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
Action!
INCLUDE "H6:REALMATH.ACT"
BYTE CH=$02FC,COLOR1=$02C5,COLOR2=$02C6
REAL r0,r4,r15,r16,r20,r22,r23,r24,r26,r28,r44,r85,r160
PROC Init()
ValR("0",r0)
ValR("0.04",r4)
ValR("0.15",r16)
ValR("0.16",r16)
ValR("0.2",r20)
ValR("0.22",r22)
ValR("0.23",r23)
ValR("0.24",r24)
ValR("0.26",r26)
ValR("0.28",r28)
ValR("0.44",r44)
ValR("0.85",r85)
ValR("1.6",r160)
RETURN
PROC Fern(REAL POINTER scale)
BYTE r
REAL x,y,xp,yp,tmp1,tmp2
INT i,ix,iy
RealAssign(r0,x)
RealAssign(r0,y)
DO
RealMult(x,scale,tmp1)
RealMult(y,scale,tmp2)
ix=Round(tmp2) ;fern is rotated to fit the screen size
iy=Round(tmp1)+85
IF (ix>=0) AND (ix<=319) AND (iy>=0) AND (iy<=191) THEN
Plot(ix,iy)
FI
r=Rand(100)
RealAssign(x,xp) ;xp=x
RealAssign(y,yp) ;yp=y
IF r<1 THEN
RealAssign(r0,x) ;x=0
RealMult(r16,yp,y) ;y=0.16*yp
ELSEIF r<86 THEN
RealMult(r85,xp,tmp1) ;tmp1=0.85*xp
RealMult(r4,yp,tmp2) ;tmp2=0.4*yp
RealAdd(tmp1,tmp2,x) ;x=0.85*xp+0.4*yp
RealMult(r4,xp,tmp1) ;tmp1=0.04*xp
RealSub(r160,tmp1,tmp2) ;tmp2=-0.04*xp+1.6
RealMult(r85,yp,tmp1) ;tmp1=0.85*yp
RealAdd(tmp1,tmp2,y) ;y=-0.04*xp+0.85*yp+1.6
ELSEIF r<93 THEN
RealMult(r20,xp,tmp1) ;tmp1=0.2*xp
RealMult(r26,yp,tmp2) ;tmp2=0.26*yp
RealSub(tmp1,tmp2,x) ;x=0.2*xp-0.26*yp
RealMult(r23,xp,tmp1) ;tmp1=0.23*xp
RealAdd(r160,tmp1,tmp2) ;tmp2=0.23*xp+1.6
RealMult(r22,yp,tmp1) ;tmp1=0.22*yp
RealAdd(tmp1,tmp2,y) ;y=0.23*xp+0.22*yp+1.6
ELSE
RealMult(r15,xp,tmp1) ;tmp1=0.15*xp
RealMult(r28,yp,tmp2) ;tmp2=0.28*yp
RealSub(tmp2,tmp1,x) ;x=-0.15*xp+0.28*yp
RealMult(r26,xp,tmp1) ;tmp1=0.26*xp
RealAdd(r44,tmp1,tmp2) ;tmp2=0.26*xp+0.44
RealMult(r24,yp,tmp1) ;tmp1=0.24*yp
RealAdd(tmp1,tmp2,y) ;y=0.26*xp+0.44*yp+0.44
FI
Poke(77,0) ;turn off the attract mode
UNTIL CH#$FF ;until key pressed
OD
CH=$FF
RETURN
PROC Main()
REAL scale
Graphics(8+16)
Color=1
COLOR1=$BA
COLOR2=$B2
Init()
ValR("30",scale)
Fern(scale)
RETURN
- Output:
Screenshot from Atari 8-bit computer
Ada
with Ada.Numerics.Discrete_Random;
with SDL.Video.Windows.Makers;
with SDL.Video.Renderers.Makers;
with SDL.Events.Events;
procedure Barnsley_Fern is
Iterations : constant := 1_000_000;
Width : constant := 500;
Height : constant := 750;
Scale : constant := 70.0;
type Percentage is range 1 .. 100;
package Random_Percentages is
new Ada.Numerics.Discrete_Random (Percentage);
Gen : Random_Percentages.Generator;
Window : SDL.Video.Windows.Window;
Renderer : SDL.Video.Renderers.Renderer;
Event : SDL.Events.Events.Events;
procedure Draw_Barnsley_Fern is
use type SDL.C.int;
subtype F1_Range is Percentage range Percentage'First .. Percentage'First;
subtype F2_Range is Percentage range F1_Range'Last + 1 .. F1_Range'Last + 85;
subtype F3_Range is Percentage range F2_Range'Last + 1 .. F2_Range'Last + 7;
subtype F4_Range is Percentage range F3_Range'Last + 1 .. F3_Range'Last + 7;
X0, Y0 : Float := 0.00;
X1, Y1 : Float;
begin
for I in 1 .. Iterations loop
case Random_Percentages.Random (Gen) is
when F1_Range =>
X1 := 0.00;
Y1 := 0.16 * Y0;
when F2_Range =>
X1 := 0.85 * X0 + 0.04 * Y0;
Y1 := -0.04 * X0 + 0.85 * Y0 + 1.60;
when F3_Range =>
X1 := 0.20 * X0 - 0.26 * Y0;
Y1 := 0.23 * X0 + 0.22 * Y0 + 1.60;
when F4_Range =>
X1 := -0.15 * X0 + 0.28 * Y0;
Y1 := 0.26 * X0 + 0.24 * Y0 + 0.44;
end case;
Renderer.Draw (Point => (X => Width / 2 + SDL.C.int (Scale * X1),
Y => Height - SDL.C.int (Scale * Y1)));
X0 := X1; Y0 := Y1;
end loop;
end Draw_Barnsley_Fern;
procedure Wait is
use type SDL.Events.Event_Types;
begin
loop
while SDL.Events.Events.Poll (Event) loop
if Event.Common.Event_Type = SDL.Events.Quit then
return;
end if;
end loop;
end loop;
end Wait;
begin
if not SDL.Initialise (Flags => SDL.Enable_Screen) then
return;
end if;
SDL.Video.Windows.Makers.Create (Win => Window,
Title => "Barnsley Fern",
Position => SDL.Natural_Coordinates'(X => 10, Y => 10),
Size => SDL.Positive_Sizes'(Width, Height),
Flags => 0);
SDL.Video.Renderers.Makers.Create (Renderer, Window.Get_Surface);
Renderer.Set_Draw_Colour ((0, 0, 0, 255));
Renderer.Fill (Rectangle => (0, 0, Width, Height));
Renderer.Set_Draw_Colour ((0, 220, 0, 255));
Random_Percentages.Reset (Gen);
Draw_Barnsley_Fern;
Window.Update_Surface;
Wait;
Window.Finalize;
SDL.Finalise;
end Barnsley_Fern;
ALGOL 68
This program generates a 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
BASIC
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
BASIC256
# adjustable window altoght
# call the subroutine with the altoght you want
# it's possible to have a window that's large than your display
call barnsley(800)
end
subroutine barnsley(alto)
graphsize alto / 2, alto
color rgb(0, 255, 0)
f = alto / 10.6
c = alto / 4 - alto / 40
x = 0 : y = 0
for n = 1 to alto * 50
p = rand * 100
begin case
case p <= 1
nx = 0
ny = 0.16 * y
case p <= 8
nx = 0.2 * x - 0.26 * y
ny = 0.23 * x + 0.22 * y + 1.6
case p <= 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
end case
x = nx : y = ny
plot(c + x * f, alto - y * f)
next n
# remove comment (#) in next line to save window as .png file
# imgsave("Barnsley_fern.png")
end subroutine
- Output:
BBC BASIC
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
uBasic/4tH
uBasic/4tH does not feature graphics or floating point, so it requires some extra code to achieve this. This version uses binary scaling.
Dim @o(5) ' 0 = SVG file, 1 = color, 2 = fillcolor, 3 = pixel, 4 = text
' === Begin Program ===
If Info("wordsize") < 64 Then Print "This program requires a 64-bit uBasic" : End
Proc _SVGopen ("svgfern.svg")
Proc _Canvas (500, 768) ' light gray background
Proc _Background (FUNC(_RGBtoColor (0, 0, 0)))
Proc _SetMode ("dot") ' we want dots, not pixels
For i = 1 To 25000
Let r = Rnd (100)
If r = 1 Then
Let x = 0
Let y = FUNC (_Fmul(FUNC(_Fdiv(16, 100)) , y))
Else
If r < 9 Then
Let x = FUNC(_Fmul(FUNC(_Fdiv(2, 10)), x)) - FUNC(_Fmul(FUNC(_Fdiv(26, 100)), y))
Let y = FUNC(_Fmul(FUNC(_Fdiv(-23, 100)), x)) + FUNC(_Fmul(FUNC(_Fdiv(22, 100)), y)) + FUNC(_Fdiv(16, 10))
Else
If r < 16 then
Let x = FUNC(_Fmul(FUNC(_Fdiv(-15, 100)), x)) + FUNC(_Fmul(FUNC(_Fdiv(28, 100)), y))
Let y = FUNC(_Fmul(FUNC(_Fdiv(26, 100)), x)) + FUNC(_Fmul(FUNC(_Fdiv(24, 100)), y)) + FUNC(_Fdiv(44, 100))
Else
Let x = FUNC(_Fmul(FUNC(_Fdiv(85, 100)), x)) + FUNC(_Fmul(FUNC(_Fdiv(4, 100)), y))
Let y = FUNC(_Fmul(FUNC(_Fdiv(-4, 100)), x)) + FUNC(_Fmul(FUNC(_Fdiv(85, 100)), y)) + FUNC(_Fdiv(16, 10))
EndIf
EndIf
EndIf
Let q = FUNC(_Fround(FUNC(_Fmul(x + FUNC(_Ntof(3)), FUNC(_Ntof(70))))))
Let p = FUNC(_Fround(FUNC(_Ntof(700)) - FUNC(_Fmul(y, FUNC(_Ntof(70))))))
Proc _SetColor (FUNC(_RGBtoColor (0, 128 + Rnd(128), 0)))
Proc _SetPixel (p+20, q)
Next
Proc _SVGclose
End
' === End Program ===
_Ntof Param (1) : Return (a@*16384)
_Ftoi Param (1) : Return ((10000*a@)/16384)
_Fmul Param (2) : Return ((a@*b@)/16384)
_Fdiv Param (2) : Return ((a@*16384)/b@)
_Fround Param (1) : Return ((a@+8192)/16384)
_RGBtoColor Param (3) : Return (a@ * 65536 + b@ * 256 + c@)
_SetColor Param (1) : @o(1) = a@ : Return
_GetColor Return (@o(1))
_SetFill Param (1) : @o(2) = a@ : Return
_GetFill Return (@o(2))
_SetPixel Param(2) : Proc @o(3)(a@, b@) : Return
_SVGclose Write @o(0), "</svg>" : Close @o(0) : Return
_color_ Param (1) : Proc _PrintRGB (a@) : Write @o(0), "\q />" : Return
_PrintRGB
Param (1)
Radix 16
If a@ < 0 Then
Write @o(0), "none";
Else
Write @o(0), Show(Str ("#!######", a@));
EndIf
Radix 10
Return
_Background
Param (1)
Write @o(0), "<rect width=\q100%\q height=\q100%\q fill=\q";
Proc _color_ (a@)
Return
_pixel_
Param (2)
Write @o(0), "<rect x=\q";b@;"\q y=\q";a@;
Write @o(0), "\q width=\q1px\q height=\q1px\q fill=\q";
Proc _color_ (@o(1))
Return
_dot_
Param (2)
Write @o(0), "<circle cx=\q";b@;"\q cy=\q";a@;
Write @o(0), "\q r=\q0.5px\q fill=\q";
Proc _color_ (@o(1))
Return
_SetMode
Param (1)
If Comp(a@, "pixel") = 0 Then
@o(3) = _pixel_
Else If Comp(a@, "dot") = 0 Then
@o(3) = _dot_
Else Print "Bad mode" : Raise 1
Endif : Endif
Return
_Canvas
Param (2)
Write @o(0), "<svg width=\q";a@;"\q height=\q";b@;"\q viewBox=\q0 0 ";a@;" ";b@;
Write @o(0), "\q xmlns=\qhttp://www.w3.org/2000/svg\q ";
Write @o(0), "xmlns:xlink=\qhttp://www.w3.org/1999/xlink\q>"
Return
_SVGopen
Param (1)
If Set (@o(0), Open (a@, "w")) < 0 Then
Print "Cannot open \q";Show (a@);"\q" : Raise 1
Else
Write @o(0), "<?xml version=\q1.0\q encoding=\qUTF-8\q standalone=\qno\q?>"
Write @o(0), "<!DOCTYPE svg PUBLIC \q-//W3C//DTD SVG 1.1//EN\q ";
Write @o(0), "\qhttp://www.w3.org/Graphics/SVG/1.1/DTD/svg11.dtd\q>"
EndIf
Return
This version uses decimal fixed-point numbers. It is not only faster, but also provides a better rendition of the Barnsley fern. It uses the very same SVG routines as the version above, so these are not included.
Dim @o(5) ' 0 = SVG file, 1 = color, 2 = fillcolor, 3 = pixel, 4 = text
Dim @c(20) ' coefficients
w = 400 : h = 600 : s = 17
Proc _coefficients
Proc _SVGopen ("svgfern.svg")
Proc _Canvas (w, h) ' light gray background
Proc _Background (FUNC(_RGBtoColor (0, 0, 0)))
Proc _SetMode ("dot") ' we want dots, not pixels
For i = 0 to 50000
Proc _transformation (FUNC (_randomchoice))
Proc _SetColor (FUNC(_RGBtoColor (0, 128 + Rnd(128), 0)))
p = h - y/s
q = w/2 + x/s
Proc _SetPixel (p, q)
Next
Proc _SVGclose
End
_coefficients
Local (1)
Push 0 , 0 , 0 , 160 , 0 ' 1% of the time - f1
Push 200 , -260 , 230 , 220 , 1600 ' 7% of the time - f3
Push -150 , 280 , 260 , 240 , 440 ' 7% of the time - f4
Push 850 , 40 , -40 , 850 , 1600 ' 85% of the time - f2
For a@ = 19 To 0 Step -1 : @c(a@) = Pop() : Next
Return
_randomchoice
Local (1)
Push Rnd (100)
a@ = (Tos() > 0)
a@ = a@ + (Tos () > 7)
Return ((a@ + (Pop () > 14)) * 5)
_transformation
Param (1)
Local (2)
b@ = @c(a@) * x
b@ = (b@ + @c(a@+1) * y) / 1000
c@ = @c(a@+2) * x
c@ = (c@ + @c(a@+3) * y) / 1000
x = b@ : y = @c(a@+4) + c@
Return
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).
#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#
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);
}
}
}
C++

#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;
}
Cross-Platform Alternative
This version uses the QImage class from the Qt toolkit as an easy way to save an image in PNG format. It also uses the C++ 11 random number library. Built and tested on macOS 10.15.4 with Qt 5.12.5.
