caseEditor/public/leaflet.mapCorrection.js

// this L.CRS.Baidu from https://github.com/muyao1987/leaflet-tileLayer-baidugaode/blob/master/src/tileLayer.baidu.js

if (L.Proj) {
    L.CRS.Baidu = new L.Proj.CRS('EPSG:900913', '+proj=merc +a=6378206 +b=6356584.314245179 +lat_ts=0.0 +lon_0=0.0 +x_0=0 +y_0=0 +k=1.0 +units=m +nadgrids=@null +wktext  +no_defs', {
        resolutions: function () {
            level = 19
            var res = [];
            res[0] = Math.pow(2, 18);
            for (var i = 1; i < level; i++) {
                res[i] = Math.pow(2, (18 - i))
            }
            return res;
        }(),
        origin: [0, 0],
        bounds: L.bounds([20037508.342789244, 0], [0, 20037508.342789244])
    });
}

L.TileLayer.ChinaProvider = L.TileLayer.extend({

    initialize: function(type, options) { // (type, Object)
        var providers = L.TileLayer.ChinaProvider.providers;

        options = options || {}

        var parts = type.split('.');

        var providerName = parts[0];
        var mapName = parts[1];
        var mapType = parts[2];

        var url = providers[providerName][mapName][mapType];

        function getcookie(objname){
            var arrstr = document.cookie.split("; ");
            for(var i=0;i<arrstr.length;i++){
              var temp = arrstr[i].split("=");
              if(temp[0]==objname)return unescape(temp[1]);
            }
        }

        var login_apikey = localStorage.apikey;
        //如果当前用户没有apikey则取配置中的默认key
        if(typeof(login_apikey) === 'undefined'){
            login_apikey = providers[providerName].key;
        }
        //url += "?apikey=" + login_apikey;

        
        options.subdomains = providers[providerName].Subdomains;
        //options.key = options.key || providers[providerName].key;
        options.key = options.key || login_apikey;

        if ('tms' in providers[providerName]) {
            options.tms = providers[providerName]['tms']
        }

        L.TileLayer.prototype.initialize.call(this, url, options);
    }
});


//
L.TileLayer.ChinaProvider.providers = {
    TianDiTu: {
        Normal: {
            Map: "http://{s}.map.jms.gd/tile/tiandi/{z}/{x}/{y}.png?apikey={key}",
            Annotion: "http://{s}.map.jms.gd/tile/tiandi_cva/{z}/{x}/{y}.png?apikey={key}",
            Ibo: "http://{s}.map.jms.gd/tile/tiandi_ibo/{z}/{x}/{y}.png?apikey={key}",
            Mycva: "http://{s}.map.jms.gd/tile/tdt/{z}/{x}/{y}.png?apikey={key}",
        },
        Satellite: {
            Map: "http://{s}.map.jms.gd/tile/tiandi_wx/{z}/{x}/{y}.png?apikey={key}",
        },
        Terrain: {
            Map: "http://a.map.jms.gd/tile/tiandi_ter/{z}/{x}/{y}.png?apikey={key}",
        },
        Subdomains: ["a", "b", "c", "d"],
        key: "jm20240118"
    },

    GaoDe: {
        Normal: {
            Map: 'http://{s}.map.jms.gd/tile/shiliang/{z}/{x}/{y}.png?apikey={key}',
            XiangTu: 'http://{s}.map.jms.gd/tile/gd_xiangtu/{z}/{x}/{y}.png?apikey={key}',
            XiangTuGray: 'http://{s}.map.jms.gd/tile/gd_xiangtu_gray/{z}/{x}/{y}.png?apikey={key}',
            WuWenZi: 'http://{s}.map.jms.gd/tile/gd_wuwenzi/{z}/{x}/{y}.png?apikey={key}',
            LuWang: 'http://{s}.map.jms.gd/tile/luwang/{z}/{x}/{y}.png?apikey={key}',
            DiBiao: 'http://{s}.map.jms.gd/tile/gd_dibiao/{z}/{x}/{y}.png?apikey={key}',
            Test: "http://{s}.map.jms.gd/tile/test/{z}/{x}/{y}.png?apikey={key}",
        },
        Satellite: {
            Map: 'http://{s}.map.jms.gd/tile/weixing/{z}/{x}/{y}.png?apikey={key}'
        },
        Subdomains: ["a", "b", "c", "d"],
        key: "jm20240118"
    },

