How can I create a Square Overlay that will cover the current region of my MKMapView. My MKMapView is set with coordinates of the users current location but they are centre coordinates. How do I calculate the square coordinates so I can create a square overlay that fits perfectly in the current view?
Thanks guys!
You can use the centerCoordinate and region properties of MKMapView and then create a MKPolygon overlay by extracting the four corners, as in the code below:
vertex[0]=CLLocationCoordinate2DMake(map.centerCoordinate.latitude+map.region.span.latitudeDelta/2.,map.centerCoordinate.longitude-map.region.span.longitudeDelta/2.);
vertex[1]=CLLocationCoordinate2DMake(map.centerCoordinate.latitude+map.region.span.latitudeDelta/2.,map.centerCoordinate.longitude+map.region.span.longitudeDelta/2.);
vertex[2]=CLLocationCoordinate2DMake(map.centerCoordinate.latitude-map.region.span.latitudeDelta/2.,map.centerCoordinate.longitude+map.region.span.longitudeDelta/2.);
vertex[3]=CLLocationCoordinate2DMake(map.centerCoordinate.latitude-map.region.span.latitudeDelta/2.,map.centerCoordinate.longitude-map.region.span.longitudeDelta/2.);
MKPolygon *square = [MKPolygon polygonWithCoordinates:vertex count:4];
Then you add the polygon as an overlay:
[map addOverlay:square]
Finally in your mapView:rendererForOverlay: you define your square rendered based on the polygon overlay:
- (MKOverlayRenderer *)mapView:(MKMapView *)mapView rendererForOverlay:(id)overlay {
if([overlay isKindOfClass:[MKPolygon class]]) {
MKPolygonRenderer *renderer = [[MKPolygonRenderer alloc] initWithPolygon:(MKPolygon *)overlay];
renderer.fillColor = [[UIColor redColor] colorWithAlphaComponent:0.25];
return renderer;
} else {
return nil;
}
}
Related
After uploading a custom image for the MKPinAnnotationView, I noticed that the pin was off-centered. The pin is supposed to be on a point on the route's polyline, and in the center of an mkcircle; however, the pin seems to be to the right of the polyline and a little north of the center. I tried experimenting with the centerOffset property, but when I plug values into the property, nothing seems to change. Here is the code,
-(MKAnnotationView *)mapView:(MKMapView *)mapView viewForAnnotation:(id <MKAnnotation>)annotation{
static NSString *viewID = #"MKPinAnnotationView";
MKPinAnnotationView *annotationView = (MKPinAnnotationView*)
[self.mapView dequeueReusableAnnotationViewWithIdentifier:viewID];
if(annotationView ==nil){
annotationView = [[MKPinAnnotationView alloc]initWithAnnotation:annotation reuseIdentifier:viewID];
}
annotationView.image = [UIImage imageNamed:#"Pin.png"];
annotationView.enabled = YES;
//doesn't move the pin, still offcentered
annotationView.centerOffset = CGPointMake(0,-50);
return annotationView;
}
Just something to add, I also noticed that with the new pin image, nothing pops up when I click on the pin. Before, with the default pin, a bubble of text would appear after clicking on the pin. Since this is the case, I want to include the code for the method that makes and places the pin on the map,
-(void) createAndAddAnnotationForCoordinate : (CLLocationCoordinate2D)coordinate{
MKPointAnnotation* annotation = [[MKPointAnnotation alloc]init];
annotation.coordinate = coordinate;
annotation.title = #"This is a pin!";
[mapView addAnnotation:annotation];
}
I also tried changing the pin image to see if that would influence the positioning of the MKPinAnnotationView. Although I was able to center the pin by editing the image, it isn't centered for other polylines. Any help would be appreciated!
First, an important point is that when using a custom annotation image, it's best to use the plain MKAnnotationView class instead of its subclass MKPinAnnotationView which is designed to automatically display a standard pin image.
This is because MKPinAnnotationView includes some built-in adjustments of the annotation view's frame and centerOffset based on its own pin image. In some cases, your custom image will even be replaced on the screen with the default pin image. So even though MKPinAnnotationView has an image property, the class will not always use it as expected.