#include <iostream>
#include <random>
#include <vector>
#include <QImage>
bool barnsleyFern(const char* fileName, int width, int height) {
constexpr int iterations = 1000000;
int bytesPerLine = 4 * ((width + 3)/4);
std::vector<uchar> imageData(bytesPerLine * height);
std::random_device dev;
std::mt19937 engine(dev());
std::uniform_int_distribution<int> distribution(1, 100);
double x = 0, y = 0;
for (int i = 0; i < iterations; ++i) {
int r = distribution(engine);
double x1, y1;
if (r == 1) {
x1 = 0;
y1 = 0.16 * y;
} else if (r <= 86) {
x1 = 0.85 * x + 0.04 * y;
y1 = -0.04 * x + 0.85 * y + 1.6;
} else if (r <= 93) {
x1 = 0.2 * x - 0.26 * y;
y1 = 0.23 * x + 0.22 * y + 1.6;
} else {
x1 = -0.15 * x + 0.28 * y;
y1 = 0.26 * x + 0.24 * y + 0.44;
}
x = x1;
y = y1;
int row = height * (1 - y/11);
int column = width * (0.5 + x/11);
imageData[row * bytesPerLine + column] = 1;
}
QImage image(&imageData[0], width, height, bytesPerLine, QImage::Format_Indexed8);
QVector<QRgb> colours(2);
colours[0] = qRgb(255, 255, 255);
colours[1] = qRgb(0, 160, 0);
image.setColorTable(colours);
return image.save(fileName);
}
int main(int argc, char *argv[]) {
if (argc != 2) {
std::cerr << "usage: " << argv[0] << " filename\n";
return EXIT_FAILURE;
}
if (!barnsleyFern(argv[1], 600, 600)) {
std::cerr << "image generation failed\n";
return EXIT_FAILURE;
}
return EXIT_SUCCESS;
}
- Output:
Common 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)))
Craft Basic
define x1 = 0, y1 = 0
bgcolor 0, 0, 0
cls graphics
for i = 1 to 10000
let r = rnd
if r > 0 and r < .01 then
let x = .0
let y = .16 * y
endif
if r > .01 and r < .08 then
let x = .22 * x - .26 * y
let y = -.23 * x + .22 * y + 1.6
endif
if r > .075 and r < .15 then
let x = .15 * x + .28 * y
let y = -.29 * x + .24 * y + .44
endif
let x = .85 * x + .04 * y
let y = -.04 * x + .85 * y + 1.6
let x1 = (x + 3) * 70
let y1 = 700 - y * 70
fgcolor 0, int(rnd * 255), 0
dot x1, y1
wait
next i
D
#!/usr/bin/env dub
/+ dub.sdl:
dependency "dlib" version="~>0.21.0"
+/
import std.random;
import dlib.image;
void main()
{
enum WIDTH = 640;
enum HEIGHT = 640;
enum ITERATIONS = 2E6;
float x = 0.0f;
float y = 0.0f;
auto rng = Random(unpredictableSeed);
auto color = Color4f(0.0f, 1.0f, 0.0f);
auto img = image(WIDTH, HEIGHT);
foreach (_; 0..ITERATIONS)
{
auto r = uniform(0, 101, rng);
if (r <= 1)
{
x = 0.0;
y = 0.16 * y;
}
else
{
if (r <= 8)
{
x = 0.20 * x - 0.26 * y;
y = 0.23 * x + 0.22 * y + 1.60;
}
else
{
if (r <= 15)
{
x = -0.15 * x + 0.28 * y;
y = 0.26 * x + 0.24 * y + 0.44;
}
else
{
x = 0.85 * x + 0.04 * y;
y = -0.04 * x + 0.85 * y + 1.6;
}
}
}
auto X = cast(int) (WIDTH / 2.0 + x * 60);
auto Y = HEIGHT - cast(int)(y * 60);
img[X, Y] = color;
}
img.saveImage(`barnsley_dlib.png`);
}
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.
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
color 060
for i = 1 to 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 y * 10
rect 0.3 0.3
.
Emacs Lisp

; Barnsley fern
(defun make-array (size)
"Create an empty array with size*size elements."
(setq m-array (make-vector size nil))
(dotimes (i size)
(setf (aref m-array i) (make-vector size 0)))
m-array)
(defun barnsley-next (p)
"Return the next Barnsley fern coordinates."
(let ((r (random 100))
(x (car p))
(y (cdr p)))
(cond ((< r 2) (setq nx 0) (setq ny (* 0.16 y)))
((< r 9) (setq nx (- (* 0.2 x) (* 0.26 y)))
(setq ny (+ 1.6 (* 0.23 x) (* 0.22 y))))
((< r 16) (setq nx (+ (* -0.15 x) (* 0.28 y)))
(setq ny (+ 0.44 (* 0.26 x) (* 0.24 y))))
(t (setq nx (+ (* 0.85 x) (* 0.04 y)))
(setq ny (+ 1.6 (* -0.04 x) (* 0.85 y)))))
(cons nx ny)))
(defun barnsley-lines (arr size)
"Turn array into a string for XPM conversion."
(setq all "")
(dotimes (y size)
(setq line "")
(dotimes (x size)
(setq line (concat line (if (= (elt (elt arr y) x) 1) "*" "."))))
(setq all (concat all "\"" line "\",\n")))
all)
(defun barnsley-show (arr size)
"Convert size*size array to XPM image and show it."
(insert-image (create-image (concat (format "/* XPM */
static char * barnsley[] = {
\"%i %i 2 1\",
\". c #000000\",
\"* c #00ff00\"," size size)
(barnsley-lines arr size) "};") 'xpm t)))
(defun barnsley (size scale max-iter)
"Plot the Barnsley fern."
(let ((arr (make-array size))
(p (cons 0 0)))
(dotimes (it max-iter)
(setq p (barnsley-next p))
(setq x (round (+ (/ size 2) (* scale (car p)))))
(setq y (round (- size (* scale (cdr p)) 1)))
(setf (elt (elt arr y) x) 1))
(barnsley-show arr size)))
(barnsley 400 35 100000)
F#
open System.Drawing
let (|F1|F2|F3|F4|) r =
if r < 0.01 then F1
else if r < 0.08 then F3
else if r < 0.15 then F4
else F2
let barnsleyFernFunction (x, y) = function
| F1 -> (0.0, 0.16*y)
| F2 -> ((0.85*x + 0.04*y), (-0.04*x + 0.85*y + 1.6))
| F3 -> ((0.2*x - 0.26*y), (0.23*x + 0.22*y + 1.6))
| F4 -> ((-0.15*x + 0.28*y), (0.26*x + 0.24*y + 0.44))
let barnsleyFern () =
let rnd = System.Random()
(0.0, 0.0)
|> Seq.unfold (fun point -> Some (point, barnsleyFernFunction point (rnd.NextDouble())))
let run width height =
let emptyBitmap = new Bitmap(int width,int height)
let bitmap =
barnsleyFern ()
|> Seq.take 250000 // calculate points
|> Seq.map (fun (x,y) -> (int (width/2.0+(width*x/11.0)), int (height-(height*y/11.0)))) // transform to pixels
|> Seq.fold (fun (b:Bitmap) (x,y) -> b.SetPixel(x-1,y-1,Color.ForestGreen); b) emptyBitmap // add pixels to bitmap
bitmap.Save("BFFsharp.png")
- Use:
BarnsleyFern.run 720 720
Forth
Fixed Point and Matrix solution
Traditionaly, Forth use Fixed-Point Arithmetic (here with a 1000 scale). For transformation function choice, a formula is used to pick coefficients in a matrix.
s" SDL2" add-lib
\c #include <SDL2/SDL.h>
c-function sdl-init SDL_Init n -- n
c-function sdl-quit SDL_Quit -- void
c-function sdl-createwindow SDL_CreateWindow a n n n n n -- a
c-function sdl-createrenderer SDL_CreateRenderer a n n -- a
c-function sdl-setdrawcolor SDL_SetRenderDrawColor a n n n n -- n
c-function sdl-drawpoint SDL_RenderDrawPoint a n n -- n
c-function sdl-renderpresent SDL_RenderPresent a -- void
c-function sdl-delay SDL_Delay n -- void
require random.fs
0 value window
0 value renderer
variable x
variable y
: initFern ( -- )
$20 sdl-init drop
s\" Rosetta Task : Barnsley fern\x0" drop 0 0 1000 1000 $0 sdl-createwindow to window
window -1 $2 sdl-createrenderer to renderer
renderer 0 255 0 255 sdl-setdrawcolor drop
;
create coefficients
0 , 0 , 0 , 160 , 0 , \ 1% of the time - f1
200 , -260 , 230 , 220 , 1600 , \ 7% of the time - f3
-150 , 280 , 260 , 240 , 440 , \ 7% of the time - f4
850 , 40 , -40 , 850 , 1600 , \ 85% of the time - f2
: nextcoeff ( n -- n+1 coeff ) coefficients over cells + @ swap 1+ swap ;
: transformation ( n -- )
nextcoeff x @ * swap nextcoeff y @ * rot + 1000 / swap
nextcoeff x @ * swap nextcoeff y @ * rot + 1000 / swap nextcoeff rot + y ! drop
x ! \ x shall be modified after y calculation
;
: randomchoice ( -- index )
100 random
dup 0 > swap
dup 7 > swap
dup 14 > swap drop
+ + negate 5 *
;
: fern
initFern
20000 0 do
randomchoice transformation
renderer x @ 10 / 500 + y @ 10 / sdl-drawpoint drop
loop
renderer sdl-renderpresent
5000 sdl-delay
sdl-quit
;
fern
Floating Point and Multiple Functions solution
Forth may use a dedicated Floating Point Stack. For transformation, a pointer to one of the 4 functions is used to be be called at the end of the loop.
s" SDL2" add-lib
\c #include <SDL2/SDL.h>
c-function sdl-init SDL_Init n -- n
c-function sdl-quit SDL_Quit -- void
c-function sdl-createwindow SDL_CreateWindow a n n n n n -- a
c-function sdl-createrenderer SDL_CreateRenderer a n n -- a
c-function sdl-setdrawcolor SDL_SetRenderDrawColor a n n n n -- n
c-function sdl-drawpoint SDL_RenderDrawPoint a n n -- n
c-function sdl-renderpresent SDL_RenderPresent a -- void
c-function sdl-delay SDL_Delay n -- void
require random.fs
0 value window
0 value renderer
0 value diceThrow
fvariable x
fvariable y
variable transformation
: initFern ( -- )
$20 sdl-init drop
s\" Rosetta Task : Barnsley fern\x0" drop 0 0 1000 1000 $0 sdl-createwindow to window
window -1 $2 sdl-createrenderer to renderer
renderer 0 255 0 255 sdl-setdrawcolor drop
;
: closeFern sdl-quit ;
: f1
0e0 x f!
y f@ 0.16e0 f* y f!
;
: f2
x f@ 0.85e0 f* y f@ 0.040e0 f* f+
x f@ -0.04e0 f* y f@ 0.850e0 f* f+ 1.600e0 f+ y f!
x f!
;
: f3
x f@ 0.200e0 f* y f@ -0.260e0 f* f+
x f@ 0.230e0 f* y f@ 0.220e0 f* f+ 1.600e0 f+ y f!
x f!
;
: f4
x f@ -0.150e0 f* y f@ 0.280e0 f* f+
x f@ 0.260e0 f* y f@ 0.240e0 f* f+ 0.440e0 f+ y f!
x f!
;
: fern
initFern
0e0 x f!
0e0 y f!
20000 0 do
renderer x f@ 50e0 f* f>s 500 + y f@ 50e0 f* f>s sdl-drawpoint drop
100 random to diceThrow
['] f2 transformation !
diceThrow 15 < if ['] f4 transformation ! then
diceThrow 8 < if ['] f3 transformation ! then
diceThrow 1 < if ['] f1 transformation ! then
transformation @ execute
loop
renderer sdl-renderpresent
5000 sdl-delay
closeFern
;
fern
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
Frink
g = new graphics
g.backgroundColor[0,0,0] // black
g.color[0,0.5,0] // green
x = 0
y = 0
for i = 1 to 100000
{
g.fillEllipseCenter[x*10,y*-10,0.25,0.25]
z = random[1, 100]
if z == 1
{
xn = 0
yn = 0.16 * y
}
if z >= 2 and z <= 86
{
xn = 0.85 * x + 0.04 * y
yn = -0.04 * x + 0.85 * y + 1.6
}
if z >= 87 and z <= 93
{
xn = 0.2 * x - 0.26 * y
yn = 0.23 * x + 0.22 * y + 1.6
}
if z >= 94 and z <= 100
{
xn = -0.15 * x + 0.28 * y
yn = 0.26 * x + 0.24 * y + 0.44
}
x = xn
y = yn
}
g.show[]
FutureBasic
void local fn BarnsleyFern( height as long )
double x = 0, y = 0, xn, yn, f = height / 10.6
long n, r, offsetX = height / 4 - height / 40
for n = 1 to height * 50
r = rnd(100) - 1
select
case r >= 0 && r <= 84
xn = 0.85 * x + 0.04 * y
yn = -0.04 * x + 0.85 * y + 1.6
case r >= 85 && r <= 91
xn = 0.2 * x - 0.26 * y
yn = 0.23 * x + 0.22 * y + 1.6
case r >= 92 && r <= 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
pen -1
oval fill (offsetX + x * f, height - y * f, 1.5, 1.5), _zGreen
next
end fn
window 1, @"Barnsley fern", (0,0,300,600)
WindowSetBackgroundColor( 1, fn ColorBlack )
fn BarnsleyFern( 600 )
HandleEvents
Fōrmulæ
Fōrmulæ programs are not textual, visualization/edition of programs is done showing/manipulating structures but not text. 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 storage and transfer purposes more than visualization and edition.
Programs in Fōrmulæ are created/edited online in its website.
In this page you can see and run the program(s) related to this task and their results. You can also change either the programs or the parameters they are called with, for experimentation, but remember that these programs were created with the main purpose of showing a clear solution of the task, and they generally lack any kind of validation.
