// 初始化地图
function initMap() {
  const map = new google.maps.Map(document.getElementById("map"), {
    zoom: 7,
    center: { lat: 39.9042, lng: 116.4074 }, // 北京坐标
  });
  
  const directionsService = new google.maps.DirectionsService();
  const directionsRenderer = new google.maps.DirectionsRenderer();
  directionsRenderer.setMap(map);
  
  // 计算并显示路线
  calculateAndDisplayRoute(directionsService, directionsRenderer);
}

// 计算并显示路线
function calculateAndDisplayRoute(directionsService, directionsRenderer) {
  directionsService.route(
    {
      origin: { lat: 39.9042, lng: 116.4074 }, // 起点：北京
      destination: { lat: 31.2304, lng: 121.4737 }, // 终点：上海
      travelMode: google.maps.TravelMode.DRIVING, // 驾车模式
    },
    (response, status) => {
      if (status === "OK") {
        directionsRenderer.setDirections(response);
      } else {
        window.alert("路线请求失败: " + status);
      }
    }
  );
}

// 确保正确加载API
<script src="https://maps.googleapis.com/maps/api/js?key=YOUR_API_KEY&callback=initMap" async defer></script>

#map {
  height: 100%;
  width: 100%;
  position: absolute;
  top: 0;
  left: 0;
}

function calculateMultiLegRoute() {
  const waypts = [
    { location: { lat: 34.0522, lng: -118.2437 }, stopover: true }, // 洛杉矶
    { location: { lat: 41.8781, lng: -87.6298 }, stopover: true }  // 芝加哥
  ];
  
  directionsService.route({
    origin: { lat: 40.7128, lng: -74.0060 }, // 纽约
    destination: { lat: 37.7749, lng: -122.4194 }, // 旧金山
    waypoints: waypts,
    optimizeWaypoints: true,
    travelMode: google.maps.TravelMode.DRIVING
  }, callback);
}

directionsRenderer.setOptions({
  polylineOptions: {
    strokeColor: '#FF0000',
    strokeOpacity: 1.0,
    strokeWeight: 3
  },
  suppressMarkers: true // 隐藏默认标记
});