public/zh/builder/src/echarts/chart/graph/circularLayoutHelper.js

/*
* Licensed to the Apache Software Foundation (ASF) under one
* or more contributor license agreements.  See the NOTICE file
* distributed with this work for additional information
* regarding copyright ownership.  The ASF licenses this file
* to you under the Apache License, Version 2.0 (the
* "License"); you may not use this file except in compliance
* with the License.  You may obtain a copy of the License at
*
*   http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing,
* software distributed under the License is distributed on an
* "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
* KIND, either express or implied.  See the License for the
* specific language governing permissions and limitations
* under the License.
*/
import * as vec2 from 'zrender/src/core/vector';
import { getSymbolSize, getNodeGlobalScale } from './graphHelper';
var PI = Math.PI;
var _symbolRadiansHalf = [];
/**
 * `basedOn` can be:
 * 'value':
 *     This layout is not accurate and have same bad case. For example,
 *     if the min value is very smaller than the max value, the nodes
 *     with the min value probably overlap even though there is enough
 *     space to layout them. So we only use this approach in the as the
 *     init layout of the force layout.
 *     FIXME
 *     Probably we do not need this method any more but use
 *     `basedOn: 'symbolSize'` in force layout if
 *     delay its init operations to GraphView.
 * 'symbolSize':
 *     This approach work only if all of the symbol size calculated.
 *     That is, the progressive rendering is not applied to graph.
 *     FIXME
 *     If progressive rendering is applied to graph some day,
 *     probably we have to use `basedOn: 'value'`.
 *
 * @param {module:echarts/src/model/Series} seriesModel
 * @param {string} basedOn 'value' or 'symbolSize'
 */

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

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

  var rect = coordSys.getBoundingRect();
  var nodeData = seriesModel.getData();
  var graph = nodeData.graph;
  var cx = rect.width / 2 + rect.x;
  var cy = rect.height / 2 + rect.y;
  var r = Math.min(rect.width, rect.height) / 2;
  var count = nodeData.count();
  nodeData.setLayout({
    cx: cx,
    cy: cy
  });

  if (!count) {
    return;
  }

  _layoutNodesBasedOn[basedOn](seriesModel, coordSys, graph, nodeData, r, cx, cy, count);

  graph.eachEdge(function (edge) {
    var curveness = edge.getModel().get('lineStyle.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]);
  });
}
var _layoutNodesBasedOn = {
  value: function (seriesModel, coordSys, graph, nodeData, r, cx, cy, count) {
    var angle = 0;
    var sum = nodeData.getSum('value');
    var unitAngle = Math.PI * 2 / (sum || count);
    graph.eachNode(function (node) {
      var value = node.getValue('value');
      var radianHalf = unitAngle * (sum ? value : 1) / 2;
      angle += radianHalf;
      node.setLayout([r * Math.cos(angle) + cx, r * Math.sin(angle) + cy]);
      angle += radianHalf;
    });
  },
  symbolSize: function (seriesModel, coordSys, graph, nodeData, r, cx, cy, count) {
    var sumRadian = 0;
    _symbolRadiansHalf.length = count;
    var nodeScale = getNodeGlobalScale(seriesModel);
    graph.eachNode(function (node) {
      var symbolSize = getSymbolSize(node); // Normally this case will not happen, but we still add
      // some the defensive code (2px is an arbitrary value).

      isNaN(symbolSize) && (symbolSize = 2);
      symbolSize < 0 && (symbolSize = 0);
      symbolSize *= nodeScale;
      var symbolRadianHalf = Math.asin(symbolSize / 2 / r); // when `symbolSize / 2` is bigger than `r`.

      isNaN(symbolRadianHalf) && (symbolRadianHalf = PI / 2);
      _symbolRadiansHalf[node.dataIndex] = symbolRadianHalf;
      sumRadian += symbolRadianHalf * 2;
    });
    var halfRemainRadian = (2 * PI - sumRadian) / count / 2;
    var angle = 0;
    graph.eachNode(function (node) {
      var radianHalf = halfRemainRadian + _symbolRadiansHalf[node.dataIndex];
      angle += radianHalf;
      node.setLayout([r * Math.cos(angle) + cx, r * Math.sin(angle) + cy]);
      angle += radianHalf;
    });
  }
};