    Pengjiang: {
        Normal: {
            Map: "http://{s}.map.jms.gd/tile/pengjiang/{z}/{x}/{y}.png?apikey={key}"
        },
        Subdomains: ["a", "b", "c", "d"],
        key: "jm20240118"
    },
    Taishan: {
        Normal: {
            Map: "http://{s}.map.jms.gd/tile/taishan/{z}/{x}/{y}.png?apikey={key}"
        },
        Subdomains: ["a", "b", "c", "d"],
        key: "jm20240118"
    },

    Test: {
        Normal: {
            Test: "http://f.map.jms.gd/tile/test/{z}/{x}/{y}.png?apikey={key}",
            Test1: "http://f.map.jms.gd/tile/test1/{z}/{x}/{y}.png?apikey={key}",
        },
        Subdomains: ["a", "b", "c", "d"],
        key: "jm20240118"
    },

    Guangzhou: {
        Normal: {
            Hdpi: "http://{s}.map.jms.gd/tile/gz_hdpi/{z}/{x}/{y}.png?apikey={key}"
        },
        Subdomains: ["a", "b", "c", "d"],
        key: "jm20240118"
    },
    
    Google: {
        Normal: {
            Map: "",
        },
        Satellite: {
            Map: "http://{s}.map.jms.gd/tile/google_s/{z}/{x}/{y}.png?apikey={key}",
        },
        Subdomains: ["a", "b", "c", "d"],
        key: "jm20240118"
    },

    GoogleCn: {
        Normal: {
            Map: "http://{s}.map.jms.gd/tile/google/{z}/{x}/{y}.png?apikey={key}",
            Terrain: "http://{s}.map.jms.gd/tile/google_dx/{z}/{x}/{y}.png?apikey={key}",
            Annotion: "http://{s}.map.jms.gd/tile/google_h/{z}/{x}/{y}.png?apikey={key}",
            Ter: "http://{s}.map.jms.gd/tile/google_t/{z}/{x}/{y}.png?apikey={key}",
        },
        Satellite: {
            Map: "http://{s}.map.jms.gd/tile/google_s/{z}/{x}/{y}.png?apikey={key}",
            Annotion: "http://{s}.map.jms.gd/tile/google_wx/{z}/{x}/{y}.png?apikey={key}",
        },
        Subdomains: ["a", "b", "c", "d"],
        key: "jm20240118"
    },

    Tengxun: {
        Normal: {
            Map: "http://{s}.map.jms.gd/tile/tengxun/{z}/{x}/{y}.png?apikey={key}",
            Map9: "http://{s}.map.jms.gd/tile/tengxun_9/{z}/{x}/{y}.png?apikey={key}",
            Map8: "http://{s}.map.jms.gd/tile/tengxun_8/{z}/{x}/{y}.png?apikey={key}",
            Map4: "http://f.map.jms.gd/tile/tengxun_4/{z}/{x}/{y}.png?apikey={key}",
            Map3: "http://{s}.map.jms.gd/tile/tengxun_3/{z}/{x}/{y}.png?apikey={key}",
            Map2: "http://{s}.map.jms.gd/tile/tengxun_2/{z}/{x}/{y}.png?apikey={key}",
            Map1: "http://{s}.map.jms.gd/tile/tengxun_1/{z}/{x}/{y}.png?apikey={key}",
        },
        Satellite: {
            Map: "http://{s}.map.jms.gd/tile/tengxun_wx/{z}/{x}/{y}.png?apikey={key}"
        },
        Subdomains: ["a", "b", "c", "d"],
        key: "jm20240118"
    },

    Carto: {
        Normal: {
            Map: "http://{s}.map.jms.gd/tile/carto_label/{z}/{x}/{y}.png?apikey={key}",
            Light: "http://{s}.map.jms.gd/tile/railmap/{z}/{x}/{y}.png?apikey={key}",
            Dark: "http://{s}.map.jms.gd/tile/carto_dark/{z}/{x}/{y}.png?apikey={key}",
        },
        Subdomains: ["a", "b", "c", "d"],
        key: "jm20240118"
    },