Solution
Test case
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
## 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)
}
}
Groovy
import javafx.animation.AnimationTimer
import javafx.application.Application
import javafx.scene.Group
import javafx.scene.Scene
import javafx.scene.image.ImageView
import javafx.scene.image.WritableImage
import javafx.scene.paint.Color
import javafx.stage.Stage
class BarnsleyFern extends Application {
@Override
void start(Stage primaryStage) {
primaryStage.title = 'Barnsley Fern'
primaryStage.scene = getScene()
primaryStage.show()
}
def getScene() {
def root = new Group()
def scene = new Scene(root, 640, 640)
def imageWriter = new WritableImage(640, 640)
def imageView = new ImageView(imageWriter)
root.children.add imageView
def pixelWriter = imageWriter.pixelWriter
def x = 0, y = 0
({
50.times {
def r = Math.random()
if (r <= 0.01) {
x = 0
y = 0.16 * y
} else if (r <= 0.08) {
x = 0.2 * x - 0.26 * y
y = 0.23 * x + 0.22 * y + 1.6
} else if (r <= 0.15) {
x = -0.15 * x + 0.28 * y
y = 0.26 * x + 0.24 * y + 0.44
} else {
x = 0.85 * x + 0.04 * y
y = -0.04 * x + 0.85 * y + 1.6
}
pixelWriter.setColor(Math.round(640 / 2 + x * 640 / 11) as Integer, Math.round(640 - y * 640 / 11) as Integer, Color.GREEN)
}
} as AnimationTimer).start()
scene
}
static void main(args) {
launch(BarnsleyFern)
}
}
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)
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
J

require 'plot'
f=: |: 0 ". 1 2 }. ];._2 noun define
w a b c d e f prob
f1 0 0 0 0.16 0 0 0.01
f2 0.85 -0.04 0.04 0.85 0 1.60 0.85
f3 0.20 0.23 -0.26 0.22 0 1.60 0.07
f4 -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;frame 0;grids 0;tics 0;labels 0;aspect 2;color green' plot ;/@|:
plotFern getPoints 0 0
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);
});
}
}
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
}
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
using Images
mutable struct BarnsleyFern
width::Int
height::Int
color::RGB
x::Float64
y::Float64
fern::Matrix{RGB}
function BarnsleyFern(width, height, color = RGB(0.0, 1.0, 0.0), bgcolor = RGB(0.0, 0.0, 0.0))
img = [bgcolor for x in 1:width, y in 1:height]
cx = Int(floor(2.182 * (width - 1) / 4.8378) + 1)
cy = Int(floor(9.9983 * (height - 1) / 9.9983) + 1)
img[cx, cy] = color
return new(width, height, color, 0.0, 0.0, img)
end
end
function transform(f::BarnsleyFern)
r = rand(0:99)
f.x, f.y = r < 1 ? (0.0, 0.16 * f.y) :
1 <= r < 86 ? (0.85 * f.x + 0.04 * f.y, -0.04 * f.x + 0.85 * f.y + 1.6) :
86 <= r < 93 ? (0.2 * f.x - 0.26 * f.y, 0.23 * f.x + 0.22 * f.y + 1.6) :
(-0.15 * f.x + 0.28 * f.y, 0.26 * f.x + 0.24 * f.y + 0.44)
cx = Int(floor((f.x + 2.182) * (f.width - 1) / 4.8378) + 1)
cy = Int(floor((9.9983 - f.y) * (f.height - 1) / 9.9983) + 1)
f.fern[cx, cy] = f.color
end
const fern = BarnsleyFern(500, 500)
for _ in 1:1000000
transform(fern)
end
fern.fern'
Kotlin
// 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)
}
}
Lambdatalk
{def fern
{lambda {:size :sign}
{if {> :size 2}
then M:size
T{* 70 :sign}
{fern {* :size 0.5} {- :sign}}
T{* {- 70} :sign}
M:size
T{* {- 70} :sign}
{fern {* :size 0.5} :sign}
T{* 70 :sign}
T{* 7 :sign}
{fern {- :size 1} :sign}
T{* {- 7} :sign}
M{* -:size 2}
else }}}
{def F {fern 25 1}}
The output can be seen in http://lambdaway.free.fr/lambdawalks/?view=fern
Liberty BASIC
nomainwin
WindowWidth=800
WindowHeight=600
open "Barnsley Fern" for graphics_nf_nsb as #1
#1 "trapclose [q];down;fill black;flush;color green"
for n = 1 To WindowHeight * 50
r = int(rnd(1)*100)
Select Case
Case (r>=0) and (r<=84)
xn=0.85*x+0.04*y
yn=-0.04*x+0.85*y+1.6
Case (r>84) and (r<=91)
xn=0.2*x-0.26*y
yn=0.23*x+0.22*y+1.6
Case (r>91) and (r<=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
#1 "set ";x*80+300;" ";WindowHeight/1.1-y*50
next n
#1 "flush"
wait
[q]
close #1
Locomotive Basic

10 mode 2:ink 0,0:ink 1,18:randomize time
20 scale=38
30 maxpoints=20000: x=0: y=0
40 for z=1 to maxpoints
50 p=rnd*100
60 if p<=1 then nx=0: ny=0.16*y: goto 100
70 if p<=8 then nx=0.2*x-0.26*y: ny=0.23*x+0.22*y+1.6: goto 100
80 if p<=15 then nx=-0.15*x+0.28*y: ny=0.26*x+0.24*y+0.44: goto 100
90 nx=0.85*x+0.04*y: ny=-0.04*x+0.85*y+1.6
100 x=nx: y=ny
110 plot scale*x+320,scale*y
120 next
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
Mathematica / 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}]]
MiniScript
clear
x = 0
y = 0
for i in range(100000)
gfx.setPixel 300 + 58 * x, 58 * y, color.green
roll = rnd * 100
xp = x
if roll < 1 then
x = 0
y = 0.16 * y
else if roll < 86 then
x = 0.85 * x + 0.04 * y
y = -0.04 * xp + 0.85 * y + 1.6
else if roll < 93 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 if
end for
Nim
import nimPNG, std/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 = rand(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)
Oberon-2
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.
Oberon-07
The Barnsley fern is one of the examples distributed with Oberonc (Oberon-07 compiler for the JVM), source and bitmap on github.
PARI/GP
\\ 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

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');
Phix
You can run this online here, or see the output on imgur
-- -- pwa\phix\BarnsleyFern.exw -- ========================= -- with javascript_semantics include pGUI.e Ihandle dlg, canvas cdCanvas cddbuffer, cdcanvas function redraw_cb(Ihandle /*canvas*/, integer /*posx*/, integer /*posy*/) atom x = 0, y = 0 integer {width, height} = IupGetIntInt(canvas, "DRAWSIZE") cdCanvasActivate(cddbuffer) for i=1 to 100000 do integer 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}))) if r<=1 then {x, y} = { 0, 0.16*y } elsif r<=8 then {x, y} = { 0.20*x-0.26*y, 0.23*x+0.22*y+1.60} elsif r<=15 then {x, y} = {-0.15*x+0.28*y, 0.26*x+0.24*y+0.44} else {x, y} = { 0.85*x+0.04*y,-0.04*x+0.85*y+1.60} end if cdCanvasPixel(cddbuffer, width/2+x*50, y*50, CD_DARK_GREEN) end for cdCanvasFlush(cddbuffer) return IUP_DEFAULT end function IupOpen() canvas = IupCanvas(Icallback("redraw_cb"),"RASTERSIZE=340x540") dlg = IupDialog(canvas,`TITLE="Barnsley Fern"`) IupMap(dlg) cdcanvas = cdCreateCanvas(CD_IUP, canvas) cddbuffer = cdCreateCanvas(CD_DBUFFER, cdcanvas) IupSetAttribute(canvas, "RASTERSIZE", NULL) -- release the minimum limitation IupShow(dlg) if platform()!=JS then IupMainLoop() IupClose() end if
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();
}
Processing Python mode
size(640, 640)
background(0)
x = 0
y = 0
for _ in range(100000):
xt = 0
yt = 0
r = random(100)
if r <= 1:
xt = 0
yt = 0.16 * y
elif r <= 8:
xt = 0.20 * x - 0.26 * y
yt = 0.23 * x + 0.22 * y + 1.60
elif 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
size(640, 640)
background(0)
x = 0
y = 0
for _ in range(100000):
xt = 0
yt = 0
r = random(100)
if r <= 1:
xt = 0
yt = 0.16*y
elif r <= 8:
xt = 0.20*x - 0.26*y
yt = 0.23*x + 0.22*y + 1.60
elif 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
m = round(width/2 + 60*x)
n = height-round(60*y)
set(m, n, "#00ff00")
x = xt
y = yt
m = round(width / 2 + 60 * x)
n = height - round(60 * y)
set(m, n, "#00ff00")
Prolog
% a straight forward adaption from the Ada example
% these imports are needed for Ciao Prolog but needed
% modules will vary with your Prolog system
:- use_module(library(streams)).
:- use_module(library(stream_utils)).
:- use_module(library(lists)).
:- use_module(library(llists)).
:- use_module(library(hiordlib)).
:- use_module(library(random)).
