setpixel(x => $w / 2 + $x * 60, y => $y * 60, color => $green);
}
$img->flip(dir => 'v');
$img->write(file => 'barnsleyFern.png');
Perl 6
{{works with|Rakudo|2016.03}} {{trans|Perl}} [[File:Barnsley-fern-perl6.png|250px|thumb|right]]
use Image::PNG::Portable;
my ($w, $h) = (640, 640);
my $png = Image::PNG::Portable.new: :width($w), :height($h);
my ($x, $y) = (0, 0);
for ^2e5 {
my $r = 100.rand;
($x, $y) = do given $r {
when $r <= 1 { ( 0, 0.16 * $y ) }
when $r <= 8 { ( 0.20 * $x - 0.26 * $y, 0.23 * $x + 0.22 * $y + 1.60) }
when $r <= 15 { (-0.15 * $x + 0.28 * $y, 0.26 * $x + 0.24 * $y + 0.44) }
default { ( 0.85 * $x + 0.04 * $y, -0.04 * $x + 0.85 * $y + 1.60) }
};
$png.set(($w / 2 + $x * 60).Int, $h - ($y * 60).Int, 0, 255, 0);
}
$png.write: 'Barnsley-fern-perl6.png';
Phix
{{libheader|pGUI}} This file is included in the distro as [[File:PhixBarnsleyFern.png|250px|thumb|right]]
--
-- demo\rosetta\BarnsleyFern.exw
--
include pGUI.e
Ihandle dlg, canvas
cdCanvas cddbuffer, cdcanvas
function redraw_cb(Ihandle /*ih*/, integer /*posx*/, integer /*posy*/)
atom {x,y,r} @= 0
integer {width, height} = IupGetIntInt(canvas, "DRAWSIZE")
cdCanvasActivate(cddbuffer)
for i=1 to 20000 do
r = rand(100)
{x, y} = iff(r<=1? { 0, 0.16*y } :
iff(r<=8? { 0.20*x-0.26*y, 0.23*x+0.22*y+1.60} :
iff(r<=15?{-0.15*x+0.28*y, 0.26*x+0.24*y+0.44} :
{ 0.85*x+0.04*y,-0.04*x+0.85*y+1.60})))
cdCanvasPixel(cddbuffer, width/2+x*60, y*60, #00FF00)
end for
cdCanvasFlush(cddbuffer)
return IUP_DEFAULT
end function
function map_cb(Ihandle ih)
cdcanvas = cdCreateCanvas(CD_IUP, ih)
cddbuffer = cdCreateCanvas(CD_DBUFFER, cdcanvas)
cdCanvasSetBackground(cddbuffer, CD_WHITE)
cdCanvasSetForeground(cddbuffer, CD_RED)
return IUP_DEFAULT
end function
function esc_close(Ihandle /*ih*/, atom c)
if c=K_ESC then return IUP_CLOSE end if
return IUP_CONTINUE
end function
procedure main()
IupOpen()
canvas = IupCanvas(NULL)
IupSetAttribute(canvas, "RASTERSIZE", "340x620") -- initial size
IupSetCallback(canvas, "MAP_CB", Icallback("map_cb"))
dlg = IupDialog(canvas)
IupSetAttribute(dlg, "TITLE", "Barnsley Fern")
IupSetCallback(dlg, "K_ANY", Icallback("esc_close"))
IupSetCallback(canvas, "ACTION", Icallback("redraw_cb"))
IupMap(dlg)
IupSetAttribute(canvas, "RASTERSIZE", NULL) -- release the minimum limitation
IupShowXY(dlg,IUP_CENTER,IUP_CENTER)
IupMainLoop()
IupClose()
end procedure
main()
PicoLisp
`(== 64 64)
(seed (in "/dev/urandom" (rd 8)))
(scl 20)
(de gridX (X)
(*/ (+ 320.0 (*/ X 58.18 1.0)) 1.0) )
(de gridY (Y)
(*/ (- 640.0 (*/ Y 58.18 1.0)) 1.0) )
(de calc (R X Y)
(cond
((< R 1) (list 0 (*/ Y 0.16 1.0)))
((< R 86)
(list
(+ (*/ 0.85 X 1.0) (*/ 0.04 Y 1.0))
(+ (*/ -0.04 X 1.0) (*/ 0.85 Y 1.0) 1.6) ) )
((< R 93)
(list
(- (*/ 0.2 X 1.0) (*/ 0.26 Y 1.0))
(+ (*/ 0.23 X 1.0) (*/ 0.22 Y 1.0) 1.6) ) )
(T
(list
(+ (*/ -0.15 X 1.0) (*/ 0.28 Y 1.0))
(+ (*/ 0.26 X 1.0) (*/ 0.24 Y 1.0) 0.44) ) ) ) )
(let
(X 0
