Question

enter image description here 的总结： 我无法强制CALayer正确响应方向更改。每当我尝试使用cgaffinetransform时，我都会得到奇怪的结果（图层不居中）。任何帮助将不胜感激！感谢，

过程我正在使用AVCaptureVideoPreviewLayer子类添加视频预览。当设备处于纵向时，一切看起来都很好。当设备旋转到横向（左或右）或纵向上下颠倒时，会出现问题。

我正在使用AVCaptureVideoPreviewLayer子类添加视频预览。当设备处于纵向时，一切看起来都很好。当设备旋转到横向（左或右）或纵向上下颠倒时，会出现问题。

我正在使用以下代码添加预览图层：

CGRect layerRect = [[[self view] layer] bounds];
[[[self captureManager] previewLayer] setBounds:layerRect];
[[[self captureManager] previewLayer]setFrame:CGRectMake(0, height, width, height)];
[[[self captureManager] previewLayer] setPosition:CGPointMake(CGRectGetMidX(layerRect),CGRectGetMidY(layerRect))];

在纵向模式下正确显示。当我尝试旋转设备时，预览图层表现得很奇怪。它似乎没有调整自身大小，并且无法正确旋转。

我尝试通过添加以下方法来修复它

-(void)rotateLayer{
CALayer * stuckview = [[self captureManager] previewLayer];
CGRect layerRect = [[[self view] layer] bounds];

UIDeviceOrientation orientation =[[UIDevice currentDevice]orientation];

switch (orientation) {
    case UIDeviceOrientationLandscapeLeft:
        stuckview.affineTransform = CGAffineTransformMakeRotation(M_PI+ M_PI_2); // 270 degress
        NSLog(@"Landscape Left");
        [stuckview setPosition: CGPointMake(self.view.bounds.size.width /2.0, self.view.bounds.size.height /2.0)];

        break;
    case UIDeviceOrientationLandscapeRight:
        stuckview.affineTransform = CGAffineTransformMakeRotation(M_PI_2); // 90 degrees
        NSLog(@"Landscape Right");
        [stuckview setPosition: CGPointMake(self.view.bounds.size.width /2.0, self.view.bounds.size.height /2.0)];
        break;
    case UIDeviceOrientationPortraitUpsideDown:
        stuckview.affineTransform = CGAffineTransformMakeRotation(M_PI); // 180 degrees
        NSLog(@"Landscape Upside down");
        break;
    default:
        stuckview.affineTransform = CGAffineTransformMakeRotation(0.0);
        break;
}
 float h1 = stuckview.frame.size.height;
   float w1 = stuckview.frame.size.width;

if(UIDeviceOrientationIsPortrait(orientation))
{
  stuckview.position =CGPointMake(h1/2.0, w1/2.0);
    NSLog(@"Portrait");
}
else{
  stuckview.position =CGPointMake(w1/2.0, h1/2.0);
    NSLog(@"Portrait");
}

}

添加上述方法后，我可以看到进度。现在图层旋转正确反映当前设备方向，并且在横向模式下正确显示，但不在纵向模式下显示。

图层位置不正确，它不在屏幕中心（查看屏幕截图）。为了看看发生了什么，我添加了以下调试语句：

CALayer * stuckview = [[self captureManager] previewLayer];
CGRect layerRect = [[[self view] layer] bounds];
float h = stuckview.bounds.size.height;
float w = stuckview.bounds.size.width;

float x = stuckview.bounds.origin.x;
float y = stuckview.bounds.origin.y;

float h1 = stuckview.frame.size.height;
float w1 = stuckview.frame.size.width;

float x1 = stuckview.frame.origin.x;
float y1 = stuckview.frame.origin.y;

NSLog(@"%f %f %f %f ", h,w,x,y );
NSLog(@"%f %f %f %f ", h1,w1,x1,y1 );

NSLog(@"Anchor Point: %f  %f",stuckview.anchorPoint.x, stuckview.anchorPoint.y);
NSLog(@"Position: %f  %f",stuckview.position.x, stuckview.position.y);

CGAffineTransform at = stuckview.affineTransform;

NSLog(@"Affine Transform After : %f %f %f %f %f %f %f", at.a,at.b, at.c, at.d, at.tx,at.tx, at.ty);

获得以下输出：

2012-09-30 13:25:12.067 RotatePreviewLayer[2776:907] 1024.000000 768.000000 0.000000 0.000000