Second, set the centerOffset such that as the map is zoomed, the part of the image that "points" to the coordinate keeps pointing to the coordinate. This is because the centerOffset is in screen CGPoints and does not scale with the zoom level of the map. If the centerOffset is not set properly, the "point" of the image will start to drift from the target coordinate.
Also note you may not even need to set centerOffset since the default will put the center of the image at the coordinate which you may be ok with.
Based on the image you posted, here is the code and resulting appearance without setting centerOffset (leaving it at the default):
-(MKAnnotationView *)mapView:(MKMapView *)mapView viewForAnnotation:(id <MKAnnotation>)annotation{
static NSString *viewID = #"MKPinAnnotationView";
MKAnnotationView *annotationView = [mapView dequeueReusableAnnotationViewWithIdentifier:viewID];
if (annotationView ==nil) {
annotationView = [[MKAnnotationView alloc] initWithAnnotation:annotation reuseIdentifier:viewID];
annotationView.image = [UIImage imageNamed:#"Pin.png"];
annotationView.canShowCallout = YES;
}
else {
annotationView.annotation = annotation;
}
return annotationView;
}
(I added the red center lines to show where the target coordinate is relative to the pin image.)
Here is the code and resulting appearance with centerOffset set so that the bottom points to the coordinate:
-(MKAnnotationView *)mapView:(MKMapView *)mapView viewForAnnotation:(id <MKAnnotation>)annotation{
static NSString *viewID = #"MKPinAnnotationView";
MKAnnotationView *annotationView = [mapView dequeueReusableAnnotationViewWithIdentifier:viewID];
if (annotationView ==nil) {
annotationView = [[MKAnnotationView alloc] initWithAnnotation:annotation reuseIdentifier:viewID];
annotationView.image = [UIImage imageNamed:#"Pin.png"];
annotationView.canShowCallout = YES;
annotationView.centerOffset = CGPointMake(0,-15);
}
else {
annotationView.annotation = annotation;
}
return annotationView;
}
You have to set MKCoordinateRegion to load the map, edit your createAndAddAnnotationForCoordinate method as below
-(void) createAndAddAnnotationForCoordinate : (CLLocationCoordinate2D)coordinate{
MKCoordinateRegion viewRegion = MKCoordinateRegionMakeWithDistance(coordinate, 3000, 3000); //Set zooming level
MKCoordinateRegion adjustedRegion = [mapView regionThatFits:viewRegion]; //add location to map
[mapView setRegion:adjustedRegion animated:YES]; // create animation zooming
MKPointAnnotation* annotation = [[MKPointAnnotation alloc]init];
annotation.coordinate = coordinate;
annotation.title = #"This is a pin!";
[mapView addAnnotation:annotation];
}
I create new overlays like this:
MKCircle *circle = [MKCircle circleWithCenterCoordinate:region.coordinate radius:region.radius];
[self.mapView addOverlay:circle];
also I implemented delegate method:
- (MKOverlayRenderer *)mapView:(MKMapView *)mapView rendererForOverlay:(id<MKOverlay>)overlay {
MKCircleRenderer *circleRenderer = [[MKCircleRenderer alloc] init];
circleRenderer.fillColor = [UIColor greenColor];
circleRenderer.alpha = 1.f;
return circleRenderer;
}
both parts of code are called, mapView != nil at that moment, it's delegate set,
but I cannot see the circle on my map.
What am I doing wrong?
As per #Rob suggestion you need to init MKCircleRenderer using other method initWithCircle.
- (MKOverlayRenderer *)mapView:(MKMapView *)mapView rendererForOverlay:(id<MKOverlay>)overlay {
MKCircleRenderer *circleRenderer = [[MKCircleRenderer alloc] initWithCircle:overlay];
circleRenderer.fillColor = [UIColor greenColor];
circleRenderer.alpha = 1.f;
return circleRenderer;
}
Also make sure that fence distance is proper enough to visible the circle in map.
For example:
CLLocationDistance fenceDistance = 100000;
MKCircle *circle = [MKCircle circleWithCenterCoordinate:region.coordinate radius:fenceDistance];
[self.mapView addOverlay:circle];
Rather than init, call the MKCircleRenderer method initWithCircle.
