Method _getScales

src/common/mapping/WebMapV2.js:267–324

(mapInfo)

    }

    async _getScales(mapInfo) {
      const baseLayerInfo = mapInfo.baseLayer;
      const scales = [];
      let coordUnit = baseLayerInfo.coordUnit || baseLayerInfo.units || mapRepo.CRS.get(this.baseProjection).unit;
      if (!coordUnit) {
        coordUnit = this.baseProjection == 'EPSG:3857' ? 'm' : 'degree';
      }
      let visibleScales = null;
      if (baseLayerInfo.layerType === 'TILE') {
        try {
          const reqOptions = {
            withoutFormatSuffix: true,
            withCredentials: this.webMapService.handleWithCredentials('', baseLayerInfo.url, false)
          };
          const res = await this.getBounds(`${baseLayerInfo.url}.json`, reqOptions)
          if (res && res.visibleScales) {
            visibleScales = res.visibleScales;
          }
        } catch (error) {
          console.error(error);
        }
      }
      if (visibleScales && visibleScales.length > 0) {
        //底部设置过固定比例尺，则使用设置的
        visibleScales.forEach((scale) => {
          const value = 1 / scale;
          scales.push(`1:${value}`);
        });
      } else if (baseLayerInfo.layerType === 'WMTS') {
        try {
          const result = await this.webMapService.getWmtsInfo(baseLayerInfo, this.baseProjection);
          result.scales.forEach((scale) => {
            scales.push(`1:${scale}`);
          });
        } catch (error) {
          console.error(error);
        }
      } else if (baseLayerInfo.layerType === 'ZXY_TILE') {
        const { resolutions: visibleResolution } = baseLayerInfo;
        visibleResolution.forEach((result) => {
          const currentScale = '1:' + Util.getScaleFromResolution(result, coordUnit);
          scales.push(currentScale);
        });
      } else {
        const extent = baseLayerInfo.layerType === 'MAPBOXSTYLE' ? mapRepo.CRS.get(this.baseProjection).extent : mapInfo.extent;
        const resolutions = this._getResolutionsByExtent({
          extent: this._transExtentToBounds(extent),
          tileSize: 512
        });
        for (const res of resolutions) {
          const scale = '1:' + Util.getScaleFromResolution(res, coordUnit);
          if (scales.indexOf(scale) === -1) {
            scales.push(scale);
          }
        }
      }
      return scales;
    }