Peano curve: Difference between revisions

=={{header|Action!}}==

Action! language does not support recursion. Therefore an iterative approach with a stack has been proposed.

 

INT ARRAY

DO UNTIL CH#$FF OD

CH=$FF

{{out}}

[https://gitlab.com/amarok8bit/action-rosetta-code/-/raw/master/images/Peano_curve.png Screenshot from Atari 8-bit computer]

{{trans|C}}

{{libheader|APDF}}

 

procedure Peano_Curve is

Draw_Peano;

PDF.Close;

 

=={{header|AutoHotkey}}==

{{trans|C}}

Requires [https://www.autohotkey.com/boards/viewtopic.php?t=6517 Gdip Library]

PeanoX := A_ScreenWidth/2 - 100, PeanoY := A_ScreenHeight/2 - 100

Peano(PeanoX, PeanoY, 3**3, 5, 5, Arr:=[])

ExitApp

Return

 

=={{header|C}}==

Adaptation of the C program in the [https://www.researchgate.net/profile/Christoph_Schierz2/publication/228982573_A_recursive_algorithm_for_the_generation_of_space-filling_curves/links/0912f505c2f419782c000000/A-recursive-algorithm-for-the-generation-of-space-filling-curves.pdf Breinholt-Schierz paper] , requires the [http://www.cs.colorado.edu/~main/bgi/cs1300/ WinBGIm] library.

/*Abhishek Ghosh, 14th September 2018*/

 

return 0;

}

 

=={{header|C++}}==

#include <fstream>

#include <iostream>

pc.write(out, 656, 8, 4);

return 0;

 

{{out}}

 

=={{header|Factor}}==

{{works with|Factor|0.99 2020-08-14}}

 

: peano ( L-system -- L-system )

} >>rules ;

 

 

 

When using the L-system visualizer, the following controls apply:

=={{header|Fōrmulæ}}==

 

 

 

 

=={{header|FreeBASIC}}==

{{trans|Yabasic}}

 

Screenres 700,700

Peano(0, 0, anchura, 0, 0)

 

 

 

=={{header|Go}}==

<br>

The following is based on the recursive algorithm and C code in [https://www.researchgate.net/profile/Christoph_Schierz2/publication/228982573_A_recursive_algorithm_for_the_generation_of_space-filling_curves/links/0912f505c2f419782c000000/A-recursive-algorithm-for-the-generation-of-space-filling-curves.pdf this paper] scaled up to 81 x 81 points. The image produced is a variant known as a Peano-Meander curve (see Figure 1(b) [https://www5.in.tum.de/lehre/vorlesungen/asc/ss17/blatt10/ws10.pdf here]).

 

import "github.com/fogleman/gg"

dc.Stroke()

dc.SavePNG("peano.png")

 

=={{header|IS-BASIC}}==

110 OPTION ANGLE DEGREES

120 SET VIDEO MODE 5:SET VIDEO COLOR 0:SET VIDEO X 40:SET VIDEO Y 27

240 CALL PEANO(D,-A,LEV-1)

250 PLOT LEFT A;

 

=={{header|J}}==

This Hilbert variant is taken directly from the j lab "viewmat".

load'viewmat'

hp=: 3 : '(|.,]) 1 (0 _2 _2 ,&.> _2 _1 0 + #y) } (,.|:) y'

WR=: 16777215 16711680

viewrgb WR {~ hp ^:7 HP

 

hp=: 3 : '(|.,]) 1 (0 _2 _2 ,&.> _2 _1 0 + #y) } (,.|:) y'

MG=: 256 #. 128 0 128,:0 192 0

 

=={{header|Java}}==

Output is a file in SVG format.

 

public class PeanoCurve {

private int currentAngle;

private static final int ANGLE = 90;

 

{{out}}

 

=={{header|jq}}==

The output converted to a .png file can be viewed at https://imgur.com/gallery/4QbUN7I

====Simple Turtle Graphics====

# => = 0 degrees

# ^ = 90 degrees

 

def draw:

 

====Peano Curve====

def rules:

{ L: "LFRFL-F-RFLFR+F+LFRFL",

 

peano_curve(4)

{{out}}

See https://imgur.com/gallery/4QbUN7I

</pre>

 

# Output: the array augmented with another x,y pair

def peano($x; $y; $lg; $i1; $i2):

svg,

( path("none"; "red") + peanoCurve + endpath)

{{out}}

https://imgur.com/a/RGQr17J

=={{header|Julia}}==

The peano function is from the C version.

 

function peano(ctx, x, y, lg, i1, i2)

signal_connect(endit, win, :destroy)

wait(cond)

 

=={{header|Lua}}==

Using the Bitmap class [[Bitmap#Lua|here]], with an ASCII pixel representation, then extending..

axiom = "L",

rules = {

bitmap:clear(" ")

bitmap:drawPath(PeanoLSystem:eval(3), 0, 0, 0, 1)

{{out}}

<pre style="font-size:50%;">@ +---+ +---+ +---+ +---+ +---+ +---+ +---+ +---+ +---+ +---+ +---+ +---+ +---+

Draw to M2000 console (which has graphic capabilities). Sub is a copy from freebasic, changed *Line* statement to *Draw to*

 

Module Peano_curve {

Cls 1, 0

}

Peano_curve

 

=={{header|Mathematica}}/{{header|Wolfram Language}}==

{{out}}

Outputs a graphical representation of a 4th order PeanoCurve.