    Thunderforest: {
        Normal: {
            Opencyclemap: "http://{s}.map.jms.gd/tile/opencyclemap/{z}/{x}/{y}.png?apikey={key}",
            Transport: "http://{s}.map.jms.gd/tile/transport/{z}/{x}/{y}.png?apikey={key}",
            Landscape: "http://{s}.map.jms.gd/tile/landscape/{z}/{x}/{y}.png?apikey={key}",
            Mobile: "http://{s}.map.jms.gd/tile/mobile-atlas/{z}/{x}/{y}.png?apikey={key}",
            Pioneer: "http://{s}.map.jms.gd/tile/pioneer/{z}/{x}/{y}.png?apikey={key}",
            Neighbourhood: "http://{s}.map.jms.gd/tile/neighbourhood/{z}/{x}/{y}.png?apikey={key}",
            Outdoors: "http://{s}.map.jms.gd/tile/outdoors/{z}/{x}/{y}.png?apikey={key}",
            Atlas: "http://{s}.map.jms.gd/tile/atlas/{z}/{x}/{y}.png?apikey={key}",
            TransportDark: "http://{s}.map.jms.gd/tile/transport-dark/{z}/{x}/{y}.png?apikey={key}",
            Spinal: "http://{s}.map.jms.gd/tile/spinal-map/{z}/{x}/{y}.png?apikey={key}",
        },
        Subdomains: ["a", "b", "c", "d"],
        key: "jm20240118"
    },

    OSM: {
        Normal: {
            Map: "http://{s}.map.jms.gd/tile/osm/{z}/{x}/{y}.png?apikey={key}",
            Topo: "http://{s}.map.jms.gd/tile/osm_topo/{z}/{x}/{y}.png?apikey={key}",
            Openstreetmap: "http://{s}.map.jms.gd/tile/openstreetmap/{z}/{x}/{y}.png?apikey={key}",
            winter: "http://{s}.map.jms.gd/tile/osm_winter/{z}/{x}/{y}.png?apikey={key}",
            summer: "http://{s}.map.jms.gd/tile/osm_summer/{z}/{x}/{y}.png?apikey={key}",
            cycling: "http://{s}.map.jms.gd/tile/osm_cycling/{z}/{x}/{y}.png?apikey={key}",
        },
        Subdomains: ["a", "b", "c", "d"],
        key: "jm20240118"
    },

    Opentopomap: {
        Normal: {
            Map: "http://{s}.map.jms.gd/tile/opentopomap/{z}/{x}/{y}.png?apikey={key}",
        },
        Subdomains: ["a", "b", "c", "d"],
        key: "jm20240118"
    },

    Baidu: {
        Normal: {
            Map: 'http://{s}.map.jms.gd/tile/baidu/{z}/{x}/{y}.png?apikey={key}'
        },
        Satellite: {
            Map: 'http://{s}.map.jms.gd/tile/baidu_wx/{z}/{x}/{y}.png?apikey={key}',
        },
        Subdomains: ["a", "b", "c", "d"],
        key: "jm20240118",
        tms: true
    },

    Openrailway: {
        Normal: {
            Map: "http://{s}.map.jms.gd/tile/openrailway/{z}/{x}/{y}.png?apikey={key}",
            Maxspeed: "http://{s}.map.jms.gd/tile/openrailway_maxspeed/{z}/{x}/{y}.png?apikey={key}",
            Elec: "http://{s}.map.jms.gd/tile/openrailway_elec/{z}/{x}/{y}.png?apikey={key}",
        },
        Subdomains: ["a", "b", "c", "d"],
        key: "jm20240118"
    },

    Stadia: {
        Normal: {
            Alidade_smooth: "http://{s}.map.jms.gd/tile/alidade_smooth/{z}/{x}/{y}.png?apikey={key}",
            Watercolor: "http://{s}.map.jms.gd/tile/stamen_watercolor/{z}/{x}/{y}.jpg?apikey={key}",
            Terrain: "http://{s}.map.jms.gd/tile/stamen_terrain/{z}/{x}/{y}.png?apikey={key}",
            Toner: "http://{s}.map.jms.gd/tile/stamen_toner/{z}/{x}/{y}.png?apikey={key}",
        },
        Subdomains: ["a", "b", "c", "d"],
        key: "jm20240118"
    },