Y 0
G (make (do 640 (link (need 640 0)))) )
(do 100000
(let ((A B) (calc (rand 0 99) X Y))
(setq X A Y B)
(set (nth G (gridY Y) (gridX X)) 1) ) )
(out "fern.pbm"
(prinl "P1")
(prinl 640 " " 640)
(mapc prinl G) ) )
Processing
void setup() {
size(640, 640);
background(0, 0, 0);
}
float x = 0;
float y = 0;
void draw() {
for (int i = 0; i < 100000; i++) {
float xt = 0;
float yt = 0;
float r = random(100);
if (r <= 1) {
xt = 0;
yt = 0.16*y;
} else if (r <= 8) {
xt = 0.20*x - 0.26*y;
yt = 0.23*x + 0.22*y + 1.60;
} else if (r <= 15) {
xt = -0.15*x + 0.28*y;
yt = 0.26*x + 0.24*y + 0.44;
} else {
xt = 0.85*x + 0.04*y;
yt = -0.04*x + 0.85*y + 1.60;
}
x = xt;
y = yt;
int m = round(width/2 + 60*x);
int n = height-round(60*y);
set(m, n, #00ff00);
}
noLoop();
}
PureBasic
EnableExplicit
DisableDebugger
DataSection
R84: : Data.d 0.85,0.04,-0.04,0.85,1.6
R91: : Data.d 0.2,-0.26,0.23,0.22,1.6
R98: : Data.d -0.15,0.28,0.26,0.24,0.44
R100: : Data.d 0.0,0.0,0.0,0.16,0.0
EndDataSection
Procedure Barnsley(height.i)
Define x.d, y.d, xn.d, yn.d, v1.d, v2.d, v3.d, v4.d, v5.d,
f.d=height/10.6,
offset.i=Int(height/4-height/40),
n.i, r.i
For n=1 To height*50
r=Random(99,0)
Select r
Case 0 To 84 : Restore R84
Case 85 To 91 : Restore R91
Case 92 To 98 : Restore R98
Default : Restore R100
EndSelect
Read.d v1 : Read.d v2 : Read.d v3 : Read.d v4 : Read.d v5
xn=v1*x+v2*y : yn=v3*x+v4*y+v5
x=xn : y=yn
Plot(offset+x*f,height-y*f,RGB(0,255,0))
Next
EndProcedure
Define w1.i=400,
h1.i=800
If OpenWindow(0,#PB_Ignore,#PB_Ignore,w1,h1,"Barnsley fern")
If CreateImage(0,w1,h1,24,0) And StartDrawing(ImageOutput(0))
Barnsley(h1)
StopDrawing()
EndIf
ImageGadget(0,0,0,0,0,ImageID(0))
Repeat : Until WaitWindowEvent(50)=#PB_Event_CloseWindow
EndIf
End
Python
import random
from PIL import Image
class BarnsleyFern(object):
def __init__(self, img_width, img_height, paint_color=(0, 150, 0),
bg_color=(255, 255, 255)):
self.img_width, self.img_height = img_width, img_height
self.paint_color = paint_color
self.x, self.y = 0, 0
self.age = 0
self.fern = Image.new('RGB', (img_width, img_height), bg_color)
self.pix = self.fern.load()
self.pix[self.scale(0, 0)] = paint_color
def scale(self, x, y):
h = (x + 2.182)*(self.img_width - 1)/4.8378
k = (9.9983 - y)*(self.img_height - 1)/9.9983
return h, k
def transform(self, x, y):
rand = random.uniform(0, 100)
if rand < 1:
return 0, 0.16*y
elif 1 <= rand < 86:
return 0.85*x + 0.04*y, -0.04*x + 0.85*y + 1.6
elif 86 <= rand < 93:
return 0.2*x - 0.26*y, 0.23*x + 0.22*y + 1.6
else:
return -0.15*x + 0.28*y, 0.26*x + 0.24*y + 0.44
def iterate(self, iterations):
for _ in range(iterations):
self.x, self.y = self.transform(self.x, self.y)
self.pix[self.scale(self.x, self.y)] = self.paint_color
self.age += iterations
fern = BarnsleyFern(500, 500)
fern.iterate(1000000)
fern.fern.show()
R
{{trans|PARI/GP}} [[File:BarnsleyFernR.png|right|thumb|Output BarnsleyFernR.png]]