Obviously, make sure the delegate of the map view is set, that your code that adds the overlay and that instantiates the renderer is called at all, etc., but initWithCircle is the likely culprit.
I have Map in my app in which is moving as per user location.I have successfully drawn a polyline for source and destination.
Using following code
- (MKOverlayView *)mapView:(MKMapView *)mapView viewForOverlay:(id < MKOverlay >)overlay{
MKPolylineView *view1 = [[MKPolylineView alloc] initWithOverlay:overlay];
view1.lineWidth = 27.0;
view1.strokeColor = [UIColor colorWithRed:55.0/255.0 green:168.0/255.0 blue:219.0/255.0 alpha:1];
return view1;
}
But my problem is when map is moving , mean i am changing region of map as user moves , then some times polyline is not shown good some time its show thicker than actual size as you can see in below image.
i am attaching the image below, please let me know what can i do for smooth polyline when map is moving.
EDIT
As Matt suggested i create a subclass of MKPolylineRenderer and implement drawMapRect method as below:
-(void)drawMapRect:(MKMapRect)mapRect zoomScale:(MKZoomScale)zoomScale inContext:(CGContextRef)context{
CGMutablePathRef fullPath = CGPathCreateMutable();
BOOL pathIsEmpty = YES;
//merging all the points as entire path
for (int i=0;i< self.polyline.pointCount;i++){
CGPoint point = [self pointForMapPoint:self.polyline.points[i]];
if (pathIsEmpty){
CGPathMoveToPoint(fullPath, nil, point.x, point.y);
pathIsEmpty = NO;
} else {
CGPathAddLineToPoint(fullPath, nil, point.x, point.y);
}
}
//get bounding box out of entire path.
CGRect pointsRect = CGPathGetBoundingBox(fullPath);
CGRect mapRectCG = [self rectForMapRect:mapRect];
//stop any drawing logic, cuz there is no path in current rect.
if (!CGRectIntersectsRect(pointsRect, mapRectCG))return;
UIColor *darker = [UIColor blackColor];
CGFloat baseWidth = 10 / zoomScale;
// draw the dark colour thicker
CGContextAddPath(context, self.path);
CGContextSetStrokeColorWithColor(context, darker.CGColor);
CGContextSetLineWidth(context, baseWidth * 1.5);
CGContextSetLineCap(context, self.lineCap);
CGContextStrokePath(context);
// now draw the stroke color with the regular width
CGContextAddPath(context, self.path);
CGContextSetStrokeColorWithColor(context, [UIColor redColor].CGColor);
CGContextSetLineWidth(context, baseWidth);
CGContextSetLineCap(context, self.lineCap);
CGContextStrokePath(context);
[super drawMapRect:mapRect zoomScale:zoomScale inContext:context];
}
But Same problem
See below image:
ok, i think i got problem , my polyline is added once, but as user's speed i changing zoom level of MKMapView, zoom level is changed , but polyline width is not refresh,
SO how can i dynamically change lineWidth of mkpolyline ??
The problem is that you are setting your lineWidth at a fixed width (a really big fixed width). This gets larger or smaller as the map is zoomed larger or smaller.
Instead, implement your own MKOverlayRenderer subclass, and override drawMapRect:zoomScale:inContext:. It receives a zoomScale parameter, and so you can adjust the width of your line to look good at what the current scale may be.
