Question

我正在使用Mapbox iOS SDK并尝试绘制没有geojson的折线。我试图用这种方法得到路线：

func calculateRoute() {

    ...

    let options = NavigationRouteOptions(waypoints: [origin, destination], profileIdentifier: .automobileAvoidingTraffic)
    Directions.shared.calculate(options) { (waypoints, routes, error) in 
        guard let route = routes?.first else { return }
        self.showPreview(route: route)
    }
}

然后我试图画一条路线。

func showPreview(route: Route) {

    guard let steps = route.legs.first?.steps else { return }
    var points = [CLLocationCoordinate2D]()
    for step in steps {
        points.append(step.maneuverLocation)
    }
    let line = MGLPolyline(coordinates: &points, count: UInt(points.count))
    mapView?.addAnnotation(line)
}

它在地图视图上绘制一条折线。我可以使用两个委托方法（MGLMapViewDelegate）更改折线的颜色和宽度：

func mapView(_ mapView: MGLMapView, lineWidthForPolylineAnnotation annotation: MGLPolyline) -> CGFloat {
    return 10
}

func mapView(_ mapView: MGLMapView, strokeColorForShapeAnnotation annotation: MGLShape) -> UIColor {
    return .blue
}

但是我找不到在折线周围设置边框宽度和边框颜色的方法。有什么办法吗？

Answer 1

看起来我有一个与您相似的用例（即不使用geojson），最终得到了类似的结果。通过将路线与MGLLineStyleLayer关联，您可以控制线路的视觉参数。

func showPreview(route: Route) {
    guard route.coordinateCount > 0 else { return }
    // Convert the route’s coordinates into a polyline
    var routeCoordinates = route.coordinates!
    let polyline = MGLPolylineFeature(coordinates: &routeCoordinates, count: route.coordinateCount)

    // If there's already a route line on the map, reset its shape to the new route
    if let source = mapView.style?.source(withIdentifier: "route-source") as? MGLShapeSource {
        source.shape = polyline
    } else {
        let source = MGLShapeSource(identifier: "route-source", features: [polyline], options: nil)

        // Customize the route line color and width
        let lineStyle = MGLLineStyleLayer(identifier: "route-style", source: source)
        lineStyle.lineColor = NSExpression(forConstantValue: UIColor.blue)
        lineStyle.lineWidth = NSExpression(forConstantValue: 3)

        // Add the source and style layer of the route line to the map
        mapView.style?.addSource(source)
        mapView.style?.addLayer(lineStyle)
    }
}

您要添加边框并控制其外观。如果您在Mapbox网站上查看以下示例：Line style Example，他们将通过创建第二个MGLLineStyleLayer并将其插入第一个casingLayer来完成您想要的操作。他们称第二层为let casingLayer = MGLLineStyleLayer(identifier: "polyline-case", source: source) // Add your formatting attributes here. See example on website.。这是他们的代码，因此您可以看到它的构成与第一层相同。

style.insertLayer(casingLayer, below: lineStyle)

然后他们将其插入第一行下方，并且由于其宽度较宽，因此显示为边框。

{  
   "requests":[  
      {  
         "id":"1",
         "method":"PATCH",
         "url":"https://graph.microsoft.com/v1.0/me/onenote/pages/1-98c2295df76a4067a6036efc6a8f6f74!84-f754d551-02d2-4416-af42-8fcc644f10e6/content",
         "headers":{  
            "Content-Type":"application/json"
         },
         "body":[  
            {  
               "target":"title",
               "action":"replace",
               "content":"2 - Test1"
            }
         ]
      }
   ]
}

希望这会有所帮助。

使用边框贴图框绘制折线，iOS

1 个答案: