Move your mouse to edit the size of the circle
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January 3, 2018 14:21
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Fixed arcs in a variable circle
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| license: mit | |
| border: no | |
| scrolling: no |
This file contains hidden or bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
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| <!DOCTYPE html> | |
| <head> | |
| <meta charset="utf-8"> | |
| <script src="https://d3js.org/d3.v4.min.js"></script> | |
| <style> | |
| body { font-family:sans-serif; margin:0;position:fixed;top:0;right:0;bottom:0;left:0; } | |
| circle {fill:none; stroke:#000; stroke-width:2} | |
| text {text-anchor:middle} | |
| line {stroke:#000} | |
| </style> | |
| </head> | |
| <body> | |
| <script> | |
| var radius = 117; | |
| const arcLength = 100 | |
| var arc = d3.arc(); | |
| var margin = { top: 0, right: 0, bottom: 0, left: 0 }, | |
| width = document.body.clientWidth - margin.left - margin.right, | |
| height = document.body.clientHeight - margin.top - margin.bottom; | |
| var startRadius; | |
| var svg = d3.select("body").append("svg") | |
| .attr("width", width) | |
| .attr("height", height) | |
| svg.append("circle").attr("cx", width/2).attr("cy", height/2) | |
| svg.append("line").attr("class", "radius").attr("x1", width/2).attr("y1", height/2).attr("y2", height/2) | |
| svg.append("text").attr("class", "radiusLabel") | |
| svg.append("text").attr("class", "circLabel") | |
| svg.append("text").attr("class", "arcsLabel").attr("x", width-20).attr("y", 30).style("text-anchor","end") | |
| svg.append("text").attr("class", "gapLabel").attr("x", width-20).attr("y", 60).style("text-anchor","end") | |
| d3.selectAll("body").call(d3.drag().on("start", dragStarted)); | |
| function dragStarted() { | |
| d3.event.on("drag", dragged) | |
| startRadius = radius; | |
| function dragged(d) { | |
| radius = Math.abs(startRadius - d3.event.x); | |
| update(); | |
| } | |
| } | |
| function update() { | |
| var circ = radius*Math.PI*2; | |
| var arcs = d3.range(0, Math.floor(circ/arcLength)); | |
| var arcDegrees = (arcLength / circ) * (Math.PI*2); | |
| var arcsEl = svg.selectAll(".arc").data(arcs) | |
| arcsEl.exit().remove() | |
| arcsEl.enter() | |
| .append("g") | |
| .attr("transform", `translate(${width/2}, ${height/2})`) | |
| .append("path") | |
| .attr("fill", "red").attr("class", "arc") | |
| arcsEl | |
| .attr("d", d=>{ | |
| var startAngle = (d / arcs.length) * Math.PI *2; | |
| var endAngle = startAngle + arcDegrees; | |
| return arc({ | |
| innerRadius: radius*1.03, | |
| outerRadius: radius*1.03+4, | |
| startAngle: startAngle, | |
| endAngle: endAngle | |
| }) | |
| }) | |
| svg.select(".radius").attr("x2", width/2 + radius) | |
| svg.select("circle").attr("r", radius) | |
| svg.select(".radiusLabel").text(`r = ${radius}`).attr("x", width/2).attr("y", height/2 -10 ) | |
| svg.select(".circLabel").text(`c = ${rd(circ)}`).attr("x", width/2+radius).attr("y", height/2+radius*1.1) | |
| svg.select(".arcsLabel").text(`${arcs.length} arcs of length ${arcLength}`) | |
| svg.select(".gapLabel").text(`${rd((circ - (arcLength*arcs.length))/(arcs.length-1))} gap between arcs`) | |
| } | |
| function rd(n) { | |
| return (Math.round(n*100)/100).toFixed(2); | |
| } | |
| update(); | |
| </script> | |
| </body> |
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