ios AVFoundation 点击​​聚焦

Question

我正在尝试创建一个相机应用程序，它或多或少会像默认相机应用程序一样工作。 目前对我不起作用的事情是点击聚焦。我希望相机聚焦并在我的触摸点上做任何事情，就像真正的相机应用一样。

这是我的 viewDidLoad

- (void)viewDidLoad
{
    [super viewDidLoad];

    // Session
    _session = [[AVCaptureSession alloc] init];
    _session.sessionPreset = AVCaptureSessionPresetPhoto;

    // Input
    _videoDevice = [AVCaptureDevice defaultDeviceWithMediaType:AVMediaTypeVideo];
    _videoInput = [AVCaptureDeviceInput deviceInputWithDevice:_videoDevice error:nil];

    // Output
    _frameOutput = [[AVCaptureVideoDataOutput alloc] init];
    _frameOutput.videoSettings = [NSDictionary dictionaryWithObject:AVVideoCodecJPEG forKey:AVVideoCodecKey];

    [_frameOutput setSampleBufferDelegate:self queue:dispatch_get_main_queue()];
    [_session addInput:_videoInput];
    [_session addOutput:_frameOutput];
    [_session startRunning];
};

这是让我的相机在点击时对焦的方法。

-(void)touchesBegan:(NSSet *)touches withEvent:(UIEvent *)event {

    [touches enumerateObjectsUsingBlock:^(id obj, BOOL *stop) {
        UITouch *touch = obj;
        CGPoint touchPoint = [touch locationInView:touch.view];
        focusLayer.frame = CGRectMake((touchPoint.x-25), (touchPoint.y-25), 50, 50);

        if ([_videoDevice isFocusPointOfInterestSupported]) {
            NSError *error;
            if ([_videoDevice lockForConfiguration:&error]) {
                [_videoDevice setFocusPointOfInterest:touchPoint];
                [_videoDevice setExposurePointOfInterest:touchPoint];

                [_videoDevice setFocusMode:AVCaptureFocusModeAutoFocus];
                if ([_videoDevice isExposureModeSupported:AVCaptureExposureModeAutoExpose]){
                    [_videoDevice setExposureMode:AVCaptureExposureModeAutoExpose];
                }
                [_videoDevice unlockForConfiguration];
            }
        }


        // NSLog(@"x = %f, y = %f", touchPoint.x, touchPoint.y);
    }];
}

点击屏幕后什么都没有发生。

Answer 1

您必须使用以下代码将 touchPoint 调整为 [0,1] 的范围：

    CGRect screenRect = [[UIScreen mainScreen] bounds];
    screenWidth = screenRect.size.width;
    screenHeight = screenRect.size.height;  
    double focus_x = thisFocusPoint.center.x/screenWidth;
    double focus_y = thisFocusPoint.center.y/screenHeight;

    [[self captureManager].videoDevice lockForConfiguration:&error];
    [[self captureManager].videoDevice setFocusPointOfInterest:CGPointMake(focus_x,focus_y)];
    [[self captureManager].videoDevice unlockForConfiguration];

这方面的文档可以在Apple - AV Foundation Programming Guidelines - see section Media Capture where you will find information on Focus Modes找到：

如果支持，您可以使用 focusPointOfInterest 设置焦点。您传递一个 CGPoint，其中 {0,0} 代表图片区域的左上角，{1,1} 代表横向模式下的右下角，主页按钮位于右侧——即使设备处于纵向模式也适用.