2012-09-30 RotatePreviewLayer [2776：907] 1024.000000 768.000000 128.000000 -128.000000

2012-09-30 13:25:12.070 RotatePreviewLayer[2776:907] Portrait
2012-09-30 13:25:12.072 RotatePreviewLayer[2776:907] Anchor Point: 0.500000  0.500000
2012-09-30 13:25:12.074 RotatePreviewLayer[2776:907] Position: 512.000000  384.000000
2012-09-30 13:25:12.076 RotatePreviewLayer[2776:907] Affine Transform after: -1.000000 0.000000 -0.000000 -1.000000 0.000000 0.000000 0.000000

注意调试输出的第二行。预览图层的帧移动128，-128。任何人都可以解释我为什么会发生这种情况以及如何解决预览图层的方向问题？谢谢，雅努什

Answer 1

这个怎么样？

- (void)willRotateToInterfaceOrientation:(UIInterfaceOrientation)toInterfaceOrientation duration:(NSTimeInterval)duration
{
    _videoPreviewLayer.connection.videoOrientation = toInterfaceOrientation;
}

Answer 2

这是我在视图控制器中使用的方法，用于维护捕获层的方向，使其始终正面朝上：

- (void)willRotateToInterfaceOrientation:(UIInterfaceOrientation)toInterfaceOrientation duration:(NSTimeInterval)duration
    if (_previewLayer.connection.supportsVideoOrientation)
    {
    switch (toInterfaceOrientation)
        {
        case UIInterfaceOrientationPortrait:
            {
            _previewLayer.connection.videoOrientation = AVCaptureVideoOrientationPortrait;
            break;
            }
        case UIInterfaceOrientationPortraitUpsideDown:
            {
            _previewLayer.connection.videoOrientation = AVCaptureVideoOrientationPortraitUpsideDown;
            break;
            }
        case UIInterfaceOrientationLandscapeLeft:
            {
            _previewLayer.connection.videoOrientation = AVCaptureVideoOrientationLandscapeLeft;
            break;
            }
        case UIInterfaceOrientationLandscapeRight:
            {
            _previewLayer.connection.videoOrientation = AVCaptureVideoOrientationLandscapeRight;
            break;
            }
        }
    }

有点罗嗦，但即使将来任何枚举都发生变化也是安全的。

Answer 3

我仍然不确定导致问题的是什么，但我设法解决了这个问题。我是这样做的：

在viewDidLoad中我正在添加一个图层：

CGRect layerRect = [[[self view] layer] bounds];
    [[[self captureManager] previewLayer] setBounds:layerRect];
    [[[self captureManager] previewLayer] setPosition:CGPointMake(CGRectGetMidX(layerRect),CGRectGetMidY(layerRect))];
    [[[self view] layer] addSublayer:[[self captureManager] previewLayer]];

然后我将rotateLayer方法的调用添加到didRotate

- (void)didRotateFromInterfaceOrientation:(UIInterfaceOrientation)fromInterfaceOrientation{
    [self rotateLayer];
}

最后，rotateLayer方法如下：

-(void)rotateLayer{
    CALayer * stuckview = [[self captureManager] previewLayer];
    CGRect layerRect = [[[self view] layer] bounds];

    UIDeviceOrientation orientation =[[UIDevice currentDevice]orientation];

    switch (orientation) {
        case UIDeviceOrientationLandscapeLeft:
            stuckview.affineTransform = CGAffineTransformMakeRotation(M_PI+ M_PI_2); // 270 degress

            break;
        case UIDeviceOrientationLandscapeRight:
            stuckview.affineTransform = CGAffineTransformMakeRotation(M_PI_2); // 90 degrees
            break;
        case UIDeviceOrientationPortraitUpsideDown:
            stuckview.affineTransform = CGAffineTransformMakeRotation(M_PI); // 180 degrees
            break;
        default:
            stuckview.affineTransform = CGAffineTransformMakeRotation(0.0);
            [stuckview setBounds:layerRect];
            break;
    }
    [stuckview setPosition:CGPointMake(CGRectGetMidX(layerRect),CGRectGetMidY(layerRect))];
}

我仍然不明白为什么它以这种方式运作。如果有人能解释它会很棒。

Answer 4

@Janusz Chudzynski这里是rotateLayer方法做的详细解释

这个方法是在检查了不同的方向如何影响previewLayer之后创建的，因此当方向位于LandscapeLeft时，创造者已经检查了它然后应该旋转270度以使其处于正确位置以便他使用

stuckview.affineTransform = CGAffineTransformMakeRotation(M_PI+ M_PI_2);