:- use_module(library(format)).
replicate(Term, Times, L) :-
length(L, Times),
maplist(=(Term), L).
replace(0, [_|T], E, [E|T]).
replace(X, [H|T0], E, [H|T]) :-
X0 is X -1,
replace(X0, T0, E, T).
replace_2d(X, 0, [H|T], E, [R|T]) :-
replace(X, H, E, R).
replace_2d(X, Y, [H|T0], E, [H|T]) :-
Y0 is Y -1,
replace_2d(X, Y0, T0, E, T).
fern_iteration(10000, _X, _Y, Final, Final).
fern_iteration(N, X, Y, I, Final) :-
random(R),
( R =< 0.01
-> ( X1 is 0.0,
Y1 is 0.16*Y )
; ( R =< 0.86
-> ( X1 is 0.85*X + 0.04*Y,
Y1 is -0.04*X + 0.85*Y + 1.6 )
; ( R =< 0.93
-> ( X1 is 0.20*X - 0.26*Y,
Y1 is 0.23*X + 0.22*Y + 1.60 )
; ( X1 is -0.15*X + 0.28*Y,
Y1 is 0.26*X + 0.24*Y + 0.44 )
) ) ),
PointX is 250 + floor(70.0*X1),
PointY is 750 - floor(70.0*Y1),
replace_2d(PointX, PointY, I, [0, 255, 0], I1), !,
N1 is N + 1,
fern_iteration(N1, X1, Y1, I1, Final).
draw_fern :-
replicate([0, 0, 0], 500, Row),
replicate(Row, 750, F),
fern_iteration(0, 0, 0, F, Fern),
% the following lines are written for ciao prolog and
% write to a ppm6 file for viewing
% adapting to SWI or Scryer should be straighforward
open('fern.ppm', write, File),
flatten(Fern, FP),
format(File, "P6\n~d ~d\n255\n", [500, 750]),
write_bytes(File, FP),
close(File).
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()
QB64
_Title "Barnsley Fern"
Dim As Integer sw, sh
sw = 400: sh = 600
Screen _NewImage(sw, sh, 8)
Dim As Long i, ox, oy
Dim As Single sRand
Dim As Double x, y, x1, y1, sx, sy
sx = 60: sy = 59
ox = 180: oy = 4
Randomize Timer
x = 0
y = 0
For i = 1 To 400000
sRand = Rnd
Select Case sRand
Case Is < 0.01
x1 = 0: y1 = 0.16 * y
Case Is < 0.08
x1 = 0.2 * x - 0.26 * y: y1 = 0.23 * x + 0.22 * y + 1.6
Case Is < 0.15
x1 = -0.15 * x + 0.28 * y: y1 = 0.26 * x + 0.24 * y + 0.44
Case Else
x1 = 0.85 * x + 0.04 * y: y1 = -0.04 * x + 0.85 * y + 1.6
End Select
x = x1
y = y1
PSet (x * sx + ox, sh - (y * sy) - oy), 10
Next
Sleep
System
Quackery
[ $ "turtleduck.qky" loadfile ] now!
[ ' [ 79 121 66 ] fill
[ 3 2 circle ] ] is dot ( --> )
[ 1 fly
-1 4 turn
1 fly
1 4 turn ] is toxy ( n n --> )
[ 100 1 v* /
dip [ 100 1 v* / ]
2dup toxy
dot
1 2 turn
toxy
1 2 turn ] is plot ( n n --> )
[ 2swap 2drop 0 1
2swap 16 100 v* ] is f1 ( n/d n/d --> n/d n/d )
[ 2over -4 100 v*
2over 85 100 v*
16 10 v+ v+
join dip
[ 4 100 v*
2swap 85 100 v*
v+ ]
do ] is f2 ( n/d n/d --> n/d n/d )
[ 2over 23 100 v*
2over 22 100 v*
16 10 v+ v+
join dip
[ -26 100 v*
2swap 20 100 v*
v+ ]
do ] is f3 ( n/d n/d --> n/d n/d )
[ 2over 26 100 v*
2over 24 100 v*
44 100 v+ v+
join dip
[ 28 100 v*
2swap -15 100 v*
v+ ]
do ] is f4 ( n/d n/d --> n/d n/d )
[ 100 random
[ dup 0 = iff
[ drop f1 ] done
dup 86 < iff
[ drop f2 ] done
93 < iff f3 done
f4 ]
2swap 1000000000 round
2swap 1000000000 round
2over 2over plot ] is nextpoint ( n/d n/d --> n/d n/d )
turtle
' [ 79 121 66 ] colour
-500 1 fly
0 1 0 1
0 frames
20000 times nextpoint
1 frames
4 times drop
- Output:

R
Matrix solution
## 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
'Obvious' solution
The matrix solution above is a clever approach, but the following solution is more readable if you're unfamiliar with linear algebra. This is very much a blind "just do what the task says" solution. It's so simple that it probably runs unadapted in S. I suspect that there is room for an interesting use of R's ifelse function somewhere, but I couldn't find a clean way.
fernOfNPoints <- function(n)
{
currentX <- currentY <- newX <- newY <- 0
plot(0, 0, xlim = c(-2, 3), ylim = c(0, 10), xlab = "", ylab = "", pch = 20, col = "darkgreen", cex = 0.1)
f1 <- function()#ran 1% of the time
{
newX <<- 0
newY <<- 0.16 * currentY
}
f2 <- function()#ran 85% of the time
{
newX <<- 0.85 * newX + 0.04 * newY
newY <<- -0.04 * newX + 0.85 * newY + 1.6
}
f3 <- function()#ran 7% of the time
{
newX <<- 0.2 * newX - 0.26 * newY
newY <<- 0.23 * newX + 0.22 * newY + 1.6
}
f4 <- function()#ran 7% of the time
{
newX <<- -0.15 * newX + 0.28 * newY
newY <<- 0.26 * newX + 0.24 * newY + 0.44
}
for(i in 2:n)#We've already plotted (0,0), so we can skip one run.
{
case <- runif(1)
if(case <= 0.01) f1()
else if(case <= 0.86) f2()
else if(case <= 0.93) f3()
else f4()
points(newX, newY, pch = 20, col = "darkgreen", cex = 0.1)
}
return(invisible())
}
#To plot the fern, use:
fernOfNPoints(500000)
#It will look better if you use a bigger input, but the plot might take a while.
#I find that there's a large delay between RStudio saying that my code is finished running and the plot appearing.
#If your input is truly big, you may want to reduce the two cex parameters (to make the points smaller).
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)
Raku
(formerly Perl 6)

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';
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. */
- output 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
Ruby
MAX_ITERATIONS = 200_000
def setup
sketch_title 'Barnsley Fern'
no_loop
puts 'Be patient. This takes about 10 seconds to render.'
end
def draw
background 0
load_pixels
x0 = 0.0
y0 = 0.0
x = 0.0
y = 0.0
MAX_ITERATIONS.times do
r = rand(100)
if r < 85
x = 0.85 * x0 + 0.04 * y0
y = -0.04 * x0 + 0.85 * y0 + 1.6
elsif r < 92
x = 0.2 * x0 - 0.26 * y0
y = 0.23 * x0 + 0.22 * y0 + 1.6
elsif r < 99
x = -0.15 * x0 + 0.28 * y0
y = 0.26 * x0 + 0.24 * y0 + 0.44
else
x = 0
y = 0.16 * y
end
i = height - (y * 48).to_i
j = width / 2 + (x * 48).to_i
pixels[i * height + j] += 2_560
x0 = x
y0 = y
end
update_pixels
end
def settings
size 500, 500
end
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
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
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.