## pBarnsleyFern(fn, n, clr, ttl, psz=600): Plot Barnsley fern fractal.
## Where: fn - file name; n - number of dots; clr - color; ttl - plot title;
## psz - picture size.
## 7/27/16 aev
pBarnsleyFern <- function(fn, n, clr, ttl, psz=600) {
cat(" *** START:", date(), "n=", n, "clr=", clr, "psz=", psz, "\n");
cat(" *** File name -", fn, "\n");
pf = paste0(fn,".png"); # pf - plot file name
A1 <- matrix(c(0,0,0,0.16,0.85,-0.04,0.04,0.85,0.2,0.23,-0.26,0.22,-0.15,0.26,0.28,0.24), ncol=4, nrow=4, byrow=TRUE);
A2 <- matrix(c(0,0,0,1.6,0,1.6,0,0.44), ncol=2, nrow=4, byrow=TRUE);
P <- c(.01,.85,.07,.07);
# Creating matrices M1 and M2.
M1=vector("list", 4); M2 = vector("list", 4);
for (i in 1:4) {
M1[[i]] <- matrix(c(A1[i,1:4]), nrow=2);
M2[[i]] <- matrix(c(A2[i, 1:2]), nrow=2);
}
x <- numeric(n); y <- numeric(n);
x[1] <- y[1] <- 0;
for (i in 1:(n-1)) {
k <- sample(1:4, prob=P, size=1);
M <- as.matrix(M1[[k]]);
z <- M%*%c(x[i],y[i]) + M2[[k]];
x[i+1] <- z[1]; y[i+1] <- z[2];
}
plot(x, y, main=ttl, axes=FALSE, xlab="", ylab="", col=clr, cex=0.1);
# Writing png-file
dev.copy(png, filename=pf,width=psz,height=psz);
# Cleaning
dev.off(); graphics.off();
cat(" *** END:",date(),"\n");
}
## Executing:
pBarnsleyFern("BarnsleyFernR", 100000, "dark green", "Barnsley Fern Fractal", psz=600)
{{Output}}
> pBarnsleyFern("BarnsleyFernR", 100000, "dark green", "Barnsley Fern Fractal", psz=600)
*** START: Wed Jul 27 13:50:49 2016 n= 1e+05 clr= dark green psz= 600
*** File name - BarnsleyFernR
*** END: Wed Jul 27 13:50:56 2016
+ BarnsleyFernR.png file
Racket
[[File:racket-barnsley-fern.png]] : file uploading broken :-(
#lang racket
(require racket/draw)
(define fern-green (make-color #x32 #xCD #x32 0.66))
(define (fern dc n-iterations w h)
(for/fold ((x #i0) (y #i0))
((i n-iterations))
(define-values (x′ y′)
(let ((r (random)))
(cond
[(<= r 0.01) (values 0
(* y 16/100))]
[(<= r 0.08) (values (+ (* x 20/100) (* y -26/100))
(+ (* x 23/100) (* y 22/100) 16/10))]
[(<= r 0.15) (values (+ (* x -15/100) (* y 28/100))
(+ (* x 26/100) (* y 24/100) 44/100))]
[else (values (+ (* x 85/100) (* y 4/100))
(+ (* x -4/100) (* y 85/100) 16/10))])))
(define px (+ (/ w 2) (* x w 1/11)))
(define py (- h (* y h 1/11)))
(send dc set-pixel (exact-round px) (exact-round py) fern-green)
(values x′ y′)))
(define bmp (make-object bitmap% 640 640 #f #t 2))
(fern (new bitmap-dc% [bitmap bmp]) 200000 640 640)
bmp
(send bmp save-file "images/racket-barnsley-fern.png" 'png)
REXX
This REXX version is modeled after the '''Fortran''' entry; it generates an output file ("BARNSLEY.DAT") that
contains the '''X''' and '''Y''' coördinates for a scatter plot that can be visualized with a plotting program.
