Peano curve: Difference between revisions
→{{header|Fōrmulæ}}: added Peano-Meander variant by L-system
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PDF.Close;
end Peano_Curve;</syntaxhighlight>
=={{header|ALGOL 68}}==
{{libheader|ALGOL 68-l-system}}
Generates an SVG file containing the curve using the L-System. Very similar to the Algol 68 Sierpinski square curve sample. Note the Algol 68 L-System library source code is on a separate page on Rosetta Code - follow the above link and then to the Talk page.<syntaxhighlight lang="algol68">
BEGIN # Peano Curve in SVG #
# uses the RC Algol 68 L-System library for the L-System evaluation & #
# interpretation #
PR read "lsystem.incl.a68" PR # include L-System utilities #
PROC peano curve = ( STRING fname, INT size, length, order, init x, init y )VOID:
IF FILE svg file;
BOOL open error := IF open( svg file, fname, stand out channel ) = 0
THEN
# opened OK - file already exists and #
# will be overwritten #
FALSE
ELSE
# failed to open the file #
# - try creating a new file #
establish( svg file, fname, stand out channel ) /= 0
FI;
open error
THEN # failed to open the file #
print( ( "Unable to open ", fname, newline ) );
stop
ELSE # file opened OK #
REAL x := init x;
REAL y := init y;
INT angle := 90;
put( svg file, ( "<svg xmlns='http://www.w3.org/2000/svg' width='"
, whole( size, 0 ), "' height='", whole( size, 0 ), "'>"
, newline, "<rect width='100%' height='100%' fill='white'/>"
, newline, "<path stroke-width='1' stroke='black' fill='none' d='"
, newline, "M", whole( x, 0 ), ",", whole( y, 0 ), newline
)
);
LSYSTEM ssc = ( "L"
, ( "L" -> "LFRFL-F-RFLFR+F+LFRFL"
, "R" -> "RFLFR+F+LFRFL-F-RFLFR"
)
);
STRING curve = ssc EVAL order;
curve INTERPRET ( ( CHAR c )VOID:
IF c = "F" THEN
x +:= length * cos( angle * pi / 180 );
y +:= length * sin( angle * pi / 180 );
put( svg file, ( " L", whole( x, 0 ), ",", whole( y, 0 ), newline ) )
ELIF c = "+" THEN
angle +:= 90 MODAB 360
ELIF c = "-" THEN
angle -:= 90 MODAB 360
FI
);
put( svg file, ( "'/>", newline, "</svg>", newline ) );
close( svg file )
FI # sierpinski square # ;
peano curve( "peano.svg", 1200, 12, 3, 50, 50 )
END
</syntaxhighlight>
=={{header|AutoHotkey}}==
Line 379 ⟶ 444:
{{out}}
[[Media:Peano_curve_cpp.svg]]
=={{header|EasyLang}}==
[https://easylang.online/show/#cod=jZK9boMwFIV3P8WRhbogrKQ/QwavnphYIwYXnMaqY5BNArx95YAJoR06INnnfNzje3Vb11QwfvRqaGHUTRkwyEE3lwTuapRPjiUYAXBqHAy6ZqKCAkDaBByUztfAVAm0he9cdZbOz7Vmf0Y0OPbwnWrxOlW0S9iDBKBPUdclOKrkyQVCGF8QpNiXW+LTKfmN/ZPMyF/H0MvLKiRavpdtHIm0d5cRRto4udrJPvoDRkj7BTb9bbRVva67M3bsLQiX5qYCRP4xLH2a2qOCPh45IOWoGo9au4c6BtVr+6yG9BgGQJmlYraqWGuHjIdX/+bSDZeuORYnMffOQXNKlqXhOAYBNBeFyDORFSIXRSrS+52CFuFba5GhKElcyfftMpLtyD9w2OGwI+QH Run it]
<syntaxhighlight>
proc lsysexp level . axiom$ rules$[] .
for l to level
an$ = ""
for c$ in strchars axiom$
for i = 1 step 2 to len rules$[]
if rules$[i] = c$
c$ = rules$[i + 1]
break 1
.
.
an$ &= c$
.
swap axiom$ an$
.
.
proc lsysdraw axiom$ x y ang . .
linewidth 0.3
move x y
for c$ in strchars axiom$
if c$ = "F"
x += cos dir
y += sin dir
line x y
elif c$ = "-"
dir -= ang
elif c$ = "+"
dir += ang
.
.
.
axiom$ = "L"
rules$[] = [ "L" "LFRFL-F-RFLFR+F+LFRFL" "R" "RFLFR+F+LFRFL-F-RFLFR" ]
lsysexp 4 axiom$ rules$[]
lsysdraw axiom$ 5 90 90
</syntaxhighlight>
=={{header|Factor}}==
Line 429 ⟶ 534:
=={{header|Fōrmulæ}}==
{{FormulaeEntry|page=https://formulae.org/?script=examples/Peano_curve}}
'''Solution'''
=== Peano-Meander variant, by recursion ===
[[File:Fōrmulæ - Peano curve 01.png]]
[[File:Fōrmulæ - Peano curve 02.png]]
[[File:Fōrmulæ - Peano curve 03.png]]
'''Test cases'''
=== Peano-Meander variant, by L-system ===
There are generic functions written in Fōrmulæ to compute an L-system in the page [[L-system#Fōrmulæ | L-system]].
