Sunflower fractal

From Rosetta Code
Sunflower fractal is a draft programming task. It is not yet considered ready to be promoted as a complete task, for reasons that should be found in its talk page.

Draw Sunflower fractal


C[edit]

The colouring of the "fractal" is determined with every iteration to ensure that the resulting graphic looks similar to a real Sunflower, thus the parameter diskRatio determines the radius of the central disk as the maximum radius of the flower is known from the number of iterations. The scaling factor is currently hardcoded but can also be externalized. Requires the WinBGIm library.

 
/*Abhishek Ghosh, 14th September 2018*/
 
#include<graphics.h>
#include<math.h>
 
#define pi M_PI
 
void sunflower(int winWidth, int winHeight, double diskRatio, int iter){
double factor = .5 + sqrt(1.25),r,theta;
double x = winWidth/2.0, y = winHeight/2.0;
double maxRad = pow(iter,factor)/iter;
 
int i;
 
setbkcolor(LIGHTBLUE);
 
for(i=0;i<=iter;i++){
r = pow(i,factor)/iter;
 
r/maxRad < diskRatio?setcolor(BLACK):setcolor(YELLOW);
 
theta = 2*pi*factor*i;
circle(x + r*sin(theta), y + r*cos(theta), 10 * i/(1.0*iter));
}
}
 
int main()
{
initwindow(1000,1000,"Sunflower...");
 
sunflower(1000,1000,0.5,3000);
 
getch();
 
closegraph();
 
return 0;
}
 

Go[edit]

Library: Go Graphics
Translation of: Ring


The image produced, when viewed with (for example) EOG, is similar to the Ring entry.

package main
 
import (
"github.com/fogleman/gg"
"math"
)
 
func main() {
dc := gg.NewContext(400, 400)
dc.SetRGB(1, 1, 1)
dc.Clear()
dc.SetRGB(0, 0, 1)
c := (math.Sqrt(5) + 1) / 2
numberOfSeeds := 3000
for i := 0; i <= numberOfSeeds; i++ {
fi := float64(i)
fn := float64(numberOfSeeds)
r := math.Pow(fi, c) / fn
angle := 2 * math.Pi * c * fi
x := r*math.Sin(angle) + 200
y := r*math.Cos(angle) + 200
fi /= fn / 5
dc.DrawCircle(x, y, fi)
}
dc.SetLineWidth(1)
dc.Stroke()
dc.SavePNG("sunflower_fractal.png")
}

JavaScript[edit]

HTML to test

<!DOCTYPE html>
<html>
    <head>
        <meta charset="utf-8" />
        <meta http-equiv="X-UA-Compatible" content="IE=edge">
        <title>Vibrating rectangles</title>
        <meta name="viewport" content="width=device-width, initial-scale=1">
        <style>
            body{background-color:black;text-align:center;margin-top:150px}
        </style>
        <script src="sunflower.js"></script>
    </head>
    <body onload="start()">
        <div id='wnd'></div>
    </body>
</html>
 
const SIZE = 400, HS = SIZE >> 1, WAIT = .005, SEEDS = 3000,
TPI = Math.PI * 2, C = (Math.sqrt(10) + 1) / 2;
class Sunflower {
constructor() {
this.wait = WAIT;
this.colorIndex = 0;
this.dimension = 0;
this.lastTime = 0;
this.accumulator = 0;
this.deltaTime = 1 / 60;
this.colors = ["#ff0000", "#ff8000", "#ffff00", "#80ff00", "#00ff00", "#00ff80",
"#00ffff", "#0080ff", "#0000ff", "#8000ff", "#ff00ff", "#ff0080"];
this.canvas = document.createElement('canvas');
this.canvas.width = SIZE;
this.canvas.height = SIZE;
const d = document.getElementById("wnd");
d.appendChild(this.canvas);
this.ctx = this.canvas.getContext('2d');
}
draw(clr, d) {
let r = Math.pow(d, C) / SEEDS;
let angle = TPI * C * d;
let x = HS + r * Math.sin(angle),
y = HS + r * Math.cos(angle);
this.ctx.strokeStyle = clr;
this.ctx.beginPath();
this.ctx.arc(x, y, d / (SEEDS / 50), 0, TPI);
this.ctx.closePath();
this.ctx.stroke();
}
update(dt) {
if((this.wait -= dt) < 0) {
this.draw(this.colors[this.colorIndex], this.dimension);
this.wait = WAIT;
if((this.dimension++) > 600) {
this.dimension = 0;
this.colorIndex = (this.colorIndex + 1) % this.colors.length;
}
}
}
start() {
this.loop = (time) => {
this.accumulator += (time - this.lastTime) / 1000;
while(this.accumulator > this.deltaTime) {
this.accumulator -= this.deltaTime;
this.update(Math.min(this.deltaTime));
}
this.lastTime = time;
requestAnimationFrame(this.loop);
}
this.loop(0);
}
}
function start() {
const sunflower = new Sunflower();
sunflower.start();
}
 
 

Microsoft Small Basic[edit]