/*REXX pgm gens X & Y coördinates for a scatter plot to be used to show a Barnsley fern.*/
parse arg N FID seed . /*obtain optional arguments from the CL*/
if N=='' | N=="," then N= 100000 /*Not specified? Then use the default*/
if FID=='' | FID=="," then FID= 'BARNSLEY.DAT' /* " " " " " " */
if datatype(seed,'W') then call random ,,seed /*if specified, then use random seed. */
call lineout FID, , 1 /*just set the file ptr to the 1st line*/
x=0 /*set the initial value for X coörd. */
y=0 /* " " " " " Y " */
do #=1 for N /*generate N number of plot points.*/
?=random(, 100) /*generate a random number: 0 ≤ ? ≤ 100*/
select
when ?==0 then do; xx= 0 ; yy= .16*y ; end
when ?< 8 then do; xx= .2 *x - .26*y; yy= .23*x + .22*y + 1.6 ; end
when ?<15 then do; xx= -.15*x + .28*y; yy= .26*x + .24*y + .44; end
otherwise xx= .85*x + .04*y; yy= -.04*x + .85*y + 1.6
end /*select*/
x=xx; y=yy
if #==1 then do; minx= x; maxx= x; miny= y; maxy= y
end
minx= min(minx, x); miny= min(miny, y)
maxx= max(maxx, x); maxy= max(maxy, y)
call lineout FID, x","y
end /*#*/ /* [↓] close the file (safe practice).*/
call lineout FID /*stick a fork in it, we're all done. */
{{out|output|text= is generated to an output file: BARNSLEY.DAT which contains the '''X''' and '''Y''' coördinates of a scatter plot.}}
Ring
Load "guilib.ring"
/*
+---------------------------------------------------------------------------
+ Program Name : Draw Barnsley Fern
+ Purpose : Draw Fern using Quadratic Equation and Random Number
+---------------------------------------------------------------------------
*/
###-------------------------------
### DRAW CHART size 400 x 500
###-------------------------------
New qapp {
win1 = new qwidget() {
### Position and Size on Screen
setwindowtitle("Drawing using QPainter")
setgeometry( 10, 25, 400, 500)
### Draw within this Win Box
label1 = new qlabel(win1) {
### Label Position and Size
setgeometry(10, 10, 400, 500)
settext(" ")
}
buttonFern = new qpushbutton(win1) {
### Button DrawFern
setgeometry(10, 10, 80, 20)
settext("Draw Fern")
setclickevent("DrawFern()") ### Call DRAW function
}
show()
}
exec()
}
###------------------------
### FUNCTIONS
###------------------------
Func DrawFern
p1 = new qpicture()
colorGreen = new qcolor() { setrgb(0,255,0,255) }
penGreen = new qpen() { setcolor(colorGreen) setwidth(1) }
new qpainter() {
begin(p1)
setpen(penGreen)
###-------------------------------------
### Quadratic equation matrix of arrays
a = [ 0, 0.85, 0.2, -0.15 ]
b = [ 0, 0.04, -0.26, 0.28 ]
c = [ 0, -0.04, 0.23, 0.26 ]
d = [ 0.16, 0.85, 0.22, 0.24 ]
e = [ 0, 0, 0, 0 ]
f = [ 0, 1.6, 1.6, 0.44 ]
### Initialize x, y points
xf = 0.0
yf = 0.0
### Size of output screen
MaxX = 400
MaxY = 500
MaxIterations = MaxY * 200
Count = 0
###------------------------------------------------
while ( Count <= MaxIterations )
### NOTE *** RING *** starts at Index 1,
### Do NOT use Random K=0 result
k = random() % 100
k = k +1
### if (k = 0) k = 1 ok ### Do NOT use
if ((k > 0) and (k <= 85)) k = 2 ok
if ((k > 85) and (k <= 92)) k = 3 ok
if (k > 92) k = 4 ok
TempX = ( a[k] * xf ) + ( b[k] * yf ) + e[k]
TempY = ( c[k] * xf ) + ( d[k] * yf ) + f[k]
xf = TempX
yf = TempY
if( (Count >= MaxIterations) or (Count != 0) )
xPoint = (floor(xf * MaxY / 11) + floor(MaxX / 2))
yPoint = (floor(yf * -MaxY / 11) + MaxY )
drawpoint( xPoint , yPoint )