    ArcgisCn: {
        Normal: {
            Community: "http://{s}.map.jms.gd/tile/arcgis_comm/{z}/{x}/{y}.png?apikey={key}",
            Gray: "http://{s}.map.jms.gd/tile/arcgis_gray/{z}/{x}/{y}.jpg?apikey={key}",
            Blue: "http://{s}.map.jms.gd/tile/arcgis_blue/{z}/{x}/{y}.png?apikey={key}",
            Warm: "http://{s}.map.jms.gd/tile/arcgis_warm/{z}/{x}/{y}.png?apikey={key}",
        },
        Subdomains: ["a", "b", "c", "d"],
        key: "jm20240118"
    },

    Arcgis: {
        Normal: {
            Street: "http://{s}.map.jms.gd/tile/arcgis_world_street/{z}/{x}/{y}.png?apikey={key}",
            Hillshade: "http://{s}.map.jms.gd/tile/arcgis_world_hillshade/{z}/{x}/{y}.png?apikey={key}",
        },
        Satellite: {
            Map: "http://{s}.map.jms.gd/tile/arcgis_world_imagery/{z}/{x}/{y}.png?apikey={key}",
        },
        Subdomains: ["a", "b", "c", "d"],
        key: "jm20240118"
    },

    Jl1: {
        Normal: {
            Map: "http://{s}.map.jms.gd/tile/jl1_2022/{z}/{x}/{y}.png?apikey={key}",
            Map2023: "http://{s}.map.jms.gd/tile/jl1_2023/{z}/{x}/{y}.png?apikey={key}",
            Map2024: "http://{s}.map.jms.gd/tile/jl1_2024/{z}/{x}/{y}.png?apikey={key}",
        },
        Subdomains: ["a", "b", "c", "d"],
        key: "jm20240118"
    },

    Geovis: {
        Normal: {
            Base: "http://{s}.map.jms.gd/tile/geovis_base/{z}/{x}/{y}.png?apikey={key}",
        },
        Subdomains: ["a", "b", "c", "d"],
        key: "jm20240118"
    },

    Stamen: {
        Terrain: {
            Lines: "http://{s}.map.jms.gd/tile/stamen_terrain_lines/{z}/{x}/{y}.png?apikey={key}",
        },
        Toner: {
            Lines: "http://{s}.map.jms.gd/tile/stamen_toner_lines/{z}/{x}/{y}.png?apikey={key}",
        },
        Subdomains: ["a", "b", "c", "d"],
        key: "jm20240118"
    },

    BingCn: {
        Normal: {
            Map: "http://{s}.map.jms.gd/tile/bing/{z}/{x}/{y}.png?apikey={key}",
            Dark: "http://{s}.map.jms.gd/tile/bing_dark/{z}/{x}/{y}.png?apikey={key}",
            Cf: "http://{s}.map.jms.gd/tile/bing_cf/{z}/{x}/{y}.png?apikey={key}", //实时路况
        },
        Subdomains: ["a", "b", "c", "d"],
        key: "jm20240118"
    },

    Bing: {
        Satellite: {
            Map: "http://{s}.map.jms.gd/tile/bing_aerial/{z}/{x}/{y}.png?apikey={key}",
        },
        Subdomains: ["a", "b", "c", "d"],
        key: "jm20240118"
    },

    Jiangmen: {
        Normal: {
            Map: "http://68.196.3.198/map/mapimg/tile/{z}/{x}/{y}?apikey={key}",
        },
        Subdomains: ["a", "b", "c", "d"],
        key: "jm20240118"
    },

    Maptiler: {
        Normal: {
            basic: "http://{s}.map.jms.gd/tile/maptiler_basic/{z}/{x}/{y}.png?apikey={key}",
            backdrop: "http://{s}.map.jms.gd/tile/maptiler_backdrop/{z}/{x}/{y}.png?apikey={key}",
            streets: "http://{s}.map.jms.gd/tile/maptiler_streets/{z}/{x}/{y}.png?apikey={key}",
            winter: "http://{s}.map.jms.gd/tile/maptiler_winter/{z}/{x}/{y}.png?apikey={key}",
            ocean: "http://{s}.map.jms.gd/tile/maptiler_ocean/{z}/{x}/{y}.png?apikey={key}",
            toner: "http://{s}.map.jms.gd/tile/maptiler_toner/{z}/{x}/{y}.png?apikey={key}",
            topo: "http://{s}.map.jms.gd/tile/maptiler_topo/{z}/{x}/{y}.png?apikey={key}",
            dataviz: "http://{s}.map.jms.gd/tile/maptiler_dataviz/{z}/{x}/{y}.png?apikey={key}",
        },
        Subdomains: ["a", "b", "c", "d"],
        key: "jm20240118"
    },

    mapbox: {
        Normal: {
            mapbox01: "http://{s}.map.jms.gd/tile/mapbox01/{z}/{x}/{y}.png?apikey={key}",
        },
        Subdomains: ["a", "b", "c", "d"],
        key: "jm20240118"
    },

