ios - 如何使相机输入图像与输出图像的比例相同？

Question

我创建了一个自定义相机，与它的问题是当我拍照时它以不同的比例出来，然后当我拍照时。

实施例：

之前：

后：

通知图像已被几乎侧身压扁。我想解决这个问题。我希望最终结果与输入图像完全相同。

我已经创建了一个视图，它是屏幕的大小，并用它来制作相机的框架，然后我制作了一个图像视图，它与覆盖屏幕的大小相同，由于某些原因照片不同。

下面是用于我的相机类我的源代码：

#import "CameraViewController.h" 
#import <AVFoundation/AVFoundation.h> 

@interface CameraViewController() 

@end 

@implementation CameraViewController { 
    BOOL isFront; 
} 
AVCaptureSession *session; 
AVCaptureStillImageOutput *imageOutput; 

@synthesize cancelButton; 

-(BOOL)prefersStatusBarHidden { 
    return YES; 
} 

-(void)viewDidAppear:(BOOL)animated { 
    isFront = NO; 
    session = [[AVCaptureSession alloc]init]; 
    [session setSessionPreset:AVCaptureSessionPresetPhoto]; 

    AVCaptureDevice *device = [AVCaptureDevice defaultDeviceWithMediaType:AVMediaTypeVideo]; 
    NSError *error; 
    AVCaptureDeviceInput *deviceInput = [AVCaptureDeviceInput deviceInputWithDevice:device error:&error]; 

    if ([session canAddInput:deviceInput]) { 
     [session addInput:deviceInput]; 
    } 

    AVCaptureVideoPreviewLayer *previewLayer = [[AVCaptureVideoPreviewLayer alloc]initWithSession:session]; 
    [previewLayer setVideoGravity:AVLayerVideoGravityResizeAspectFill]; 
    CALayer *rootLayer = [[self view]layer]; 
    [rootLayer setMasksToBounds:YES]; 
    CGRect frame = self.captureFrame.frame; 

    [previewLayer setFrame:frame]; 

    [rootLayer insertSublayer:previewLayer atIndex:0]; 

    imageOutput = [[AVCaptureStillImageOutput alloc]init]; 

    NSDictionary *outputSettings = [[NSDictionary alloc]initWithObjectsAndKeys:AVVideoCodecJPEG, AVVideoCodecKey, nil]; 
    [imageOutput setOutputSettings:outputSettings]; 

    [session addOutput:imageOutput]; 

    [session startRunning]; 



} 

- (void)viewDidLoad { 
    [super viewDidLoad]; 
    // Do any additional setup after loading the view. 
    cancelButton.hidden = YES; 
} 

- (IBAction)capture:(id)sender { 
    AVCaptureConnection *videoConnection = nil; 

    for (AVCaptureConnection * connection in imageOutput.connections) { 
     for (AVCaptureInputPort *port in [connection inputPorts]) { 
      if ([port.mediaType isEqual:AVMediaTypeVideo]) { 
       videoConnection = connection; 
       break; 
      } 
     } 
     if (videoConnection) { 
      break; 
     } 
    } 

    [imageOutput captureStillImageAsynchronouslyFromConnection:videoConnection completionHandler:^(CMSampleBufferRef imageDataSampleBuffer, NSError *error) { 
     if (imageDataSampleBuffer != NULL) { 

      NSData *imageData = [AVCaptureStillImageOutput jpegStillImageNSDataRepresentation:imageDataSampleBuffer]; 
      UIImage *image = [UIImage imageWithData:imageData]; 

      // Need to rescale image 
      if (isFront == NO) { 
       self.imageView.image = image; 
       cancelButton.hidden = NO; 
      }else if (isFront == YES) 

      //Need to flip image here 

      self.imageView.image = image; 
      cancelButton.hidden = NO; 
     } 
    }]; 

} 


// Delete photo just taking 
- (IBAction)cancelAction:(id)sender { 
    cancelButton.hidden = YES; 
    self.imageView.image = nil; 
} 

// Dismiss this viewcontroller 
-(IBAction)backButton:(id)sender{ 
    [[NSNotificationCenter defaultCenter] postNotificationName:@"DISMISSCAMERA"object:nil]; 

} 

// Switch Camera 
- (IBAction)switchCamera:(id)sender { 
    if(session) 
    { 

     if (isFront == NO) { 
      isFront = YES; 
     }else if (isFront == YES) { 
      isFront = NO; 
     } 

     //Indicate that some changes will be made to the session 
     [session beginConfiguration]; 

     //Remove existing input 
     AVCaptureInput* currentCameraInput = [session.inputs objectAtIndex:0]; 
     [session removeInput:currentCameraInput]; 

     //Get new input 
     AVCaptureDevice *newCamera = nil; 
     if(((AVCaptureDeviceInput*)currentCameraInput).device.position == AVCaptureDevicePositionBack) 
     { 
      newCamera = [self cameraWithPosition:AVCaptureDevicePositionFront]; 
     } 
     else 
     { 
      newCamera = [self cameraWithPosition:AVCaptureDevicePositionBack]; 
     } 

     //Add input to session 
     NSError *err = nil; 
     AVCaptureDeviceInput *newVideoInput = [[AVCaptureDeviceInput alloc] initWithDevice:newCamera error:&err]; 
     if(!newVideoInput || err) 
     { 
      NSLog(@"Error creating capture device input: %@", err.localizedDescription); 
     } 
     else 
     { 
      [session addInput:newVideoInput]; 
     } 

     //Commit all the configuration changes at once 
     [session commitConfiguration]; 
    } 
} 
// Find a camera with the specified AVCaptureDevicePosition, returning nil if one is not found 
- (AVCaptureDevice *) cameraWithPosition:(AVCaptureDevicePosition) position 
{ 
    NSArray *devices = [AVCaptureDevice devicesWithMediaType:AVMediaTypeVideo]; 
    for (AVCaptureDevice *device in devices) 
    { 
     if ([device position] == position) return device; 
    } 
    return nil; 
} 

@end 

Answer 1

原来，这是问题：

[previewLayer setVideoGravity:AVLayerVideoGravityResizeAspectFill]; 

我将它设置为这个代替：

[previewLayer setVideoGravity:AVLayerVideoGravityResize]; 

奇迹般有效。