ok
Count++
end
###----------------------------------------------------
endpaint()
}
label1 { setpicture(p1) show() }
return
Run BASIC
'Barnsley Fern - Run BASIC
'http://rosettacode.org/wiki/Barnsley_fern#Run_BASIC
'copy code and run it at http://www.runbasic.com
'
' -----------------------------------
' Barnsley Fern
' -----------------------------------maxpoints = 20000
graphic #g, 200, 200
#g fill("blue")
FOR n = 1 TO maxpoints
p = RND(0)*100
IF p <= 1 THEN
nx = 0
ny = 0.16 * y
else if p <= 8 THEN
nx = 0.2 * x - 0.26 * y
ny = 0.23 * x + 0.22 * y + 1.6
else if p <= 15 THEN
nx = -0.15 * x + 0.28 * y
ny = 0.26 * x + 0.24 * y + 0.44
else
nx = 0.85 * x +0.04 * y
ny = -0.04 * x +0.85 * y + 1.6
end if
x = nx
y = ny
#g "color green ; set "; x * 17 + 100; " "; y * 17
NEXT n
render #g
#g "flush"
Rust
{{trans|Java}} {{libheader|rand}}
extern crate rand;
extern crate raster;
use rand::Rng;
fn main() {
let max_iterations = 200_000u32;
let height = 640i32;
let width = 640i32;
let mut rng = rand::thread_rng();
let mut image = raster::Image::blank(width, height);
raster::editor::fill(&mut image, raster::Color::white()).unwrap();
let mut x = 0.;
let mut y = 0.;
for _ in 0..max_iterations {
let r = rng.gen::<f32>();
let cx: f64;
let cy: f64;
if r <= 0.01 {
cx = 0f64;
cy = 0.16 * y as f64;
} else if r <= 0.08 {
cx = 0.2 * x as f64 - 0.26 * y as f64;
cy = 0.23 * x as f64 + 0.22 * y as f64 + 1.6;
} else if r <= 0.15 {
cx = -0.15 * x as f64 + 0.28 * y as f64;
cy = 0.26 * x as f64 + 0.26 * y as f64 + 0.44;
} else {
cx = 0.85 * x as f64 + 0.04 * y as f64;
cy = -0.04 * x as f64 + 0.85 * y as f64 + 1.6;
}
x = cx;
y = cy;
let _ = image.set_pixel(
((width as f64) / 2. + x * (width as f64) / 11.).round() as i32,
((height as f64) - y * (height as f64) / 11.).round() as i32,
raster::Color::rgb(50, 205, 50));
}
raster::save(&image, "fractal.png").unwrap();
}
Scala
Java Swing Interoperability
import java.awt._
import java.awt.image.BufferedImage
import javax.swing._
object BarnsleyFern extends App {
SwingUtilities.invokeLater(() =>
new JFrame("Barnsley Fern") {
private class BarnsleyFern extends JPanel {
val dim = 640
val img = new BufferedImage(dim, dim, BufferedImage.TYPE_INT_ARGB)
private def createFern(w: Int, h: Int): Unit = {
var x, y = 0.0
for (i <- 0 until 200000) {
var tmpx, tmpy = .0
val r = math.random
if (r <= 0.01) {
tmpx = 0
tmpy = 0.16 * y
}
else if (r <= 0.08) {
tmpx = 0.2 * x - 0.26 * y
tmpy = 0.23 * x + 0.22 * y + 1.6
}
else if (r <= 0.15) {
tmpx = -0.15 * x + 0.28 * y
tmpy = 0.26 * x + 0.24 * y + 0.44
}
else {
tmpx = 0.85 * x + 0.04 * y
tmpy = -0.04 * x + 0.85 * y + 1.6
}
x = tmpx
y = tmpy
img.setRGB((w / 2 + tmpx * w / 11).round.toInt,
(h - tmpy * h / 11).round.toInt, 0xFF32CD32)
}
}
override def paintComponent(gg: Graphics): Unit = {
super.paintComponent(gg)
val g = gg.asInstanceOf[Graphics2D]
g.setRenderingHint(RenderingHints.KEY_ANTIALIASING, RenderingHints.VALUE_ANTIALIAS_ON)
g.drawImage(img, 0, 0, null)
}
setBackground(Color.white)
setPreferredSize(new Dimension(dim, dim))
createFern(dim, dim)
}
add(new BarnsleyFern, BorderLayout.CENTER)
pack()
setDefaultCloseOperation(WindowConstants.EXIT_ON_CLOSE)
setLocationRelativeTo(null)
setResizable(false)
setVisible(true)
})
}
Scheme
This version creates a list of points, defining the fern, which are then rescaled and output to an eps file.
(import (scheme base)
(scheme cxr)
(scheme file)
(scheme inexact)
(scheme write)
(srfi 27)) ; for random numbers
(define (create-fern x y num-points)
(define (new-point xn yn)
(let ((r (* 100 (random-real))))
(cond ((< r 1) ; f1
(list 0 (* 0.16 yn)))
((< r 86) ; f2
(list (+ (* 0.85 xn) (* 0.04 yn))
(+ (* -0.04 xn) (* 0.85 yn) 1.6)))
((< r 93) ; f3
(list (- (* 0.2 xn) (* 0.26 yn))
(+ (* 0.23 xn) (* 0.22 yn) 1.6)))
(else ; f4
(list (+ (* -0.15 xn) (* 0.28 yn))
(+ (* 0.26 xn) (* 0.24 yn) 0.44))))))
;
(random-source-randomize! default-random-source)
(do ((i 0 (+ i 1))
(pts (list (list x y)) (cons (new-point (caar pts) (cadar pts)) pts)))
((= i num-points) pts)))
;; output the fern to an eps file
(define (output-fern-as-eps filename fern)
(when (file-exists? filename) (delete-file filename))
(with-output-to-file
filename
(lambda ()
(let* ((width 600)
(height 800)
(min-x (apply min (map car fern)))
(max-x (apply max (map car fern)))
(min-y (apply min (map cadr fern)))
(max-y (apply max (map cadr fern)))
(scale-x (/ (- width 50) (- max-x min-x)))
(scale-y (/ (- height 50) (- max-y min-y)))
(scale-points (lambda (point)
(list (truncate (+ 20 (* scale-x (- (car point) min-x))))
(truncate (+ 20 (* scale-y (- (cadr point) min-y))))))))
(display
(string-append "%!PS-Adobe-3.0 EPSF-3.0\n%%BoundingBox: 0 0 "
(number->string width) " " (number->string height) "\n"))
;; add each point in fern as an arc - sets linewidth based on depth in tree
(for-each (lambda (point)
(display
(string-append (number->string (list-ref point 0))
" "
(number->string (list-ref point 1))
" 0.1 0 360 arc\nstroke\n")))
(map scale-points fern))
(display "\n%%EOF")))))
(output-fern-as-eps "barnsley.eps" (create-fern 0 0 50000))
Scilab
{{Works with|Scilab|5.4.0 and above}}
This version creates a list of points, defining the fern, and shows them on a graphic window which can then be saved to a file via the GUI or the console by the user.
XY=zeros(2,iteractions+1); x=0; y=0;
i=2; while i<iteractions+2 random_numbers=rand(); xp=x; if random_numbers(1) < 0.01 then x = 0; y = 0.16 * y; elseif random_numbers(1) >= 0.01 & random_numbers(1) < 0.01+0.85 then x = 0.85 * x + 0.04 * y; y = -0.04 * xp + 0.85 * y + 1.6; elseif random_numbers(1) >= 0.86 & random_numbers(1) < 0.86+0.07 then x = 0.2 * x - 0.26 * y; y = 0.23 * xp + 0.22 * y + 1.6; else x = -0.15 * x + 0.28 * y; y = 0.26 * xp + 0.24 * y + 0.44; end
XY(1,i)=x;
XY(2,i)=y;
i=i+1;
end
scf(0); clf(); xname('Barnsley fern'); plot2d(XY(1,:),XY(2,:),-0) axes=gca(); axes.isoview="on"; axes.children.children.mark_foreground=13;
## SequenceL
'''Tail-Recursive SequenceL Code:'''
```sequencel>import <Utilities/Math.sl
;
import <Utilities/Random.sl>;
transform(p(1), rand) :=
let
x := p[1]; y := p[2];
in
[0.0, 0.16*y] when rand <= 0.01
else
[0.85*x + 0.04*y, -0.04*x + 0.85*y + 1.6] when rand <= 0.86
else
[0.2*x - 0.26*y, 0.23*x + 0.22*y + 1.6] when rand <= 0.93
else
[-0.15*x + 0.28*y, 0.26*x + 0.24*y + 0.44];
barnsleyFern(rand, count, result(2)) :=
let
nextRand := getRandom(rand);
next := transform(result[size(result)], nextRand.value / 2147483647.0);
in
result when count <= 0
else
barnsleyFern(nextRand.generator, count - 1, result ++ [next]);
scale(p(1), width, height) := [round((p[1] + 2.182) * width / 4.8378),
round((9.9983 - p[2]) * height / 9.9983)];
entry(seed, count, width, height) :=
let
fern := barnsleyFern(seedRandom(seed), count, [[0.0,0.0]]);
in
scale(fern, width, height);
'''C++ Driver Code:'''
{{libheader|CImg}}
#include "SL_Generated.h"
#include "CImg.h"
using namespace cimg_library;
int main(int argc, char** argv)
{
int threads = 0; if(argc > 1) threads = atoi(argv[1]);
int width = 300; if(argc > 2) width = atoi(argv[2]);
int height = 600; if(argc > 3) height = atoi(argv[3]);
int steps = 10000; if(argc > 4) steps = atoi(argv[4]);
int seed = 314159; if(argc > 5) seed = atoi(argv[5]);
CImg<unsigned char> visu(width, height, 1, 3, 0);
Sequence< Sequence<int> > result;
sl_init(threads);
sl_entry(seed, steps, width-1, height-1, threads, result);
visu.fill(0);
for(int i = 1; i <= result.size(); i++)
visu(result[i][1], result[i][2],1) = 255;
CImgDisplay draw_disp(visu);
draw_disp.set_title("Barnsley Fern in SequenceL");
visu.display(draw_disp);
while(!draw_disp.is_closed()) draw_disp.wait();
sl_done();
return 0;
}
{{out}} [https://i.imgur.com/zerRZo8.png Output Screenshot]
Sidef
require('Imager')
var w = 640
var h = 640
var img = %O<Imager>.new(xsize => w, ysize => h, channels => 3)
var green = %O<Imager::Color>.new('#00FF00')
var (x, y) = (0.float, 0.float)
1e5.times {
var r = 100.rand
(x, y) = (
if (r <= 1) { ( 0.00*x - 0.00*y, 0.00*x + 0.16*y + 0.00) }
elsif (r <= 8) { ( 0.20*x - 0.26*y, 0.23*x + 0.22*y + 1.60) }
elsif (r <= 15) { (-0.15*x + 0.28*y, 0.26*x + 0.24*y + 0.44) }
else { ( 0.85*x + 0.04*y, -0.04*x + 0.85*y + 1.60) }
)
img.setpixel(x => w/2 + 60*x, y => 60*y, color => green)
}
img.flip(dir => 'v')
img.write(file => 'barnsleyFern.png')
Output image: [https://github.com/trizen/rc/blob/master/img/barnsley-fern-sidef.png Barnsley fern]
SPL
w,h = #.scrsize()
x,y = 0
>
r = #.rnd(100)
? r<85, x,y = f2(x,y)
? r!<85 & r<92, x,y = f3(x,y)
? r!<92 & r<99, x,y = f4(x,y)
? r!<99, x,y = f1(y)
#.drawpoint(x/10*w+w/2,h-y/10*h,0,0.5,0,0.1)
<
f1(y) <= 0, 0.16*y
f2(x,y) <= 0.85*x+0.04*y, -0.04*x+0.85*y+1.6
f3(x,y) <= 0.2*x-0.26*y, 0.23*x+0.22*y+1.6
f4(x,y) <= -0.15*x+0.28*y, 0.26*x+0.24*y+0.44
Swift
Output is viewable in a playground.
import UIKit
import CoreImage
import PlaygroundSupport
let imageWH = 300
let context = CGContext(data: nil,
width: imageWH,
height: imageWH,
bitsPerComponent: 8,
bytesPerRow: 0,
space: CGColorSpace(name: CGColorSpace.sRGB)!,
bitmapInfo: CGImageAlphaInfo.premultipliedFirst.rawValue)!
var x0 = 0.0
var x1 = 0.0
var y0 = 0.0
var y1 = 0.0
context.setFillColor(#colorLiteral(red: 0, green: 0, blue: 0, alpha: 1))
context.fill(CGRect(x: 0, y: 0, width: imageWH, height: imageWH))
context.setFillColor(#colorLiteral(red: 0.539716677, green: 1, blue: 0.265400682, alpha: 1))
for _ in 0..<100_000 {
switch Int(arc4random()) % 100 {
case 0:
x1 = 0
y1 = 0.16 * y0
case 1...7:
x1 = -0.15 * x0 + 0.28 * y0
y1 = 0.26 * x0 + 0.24 * y0 + 0.44
case 8...15:
x1 = 0.2 * x0 - 0.26 * y0
y1 = 0.23 * x0 + 0.22 * y0 + 1.6
default:
x1 = 0.85 * x0 + 0.04 * y0
y1 = -0.04 * x0 + 0.85 * y0 + 1.6
}
context.fill(CGRect(x: 30 * x1 + Double(imageWH) / 2.0, y: 30 * y1,
width: 1, height: 1))
(x0, y0) = (x1, y1)
}
let uiImage = UIImage(cgImage: context.makeImage()!)
VBA
Private Sub plot_coordinate_pairs(x As Variant, y As Variant)
Dim chrt As Chart
Set chrt = ActiveSheet.Shapes.AddChart.Chart
With chrt
.ChartType = xlXYScatter
.HasLegend = False
.SeriesCollection.NewSeries
.SeriesCollection.Item(1).XValues = x
.SeriesCollection.Item(1).Values = y
End With
End Sub
Public Sub barnsley_fern()
Const MAX = 50000
Dim x(MAX) As Double
Dim y(MAX) As Double
x(0) = 0: y(0) = 0
For i = 1 To MAX
Select Case CInt(100 * Rnd)
Case 0 To 1
x(i) = 0
y(i) = 0.16 * y(i - 1)
Case 2 To 85
x(i) = 0.85 * x(i - 1) + 0.04 * y(i - 1)
y(i) = -0.04 * x(i - 1) + 0.85 * y(i - 1) + 1.6
Case 86 To 92
x(i) = 0.2 * x(i - 1) - 0.26 * y(i - 1)
y(i) = 0.23 * x(i - 1) + 0.22 * y(i - 1) + 1.6
Case 93 To 100
x(i) = -0.15 * x(i - 1) + 0.28 * y(i - 1)
y(i) = 0.26 * x(i - 1) + 0.24 * y(i - 1) + 0.44
End Select
Next i
plot_coordinate_pairs x, y
End Sub
Yabasic
{{trans|ZX Spectrum Basic}} Classic style
10 REM Fractal Fern
20 LET wid = 800 : LET hei = 600 : open window wid, hei : window origin "cb"
25 backcolor 0, 0, 0 : color 0, 255, 0 : clear window
30 LET maxpoints=wid*hei/2: LET x=0: LET y=0
40 FOR n=1 TO maxpoints
50 LET p=RAN(100)
60 IF p<=1 LET nx=0: LET ny=0.16*y: GOTO 100
70 IF p<=8 LET nx=0.2*x-0.26*y: LET ny=0.23*x+0.22*y+1.6: GOTO 100
80 IF p<=15 LET nx=-0.15*x+0.28*y: LET ny=0.26*x+0.24*y+0.44: GOTO 100
90 LET nx=0.85*x+0.04*y: LET ny=-0.04*x+0.85*y+1.6
100 LET x=nx: LET y=ny
110 DOT x*wid/12,y*hei/12
120 NEXT n
Modern style
REM Fractal Fern
wid = 800 : hei = 600 : open window wid, hei : window origin "cb"
backcolor 0, 0, 0 : color 0, 255, 0 : clear window
maxpoints = wid * hei / 2 : x = 0 : y = 0
for n = 1 to maxpoints
p = ran(100)
if p <= 1 then nx = 0 : ny = 0.16 * y
elseif p <= 8 then nx = 0.2 * x - 0.26 * y : ny = 0.23 * x + 0.22 * y + 1.6
elseif p <= 15 then nx = -0.15 * x + 0.28 * y : ny = 0.26 * x + 0.24 * y + 0.44
else nx = 0.85 * x + 0.04 * y : ny = -0.04 * x + 0.85 * y + 1.6
end if
x = nx : y = ny
dot x * wid / 12, y * hei / 12
next
zkl
[[File:BarnsleyFern.zkl.jpg|250px|thumb|right]] Uses the PPM class from http://rosettacode.org/wiki/Bitmap/Bresenham%27s_line_algorithm#zkl {{trans|Java}}
fcn barnsleyFern(){
w,h:=640,640;
bitmap:=PPM(w+1,h+1,0xFF|FF|FF); // White background
x,y, nx,ny:=0.0, 0.0, 0.0, 0.0;
do(0d100_000){
r:=(0).random(100); // [0..100)%
if (r<= 1) nx,ny= 0, 0.16*y;
else if(r<= 8) nx,ny= 0.2*x - 0.26*y, 0.23*x + 0.22*y + 1.6;
else if(r<=15) nx,ny=-0.15*x + 0.28*y, 0.26*x + 0.24*y + 0.44;
else nx,ny= 0.85*x + 0.04*y, -0.04*x + 0.85*y + 1.6;
x,y=nx,ny;
bitmap[w/2 + x*60, y*60] = 0x00|FF|00; // Green dot
}
bitmap.writeJPGFile("barnsleyFern.jpg");
}();
ZX Spectrum Basic
{{trans|zkl}}
10 REM Fractal Fern
20 PAPER 7: BORDER 7: BRIGHT 1: INK 4: CLS
30 LET maxpoints=20000: LET x=0: LET y=0
40 FOR n=1 TO maxpoints
50 LET p=RND*100
60 IF p<=1 THEN LET nx=0: LET ny=0.16*y: GO TO 100
70 IF p<=8 THEN LET nx=0.2*x-0.26*y: LET ny=0.23*x+0.22*y+1.6: GO TO 100
80 IF p<=15 THEN LET nx=-0.15*x+0.28*y: LET ny=0.26*x+0.24*y+0.44: GO TO 100
90 LET nx=0.85*x+0.04*y: LET ny=-0.04*x+0.85*y+1.6
100 LET x=nx: LET y=ny
110 PLOT x*17+127,y*17
120 NEXT n
It is recommended to run on an emulator that supports running at full speed.