    Nothing: {
        Normal: {
            Map: "http://map.jms.gd/static/img/512.png?apikey={key}",
        },
        Subdomains: ["a", "b", "c", "d"],
        key: "jm20240118"
    },
};

L.tileLayer.chinaProvider = function(type, options) {
    return new L.TileLayer.ChinaProvider(type, options);
};


//坐标转换
L.CoordConver = function () {

    /**百度转84*/
    this.bd09_To_gps84 = function(lng, lat) {
        var gcj02 = this.bd09_To_gcj02(lng, lat);
        var map84 = this.gcj02_To_gps84(gcj02.lng, gcj02.lat);
        return map84;
    }
    /**84转百度*/
    this.gps84_To_bd09 = function (lng, lat) {
        var gcj02 = this.gps84_To_gcj02(lng, lat);
        var bd09 = this.gcj02_To_bd09(gcj02.lng, gcj02.lat);
        return bd09;
    }
    /**84转火星*/
    this.gps84_To_gcj02 = function (lng, lat) {
        var dLat = transformLat(lng - 105.0, lat - 35.0);
        var dLng = transformLng(lng - 105.0, lat - 35.0);
        var radLat = lat / 180.0 * pi;
        var magic = Math.sin(radLat);
        magic = 1 - ee * magic * magic;
        var sqrtMagic = Math.sqrt(magic);
        dLat = (dLat * 180.0) / ((a * (1 - ee)) / (magic * sqrtMagic) * pi);
        dLng = (dLng * 180.0) / (a / sqrtMagic * Math.cos(radLat) * pi);
        var mgLat = lat + dLat;
        var mgLng = lng + dLng;
        var newCoord = {
            lng: mgLng,
            lat: mgLat
        };
        return newCoord;
    }
    /**火星转84*/
    this.gcj02_To_gps84 = function (lng, lat) {
        var coord = transform(lng, lat);
        var lontitude = lng * 2 - coord.lng;
        var latitude = lat * 2 - coord.lat;
        var newCoord = {
            lng: lontitude,
            lat: latitude
        };
        return newCoord;
    }
    /**火星转百度*/
    this.gcj02_To_bd09 = function (x, y) {
        var z = Math.sqrt(x * x + y * y) + 0.00002 * Math.sin(y * x_pi);
        var theta = Math.atan2(y, x) + 0.000003 * Math.cos(x * x_pi);
        var bd_lng = z * Math.cos(theta) + 0.0065;
        var bd_lat = z * Math.sin(theta) + 0.006;
        var newCoord = {
            lng: bd_lng,
            lat: bd_lat
        };
        return newCoord;
    }
    /**百度转火星*/
    this.bd09_To_gcj02 = function (bd_lng, bd_lat) {
        var x = bd_lng - 0.0065;
        var y = bd_lat - 0.006;
        var z = Math.sqrt(x * x + y * y) - 0.00002 * Math.sin(y * x_pi);
        var theta = Math.atan2(y, x) - 0.000003 * Math.cos(x * x_pi);
        var gg_lng = z * Math.cos(theta);
        var gg_lat = z * Math.sin(theta);
        var newCoord = {
            lng: gg_lng,
            lat: gg_lat
        };
        return newCoord;
    }

    var pi = 3.1415926535897932384626;
    var a = 6378245.0;
    var ee = 0.00669342162296594323;
    var x_pi = pi * 3000.0 / 180.0;
    var R = 6378137;

    function transform(lng, lat) {
        var dLat = transformLat(lng - 105.0, lat - 35.0);
        var dLng = transformLng(lng - 105.0, lat - 35.0);
        var radLat = lat / 180.0 * pi;
        var magic = Math.sin(radLat);
        magic = 1 - ee * magic * magic;
        var sqrtMagic = Math.sqrt(magic);
        dLat = (dLat * 180.0) / ((a * (1 - ee)) / (magic * sqrtMagic) * pi);
        dLng = (dLng * 180.0) / (a / sqrtMagic * Math.cos(radLat) * pi);
        var mgLat = lat + dLat;
        var mgLng = lng + dLng;
        var newCoord = {
            lng: mgLng,
            lat: mgLat
        };
        return newCoord;
    }

