iOS 6 MkMapView在更改区域时保留旋转

概述在iOS 6中,我试图实现在不改变旋转的情况下更改MkMapView区域的功能. 基本上,我需要能够移动地图以显示区域(因此设置缩放),但我也不想在调用[mapView setRegion：]时旋转地图. [mapView setCenterCoordinate：]运行良好,但不允许我更改缩放级别. 在iOS 7中,我使用[mapView setCamera：],其中我有一个具有中心坐标和指定缩放 在iOS 6中,我试图实现在不改变旋转的情况下更改MkMapVIEw区域的功能.

基本上,我需要能够移动地图以显示区域(因此设置缩放),但我也不想在调用[mapVIEw setRegion：]时旋转地图.

[mapVIEw setCenterCoordinate：]运行良好,但不允许我更改缩放级别.

在iOS 7中,我使用[mapVIEw setCamera：],其中我有一个具有中心坐标和指定缩放级别的相机……我在iOS 6中基本上需要此功能.

有任何想法吗？谢谢！

解决方法 我有这个完全相同的问题,并最终完全放弃[mapVIEw setRegion：]方法,支持[mapVIEw setCamera：]使用原始区域和标题作为如何定向相机的基础.

MKCoordinateRegion currentRegion = MKCoordinateRegionMake(center,span);double altitude = [self determineAltitudeForMapRect:MKMapRectForCoordinateRegion(currentRegion) withheading:_heading anDWithVIEwport:[[UIScreen mainScreen] bounds].size];MKMapCamera *currentCamera = [MKMapCamera new];[currentCamera setheading:_heading];[currentCamera setCenterCoordinate:center];[currentCamera setAltitude:altitude];[_mapVIEw setCamera:currentCamera];

这个选项的技巧是如何确定[currentCamera setAltitude：]值,这通常是使用[mapVIEw setRegion：]自动设置的

我的解决方案是改编这个答案https://stackoverflow.com/a/21034410/1130983,它使用一些简单的触发来确定高度,假设地图camara有大约30度的视角.但是,我没有传入多边形,而是直接传入MKMapRect：

- (double)determineAltitudeForMapRect:(MKMapRect)boundingRect withheading:(double)heading anDWithVIEwport:(CGSize)vIEwport{    // Get a bounding rectangle that encompasses the polygon and represents its    // true aspect ratio based on the understanding of its heading.    MKCoordinateRegion boundingRectRegion = MKCoordinateRegionForMapRect(boundingRect);    // Calculate a new bounding rectangle that is corrected for the aspect ratio    // of the vIEwport/camera -- this will be needed to ensure the resulting    // altitude actually fits the polygon in vIEw for the observer.    CLLocationCoordinate2D upperleftCoord = CLLocationCoordinate2DMake(boundingRectRegion.center.latitude + boundingRectRegion.span.latitudeDelta / 2,boundingRectRegion.center.longitude - boundingRectRegion.span.longitudeDelta / 2);    CLLocationCoordinate2D upperRightCoord = CLLocationCoordinate2DMake(boundingRectRegion.center.latitude + boundingRectRegion.span.latitudeDelta / 2,boundingRectRegion.center.longitude + boundingRectRegion.span.longitudeDelta / 2);    CLLocationCoordinate2D lowerleftCoord = CLLocationCoordinate2DMake(boundingRectRegion.center.latitude - boundingRectRegion.span.latitudeDelta / 2,boundingRectRegion.center.longitude - boundingRectRegion.span.longitudeDelta / 2);    CLLocationdistance hdist = MKMetersBetweenMapPoints(MKMapPointForCoordinate(upperleftCoord),MKMapPointForCoordinate(upperRightCoord));    CLLocationdistance vdist = MKMetersBetweenMapPoints(MKMapPointForCoordinate(upperleftCoord),MKMapPointForCoordinate(lowerleftCoord));    double adjacent;    if (boundingRect.size.height > boundingRect.size.wIDth)    {        adjacent = vdist / 2;    }    else    {        adjacent = hdist / 2;    }    double result = adjacent / tan(degrees_TO_radians(15));    return result;}

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