{{trans|Go}}

{{libheader|imageman}}

 

const Width = 81

for i in 1..points.high:

image.drawLine(points[i - 1], points[i], color)

 

=={{header|Perl}}==

use List::Util qw(max min);

 

open $fh, '>', 'peano_curve.svg';

print $fh $svg->xmlify(-namespace=>'svg');

[https://github.com/SqrtNegInf/Rosettacode-Perl5-Smoke/blob/master/ref/peano_curve.svg Peano curve] (offsite image)

 

You can run this online [http://phix.x10.mx/p2js/peano.htm here].

Space key toggles between switchback and meander curves.

<span style="color: #000080;font-style:italic;">--

-- demo\rosetta\peano_curve.exw

<span style="color: #000000;">main</span><span style="color: #0000FF;">()</span>

 

=={{header|Processing}}==

{{trans|C}}

//Abhishek Ghosh, 28th June 2022

 

Peano(0, 0, 1000, 0, 0);

}

 

=={{header|Prolog}}==

{{works with|SWI Prolog}}

write_peano_curve('peano_curve.svg', 656, 4).

 

execute(Stream, X, Y, Length, Angle1, Chars).

execute(Stream, X, Y, Length, Angle, [_|Chars]):-

 

{{out}}

 

=={{header|Python}}==

This implementation is, as I think, a variant of the Peano curve (just because it's different in the images). And it's supposed to be like a fullscreen app. And because of scale, the "steps" of the curve will be different in horizontal and vertical (it'll be quite nice if your screen is square :D). If <code>peano(4)</code> (in the last line of code) is runned with the input higher than 8, the void between the steps will be filled with steps, and the hole screen will fill (of course, this depends of your screen size). It's also produces a graphic with the current stack pilled, timed by the current function runned.

 

import turtle as tt

import inspect

P.plot(stack)

P.show()

 

You can see the output image [https://github.com/jlfcosta/Projeto_2019_v2/blob/master/Exerc%C3%ADcios/Curva%20de%20Peano/opahehe1.png <ins>here</ins>] and the output stack graphic [https://github.com/jlfcosta/Projeto_2019_v2/blob/master/Exerc%C3%ADcios/Curva%20de%20Peano/opahehestacks1.png <ins>here</ins>].

=={{header|Quackery}}==

 

[ stack ] is switch.arg ( --> [ )

char L case [ -1 4 turn ]

char R case [ 1 4 turn ]

 

{{output}}

 

 

=={{header|R}}==

 

 

#to install hilbercurve library, biocmanager needs to be installed first

install.packages("BiocManager")

peano = HilbertCurve(1, 512, level = 4, reference = TRUE, arrow = FALSE)

hc_points(peano, x1 = i, np = NULL, pch = 16, size = unit(3, "mm"))

 

=={{header|Racket}}==

 

See also https://pdfs.semanticscholar.org/fee6/187cc2dd1679d4976db9522b06a49f63be46.pdf

/* Jens Axel Søgaard, 27th December 2018*/

#lang racket

(peano 6 90 3)

(draw* c))

 

=={{header|Raku}}==

(formerly Perl 6)

{{works with|Rakudo|2018.06}}

 

role Lindenmayer {

:polyline[ :points(@points.join: ','), :fill<black> ],

],

 

See: [https://github.com/thundergnat/rc/blob/master/img/peano-perl6.svg Peano curve] (SVG image)

<br/>

Implemented as a Lindenmayer System, depends on JRuby or JRubyComplete see Hilbert for grammar

load_library :grammar

 

size(800, 800)

end

 

=={{header|Rust}}==

// svg = "0.8.0"

 

fn main() {

PeanoCurve::save("peano_curve.svg", 656, 4).unwrap();

 

{{out}}

 

=={{header|Sidef}}==

Uses the LSystem class defined at [https://rosettacode.org/wiki/Hilbert_curve#Sidef Hilbert curve].

l => 'lFrFl-F-rFlFr+F+lFrFl',

r => 'rFlFr+F+lFrFl-F-rFlFr',

)

 

Output image: [https://github.com/trizen/rc/blob/master/img/peano_curve-sidef.png Peano curve]

 

=={{header|VBA}}==

{{trans|C}}

Dim n As Long

Dim points() As Single

Call Peano(0, 0, WIDTH, 0, 0) 'Start Peano recursion to generate and store points

ActiveSheet.Shapes.AddPolyline points 'Excel assumed

 

=={{header|VBScript}}==

 

option explicit

peano 7,1

set x=nothing 'show image in browser

 

=={{header|Wren}}==

{{trans|Go}}

{{libheader|DOME}}

import "dome" for Window

 

 

static draw(dt) {}

 

=={{header|Yabasic}}==

{{trans|VBA}}

 

open window 700, 700

Peano(x + ((2 - i1 - i2) * lg), y + ((1 + i2 - i1) * lg), lg, 1 - i1, i2)

Peano(x + (2 * (1 - i2) * lg), y + (2 * i2 * lg), lg, 1 - i1, i2)

 

=={{header|zkl}}==

Using a Lindenmayer system and turtle graphics & turned 90°:

Dictionary("L","LFRFL-F-RFLFR+F+LFRFL", "R","RFLFR+F+LFRFL-F-RFLFR"), # rules

"+-F", 4) // constants, order

}

buf1.text // n=4 --> 16,401 characters

Using Image Magick and

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

const D=10.0;

dir,angle, x,y := 0.0, (90.0).toRad(), 20.0, 830.0; // turtle; x,y are float

}

img.writeJPGFile("peanoCurve.zkl.jpg");

{{out}}

Image at [http://www.zenkinetic.com/Images/RosettaCode/peanoCurve.zkl.jpg Peano curve]