Peano curve: Difference between revisions
→{{header|jq}}: Add turtle graphics solution
(→{{header|jq}}: '''Adapted from #Go''') |
(→{{header|jq}}: Add turtle graphics solution) |
||
Line 567:
=={{header|jq}}==
'''Adapted from [[#Go]]'''▼
{{works with|jq}}
'''Works with gojq, the Go implementation of jq'''
This entry includes two distinct solutions. In both cases, the jq program generates
a SVG document, which can be viewed directly in the browser,
a .png version of the image can be viewed at https://imgur.com/a/RGQr17J▼
===Using a Lindenmayer System===
In this section, a Lindenmayer system of rules is used with turtle
graphics.
The output converted to a .png file can be viewed at https://imgur.com/gallery/4QbUN7I
====Simple Turtle Graphics====
<lang jq>
# => = 0 degrees
# ^ = 90 degrees
# <= = 180 degrees
# v = 270 degrees
# $start : [$x, $y]
def turtle($start):
$start
| if type == "array" then "M \($start|join(","))" else "M 0,0" end
| {svg: ., up:true, angle:0};
def turtleUp: .up=true;
def turtleDown: .up=false;
def turtleRotate($angle): .angle = (360 + (.angle + $angle)) % 360;
def turtleForward($d):
if .up
then if .angle== 0 then .svg += " m \($d),0"
elif .angle== 90 then .svg += " m 0,-\($d)"
elif .angle==180 then .svg += " m -\($d),0"
elif .angle==270 then .svg += " m 0,\($d)"
else "unsupported angle \(.angle)" | error
end
else if .angle== 0 then .svg += " h \($d)"
elif .angle== 90 then .svg += " v -\($d)"
elif .angle==180 then .svg += " h -\($d)"
elif .angle==270 then .svg += " v \($d)"
else "unsupported angle \(.angle)" | error
end
end;
def svg($size):
"<svg viewBox=\"0 0 \($size) \($size)\" xmlns=\"http://www.w3.org/2000/svg\">",
.,
"</svg>";
def path($fill; $stroke):
"<path fill=\"\($fill)\" stroke=\"\($stroke)\" stroke-width=\"0.1\" d=\"\(.svg)\" />";
def draw:
path("none"; "red") | svg(100) ;</lang>
====Peano Curve====
<lang jq># Compute the curve using a Lindenmayer system of rules
def rules:
{ L: "LFRFL-F-RFLFR+F+LFRFL",
R: "RFLFR+F+LFRFL-F-RFLFR" } ;
def peano($count):
rules as $rules
| def p($count):
if $count <= 0 then .
else gsub("L"; "l") | gsub("R"; $rules["R"]) | gsub("l"; $rules["L"]) | p($count-1)
end;
"L" | p($count) ;
def interpret($x):
if $x == "+" then turtleRotate(90)
elif $x == "-" then turtleRotate(-90)
elif $x == "F" then turtleForward(1)
else .
end;
def peano_curve($n):
peano($n)
| split("")
| reduce .[] as $action (turtle([1,1]) | turtleDown;
interpret($action) ) ;
peano_curve(4)
| draw</lang>
{{out}}
See https://imgur.com/gallery/4QbUN7I
===Peano-Meander curve===
▲'''Adapted from [[#Go]]'''
A .png version of the SVG image generated using an invocation
<pre>
jq -nr -f peano-curve.jq > peano-curve.svg
| |||