This exercise allows to displace circles in a non-overlapping way. The collision detection introduced in this gist has been used in order to guarantee a certain padding between circles. The slider on the top allows to change the padding distance between circles.
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January 31, 2024 07:39
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Non-overlapping circles through collision detection
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| .node { | |
| fill: steelblue; | |
| } | |
| .axis .domain { | |
| fill: none; | |
| stroke: #000; | |
| stroke-opacity: .3; | |
| stroke-width: 10px; | |
| stroke-linecap: round; | |
| } | |
| .axis .halo { | |
| fill: none; | |
| stroke: #ddd; | |
| stroke-width: 8px; | |
| stroke-linecap: round; | |
| } | |
| .slider .handle { | |
| fill: #fff; | |
| stroke: #000; | |
| stroke-opacity: .5; | |
| stroke-width: 1.25px; | |
| cursor: crosshair; | |
| } |
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| <!DOCTYPE html> | |
| <html> | |
| <head> | |
| <meta charset="utf-8"> | |
| <script src="http://d3js.org/d3.v3.min.js"></script> | |
| <link rel="stylesheet" type="text/css" href="index.css"> | |
| <title>Collision detection with force layout</title> | |
| </head> | |
| <body> | |
| <script src="index.js"></script> | |
| </body> | |
| </html> |
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| var width = 960, | |
| height = 500, | |
| padding = 10, | |
| min_padding = 0, | |
| max_padding = 50, | |
| maxRadius = 10, | |
| n = 200; | |
| var nodes = d3.range(n).map(function(i) { | |
| var r = Math.sqrt(1 / 1 * -Math.log(Math.random())) * maxRadius, | |
| d = {id: i, radius: r, cx: width/2+Math.random()*150-75, cy: height/2+Math.random()*150-75}; | |
| return d; | |
| }); | |
| nodes.forEach(function(d) { d.x = d.cx; d.y = d.cy; }); | |
| var svg = d3.select("body").append("svg") | |
| .attr("width", width) | |
| .attr("height", height); | |
| var circle = svg.selectAll("circle") | |
| .data(nodes); | |
| var enter_circle = circle.enter().append("circle") | |
| .attr('class', 'node'); | |
| enter_circle | |
| .attr("r", function(d) { return d.radius; }) | |
| .attr("cx", function(d) { return d.cx; }) | |
| .attr("cy", function(d) { return d.cy; }); | |
| var force = d3.layout.force() | |
| .nodes(nodes) | |
| .size([width, height]) | |
| .gravity(.02) | |
| .charge(0) | |
| .on("tick", tick) | |
| .start(); | |
| force.alpha(.05); | |
| function tick(e) { | |
| //force.alpha(.01); | |
| circle | |
| .each(gravity(.2 * e.alpha)) | |
| .each(collide(.5)) | |
| .attr("cx", function(d) { return d.x; }) | |
| .attr("cy", function(d) { return d.y; }); | |
| } | |
| /* SLIDER | |
| */ | |
| var x = d3.scale.linear() | |
| .domain([min_padding, max_padding]) | |
| .range([0, width/2]) | |
| .clamp(true); | |
| svg.append("g") | |
| .attr("class", "x axis") | |
| .attr("transform", "translate(10, 10)") | |
| .call(d3.svg.axis() | |
| .scale(x) | |
| .ticks(0) | |
| .tickSize(0)) | |
| .select(".domain") | |
| .select(function() { return this.parentNode.appendChild(this.cloneNode(true)); }) | |
| .attr("class", "halo"); | |
| var brush = d3.svg.brush() | |
| .x(x) | |
| .extent([0, 0]) | |
| .on("brush", brushed); | |
| var slider = svg.append("g") | |
| .attr("class", "slider") | |
| .call(brush); | |
| slider.selectAll(".extent,.resize") | |
| .remove(); | |
| var handle = slider.append("circle") | |
| .attr("class", "handle") | |
| .attr("transform", "translate(10, 10)") | |
| .attr("r", 9); | |
| slider | |
| .call(brush.event); | |
| function brushed() { | |
| var value = brush.extent()[0]; | |
| if (d3.event.sourceEvent) { | |
| value = x.invert(d3.mouse(this)[0]); | |
| brush.extent([value, value]); | |
| force.alpha(.01); | |
| } | |
| handle.attr("cx", x(value)); | |
| padding = value; | |
| } | |
| // Resolve collisions between nodes. | |
| function collide(alpha) { | |
| var quadtree = d3.geom.quadtree(nodes); | |
| return function(d) { | |
| var r = d.radius + maxRadius + padding, | |
| nx1 = d.x - r, | |
| nx2 = d.x + r, | |
| ny1 = d.y - r, | |
| ny2 = d.y + r; | |
| quadtree.visit(function(quad, x1, y1, x2, y2) { | |
| if (quad.point && (quad.point !== d)) { | |
| var x = d.x - quad.point.x, | |
| y = d.y - quad.point.y, | |
| l = Math.sqrt(x * x + y * y), | |
| r = d.radius + quad.point.radius + padding; | |
| if (l < r) { | |
| l = (l - r) / l * alpha; | |
| d.x -= x *= l; | |
| d.y -= y *= l; | |
| quad.point.x += x; | |
| quad.point.y += y; | |
| } | |
| } | |
| return x1 > nx2 || x2 < nx1 || y1 > ny2 || y2 < ny1; | |
| }); | |
| }; | |
| } | |
| // Move nodes toward cluster focus. | |
| function gravity(alpha) { | |
| return function(d) { | |
| d.y += (d.cy - d.y) * alpha; | |
| d.x += (d.cx - d.x) * alpha; | |
| }; | |
| } |
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