Answer 2

UITapGestureRecognizer *shortTap = [[UITapGestureRecognizer alloc] initWithTarget:self action:@selector(handleTapToFocus:)];
shortTap.numberOfTapsRequired=1;
shortTap.numberOfTouchesRequired=1;
[viewCanvasRecording addGestureRecognizer:shortTap];

然后是这个：

- (void)handleTapToFocus:(UITapGestureRecognizer *)tapGesture
{
    AVCaptureDevice *acd=!currentFrontCamera ? captureBackInput.device : captureFrontInput.device;

    if (tapGesture.state == UIGestureRecognizerStateEnded)
    {
        CGPoint thisFocusPoint = [tapGesture locationInView:viewCanvasRecording];

        double focus_x = thisFocusPoint.x/viewCanvasRecording.frame.size.width;
        double focus_y = thisFocusPoint.y/viewCanvasRecording.frame.size.height;

        if ([acd isFocusModeSupported:AVCaptureFocusModeAutoFocus] && [acd isFocusPointOfInterestSupported])
        {
            if ([acd lockForConfiguration:nil])
            {
                [acd setFocusMode:AVCaptureFocusModeAutoFocus];
                [acd setFocusPointOfInterest:CGPointMake(focus_x, focus_y)];

                /*
                if ([acd isExposureModeSupported:AVCaptureExposureModeAutoExpose] && [acd isExposurePointOfInterestSupported])
                {
                    [acd setExposureMode:AVCaptureExposureModeAutoExpose];
                    [acd setExposurePointOfInterest:CGPointMake(focus_x, focus_y)];
                }*/

                [acd unlockForConfiguration];
            }
        }
    }
}

Swift 版本：

@IBAction func tapToFocus(_ sender: UITapGestureRecognizer) {
    if (sender.state == .ended) {
        let thisFocusPoint = sender.location(in: previewView)

        print("touch to focus ", thisFocusPoint)

        let focus_x = thisFocusPoint.x / previewView.frame.size.width
        let focus_y = thisFocusPoint.y / previewView.frame.size.height

        if (captureDevice!.isFocusModeSupported(.autoFocus) && captureDevice!.isFocusPointOfInterestSupported) {
            do {
                try captureDevice?.lockForConfiguration()
                captureDevice?.focusMode = .autoFocus
                captureDevice?.focusPointOfInterest = CGPoint(x: focus_x, y: focus_y)

                if (captureDevice!.isExposureModeSupported(.autoExpose) && captureDevice!.isExposurePointOfInterestSupported) {
                    captureDevice?.exposureMode = .autoExpose;
                    captureDevice?.exposurePointOfInterest = CGPoint(x: focus_x, y: focus_y);
                 }

                captureDevice?.unlockForConfiguration()
            } catch {
                print(error)
            }
        }
    }
}

Answer 3

以下是我为 AV 摄像机预览处理手势的方法。首先设置您的 UITapGestureRecognizer，然后使用 captureDevicePointOfInterestForPoint 获取点。

- (void)setupGestures
{
  UITapGestureRecognizer *tapToFocusRecognizer = [[UITapGestureRecognizer alloc] initWithTarget:self
                                          action:@selector(handleTapToFocusAndExposureRecognizer:)];
  [self addGestureRecognizer:tapToFocusRecognizer];
}

- (void)handleTapToFocusAndExposureRecognizer:(UITapGestureRecognizer*)tabRecognizer {
  CGPoint touchPoint = [tabRecognizer locationInView:self];
  CGPoint point = [self.previewLayer captureDevicePointOfInterestForPoint:touchPoint];
  AVCaptureDevice *device = [self.videoCaptureDeviceInput device];
  NSError *error = nil;

  if (tabRecognizer.state == UIGestureRecognizerStateEnded) {
    if (![device lockForConfiguration:&error]) {
      if (error) {
        RCTLogError(@"%s: %@", __func__, error);
      }
      return;
    }

    [device setFocusPointOfInterest:CGPointMake(point.x, point.y)];
    [device setFocusMode:AVCaptureFocusModeContinuousAutoFocus];

    [device setExposurePointOfInterest:CGPointMake(point.x, point.y)];
    [device setExposureMode:AVCaptureExposureModeContinuousAutoExposure];

    [device unlockForConfiguration];
  }
}

我正在使用 AVCaptureVideoPreviewLayer 来获取接触点。但是如果你使用 GLKView 来渲染预览而不是 AVCaptureVideoPreviewLayer，你不能直接得到要点，而必须像之前的答案那样得到要点。

ios 开发的新编码器。希望这能有所帮助。