MapGIS Client for JavaScript API

import {
  Projection,
  SpatialReference,
  GeometryType,
  defaultValue,
  editGeometryByArc3
} from '@mapgis/webclient-common'
import * as L from '@mapgis/leaflet'

// @function coordsToLatLng(coords: Array): LatLng
// Creates a `LatLng` object from an array of 2 numbers (longitude, latitude)
// or 3 numbers (longitude, latitude, altitude) used in GeoJSON for points.
function coordsToLatLng(coords) {
  if (coords.length > 2) {
    return new L.LatLng(coords[1], coords[0], coords[2])
  }
  return new L.LatLng(coords[1], coords[0])
}

// @function coordsToLatLngs(coords: Array, levelsDeep?: Number, coordsToLatLng?: Function): Array
// Creates a multidimensional array of `LatLng`s from a GeoJSON coordinates array.
// `levelsDeep` specifies the nesting level (0 is for an array of points, 1 for an array of arrays of points, etc., 0 by default).
// Can use a custom [`coordsToLatLng`](#geojson-coordstolatlng) function.
function coordsToLatLngs(coords, levelsDeep, _coordsToLatLng) {
  const latlngs = []

  for (let i = 0, len = coords.length, latlng; i < len; i++) {
    latlng = levelsDeep
      ? coordsToLatLngs(coords[i], levelsDeep - 1, _coordsToLatLng)
      : (_coordsToLatLng || coordsToLatLng)(coords[i])

    latlngs.push(latlng)
  }

  return latlngs
}

function transformToWGS84(spatialReference, geo) {
  if (String(spatialReference.wkid) !== '4326') {
    geo.spatialReference = spatialReference
    return Projection.project(geo, new SpatialReference('EPSG:4326'))
  }
  return geo
}

// 二维转换geometry
class ConvertGeometryUtil {
  /**
   * @description 转换为leaflet坐标数组,注意leaflet的经纬度对象放置顺序是反的[lat,lng]
   * @param {*} geometry
   * @param {*} options
   * @return {*}
   */
  static toLeafletCoords(geometry, options) {
    let latlngs = []
    // 后面需要考虑几何上坐标系的问题,在此处统一转换为经纬度数据
    const opt = defaultValue(options, {})
    // 额外参数
    const additional = defaultValue(opt.additional, undefined)
    // 坐标系转换
    let spatialReference = defaultValue(
      SpatialReference.fromJSON(opt.spatialReference),
      new SpatialReference('EPSG:4326')
    )
    if (geometry.spatialReference) {
      spatialReference = geometry.spatialReference
    }
    switch (geometry.type) {
      case GeometryType.point: {
        let geo = geometry.clone()
        geo = transformToWGS84(spatialReference, geo)
        const coordinates = geo.coordinates
        latlngs.push(coordsToLatLng(coordinates))
        break
      }
      case GeometryType.multiPoint: {
        let geo = geometry.clone()
        geo = transformToWGS84(spatialReference, geo)
        const coordinates = geo.coordinates
        latlngs = coordsToLatLngs(coordinates, 0, coordsToLatLng)
        break
      }
      case GeometryType.lineString: {
        let geo = geometry.clone()
        // 处理三点弧段几何
        geo = editGeometryByArc3(geo, additional)
        geo = transformToWGS84(spatialReference, geo)
        const coordinates = geo.coordinates
        latlngs = coordsToLatLngs(coordinates, 0, coordsToLatLng)
        break
      }
      case GeometryType.multiLineString: {
        let geo = geometry.clone()
        // 处理三点弧段几何
        geo = editGeometryByArc3(geo, additional)
        geo = transformToWGS84(spatialReference, geo)
        const coordinates = geo.coordinates
        latlngs = coordsToLatLngs(coordinates, 1, coordsToLatLng)
        break
      }
      case GeometryType.polygon: {
        let geo = geometry.clone()
        // 处理三点弧段几何
        geo = editGeometryByArc3(geo, additional)
        geo = transformToWGS84(spatialReference, geo)
        const coordinates = geo.coordinates
        latlngs = coordsToLatLngs(coordinates, 1, coordsToLatLng)
        break
      }
      case GeometryType.multiPolygon: {
        let geo = geometry.clone()
        // 处理三点弧段几何
        geo = editGeometryByArc3(geo, additional)
        geo = transformToWGS84(spatialReference, geo)
        const coordinates = geo.coordinates
        latlngs = coordsToLatLngs(coordinates, 2, coordsToLatLng)
        break
      }
      case GeometryType.extent: {
        let geo = geometry.clone()
        geo = transformToWGS84(spatialReference, geo)
        const minX = geo.xmin
        const maxX = geo.xmax
        const minY = geo.ymin
        const maxY = geo.ymax
        latlngs.push([minY, minX])
        latlngs.push([maxY, maxX])
        break
      }
      case GeometryType.circle: {
        let geo = geometry.clone()
        geo = transformToWGS84(spatialReference, geo)
        const center = geo.center
        latlngs.push([center[1], center[0]])
        break
      }
      default: {
        break
      }
    }
    return latlngs
  }
}

export default ConvertGeometryUtil