<template>
  <div id="map" ref="map" style="width: 100vw; height: 100vh"></div>
</template>
 
<script>
import "ol/ol.css";
import { Map, View } from "ol";
import { OSM, Vector as VectorSource } from "ol/source";
import { Vector as VectorLayer, Tile as TileLayer } from "ol/layer";
import GeoJSON from "ol/format/GeoJSON";
 
import Select from "ol/interaction/Select";
import { altKeyOnly, click, pointerMove } from "ol/events/condition";
 
export default {
  name: "gif",
  data() {
    return {
      map: {},
      layer: {},
      geojsonData: {
        type: "FeatureCollection",
        features: [
          {
            type: "Feature",
            properties: {
              title: "警報1",
            },
            geometry: {
              type: "Point",
              coordinates: [91.48879670091165, 37.83814884701121],
            },
          },
          {
            type: "Feature",
            properties: {
              title: "警報2",
            },
            geometry: {
              type: "Point",
              coordinates: [99.19515576149941, 26.713646654711134],
            },
          },
          {
            type: "Feature",
            properties: {
              title: "警報3",
            },
            geometry: {
              type: "Point",
              coordinates: [123.74363825288785, 44.363694825734726],
            },
          },
        ],
      },
      select: {},
    };
  },
  mounted() {
    this.initMap();
  },
  methods: {
    // 初始化地圖
    initMap() {
      this.layer = new VectorLayer({
        source: new VectorSource({
          features: new GeoJSON().readFeatures(this.geojsonData),
        }),
      });
      this.map = new Map({
        target: "map",
        layers: [
          new TileLayer({
            source: new OSM(),
          }),
          this.layer,
        ],
        view: new View({
          projection: "EPSG:4326",
          center: [104.912777, 34.730746],
          zoom: 4.5,
        }),
      });
 
      this.select = new Select({
        condition: click, //單擊選擇
      });
      this.map.addInteraction(this.select);
      this.select.on("select", (e) => {
        let coordinate = e.mapBrowserEvent.coordinate; //獲取選擇的坐標(biāo)
        let properties = e.selected[0].getProperties(); //獲取當(dāng)前要素的所有屬性
      });
 
      // 設(shè)置鼠標(biāo)劃過矢量要素的樣式
      this.map.on("pointermove", (e) => {
        const isHover = this.map.hasFeatureAtPixel(e.pixel);
        this.map.getTargetElement().style.cursor = isHover ? "pointer" : "";
      });
    },
  },
};
</script>