Method getScales

src/openlayers/mapping/WebMap.js:441–497

* @private * @function WebMap.prototype.getScales * @description 根据级别获取每个级别对应的分辨率 * @param {Object} baseLayerInfo - 底图的图层信息

(baseLayerInfo)

   * @param {Object} baseLayerInfo - 底图的图层信息
   */
  getScales(baseLayerInfo) {
    let scales = [],
      resolutions = {},
      res,
      scale,
      resolutionArray = [],
      coordUnit = baseLayerInfo.coordUnit || baseLayerInfo.units || olProj.get(baseLayerInfo.projection).getUnits();
    if (!coordUnit) {
      coordUnit = this.baseProjection == 'EPSG:3857' ? 'm' : 'degree';
    }
    if (baseLayerInfo.visibleScales && baseLayerInfo.visibleScales.length > 0) {
      //底部设置过固定比例尺，则使用设置的
      baseLayerInfo.visibleScales.forEach((scale) => {
        let value = 1 / scale;
        res = this.getResFromScale(value, coordUnit);
        scale = `1:${value}`;
        //多此一举转换，因为toLocalString会自动保留小数点后三位，and当第二位小数是0就会保存小数点后两位。所有为了统一。
        resolutions[this.formatScale(scale)] = res;
        resolutionArray.push(res);
        scales.push(scale);
      }, this);
    } else if (baseLayerInfo.layerType === 'WMTS') {
      baseLayerInfo.scales.forEach((scale) => {
        res = this.getResFromScale(scale, coordUnit, 90.7);
        scale = `1:${scale}`;
        //多此一举转换，因为toLocalString会自动保留小数点后三位，and当第二位小数是0就会保存小数点后两位。所有为了统一。
        resolutions[this.formatScale(scale)] = res;
        resolutionArray.push(res);
        scales.push(scale);
      }, this);
    } else if(baseLayerInfo.layerType === 'ZXY_TILE') {
      const { resolutions: visibleResolution } = baseLayerInfo;
      visibleResolution.forEach(result => {
        const currentScale = this.getScaleFromRes(result, coordUnit);
        resolutions[this.formatScale(currentScale)] = result;
        scales.push(currentScale);
      })
      resolutionArray = visibleResolution;
    } else {
      let { minZoom = 0, maxZoom = 22 } = baseLayerInfo,
        view = this.map.getView();
      for (let i = minZoom; i <= maxZoom; i++) {
        res = view.getResolutionForZoom(i);
        scale = this.getScaleFromRes(res, coordUnit);
        if (scales.indexOf(scale) === -1) {
          //不添加重复的比例尺
          scales.push(scale);
          let attr = scale.replace(/,/g, '');
          resolutions[attr] = res;
          resolutionArray.push(res);
        }
      }
    }
    this.scales = scales;
    this.resolutions = resolutions;
    this.resolutionArray = resolutionArray;
  }
  /**