Translation of: Ring
' Sunflower fractal - 24/07/2018
GraphicsWindow.Width=410
GraphicsWindow.Height=400
c=(Math.SquareRoot(5)+1)/2
numberofseeds=3000
For i=0 To numberofseeds
r=Math.Power(i,c)/numberofseeds
angle=2*Math.Pi*c*i
x=r*Math.Sin(angle)+200
y=r*Math.Cos(angle)+200
GraphicsWindow.DrawEllipse(x, y, i/numberofseeds*10, i/numberofseeds*10)
EndFor
Output:

Sunflower fractal

Perl[edit]

Translation of: Sidef
use utf8;
use constant π => 3.14159265;
use constant φ => (1 + sqrt(5)) / 2;
 
my $scale = 600;
my $seeds = 5*$scale;
 
print qq{<svg xmlns="http://www.w3.org/2000/svg" width="$scale" height="$scale" style="stroke:gold">
<rect width="100%" height="100%" fill="black" />\n};
 
for $i (1..$seeds) {
$r = 2 * ($i**φ) / $seeds;
$t = 2 * π * φ * $i;
$x = $r * sin($t) + $scale/2;
$y = $r * cos($t) + $scale/2;
printf qq{<circle cx="%.2f" cy="%.2f" r="%.1f" />\n}, $x, $y, sqrt($i)/13;
}
 
print "</svg>\n";

See Phi-packing image (SVG image)

Perl 6[edit]

Works with: Rakudo version 2018.06

This is not really a fractal. It is more accurately an example of a Fibonacci spiral or Phi-packing.

Or, to be completely accurate: It is a variation of a generative Fermat's spiral using the Vogel model to implement phi-packing. See: https://thatsmaths.com/2014/06/05/sunflowers-and-fibonacci-models-of-efficiency

use SVG;
 
my $seeds = 3000;
my @center = 300, 300;
my $scale = 5;
 
constant= (3 - 5.sqrt) / 2;
 
my @c = map {
my ($x, $y) = ($scale * .sqrt) «*« |cis($_ * φ * τ).reals »+« @center;
[ $x.round(.01), $y.round(.01), (.sqrt * $scale / 100).round(.1) ]
}, 1 .. $seeds;
 
say SVG.serialize(
svg => [
:600width, :600height, :style<stroke:yellow>,
:rect[:width<100%>, :height<100%>, :fill<black>],
|@c.map( { :circle[:cx(.[0]), :cy(.[1]), :r(.[2])] } ),
],
);

See: Phi packing (SVG image)

Ring[edit]

 
# Project : Sunflower fractal
 
load "guilib.ring"
 
paint = null
 
new qapp
{
win1 = new qwidget() {
setwindowtitle("Sunflower fractal")
setgeometry(100,100,320,500)
label1 = new qlabel(win1) {
setgeometry(10,10,400,400)
settext("")
}
new qpushbutton(win1) {
setgeometry(100,400,100,30)
settext("draw")
setclickevent("draw()")
}
show()
}
exec()
}
 
func draw
p1 = new qpicture()
color = new qcolor() {
setrgb(0,0,255,255)
}
pen = new qpen() {
setcolor(color)
setwidth(1)
}
paint = new qpainter() {
begin(p1)
setpen(pen)
 
c = (sqrt(5) + 1) / 2
numberofseeds = 3000
for i = 0 to numberofseeds
r = pow(i, c ) / (numberofseeds)
angle = 2 * 3.14 * c * i
x = r * sin(angle) + 100
y = r * cos(angle) + 100
drawellipse(x, y, i / (numberofseeds / 10), i / (numberofseeds / 10))
next
 
endpaint()
}
label1 { setpicture(p1) show() }
 

Output:

Sunflower fractal

Sidef[edit]

Translation of: Go
require('Imager')
 
func draw_sunflower(seeds=3000) {
var img = %O<Imager>.new(
xsize => 400,
ysize => 400,
)
 
var c = (sqrt(1.25) + 0.5)
{ |i|
var r = (i**c / seeds)
var θ = (2 * Num.pi * c * i)
var x = (r * sin(θ) + 200)
var y = (r * cos(θ) + 200)
img.circle(x => x, y => y, r => i/(5*seeds))
} * seeds
 
return img
}
 
var img = draw_sunflower()
img.write(file => "sunflower.png")

Output image: Sunflower fractal

zkl[edit]

Translation of: Go

Uses Image Magick and the PPM class from http://rosettacode.org/wiki/Bitmap/Bresenham%27s_line_algorithm#zkl

fcn sunflower(seeds=3000){
img,color := PPM(400,400), 0x00ff00; // green
c:=((5.0).sqrt() + 1)/2;
foreach n in ([0.0 .. seeds]){ // floats
r:=n.pow(c)/seeds;
x,y := r.toRectangular(r.pi*c*n*2);
r=(n/seeds*5).toInt();
img.circle(200 + x, 200 + y, r,color);
}
img.writeJPGFile("sunflower.zkl.jpg");
}();
Output:

Image at sunflower fractal