Dynamic and visualized display of iOS map lines

Dynamic and visualized display of iOS map lines
I have encountered such a problem before, that is, to draw the distance between two points and display the line in the visible range. Below are some main code:

# Pragma mark-driving route retrieval-(void) onGetDrivingRouteResult :( BMKRouteSearch *) searcher result :( random *) result errorCode :( BMKSearchErrorCode) error {if (error = BMK_SEARCH_NO_ERROR) {// NSArray * array = [NSArray arrayWithArray: _ mapView. annotations]; [_ mapView removeAnnotations: array]; array = [NSArray arrayWithArray: _ mapView. overlays]; [_ mapView removeOverlays: array]; if (error = BMK_SEARCH_NO_ERROR) {BMKDrivingRouteLine * plan = (BMKDrivingRouteLine *) [result. routes objectAtIndex: 0]; // calculate the number of road sections in the route plan. int size = [plan. steps count]; int planPointCounts = 0; for (int I = 0; I <size; I ++) {BMKDrivingStep * transitStep = [plan. steps objectAtIndex: I]; if (I = 0) {RouteAnnotation * item = [[RouteAnnotation alloc] init]; item. coordinate = plan. starting. location; item. title = @ "Start Point"; item. type = 0; [_ mapView addAnnotation: item]; // Add start point annotation} else if (I = size-1) {RouteAnnotation * item = [[RouteAnnotation alloc] init]; item. coordinate = plan. terminal. location; item. title = @ "end"; item. type = 1; [_ mapView addAnnotation: item]; // Add start point annotation} // Add annotation node RouteAnnotation * item = [[RouteAnnotation alloc] init]; item. coordinate = transitStep. entrace. location; item. title = transitStep. entraceInstruction; item. degree = transitStep. direction * 30; item. type = 4; [_ mapView addAnnotation: item]; // planPointCounts + = transitStep. pointsCount; // ------------------------------------------------------------- if (I = 0) {// use the first coordinate point as the initial value minLat = plan. starting. location. latitude; maxLat = plan. starting. location. latitude; minLon = plan. starting. location. longpolling; maxLon = plan. starting. location. longpolling;} else {// compare and filter out the minimum latitude and maximum latitude. The minimum longitude and the maximum longitude minLat = MIN (minLat, transitStep. entrace. location. latitude); maxLat = MAX (maxLat, transitStep. entrace. location. latitude); minLon = MIN (minLon, transitStep. entrace. location. longpolling); maxLon = MAX (maxLon, transitStep. entrace. location. longpolling);} // -------------------------------------------------------------} [self setVisibleRegin]; // Add the path if (plan. wayPoints) {for (BMKPlanNode * tempNode in plan. wayPoints) {RouteAnnotation * item = [[RouteAnnotation alloc] init]; item = [[RouteAnnotation alloc] init]; item. coordinate = tempNode.pt; item. type = 5; item. title = tempNode. name; [_ mapView addAnnotation: item] ;}// track point BMKMapPoint * temppoints = new BMKMapPoint [planPointCounts]; int I = 0; for (int j = 0; j <size; j ++) {BMKDrivingStep * transitStep = [plan. steps objectAtIndex: j]; int k = 0; for (k = 0; k
 
  

  

  
-(Void) setVisibleRegin {// calculate the center point CLLocationCoordinate2D centCoor; centCoor. latitude = (CLLocationDegrees) (maxLat + minLat) * 0.5f); centCoor. longpolling = (CLLocationDegrees) (maxLon + minLon) * 0.5f); BMKCoordinateSpan span; // calculates the span of a geographical location. latitudeDelta = maxLat-minLat; span. longitudeDelta = maxLon-minLon; // obtain the data coordinate region BMKCoordinateRegion region = BMKCoordinateRegionMake (centCoor, span ); // The coordinate range of Baidu map is converted to the position of the relative view CGRect fitRect = [_ mapView convertRegion: region toRectToView: _ mapView]; // convert the location of the map view to the location of the map. BMKMapRect fitMapRect = [_ mapView convertRect: fitRect toMapRectFromView: _ mapView]; // set the visible range of the map to the location of the map where the data is located [_ mapView setVisibleMapRect: fitMapRect animated: YES];}
Thank you for your criticism !!!