Barnsley fern
You are encouraged to solve this task according to the task description, using any language you may know.
A 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
This program generates a PBM file. <lang algol68> 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 </lang>
Applesoft BASIC
<lang ApplesoftBasic> 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
</lang>
BBC BASIC
<lang bbcbasic> 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</lang>
C
This implementation requires the 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). <lang C>
- 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; } </lang>
C++
<lang cpp>
- 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;
} </lang>
C#
<lang csharp>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);
}
}
}</lang>
Common Lisp
This code uses the opticl package for generating an image and saving it as a PNG file.
<lang lisp>(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)))</lang>
Delphi
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. <lang delphi>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.</lang>
EasyLang
<lang>floatvars color 060 for i% range 200000
r = randomf if r < 0.01 nx = 0 ny = 0.16 * y elif r < 0.08 nx = 0.2 * x - 0.26 * y ny = 0.23 * x + 0.22 * y + 1.6 elif r < 0.15 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 . x = nx y = ny move 50 + x * 15 100 - y * 10 rect 0.3 0.3
.</lang>
Fōrmulæ
In 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 (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
<lang 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 </lang>
FreeBASIC
<lang 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</lang>
G'MIC
<lang c>
- 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
</lang>
gnuplot
<lang gnuplot>
- 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 </lang>
- Output:
File: BarnsleyFernGnu.png (also BarnsleyFernGnu.dat)
Go
<lang 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)
}
}</lang>
Haskell
<lang 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)</lang>
J
<lang j>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</lang>
IS-BASIC
<lang IS-BASIC>100 PROGRAM "Fern.bas" 110 RANDOMIZE 120 SET VIDEO MODE 1:SET VIDEO COLOR 0:SET VIDEO X 40:SET VIDEO Y 27 130 OPEN #101:"video:" 140 DISPLAY #101:AT 1 FROM 1 TO 27 150 SET PALETTE BLACK,GREEN 160 LET MX=16000:LET X,Y=0 170 FOR N=1 TO MX 180 LET P=RND(100) 190 SELECT CASE P 200 CASE IS<=1 210 LET NX=0:LET NY=.16*Y 220 CASE IS<=8 230 LET NX=.2*X-.26*Y:LET NY=.23*X+.22*Y+1.6 240 CASE IS<=15 250 LET NX=-.15*X+.28*Y:LET NY=.26*X+.24*Y+.44 260 CASE ELSE 270 LET NX=.85*X+.04*Y:LET NY=-.04*X+.85*Y+1.6 280 END SELECT 290 LET X=NX:LET Y=NY 300 PLOT X*96+600,Y*96 310 NEXT</lang>
Java
<lang java>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);
});
}
}</lang>
JavaScript
<lang javascript> // 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
} </lang> Executing: <lang html> <html>
<head><script src="BarnsleyFern.js"></script></head>
<body onload="pBarnsleyFern('canvas', 100000)">
Barnsley fern fractal
<canvas id="canvas" width="540" height="540" style="border: 2px inset;"></canvas> </body>
</html> </lang>
- Output:
Page with BarnsleyFernjs.png
Julia
<lang julia>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</lang>
Kotlin
<lang scala>// 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)
}
}</lang>
Lua
Needs LÖVE 2D Engine <lang Lua> 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 </lang>
Mathematica / Wolfram Language
<lang Mathematica> 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}]] </lang>
Nim
<lang 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) </lang>
Oberon-2
<lang oberon2> 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. </lang>
PARI/GP
<lang parigp> \\ 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 } </lang>
- Output:
> pBarnsleyFern(530,100000); \\ BarnsleyFern.png *** Barnsley Fern, size=530 lim=100000
Perl
<lang perl>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'); $img->write(file => 'barnsleyFern.png');</lang>
Perl 6
<lang perl6>use Image::PNG::Portable;
my ($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';</lang>
Phix
This file is included in the distro as
<lang Phix>-- -- 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()</lang>
PicoLisp
<lang 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) ) )</lang>
Processing
<lang java>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();
}</lang>
PureBasic
<lang 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</lang>
Python
<lang 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()
</lang>
R
<lang r>
- 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) {
M1i <- matrix(c(A1[i,1:4]), nrow=2);
M2i <- 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(M1k);
z <- M%*%c(x[i],y[i]) + M2k;
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) </lang>
- 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>#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)</lang>
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.
<lang rexx>/*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. */</lang>
- output is generated to an output file: BARNSLEY.DAT which contains the X and Y coördinates of a scatter plot.
Ring
<lang 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
</lang>
Run BASIC
<lang runbasic>'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"</lang>
Rust
<lang rust>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();
}</lang>
Scala
Java Swing Interoperability
<lang Scala>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)
})
}</lang>
Scheme
This version creates a list of points, defining the fern, which are then rescaled and output to an eps file. <lang scheme>(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))</lang>
Scilab
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. <lang> iteractions=1.0d6;
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; </lang>
SequenceL
Tail-Recursive SequenceL Code:
<lang 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);</lang>
C++ Driver Code:
<lang c>#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;
}</lang>
- Output:
Sidef
<lang ruby>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')</lang> Output image: Barnsley fern
SPL
<lang 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</lang>
Swift
Output is viewable in a playground.
<lang swift>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()!)</lang>
VBA
<lang vb>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</lang>
Yabasic
Classic style <lang Yabasic>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</lang> Modern style <lang Yabasic>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</lang>
zkl
Uses the PPM class from http://rosettacode.org/wiki/Bitmap/Bresenham%27s_line_algorithm#zkl
<lang zkl>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");
}();</lang>
ZX Spectrum Basic
<lang zxbasic>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 </lang> It is recommended to run on an emulator that supports running at full speed.
- Programming Tasks
- Solutions by Programming Task
- ALGOL 68
- Applesoft BASIC
- BBC BASIC
- C
- C++
- C sharp
- Common Lisp
- Delphi
- EasyLang
- Fōrmulæ
- Fortran
- FreeBASIC
- G'MIC
- Gnuplot
- Pages with broken file links
- Go
- Haskell
- J
- IS-BASIC
- Java
- JavaScript
- Julia
- Kotlin
- Lua
- Mathematica
- Wolfram Language
- Nim
- Oberon-2
- PARI/GP
- Perl
- Perl 6
- Phix
- PGUI
- PicoLisp
- Processing
- PureBasic
- Python
- R
- Racket
- REXX
- Ring
- Run BASIC
- Rust
- Rand
- Scala
- Scheme
- Scilab
- SequenceL
- CImg
- Sidef
- SPL
- Swift
- VBA
- Yabasic
- Zkl
- ZX Spectrum Basic