The program that creates a Peano-Meander curve is:
[[File:Fōrmulæ - L-system - Peano-Meander curve 01.png]]
[[File:Fōrmulæ - L-system - Peano-Meander curve 02.png]]
=== Switch-back variant, by L-system ===
The program that creates a Switch-back Peano curve is:
[[File:Fōrmulæ - L-system - Peano Curve 01.png]]
[[File:Fōrmulæ - L-system - Peano Curve 02.png]]
=={{header|FreeBASIC}}==
Line 462 ⟶ 593:
Sleep</syntaxhighlight>
=={{header|FutureBasic}}==
Couldn't help adding a little bling.
<syntaxhighlight lang="futurebasic">
_window = 1
_curveSize = 7
_curveOrder = 3 * 3 * 3 * 3 // 3^4
void local fn BuildWindow
CGRect r = fn CGRectMake( 0, 0, 565, 570 )
window _window, @"Peano Curve In FutureBasic", r, NSWindowStyleMaskTitled
WindowSetBackgroundColor( _window, fn ColorBlack )
end fn
local fn Peano( x as long, y as long, lg as long, i1 as long, i2 as long )
ColorRef color = fn ColorRed
if ( lg == 1 ) then line to x * _curveSize, y * _curveSize : exit fn
lg /= 3
select ( rnd(8) )
case 1 : color = fn ColorBrown
case 2 : color = fn ColorRed
case 3 : color = fn ColorOrange
case 4 : color = fn ColorYellow
case 5 : color = fn ColorGreen
case 6 : color = fn ColorBlue
case 7 : color = fn ColorPurple
case 8 : color = fn ColorWhite
end select
pen 2, color
fn Peano( x + 2*i1* lg, y + 2*i1* lg, lg, i1, i2 )
fn Peano( x + (i1-i2+1)*lg, y + (i1+i2)* lg, lg, i1, 1-i2 )
fn Peano( x + lg, y + lg, lg, i1, 1-i2 )
fn Peano( x + (i1+i2)* lg, y + (i1-i2+1)*lg, lg, 1-i1, 1-i2 )
fn Peano( x + 2*i2* lg, y + 2*(1-i2)* lg, lg, i1, i2 )
fn Peano( x + (1+i2-i1)*lg, y + (2-i1-i2)*lg, lg, i1, i2 )
fn Peano( x + 2*(1-i1)* lg, y + 2*(1-i1)* lg, lg, i1, i2 )
fn Peano( x + (2-i1-i2)*lg, y + (1+i2-i1)*lg, lg, 1-i1, i2 )
fn Peano( x + 2*(1-i2)* lg, y + 2*i2* lg, lg, 1-i1, i2 )
end fn
randomize
fn BuildWindow
fn Peano( 0, 0, _curveOrder, 0, 0 )
HandleEvents
</syntaxhighlight>
{{output}}
[[File:Rosetta_Code_Peano_Curve_rev.png]]
=={{header|Go}}==
Line 1,404 ⟶ 1,585:
{{output}}
[[File:Quackery Peano curve.png]]
=={{header|R}}==
Line 1,678 ⟶ 1,859:
{{out}}
[[Media:Peano_curve_rust.svg]]
=={{header|Sidef}}==
Line 1,863 ⟶ 2,044:
{{trans|Go}}
{{libheader|DOME}}
<syntaxhighlight lang="
import "dome" for Window
Line 1,907 ⟶ 2,088:
static draw(dt) {}
}</syntaxhighlight>
=={{header|XPL0}}==
{{trans|C}}
<syntaxhighlight lang "XPL0">proc Peano(X, Y, Lg, I1, I2);
int X, Y, Lg, I1, I2;
[if Lg = 1 then
[Line(3*X, 3*Y, 11 \cyan\);
return;
];
Lg:= Lg/3;
Peano(X + 2*I1* Lg, Y + 2*I1* Lg, Lg, I1, I2);
Peano(X + (I1-I2+1)*Lg, Y + (I1+I2)* Lg, Lg, I1, 1-I2);
Peano(X + Lg, Y + Lg, Lg, I1, 1-I2);
Peano(X + (I1+I2)* Lg, Y + (I1-I2+1)*Lg, Lg, 1-I1, 1-I2);
Peano(X + 2*I2* Lg, Y + 2*(1-I2)* Lg, Lg, I1, I2);
Peano(X + (1+I2-I1)*Lg, Y + (2-I1-I2)*Lg, Lg, I1, I2);
Peano(X + 2*(1-I1)* Lg, Y + 2*(1-I1)* Lg, Lg, I1, I2);
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);
];
[SetVid($13);
Peano(0, 0, 3*3*3*3, 0, 0); \start Peano recursion
]</syntaxhighlight>
{{out}}
[[File:PianoXPL0.gif]]
=={{header|Yabasic}}==
|