检测点是否在MKPolygon叠加层内 [英] detect if a point is inside a MKPolygon overlay

问题描述

我希望能够判断tap是否在MKPolygon中。

I want to be able to tell if tap is within a MKPolygon.

我有一个MKPolygon：

I have a MKPolygon:

CLLocationCoordinate2D  points[4];

points[0] = CLLocationCoordinate2DMake(41.000512, -109.050116);
points[1] = CLLocationCoordinate2DMake(41.002371, -102.052066);
points[2] = CLLocationCoordinate2DMake(36.993076, -102.041981);
points[3] = CLLocationCoordinate2DMake(36.99892, -109.045267);

MKPolygon* poly = [MKPolygon polygonWithCoordinates:points count:4];

[self.mapView addOverlay:poly];  

//create UIGestureRecognizer to detect a tap
UITapGestureRecognizer *tapRecognizer = [[UITapGestureRecognizer alloc] initWithTarget:self action:@selector(foundTap:)];
tapRecognizer.numberOfTapsRequired = 1;
tapRecognizer.numberOfTouchesRequired = 1;
[self.mapView addGestureRecognizer:tapRecognizer];

它只是科罗拉多州的基本轮廓。

its just a basic outline of the state Colorado.

我点击了转/长转换设置：

I got the tap to lat/long conversion set up:

-(IBAction)foundTap:(UITapGestureRecognizer *)recognizer
{
    CGPoint point = [recognizer locationInView:self.mapView];

    CLLocationCoordinate2D tapPoint = [self.mapView convertPoint:point toCoordinateFromView:self.view];
}

但如果我的分接点在MKPolygon内，我不确定如何技术。似乎没有办法做这个检查，所以我猜我需要将MKPolygon转换为CGRect并使用CGRectContainsPoint。

but i am unsure how to tech if my tap point is within the MKPolygon. there does not seem to be a method to do this check, so i'm guessing i need to convert the MKPolygon to a CGRect and use CGRectContainsPoint.

MKPolygon有一个.points属性，但我似乎无法让它们退出。

MKPolygon has a .points property but i can't seem to get them back out.

有什么建议吗？

编辑：

以下两种解决方案均适用于iOS 6或更低版本，但在iOS 7中有效。在iOS 7中， polygon.path 属性全部返回 NULL 。安娜女士非常友好地提供另一个SO的解决方案问题在这里。它涉及从多边形点创建自己的路径以传递到 CGPathContainsPoint（）。

Both solutions below work in iOS 6 or lower, but breaks in iOS 7. In iOS 7 the polygon.path property allways returns NULL. Ms Anna was kind enough to provide a solution in another SO question here. It involves creating your own path from the polygon points to pass into CGPathContainsPoint().

我的多边形的图像：

推荐答案

我创建了这个MKPolygon类别，以防有人想要使用它。似乎运作良好。您必须考虑内部多边形（即多边形中的孔）：

I created this MKPolygon category in case anyone wants to use it. Seems to work well. You have to account for the interior polygons (i.e. holes in the polygon):

@interface MKPolygon (PointInPolygon)
  -(BOOL) pointInPolygon:(CLLocationCoordinate2D) point mapView: (MKMapView*) mapView;
@end

@implementation MKPolygon (PointInPolygon)

-(BOOL) pointInPolygon:(CLLocationCoordinate2D) point mapView: (MKMapView*) mapView {
    MKMapPoint mapPoint = MKMapPointForCoordinate(point);
    MKPolygonView * polygonView = (MKPolygonView*)[mapView viewForOverlay:self];
    CGPoint polygonViewPoint = [polygonView pointForMapPoint:mapPoint];
    return CGPathContainsPoint(polygonView.path, NULL, polygonViewPoint, NO) && 
        ![self pointInInteriorPolygons:point mapView:mapView];
}

-(BOOL) pointInInteriorPolygons:(CLLocationCoordinate2D) point mapView: (MKMapView*) mapView {
    return [self pointInInteriorPolygonIndex:0 point:point mapView:mapView];
}

-(BOOL) pointInInteriorPolygonIndex:(int) index point:(CLLocationCoordinate2D) point mapView: (MKMapView*) mapView {
    if(index >= [self.interiorPolygons count])
        return NO;
    return [[self.interiorPolygons objectAtIndex:index] pointInPolygon:point mapView:mapView] || [self pointInInteriorPolygonIndex:(index+1) point:point mapView:mapView];
}

@end

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