Method getUniqueStyleGroup

src/openlayers/mapping/WebMap.js:3559–3624

* @private * @function WebMap.prototype.getUniqueStyleGroup * @description 获取单值专题图的styleGroup * @param {Object} parameters- 图层信息 * @param {Array} features - feature 数组 * @returns {Array} 单值样式

(parameters, features)

   * @returns {Array} 单值样式
   */
  async getUniqueStyleGroup(parameters, features) {
    // 找出所有的单值
    let featureType = parameters.featureType,
      style = parameters.style,
      themeSetting = parameters.themeSetting;
    let fieldName = themeSetting.themeField;

    let names = [],
      customSettings = themeSetting.customSettings;
    for (let i in features) {
      let attributes = features[i].get('attributes');
      let name = attributes[fieldName];
      let isSaved = false;
      for (let j in names) {
        if (names[j] === name) {
          isSaved = true;
          break;
        }
      }
      if (!isSaved) {
        names.push(name);
      }
    }

    //生成styleGroup
    let styleGroup = [];
    const usedColors = this.getCustomSettingColors(customSettings, featureType).map((item) => item.toLowerCase());
    const curentColors = this.getUniqueColors(
      themeSetting.colors || this.defaultParameters.themeSetting.colors,
      names.length + Object.keys(customSettings).length
    ).map((item) => item.toLowerCase());
    const newColors = difference(curentColors, usedColors);
    for (let index = 0; index < names.length; index++) {
      const name = names[index];
      //兼容之前自定义是用key，现在因为数据支持编辑，需要用属性值。
      let key = this.webMapVersion === '1.0' ? index : name;
      let custom = customSettings[key];
      if (Util.isString(custom)) {
        //兼容之前自定义只存储一个color
        custom = this.getCustomSetting(style, custom, featureType);
        customSettings[key] = custom;
      }
      if (!custom) {
        custom = this.getCustomSetting(style, newColors.shift(), featureType);
      }

      // 转化成 ol 样式
      let olStyle,
        type = custom.type;
      if (type === 'SYMBOL_POINT') {
        olStyle = StyleUtils.getSymbolStyle(custom);
      } else if (type === 'SVG_POINT') {
        olStyle = await StyleUtils.getSVGStyle(custom);
      } else if (type === 'IMAGE_POINT') {
        olStyle = StyleUtils.getImageStyle(custom);
      } else {
        olStyle = await StyleUtils.toOpenLayersStyle(custom, featureType);
      }