Created
December 15, 2014 17:39
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Hilbert curve generator using Javascript + SVG
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| <html> | |
| <head> | |
| <script type="text/javascript"> | |
| function createSVG(e) | |
| { | |
| return document.createElementNS("http://www.w3.org/2000/svg",e); | |
| } | |
| function left(v) | |
| { | |
| x = v[0]; | |
| y = v[1]; | |
| v[0] = y; | |
| v[1] = -x; | |
| } | |
| function right(v) | |
| { | |
| x = v[0]; | |
| y = v[1]; | |
| v[0] = -y; | |
| v[1] = x; | |
| } | |
| function A(list,v,k) | |
| { | |
| if (k > 0) | |
| { | |
| left(v); | |
| B(list,v,k-1); | |
| list.push([v[0],v[1]]); | |
| right(v); | |
| A(list,v,k-1); | |
| list.push([v[0],v[1]]); | |
| A(list,v,k-1); | |
| right(v); | |
| list.push([v[0],v[1]]); | |
| B(list,v,k-1); | |
| left(v); | |
| } | |
| } | |
| function B(list,v,k) | |
| { | |
| if (k > 0) | |
| { | |
| right(v); | |
| A(list,v,k-1); | |
| list.push([v[0],v[1]]); | |
| left(v); | |
| B(list,v,k-1); | |
| list.push([v[0],v[1]]); | |
| B(list,v,k-1); | |
| left(v); | |
| list.push([v[0],v[1]]); | |
| A(list,v,k-1); | |
| right(v); | |
| } | |
| } | |
| function doit() | |
| { | |
| var svgdiv = document.getElementById('svg1'); | |
| var r0 = 600; | |
| for (var k = 0; k < 9; ++k) | |
| { | |
| var list = []; | |
| var v = [1,0]; | |
| var f = Math.pow(0.5,k); | |
| var r = r0*f; | |
| A(list,v,k+1); | |
| var pathd = "M "+(r0*f/2)+" "+(2*r0 - r0*f/2)+" "; | |
| for (var i = 0; i < list.length; ++i) | |
| { | |
| var v = list[i]; | |
| pathd += 'l '+(v[0]*r)+' '+(v[1]*r)+' '; | |
| } | |
| console.log((list.length)+' points'); | |
| var subdiv = document.createElement('div'); | |
| var svg = createSVG('svg'); | |
| svg.setAttribute('width',r0*2); | |
| svg.setAttribute('height',r0*2); | |
| var c = createSVG('path'); | |
| c.setAttribute('d',pathd); | |
| c.setAttribute('stroke','green'); | |
| c.setAttribute('stroke-width',1); | |
| c.setAttribute('fill','none'); | |
| svg.appendChild(c); | |
| var text = document.createTextNode('Hilbert curve, iteration '+(k+1)+', '+list.length+' points'); | |
| var p = document.createElement('p'); | |
| p.appendChild(text); | |
| subdiv.appendChild(p); | |
| subdiv.appendChild(svg); | |
| svgdiv.appendChild(subdiv); | |
| } | |
| } | |
| window.onload = doit; | |
| </script> | |
| </head> | |
| <body> | |
| <div id="svg1"></div> | |
| </body> | |
| </html> |
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