Subclass MKPolylineRenderer and override applyStrokePropertiesToContext:atZoomScale: so that it ignores the scale, and draws lines at constant width:
#interface ConstantWidthPolylineRenderer : MKPolylineRenderer
#end
#implementation ConstantWidthPolylineRenderer
- (void)applyStrokePropertiesToContext:(CGContextRef)context
atZoomScale:(MKZoomScale)zoomScale
{
[super applyStrokePropertiesToContext:context atZoomScale:zoomScale];
CGContextSetLineWidth(context, self.lineWidth);
}
#end
Now use it and admire its smooth rendering:
- (MKOverlayRenderer *)mapView:(MKMapView *)mapView rendererForOverlay:(id<MKOverlay>)overlay
{
MKPolyline *polyline = (MKPolyline *)overlay;
ConstantWidthPolylineRenderer *renderer = [[ConstantWidthPolylineRenderer alloc] initWithPolyline:polyline];
renderer.strokeColor = [UIColor redColor];
renderer.lineWidth = 40;
return renderer;
}
You need to use MKPolylineRenderer instead of MKPolylineView
- (MKOverlayRenderer *)mapView:(MKMapView *)mapView rendererForOverlay:(id < MKOverlay >)overlay {
#try {
MKPolylineRenderer *renderer = [[[MKPolylineRenderer alloc] initWithOverlay:overlay];
renderer.lineWidth = 27.0;
renderer.strokeColor = [UIColor colorWithRed:55.0/255.0 green:168.0/255.0 blue:219.0/255.0 alpha:1];
return renderer;
}
#catch (NSException *exception) {
NSLog(#"exception :%#",exception.debugDescription);
}
}
Read this one:
The MKPolylineRenderer class provides the visual representation for an MKPolyline overlay object. This renderer strokes the line only; it does not fill it. You can change the color and other drawing attributes of the polygon by modifying the properties inherited from the parent class. You typically use this class as is and do not subclass it.
From Apple library
The MKPolylineView class provides the visual representation for an MKPolyline annotation object. This view strokes the path represented by the annotation. (This class does not fill the area enclosed by the path.) You can change the color and other drawing attributes of the path by modifying the properties inherited from the MKOverlayPathView class. This class is typically used as is and not subclassed.
From Apple library
I am working in a project with MapKit, and I want to update the location of circle in the center of current user location. I can do that by implementing this methods. The problem is that user location when changes its coordinates animates and the method DidUpdateUserLocation doesnt get called everytime.
What I want to do is smoothly changing position with these methods faster and animating the circle like user location (blue dot) changes (dispatch wont do any of this tasks faster)
-(void)viewDidLoad
{
[super viewDidLoad];
[self UpdateCirclePosition];
}
This method get executed when user location changes.
- (void)mapView:(MKMapView *)mv didUpdateUserLocation:(MKUserLocation *)userLocation1
{
[self UpdateCirclePosition];
}
This method is to set new coordinates for the circle
-(void)UpdateCirclePosition
{
//Removing past layouts from MapView
[self.mapView removeOverlays: [self.mapView overlays]];
//Set the circle in the middle of the current user location
MKCircle *circle = [MKCircle circleWithCenterCoordinate:locationManager.location.coordinate radius:10];
[self.mapView addOverlay:circle];
}
And this is the method when overlay changes
- (MKOverlayView *)mapView:(MKMapView *)map viewForOverlay:(id <MKOverlay>)overlay
{
MKCircleView *circleView = [[MKCircleView alloc] initWithOverlay:overlay];
circleView.strokeColor = [UIColor redColor];
if (something)
{
circleView.fillColor = [[UIColor greenColor] colorWithAlphaComponent:0.2];
}
else
{
circleView.fillColor = [[UIColor redColor] colorWithAlphaComponent:0.2];
}
circleView.lineWidth = 0.5;
return circleView;
}
didUpdateUserLocation gets the latest position, but then you ignore it and call UpdateCirclePosition. You should pass the coordinates from userLocation1 into UpdateCirclePosition and use them to reposition your circle.
I have searched far and wide for a proper solution but have yet to find any.
-(MKOverlayView *)mapView:(MKMapView *)mapView viewForOverlay:(id)overlay
{
MKCircleView* circleView = [[[MKCircleView alloc] initWithOverlay:overlay] autorelease];
circleView.fillColor=[UIColor redColor];
return circleView;
}
-(void)overlay{
MKCircle *circleOverlay;
CLLocationCoordinate2D coords = CLLocationCoordinate2DMake(1.303819,103.7689956); //giza
circleOverlay=[MKCircle circleWithCenterCoordinate:coords radius:200];
[self.mapView addOverlay:circleOverlay];
}
Is there a simple way to add a text into this circle?