    function transformLat(x, y) {
        var ret = -100.0 + 2.0 * x + 3.0 * y + 0.2 * y * y + 0.1 * x * y + 0.2 * Math.sqrt(Math.abs(x));
        ret += (20.0 * Math.sin(6.0 * x * pi) + 20.0 * Math.sin(2.0 * x * pi)) * 2.0 / 3.0;
        ret += (20.0 * Math.sin(y * pi) + 40.0 * Math.sin(y / 3.0 * pi)) * 2.0 / 3.0;
        ret += (160.0 * Math.sin(y / 12.0 * pi) + 320 * Math.sin(y * pi / 30.0)) * 2.0 / 3.0;
        return ret;
    }

    function transformLng(x, y) {
        var ret = 300.0 + x + 2.0 * y + 0.1 * x * x + 0.1 * x * y + 0.1 * Math.sqrt(Math.abs(x));
        ret += (20.0 * Math.sin(6.0 * x * pi) + 20.0 * Math.sin(2.0 * x * pi)) * 2.0 / 3.0;
        ret += (20.0 * Math.sin(x * pi) + 40.0 * Math.sin(x / 3.0 * pi)) * 2.0 / 3.0;
        ret += (150.0 * Math.sin(x / 12.0 * pi) + 300.0 * Math.sin(x / 30.0 * pi)) * 2.0 / 3.0;
        return ret;
    }
}

L.coordConver = function () {
    return new L.CoordConver()
}


L.tileLayer.chinaProvider = function (type, options) {
    options = options || {}
    options.corrdType = getCorrdType(type);
    return new L.TileLayer.ChinaProvider(type, options);

    //获取坐标类型
    function getCorrdType(type) {
        var parts = type.split('.');
        var providerName = parts[0];
        var zbName = "wgs84"
        switch (providerName) {
            case "Tengxun":
            case "GaoDe":
            case "Pengjiang":
            case "GoogleCn": //google中国地图
            case "ArcgisCn":
            case "BingCn":
            case "Test":
                zbName = "gcj02";
                break;
            case "Baidu":
                zbName = "bd09";
                break;
            case "Carto":
            case "Thunderforest":
            case "OSM":
            case "TianDiTu":
            case "Jl1":
            case "Openrailway":
            case "Bing":
            case "Jiangmen":
            case "Google":
            case "mapbox":
                zbName = "wgs84";
                break;
        }
        return zbName;
    }
};

L.GridLayer.include({
    _setZoomTransform: function (level, _center, zoom) {
        var center = _center;

        if (center != undefined && this.options) {
            if (this.options.corrdType == 'gcj02') {
                center = L.coordConver().gps84_To_gcj02(_center.lng, _center.lat);
            } else if (this.options.corrdType == 'bd09') {
                center = L.coordConver().gps84_To_bd09(_center.lng, _center.lat);
            }
        }


        var scale = this._map.getZoomScale(zoom, level.zoom),
            translate = level.origin.multiplyBy(scale)
                .subtract(this._map._getNewPixelOrigin(center, zoom)).round();

        if (L.Browser.any3d) {
            L.DomUtil.setTransform(level.el, translate, scale);
        } else {
            L.DomUtil.setPosition(level.el, translate);
        }

    },
    _getTiledPixelBounds: function (_center) {
        var center = _center;

        if (center != undefined && this.options) {
            if (this.options.corrdType == 'gcj02') {
                center = L.coordConver().gps84_To_gcj02(_center.lng, _center.lat);
            } else if (this.options.corrdType == 'bd09') {
                center = L.coordConver().gps84_To_bd09(_center.lng, _center.lat);
            }
        }

        var map = this._map,
            mapZoom = map._animatingZoom ? Math.max(map._animateToZoom, map.getZoom()) : map.getZoom(),
            scale = map.getZoomScale(mapZoom, this._tileZoom),
            pixelCenter = map.project(center, this._tileZoom).floor(),
            halfSize = map.getSize().divideBy(scale * 2);

        return new L.Bounds(pixelCenter.subtract(halfSize), pixelCenter.add(halfSize));

    }
})