medical/node_modules/echarts/lib/chart/graph/circularLayoutHelper.js

var vec2 = require("zrender/lib/core/vector");

function circularLayout(seriesModel) {
  var coordSys = seriesModel.coordinateSystem;

  if (coordSys && coordSys.type !== 'view') {
    return;
  }

  var rect = coordSys.getBoundingRect();
  var nodeData = seriesModel.getData();
  var graph = nodeData.graph;
  var angle = 0;
  var sum = nodeData.getSum('value');
  var unitAngle = Math.PI * 2 / (sum || nodeData.count());
  var cx = rect.width / 2 + rect.x;
  var cy = rect.height / 2 + rect.y;
  var r = Math.min(rect.width, rect.height) / 2;
  graph.eachNode(function (node) {
    var value = node.getValue('value');
    angle += unitAngle * (sum ? value : 1) / 2;
    node.setLayout([r * Math.cos(angle) + cx, r * Math.sin(angle) + cy]);
    angle += unitAngle * (sum ? value : 1) / 2;
  });
  nodeData.setLayout({
    cx: cx,
    cy: cy
  });
  graph.eachEdge(function (edge) {
    var curveness = edge.getModel().get('lineStyle.normal.curveness') || 0;
    var p1 = vec2.clone(edge.node1.getLayout());
    var p2 = vec2.clone(edge.node2.getLayout());
    var cp1;
    var x12 = (p1[0] + p2[0]) / 2;
    var y12 = (p1[1] + p2[1]) / 2;

    if (+curveness) {
      curveness *= 3;
      cp1 = [cx * curveness + x12 * (1 - curveness), cy * curveness + y12 * (1 - curveness)];
    }

    edge.setLayout([p1, p2, cp1]);
  });
}

exports.circularLayout = circularLayout;