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var w = window.innerWidth; |
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var h = window.innerHeight; |
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var r = 3; // point size |
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// the "radius" of the spiral |
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var n = d3.min([w, h]) / (r*2) |
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// Get Fibonacci numbers up to the maximum number in the spiral |
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var fib = [0, 1] |
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while (fib[fib.length-1] < Math.pow(2 * n, 2)) { |
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fib.push(fib[fib.length-1] + fib[fib.length-2]) |
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} |
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// create svg |
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var svg = d3.select("#svgDiv") |
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.append("svg") |
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.attr("width", w) |
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.attr("height", h); |
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// create array with locations on the spiral |
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var xloc = [0] |
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var yloc = [0] |
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for (var i = 1; i <= n; i++) { |
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// odd: down, right |
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// even: up, left |
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// odd |
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if (i % 2 != 0) { |
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// down |
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var x = xloc[xloc.length - 1] // get last item in xloc (current coordinate) |
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var y = yloc[yloc.length - 1] |
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for (var j = 1; j <= i; j++) { |
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xloc.push(x) |
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yloc.push(y + j) |
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} |
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// right |
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var x = xloc[xloc.length - 1] |
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var y = yloc[yloc.length - 1] |
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for (var j = 1; j <= i; j++) { |
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xloc.push(x + j) |
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yloc.push(y) |
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} |
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} |
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else { |
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// up |
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var x = xloc[xloc.length - 1] |
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var y = yloc[yloc.length - 1] |
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for (var j = 1; j <= i; j++) { |
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xloc.push(x) |
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yloc.push(y - j) |
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} |
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// left |
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var x = xloc[xloc.length - 1] |
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var y = yloc[yloc.length - 1] |
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for (var j = 1; j <= i; j++) { |
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xloc.push(x - j) |
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yloc.push(y) |
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} |
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} |
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} |
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var index = 0; |
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var timer = setInterval(addCircle) |
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function addCircle() { |
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svg.append('circle') |
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.attr('cx', (w/2) + r * 2 * xloc[index]) |
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.attr('cy', (h/2) + r * 2 * yloc[index]) |
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.attr('r', r) |
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.style('fill', (isPrime(index+1) ? |
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(isFibonacci(index+1) ? "#f9320c" : "#f9c00c") : // prime + fib t/f |
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(isFibonacci(index+1) ? "#00b9f1" : '#ddd')) // not prime + fib t/f |
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) |
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.append('svg:title') |
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.text(index+1) |
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index++ |
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if (index >= xloc.length - 1) {clearInterval(timer)} |
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} |
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// https://forum.tutorials7.com/1896/check-if-a-number-is-prime-in-javascript |
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function isPrime(input) { |
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let prime = true; |
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for (let i = 2; i <= Math.sqrt(input); i++) { |
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if (input % i == 0) { |
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prime = false; |
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break; |
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} |
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} |
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return prime && (input > 1); |
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} |
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function isFibonacci(input) { |
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return fib.includes(input) |
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} |
