Peano curve: Difference between revisions

 

Produce a graphical or ASCII-art representation of a [[wp:Peano curve|Peano curve]] of at least order 3.

 

=={{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|Fōrmulæ}}==

 

 

 

 

=={{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

</pre>

 

=={{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%;">@ +---+ +---+ +---+ +---+ +---+ +---+ +---+ +---+ +---+ +---+ +---+ +---+ +---+

| | | | | | | | | | | | | | | | | | | | | | | | | | |

+---+ +---+ +---+ +---+ +---+ +---+ +---+ +---+ +---+ +---+ +---+ +---+ +---+ X</pre>

 

=={{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)

 

=={{header|Phix}}==

{{libheader|Phix/pGUI}}

Space key toggles between switchback and meander curves.

 

 

 

 

 

 

 

 

 

 

 

 

=={{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|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|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]