Sunflower fractal

From Rosetta Code
Revision as of 03:15, 29 September 2018 by SqrtNegInf (talk | contribs) (→‎{{header|Perl}}: removed print handle, add link to image)
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

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.

<lang C> /*Abhishek Ghosh, 14th September 2018*/

  1. include<graphics.h>
  2. include<math.h>
  1. 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; } </lang>

Go

Library: Go Graphics
Translation of: Ring


The image produced, when viewed with (for example) EOG, is similar to the Ring entry. <lang go>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")

}</lang>

JavaScript

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>

<lang javascript> 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();

}

</lang>

Microsoft Small Basic

Translation of: Ring

<lang smallbasic>' 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 </lang>
Output:

Sunflower fractal

Perl

Translation of: Sidef

<lang perl>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 F qq{<circle cx="%.2f" cy="%.2f" r="%.1f" />\n}, $x, $y, sqrt($i)/13;

}

print "</svg>\n";</lang> See Phi-packing image (SVG image)

Perl 6

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

<lang perl6>use SVG;

my $seeds = 3000; my @center = 300, 300; my $scale = 5;

constant \φ = (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])] } ),
   ],

);</lang> See: Phi packing (SVG image)

Ring

<lang ring>

  1. 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() }

</lang> Output:

Sunflower fractal

Sidef

Translation of: Go

<lang ruby>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")</lang> Output image: Sunflower fractal

zkl

Translation of: Go

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

}();</lang>

Output:

Image at sunflower fractal

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