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// https://observablehq.com/@d3/zoomable-sunburst@357
function _1(md){return(
md`# Zoomable Sunburst

This variant of a [sunburst diagram](/@d3/sunburst) shows only two layers of the hierarchy at a time. Click a node to zoom in, or the center to zoom out. Compare to an [icicle](/@d3/zoomable-icicle).`
)}

function _chart(partition,data,d3,width,color,arc,format,radius)
{
  const root = partition(data);

  root.each(d => d.current = d);

  const svg = d3.create("svg")
      .attr("viewBox", [0, 0, width, width])
      .style("font", "10px sans-serif");

  const g = svg.append("g")
      .attr("transform", `translate(${width / 2},${width / 2})`);

  const path = g.append("g")
    .selectAll("path")
    .data(root.descendants().slice(1))
    .join("path")
      .attr("fill", d => { while (d.depth > 1) d = d.parent; return color(d.data.name); })
      .attr("fill-opacity", d => arcVisible(d.current) ? (d.children ? 0.6 : 0.4) : 0)
      .attr("pointer-events", d => arcVisible(d.current) ? "auto" : "none")

      .attr("d", d => arc(d.current));

  path.filter(d => d.children)
      .style("cursor", "pointer")
      .on("click", clicked);

  path.append("title")
      .text(d => `${d.ancestors().map(d => d.data.name).reverse().join("/")}\n${format(d.value)}`);

  const label = g.append("g")
      .attr("pointer-events", "none")
      .attr("text-anchor", "middle")
      .style("user-select", "none")
    .selectAll("text")
    .data(root.descendants().slice(1))
    .join("text")
      .attr("dy", "0.35em")
      .attr("fill-opacity", d => +labelVisible(d.current))
      .attr("transform", d => labelTransform(d.current))
      .text(d => d.data.name);

  const parent = g.append("circle")
      .datum(root)
      .attr("r", radius)
      .attr("fill", "none")
      .attr("pointer-events", "all")
      .on("click", clicked);

  function clicked(event, p) {
    parent.datum(p.parent || root);

    root.each(d => d.target = {
      x0: Math.max(0, Math.min(1, (d.x0 - p.x0) / (p.x1 - p.x0))) * 2 * Math.PI,
      x1: Math.max(0, Math.min(1, (d.x1 - p.x0) / (p.x1 - p.x0))) * 2 * Math.PI,
      y0: Math.max(0, d.y0 - p.depth),
      y1: Math.max(0, d.y1 - p.depth)
    });

    const t = g.transition().duration(750);

    // Transition the data on all arcs, even the ones that aren’t visible,
    // so that if this transition is interrupted, entering arcs will start
    // the next transition from the desired position.
    path.transition(t)
        .tween("data", d => {
          const i = d3.interpolate(d.current, d.target);
          return t => d.current = i(t);
        })
      .filter(function(d) {
        return +this.getAttribute("fill-opacity") || arcVisible(d.target);
      })
        .attr("fill-opacity", d => arcVisible(d.target) ? (d.children ? 0.6 : 0.4) : 0)
        .attr("pointer-events", d => arcVisible(d.target) ? "auto" : "none") 

        .attrTween("d", d => () => arc(d.current));

    label.filter(function(d) {
        return +this.getAttribute("fill-opacity") || labelVisible(d.target);
      }).transition(t)
        .attr("fill-opacity", d => +labelVisible(d.target))
        .attrTween("transform", d => () => labelTransform(d.current));
  }
  
  function arcVisible(d) {
    return d.y1 <= 3 && d.y0 >= 1 && d.x1 > d.x0;
  }

  function labelVisible(d) {
    return d.y1 <= 3 && d.y0 >= 1 && (d.y1 - d.y0) * (d.x1 - d.x0) > 0.03;
  }

  function labelTransform(d) {
    const x = (d.x0 + d.x1) / 2 * 180 / Math.PI;
    const y = (d.y0 + d.y1) / 2 * radius;
    return `rotate(${x - 90}) translate(${y},0) rotate(${x < 180 ? 0 : 180})`;
  }

  return svg.node();
}


function _data(FileAttachment){return(
FileAttachment("flare-2.json").json()
)}

function _partition(d3){return(
data => {
  const root = d3.hierarchy(data)
      .sum(d => d.value)
      .sort((a, b) => b.value - a.value);
  return d3.partition()
      .size([2 * Math.PI, root.height + 1])
    (root);
}
)}

function _color(d3,data){return(
d3.scaleOrdinal(d3.quantize(d3.interpolateRainbow, data.children.length + 1))
)}

function _format(d3){return(
d3.format(",d")
)}

function _width(){return(
932
)}

function _radius(width){return(
width / 6
)}

function _arc(d3,radius){return(
d3.arc()
    .startAngle(d => d.x0)
    .endAngle(d => d.x1)
    .padAngle(d => Math.min((d.x1 - d.x0) / 2, 0.005))
    .padRadius(radius * 1.5)
    .innerRadius(d => d.y0 * radius)
    .outerRadius(d => Math.max(d.y0 * radius, d.y1 * radius - 1))
)}

export default function define(runtime, observer) {
  const main = runtime.module();
  const fileAttachments = new Map([["flare-2.json",new URL("./files/e65374209781891f37dea1e7a6e1c5e020a3009b8aedf113b4c80942018887a1176ad4945cf14444603ff91d3da371b3b0d72419fa8d2ee0f6e815732475d5de",import.meta.url)]]);
  main.builtin("FileAttachment", runtime.fileAttachments(name => fileAttachments.get(name)));
  main.variable(observer()).define(["md"], _1);
  main.variable(observer("chart")).define("chart", ["partition","data","d3","width","color","arc","format","radius"], _chart);
  main.variable(observer("data")).define("data", ["FileAttachment"], _data);
  main.variable(observer("partition")).define("partition", ["d3"], _partition);
  main.variable(observer("color")).define("color", ["d3","data"], _color);
  main.variable(observer("format")).define("format", ["d3"], _format);
  main.variable(observer("width")).define("width", _width);
  main.variable(observer("radius")).define("radius", ["width"], _radius);
  main.variable(observer("arc")).define("arc", ["d3","radius"], _arc);
  return main;
}