Function crsFromMapJSON

src/leaflet/mapping/initMap.js:134–150

(mapJSONObj, mapOptions)

 * @returns {CRS}  返回CRS。
 */
export function crsFromMapJSON(mapJSONObj, mapOptions) {
    const { maxZoom = 22 } = mapOptions || {};

    const { bounds, prjCoordSys, dpi, visibleScales, coordUnit, origin } = mapJSONObj;
    let resolutions = mapJSONObj.resolutions;
    if (!resolutions) {
        resolutions = scalesToResolutions(visibleScales, bounds, dpi, coordUnit, maxZoom);
    }
    if (isPlaneProjection(prjCoordSys.type)) {
        return getNonEarthCRS(bounds, origin, resolutions);
    }
    const epsgCodeStr = getEpsgCode(prjCoordSys);
    if (!hasRegisterProj(epsgCodeStr)) {
        return;
    }
    return getCRS(epsgCodeStr, { bounds, dpi, resolutions, origin });
}

/**
 * @private