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;
SequenceL
Tail-Recursive SequenceL Code:
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:
#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;
}
- Output:
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: 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
Standard ML
Works with PolyML. Random generator copy from the Random_numbers#Standard_ML task. Window slimmed down from Animation#Standard_ML.
open XWindows ;
open Motif ;
val uniformdeviate = fn seed =>
let
val in31m = (Real.fromInt o Int32.toInt ) (getOpt (Int32.maxInt,0) );
val in31 = in31m +1.0;
val (s1,s2,v) = (41160.0 , 950665216.0 , Real.realFloor seed);
val (val1,val2) = (v*s1, v*s2);
val next1 = Real.fromLargeInt (Real.toLargeInt IEEEReal.TO_NEGINF (val1/in31)) ;
val next2 = Real.rem(Real.realFloor(val2/in31) , in31m );
val valt = val1+val2 - (next1+next2)*in31m;
val nextt = Real.realFloor(valt/in31m);
val valt = valt - nextt*in31m;
in
(valt/in31m,valt)
end;
local
val sizeup = 60.0 ;
fun toI {x=x,y=y} = {x=Real.toInt IEEEReal.TO_NEAREST (sizeup *x),y=Real.toInt IEEEReal.TO_NEAREST (sizeup*y)} ;
val next = [ (fn {x=x,y=y} => {x= 0.0, y= 0.16*y })
, (fn {x=x,y=y} => {x= 0.85*x+0.04*y, y= ~0.04*x+0.85*y+1.6})
, (fn {x=x,y=y} => {x= 0.2*x-0.26*y, y= 0.23*x+0.22*y+1.6 })
, (fn {x=x,y=y} => {x= ~0.15*x+0.28*y,y= 0.26*x+0.24*y+0.44}) ] ;
val seed = ref 100027.0
in
fun putNext 1 win usegc coord = XFlush (XtDisplay win)
| putNext N win usegc coord =
let
val (i,ns) = uniformdeviate ( !seed ) ;
val _ = seed := ns ;
val fi = List.nth (next, List.foldr (fn (a,b) => b + (if i>a then 1 else 0)) 0 [0.1,0.86,0.93,1.0] ) ;
val nwp = fi coord
in
(XDrawPoint (XtWindow win) usegc ( AddPoint ((XPoint o toI) coord, XPoint {x=300,y=0}) ) ;
putNext (N-1) win usegc nwp )
end
end;
val demoWindow = fn () =>
let
val shell = XtAppInitialise "" "demo" "top" [] [ XmNwidth 600, XmNheight 700 ] ;
val main = XmCreateMainWindow shell "main" [ XmNmappedWhenManaged true ] ;
val canvas = XmCreateDrawingArea main "drawarea" [ XmNwidth 600, XmNheight 700] ;
val usegc = DefaultGC (XtDisplay canvas) ;
val _ = XSetForeground usegc 0x4a632d ;
val drawall = fn (w,c,t)=> ( XClearWindow (XtWindow canvas ); putNext 1000000 canvas usegc {x=0.0,y=0.0} ; t )
in
(
XtSetCallbacks canvas [ (XmNexposeCallback , drawall) ] XmNarmCallback ;
XtManageChild canvas ;
XtManageChild main ;
XtRealizeWidget shell
)
end ;
call
demoWindow () ;
SuperCollider
Submitted to Rosetta Code 2024-06-07 by: MusicCoder.
The first line of code excuted is the LAST line in this listing:
drawFern.();
SuperCollider is a CLIENT / SERVER software system for the generation of music.
CLIENT = (language+IDE)
SERVER = (music-sound engine)
However, the language is a complete / general purpose OO/functional programming language.
SEE:
https://supercollider.github.io/
https://en.wikipedia.org/wiki/SuperCollider
// ==========================================================================
// START-SuperCollider solution to Rosetta Code TASK: Barnsley fern
// ==========================================================================
(
/* Barnsley_fern
https://rosettacode.org/wiki/Barnsley_fern
Create this fractal fern, using the following transformations:
ƒ1 1%: xn+1 = 0 yn+1 = 0.16 yn
ƒ2 85%: xn+1 = 0.85 xn + 0.04 yn yn+1 = −0.04 xn + 0.85 yn + 1.6
ƒ3 7% xn+1 = 0.2 xn − 0.26 yn yn+1 = 0.23 xn + 0.22 yn + 1.6
ƒ4 7% xn+1 = −0.15 xn + 0.28 yn yn+1 = 0.26 xn + 0.24 yn + 0.44.
Starting position: x = 0, y = 0
//BY: MusicCoder : 2024-06-07//
Create arrays to hold the various constants from the formulae above.
Replicate the arrays to create 100 of them,
*** biased by the percentages above ***.
Scramble the 100 arrays of constants.
Function nextXY will pick a set of constants at random and given the current
X and Y values will generate the next X and Y values.
Before we plot the X-Y values run function findScale so that we can make
sure the generated X & Y values will 'fit' within the bounds of the given display size.
SuperCollider is a CLIENT / SERVER software system for the generation of music.
CLIENT = (language+IDE)
SERVER = (music-sound engine)
However, the language is a complete / general purpose OO/functional programming language.
https://supercollider.github.io/
https://en.wikipedia.org/wiki/SuperCollider
*/
// ==========================================================================
// The first line of code executed is the LAST line in this listing:
// drawFern.();
// ==========================================================================
var fConstants =
// _NEXT_X___________ _NEXT_Y___________
// a*x + b*y +c d*x + e*y + f
( // duplicate each array of constants by the specified % number
([ 0.00, 0.00, 0.00, 0.00, 0.16, 0.00 ]!1 )++ // 1%
([ 0.85, 0.04, 0.00, -0.04, 0.85, 1.6 ]!85)++ // 85%
([ 0.2 , -0.26, 0.00, 0.23, 0.22, 1.6 ]!7 )++ // 7%
([-0.15, 0.28, 0.00, 0.26, 0.24, 0.44 ]!7) // 7%
// the ++ will construct a container array to hold theses arrays
).scramble; // randomly rearrange sub-arrays
// ==========================================================================
var fcSize = fConstants.size;
// ==========================================================================
var nextXY = {|x, y|
var a,b,c,d,e,f;
// split up the array of constants
#a,b,c,d,e,f = fConstants[fcSize.rand];
// apply the constants to the ADD and MUL operations on X and Y
// NEXT_X_________ NEXT_Y___________
[ (a*x) + (b*y) +c, (d*x) + (e*y) + f ]; // return new [x, y]
};
// ==========================================================================
var scaleAndShift = {|num, scale, shift|
roundUp((num*scale)+shift);
};
// ==========================================================================
var findScale = {|screenX=500, screenY=500, runs=1000, show=false|
// use to find min/max in loop of fern functions
var x=0, y=0;
// hold min/max results
var minX=x, maxX=x, minY=y, maxY=y;
// how much 'space' do the X and Y values need
var lengthX, lengthY;
var scaleX, scaleY;
// return the following 3 values to position & scale X and Y
// to stay within the given screen size
var shiftX=0; // add to generated X value to position X on screen
var shiftY=0; // add to generated Y value to position Y on screen
var scale; // multiply X and Y to scale the values to stay on the screen
// we need to use the same scaling factor for both X and Y to avoid distortion
// find min & max of both X and Y
runs.do {
#x, y = nextXY.(x, y);
if (x<minX) {minX=x};
if (x>maxX) {maxX=x};
if (y<minY) {minY=y};
if (y>maxY) {maxY=y};
};
// calculate amount of 'space' needed by X and by Y
lengthX = maxX-minX;
lengthY = maxY-minY;
scaleX = screenX/lengthX;
scaleY = screenY/lengthY;
// use the smaller of scaleX and scaleY as we need ONE scale to avoid distortion
// since we have only sampled possible X and Y values ...