     M_PI        3.14159265358979323846264338327950288   // pi     = 180 degree  
                                    +      
     M_PI_2      1.57079632679489661923132169163975144   // pi/2   = 90  degree

                                                         // Total  = 270 degree

因此，如果我在previewLayer中将LandscapeLeft旋转到270度，那么它将处于正确的位置，就像他为每次旋转都旋转previewLayer一样

Answer 5

- (void)willRotateToInterfaceOrientation:(UIInterfaceOrientation)toInterfaceOrientation duration:(NSTimeInterval)duration  
{  
    previewLayer.orientation = toInterfaceOrientation;  
}

Answer 6

我和@Siegfault一起，虽然我也发现当我的视图最初在iPad上以横向方向加载时，方向仍然是正确的。要解决此问题，我在viewDidAppear:中使用当前interfaceOrientation：

调用相同的委托方法

- (void)viewDidAppear:(BOOL)animated {
    [super viewDidAppear:animated];
    [self willRotateToInterfaceOrientation:self.interfaceOrientation duration:0.0];
}

Answer 7

使用willRotateToUserInterfaceOrientation的答案可以正常工作，但该方法已被弃用。因此，如果您能够使用iOS 9，那么就可以在Swift中实现这一目标：

override func viewWillTransitionToSize(size: CGSize, withTransitionCoordinator coordinator: UIViewControllerTransitionCoordinator) {
        let newOrientation = UIDevice.currentDevice().orientation
        switch newOrientation {
        case .LandscapeLeft:
            self.capturePreviewLayer?.connection.videoOrientation = .LandscapeLeft
        case .LandscapeRight:
            self.capturePreviewLayer?.connection.videoOrientation = .LandscapeRight
        case .Portrait, .Unknown, .FaceUp, .FaceDown:
            self.capturePreviewLayer?.connection.videoOrientation = .Portrait
        case .PortraitUpsideDown:
            self.capturePreviewLayer?.connection.videoOrientation = .PortraitUpsideDown
        }
        super.viewWillTransitionToSize(size, withTransitionCoordinator: coordinator)
    }

Answer 8

// layout iOS 8+ animated 
- (void)viewWillTransitionToSize:(CGSize)size withTransitionCoordinator:(id<UIViewControllerTransitionCoordinator>)coordinator
{
    [coordinator animateAlongsideTransition:^(id<UIViewControllerTransitionCoordinatorContext> context)
    {
         NSString *timingFunc = nil;
         switch ( [context completionCurve] )
         {
             case UIViewAnimationCurveEaseIn:    timingFunc = kCAMediaTimingFunctionEaseIn;          break;
             case UIViewAnimationCurveEaseInOut: timingFunc = kCAMediaTimingFunctionEaseInEaseOut;   break;
             case UIViewAnimationCurveEaseOut:   timingFunc = kCAMediaTimingFunctionEaseOut;         break;
             case UIViewAnimationCurveLinear:    timingFunc = kCAMediaTimingFunctionLinear;          break;
         }

         [CATransaction begin];
         [CATransaction setAnimationDuration:[context transitionDuration]];
         [CATransaction setAnimationTimingFunction:[CAMediaTimingFunction functionWithName:timingFunc]];
         [self updatePreviewLayer];
         [CATransaction commit];

         UIInterfaceOrientation toOrientation = [[UIApplication sharedApplication] statusBarOrientation];
         // layout ui if needed

    } completion:^(id<UIViewControllerTransitionCoordinatorContext> context)
    {

    }];

    [super viewWillTransitionToSize:size withTransitionCoordinator:coordinator];
}

- (void)updatePreviewLayer
{
    CGAffineTransform transform = CGAffineTransformIdentity;
    switch ( UIDevice.currentDevice.orientation )
    {
        case UIDeviceOrientationLandscapeLeft:
            transform = CGAffineTransformRotate(transform, -M_PI_2);
        break;
        case UIDeviceOrientationLandscapeRight:
            transform = CGAffineTransformRotate(transform, M_PI_2);
        break;
        case UIDeviceOrientationPortraitUpsideDown:
            transform = CGAffineTransformRotate(transform, M_PI);
        break;
        default:
        break;
    }
    preview.affineTransform = transform;
    preview.frame = self.view.bounds;
}

iOS CAlayer Orientation AVCaptureVideoPreviewLayer不会旋转

8 个答案: