验证latlong是否在iOS中的MKPolygon内

Question

我验证一个latlong（CLLocationCoordinate2D）是否在MKMapview上绘制的MKPolygon内。

我使用下面的代码在MKMapview上绘制MKPolygon，

MKPolygon *polygon = [MKPolygon polygonWithCoordinates:coordinates count:count];
[mapviewcontroller.mapview addOverlay:polygon];

- (MKOverlayRenderer *)mapView:(MKMapView *)mapView rendererForOverlay:(id<MKOverlay>)overlay
{
    MKPolygonRenderer *renderer = [[MKPolygonRenderer alloc] initWithPolygon:overlay];
    renderer.fillColor   = [[UIColor grayColor] colorWithAlphaComponent:0.2];
    renderer.strokeColor = [[UIColor blackColor] colorWithAlphaComponent:0.7];
    renderer.lineWidth   = 2;
    return renderer;
}

我使用

验证MKPolygon中的latlong

CLLocationCoordinate2D sampleLocation = CLLocationCoordinate2DMake(13,80);//13,80 is the latlong of clear colored area of the MKPolygon in the below image.
MKMapPoint mapPoint = MKMapPointForCoordinate(sampleLocation);
CGPoint mapPointAsCGP = CGPointMake(mapPoint.x, mapPoint.y);

for (id<MKOverlay> overlay in mapview.overlays) {
    if([overlay isKindOfClass:[MKPolygon class]]){
        MKPolygon *polygon = (MKPolygon*) overlay;

        CGMutablePathRef mpr = CGPathCreateMutable();

        MKMapPoint *polygonPoints = polygon.points;

        for (int p=0; p < polygon.pointCount; p++){
            MKMapPoint mp = polygonPoints[p];
            if (p == 0)
                CGPathMoveToPoint(mpr, NULL, mp.x, mp.y);
            else
                CGPathAddLineToPoint(mpr, NULL, mp.x, mp.y);
        }

        if(CGPathContainsPoint(mpr , NULL, mapPointAsCGP, FALSE)){
            isInside = YES;
        }

        CGPathRelease(mpr);
    }
}

它适用于正常情况，但如果用户绘制如下的多边形，即MKpolygon有一些点相交，颜色在某些区域填充，并且某些区域颜色清晰。

如果我通过MKPolygon内部的透明颜色部分的latlong，它应该返回NO。但是，它返回YES。即if(CGPathContainsPoint(mpr , NULL, mapPointAsCGP, FALSE))为真。

如果MKPolygon之间有交集，我该如何解决这个问题？如果有人建议在那个清晰的颜色区域填充颜色，情况会更好。任何建议都将不胜感激。

Answer 1

显示的图片似乎展示了偶数填充规则。通过将FALSE指定为CGPathContainsPoint的最终参数，您已要求它应用绕组编号规则。尝试传递TRUE。

有关teo规则的信息，请参阅Apple's Quartz documentation，特别是“填充路径”（略低于一半）。

Answer 2

Swift 3.0实施：

func checkIf(polygon: MKPolygon, contains point: CGPoint) -> Bool {
    let path = CGMutablePath()
    let polygonPoints = polygon.points()

    for index in 0..<polygon.pointCount {
        let mp = polygonPoints[index]

        if index == 0 {
            path.move(to: CGPoint(x: mp.x, y: mp.y))
        } else {
            path.addLine(to: CGPoint(x: mp.x, y: mp.y))
        }
    }

    return path.contains(point)
}