// ... reduce scale to 90% of calculated value to allow space to larger X or Y
scale = 0.9*min(scaleX, scaleY);
// if min X or Y is negative 'shift' the ZERO point
// so that all neg and pos values are on the screen
if (minX.isNegative) {shiftX = minX.abs * scaleX};
if (minY.isNegative) {shiftY = minY.abs * scaleY};
// if calculated shift is 0, to move ZERO away from the edge
// set it as 1% of screen size
// (this is OK as we decreased scale by 10%)
if (shiftX ==0) {shiftX = screenX/100};
if (shiftY ==0) {shiftY = screenY/100};
// round up to nearest integer values
# scale, shiftX, shiftY = roundUp([scale, shiftX, shiftY ]);
if (show) {
var minXsas = scaleAndShift.(minX, scale, shiftX);
var maxXsas = scaleAndShift.(maxX, scale, shiftX);
var minYsas = scaleAndShift.(minY, scale, shiftY);
var maxYsas = scaleAndShift.(maxY, scale, shiftY);
postln("");
postf("scale=%, shiftX=%, shiftY=%\n", scale, shiftX, shiftY);
postf("MIN scaled & shifted X value=%\n", minXsas);
postf("MIN scaled & shifted Y value=%\n", minYsas);
postf("MAX scaled & shifted X value=% screenX=%\n", maxXsas, screenX);
postf("MAX scaled & shifted Y value=% screenY=%\n", maxYsas, screenY);
};
[scale, shiftX, shiftY]; // return these three values
};
// ==========================================================================
var drawFern = {|screenX=400, screenY=600, dotSize=1, windowCorner=50, runs=1000000|
var win = Window.new("Barnsley Fern", Rect(windowCorner, windowCorner, screenX, screenY)).front;
var x=0, y=0;
var bigX, bigY;
var scale, shiftX, shiftY;
# scale, shiftX, shiftY = findScale.(screenX, screenY, show: true);
win.view.background_(Color.white);
win.drawFunc = {
runs.do {|i|
# x, y = nextXY.(x, y); // generate next X and Y values
bigX = scaleAndShift.(x, scale, shiftX);
// Y=0 is at top of screen,
// so substract Y from screenY to flip orientation
bigY = screenY - scaleAndShift.(y, scale, shiftY);
Pen.color = Color.rand(); // *** JUST FOR FUN: pick a random color ***
Pen.addRect(Rect(bigX, bigY, dotSize, dotSize));
Pen.fill;
}; // end-of: do
}; // end-of: drawFunc
win.refresh;
}; // end-of: drawFern
// ==========================================================================
// The following line of code is executed first:
drawFern.();
)
// ==========================================================================
// **END-SuperCollider solution to Rosetta Code TASK: Barnsley fern
// ==========================================================================
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()!)
TI-83 BASIC
ClrDraw
Input "ITERS:",M
[[0,0,1]]→[A]
[[0,0,0][0,.16,0][0,0,1]]→[B]
[[.85,-.04,0][.04,.85,0][0,1.6,1]]→[C]
[[.2,.23,0][-.26,.22,0][0,1.6,1]]→[D]
[[-.15,.26,0][.28,.24,0][0,.44,1]]→[E]
0→I
While I<M
randInt(1,100)→R
If R=1
Then
[A][B]→[A]
101→R
End
If R<86
Then
[A][C]→[A]
101→R
End
If R<93
Then
[A][D]→[A]
101→R
End
If R<101:Then
[A][E]→[A]
End
round([A](1,1)*8+31,0)→E
round([A](1,2)*8,0)→F
Pxl-On(E,F)
I+1→I
End
Uiua
Sideways fern for a change :-) Run it in Uiua Pad!
Fs ← [[[0 0 0] [0 0.16 0]]
[[0.85 0.04 0] [¯0.04 0.85 1.6]]
[[0.2 ¯0.26 0] [0.23 0.22 1.6]]
[[¯0.15 0.28 0] [0.26 0.24 0.44]]]
Ps ← [1 86 93 100]
PickF ← (⊡:Fs⊢⊚<Ps⌊×⚂100)
Next ← ≡/+×PickF¤⊂:1
[⍥(Next.)99999 0_0]
S ← 600
+¤[÷4S 0]⌊-1×S÷/↥/↥.-¤/↧. # Scale.
∧(⍜⊡⋅0_1_0):↯S_S_3 [0 0 0] # Plot.
- Output:

Unicon
link graphics
global x, y
procedure main()
&window := open("FERN", "g", "size=400,400", "bg=black")
x := y := 0
repeat {
draw()
delay(30)
if *Pending() > 0 then {
case Event() of {
"q"|"\e": return
}
}
}
end
procedure next_point()
local nx, ny, r
nx := 0.0
ny := 0.0
r := ?100
if r < 1 then {
nx := 0.0
ny := 0.16 * y
} else if r < 86 then {
nx := 0.85 * x + 0.04 * y
ny := -0.04 * x + 0.85 * y + 1.6
} else if r < 93 then {
nx := 0.2 * x - 0.26 * y
ny := 0.23 * x + 0.22 * y + 1.6
} else {
nx := -0.15 * x + 0.28 * y
ny := 0.26 * x + 0.24 * y + 0.44
}
x := nx
y := ny
end
procedure map(v:real, a, b, c, d)
return (v - a) / (b - a) * (d - c) + c;
end
procedure draw_point()
local px, py
px := map(x, -2.1820, 2.6558, 0.0, 400.0)
py := map(y, 0.0, 9.9983, 400.0, 0.0)
Fg("green")
DrawPoint(px, py)
end
procedure draw()
every i := 0 to 10000 do {
draw_point()
next_point()
}
end
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
/* Visual Basic .NET */ Section added
Visual Basic .NET
' Barnsley Fern - 11/11/2019
Public Class BarnsleyFern
Private Sub BarnsleyFern_Paint(sender As Object, e As PaintEventArgs) Handles Me.Paint
Const Height = 800
Dim x, y, xn, yn As Double
Dim f As Double = Height / 10.6
Dim offset_x As UInteger = Height \ 4 - Height \ 40
Dim n, r As UInteger
Dim Bmp As New Drawing.Bitmap(Height \ 2, Height) 'x,y
'In Form: xPictureBox As PictureBox(800,400)
xPictureBox.Image = Bmp
For n = 1 To Height * 50
r = Int(Rnd() * 100) ' f from 0 to 99
Select Case 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
Bmp.SetPixel(offset_x + x * f, Height - y * f, Color.FromArgb(0, 255, 0)) 'x,y 'r,g,b
Next n
End Sub 'Paint
End Class 'BarnsleyFern
Wren
import "graphics" for Canvas, Color
import "dome" for Window
import "random" for Random
var Rand = Random.new()
class BarnsleyFern {
construct new(width, height, points) {
Window.title = "Barnsley Fern"
Window.resize(width, height)
Canvas.resize(width, height)
_w = width
_h = height
_n = points
}
init() {
createFern()
}
createFern() {
var x = 0
var y = 0
var c = Color.hex("#32cd32")
for (i in 0..._n) {
var tx
var ty
var r = Rand.float()
if (r <= 0.01) {
tx = 0
ty = 0.16 * y
} else if (r <= 0.86) {
tx = 0.85 * x + 0.04 * y
ty = -0.04 * x + 0.85 * y + 1.6
} else if (r <= 0.93) {
tx = 0.2 * x - 0.26 * y
ty = 0.23 * x + 0.22 * y + 1.6
} else {
tx = -0.15 * x + 0.28 * y
ty = 0.26 * x + 0.24 * y + 0.44
}
x = tx
y = ty
Canvas.pset((_w/2 + x * _w/11).round, (_h - y * _h/11).round, c)
}
}
update() {}
draw(alpha) {}
}
var Game = BarnsleyFern.new(640, 640, 200000)
- Output:
XPL0
int N, R;
real NX, NY, X, Y;
[SetVid($12); \set 640x480x4 VGA graphics (on PC or RPi)
X:= 0.0; Y:= 0.0;
for N:= 0 to 200_000 do
[R:= Ran(100); \0..99
case of
R < 1: [NX:= 0.0; NY:= 0.16*Y];
R < 8: [NX:= 0.20*X - 0.26*Y; NY:= 0.23*X + 0.22*Y + 1.60];
R < 15: [NX:=-0.15*X + 0.28*Y; NY:= 0.26*X + 0.24*Y + 0.44]
other [NX:= 0.85*X + 0.04*Y; NY:=-0.04*X + 0.85*Y + 1.60];
X:= NX; Y:= NY;
Point(320+fix(X*40.0), 440-fix(Y*40.0), 2\green\);
]
]
Yabasic
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

Uses the PPM class from http://rosettacode.org/wiki/Bitmap/Bresenham%27s_line_algorithm#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");
}();
ZX Spectrum Basic
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.
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