public/zh/builder/src/zrender/graphic/CompoundPath.js

// CompoundPath to improve performance
import Path from './Path';
export default Path.extend({
  type: 'compound',
  shape: {
    paths: null
  },
  _updatePathDirty: function () {
    var dirtyPath = this.__dirtyPath;
    var paths = this.shape.paths;

    for (var i = 0; i < paths.length; i++) {
      // Mark as dirty if any subpath is dirty
      dirtyPath = dirtyPath || paths[i].__dirtyPath;
    }

    this.__dirtyPath = dirtyPath;
    this.__dirty = this.__dirty || dirtyPath;
  },
  beforeBrush: function () {
    this._updatePathDirty();

    var paths = this.shape.paths || [];
    var scale = this.getGlobalScale(); // Update path scale

    for (var i = 0; i < paths.length; i++) {
      if (!paths[i].path) {
        paths[i].createPathProxy();
      }

      paths[i].path.setScale(scale[0], scale[1], paths[i].segmentIgnoreThreshold);
    }
  },
  buildPath: function (ctx, shape) {
    var paths = shape.paths || [];

    for (var i = 0; i < paths.length; i++) {
      paths[i].buildPath(ctx, paths[i].shape, true);
    }
  },
  afterBrush: function () {
    var paths = this.shape.paths || [];

    for (var i = 0; i < paths.length; i++) {
      paths[i].__dirtyPath = false;
    }
  },
  getBoundingRect: function () {
    this._updatePathDirty();

    return Path.prototype.getBoundingRect.call(this);
  }
});