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<!DOCTYPE html> |
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<meta charset="utf-8"> |
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<body> |
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<script src="//d3js.org/d3.v4.js"></script> |
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<script> |
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var width = 960, |
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height = 500, |
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τ = 2 * Math.PI, |
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maxLength = 10000, |
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maxLength2 = maxLength * maxLength; |
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var nodes = d3.range(200).map(function() { |
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return { |
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x: (0.5 - Math.random()) * width, |
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y: (0.5 - Math.random()) * height |
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}; |
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}); |
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function windowCenter(){ |
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return [window.innerWidth/2, window.innerHeight/2]; |
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} |
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var force = d3.forceSimulation() |
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.nodes(nodes.slice()) |
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.force("link", d3.forceLink().id(function(d) { return d.id; })) |
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.force("charge", d3.forceManyBody().strength(function(d,i){ |
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return i ? -25 : -1000 |
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})) |
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.force("x", d3.forceX()) |
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.force("y", d3.forceY()) |
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.force("center", d3.forceCenter(0, 0)) |
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.on("tick", ticked); |
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var voronoi = d3.voronoi() |
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.x(function(d) { return d.x; }) |
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.y(function(d) { return d.y; }); |
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var canvas = d3.select("body").append("canvas") |
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.attr("width", width) |
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.attr("height", height) |
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.on("ontouchstart" in document ? "touchmove" : "mousemove", moved); |
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var context = canvas.node().getContext("2d"); |
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function moved() { |
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var p1 = d3.mouse(this); |
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nodes[0].fx = p1[0] - windowCenter()[0]; |
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nodes[0].fy = p1[1] - windowCenter()[1]; |
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force.alpha(0.1).restart(); |
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} |
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function urquhart(diagram){ |
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var urquhart = d3.map(); |
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diagram.links() |
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.forEach(function(link) { |
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var v = d3.extent([link.source.index, link.target.index]); |
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urquhart.set(v, link); |
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}); |
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urquhart._remove = []; |
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diagram.triangles() |
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.forEach(function(t) { |
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var l = 0, length = 0, i="bleh", v; |
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for (var j=0; j<3; j++) { |
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var a = t[j], b = t[(j+1)%3]; |
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v = d3.extent([a.index, b.index]); |
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length = (a.x-b.x) * (a.x-b.x) + (a.y-b.y) * (a.y-b.y); |
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if (length > l) { |
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l = length; |
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i = v; |
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} |
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} |
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urquhart._remove.push(i); |
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}); |
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//console.log(JSON.stringify(urquhart._remove)) |
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urquhart._remove.forEach(function(i) { |
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if (urquhart.has(i)) urquhart.remove(i); |
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}); |
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return urquhart.values(); |
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} |
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function ticked() { |
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var diagram = voronoi(nodes); |
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//var links = diagram.links(); |
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var links = urquhart(diagram); |
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let ctr = windowCenter(); |
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canvas .attr('width', ctr[0]*2) .attr('height', ctr[1]*2) |
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// setting width/height clear the canvas, so… |
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//context.clearRect(0, 0, ctr[0]*2, ctr[1]*2); |
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context.translate(ctr[0], ctr[1]); |
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context.beginPath(); |
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for (var i = 0, n = links.length; i < n; ++i) { |
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var link = links[i], |
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dx = link.source.x - link.target.x, |
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dy = link.source.y - link.target.y; |
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if (dx * dx + dy * dy < maxLength2) { |
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context.moveTo(link.source.x, link.source.y); |
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context.lineTo(link.target.x, link.target.y); |
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} |
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} |
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context.lineWidth = 1; |
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context.strokeStyle = "#bbb"; |
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context.stroke(); |
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context.beginPath(); |
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for (var i = 0, n = nodes.length; i < n; ++i) { |
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var node = nodes[i]; |
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context.moveTo(node.x, node.y); |
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context.arc(node.x, node.y, 2, 0, τ); |
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} |
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context.lineWidth = 3; |
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context.strokeStyle = "#fff"; |
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context.stroke(); |
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context.fillStyle = "#000"; |
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context.fill(); |
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// draw the center |
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context.beginPath(); |
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context.moveTo(0,0); |
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context.arc(0, 0, 4, 0, τ); |
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context.fillStyle = "red"; |
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context.fill(); |
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context.translate(-ctr[0], -ctr[1]); |
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} |
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</script> |