OpenCv iOS Kamera Vorschau einzelne Ausrichtung nur ohne Dehnen

Question

Ich schreibe ein OpenCv Cordova Plugin für iOS. Ich brauchte die Kameravorschau, um Vollbild zu sehen und das Seitenverhältnis für alle iOS-Geräte (iPhone, iPads) beizubehalten.

Ich konnte Portrait-Modus (siehe Code) und es funktioniert perfekt auf iPhone 6/Plus, aber die Kameravorschau gestreckt leicht auf iPads möglicherweise aufgrund der Tatsache, dass AVCaptureSessionPresetHigh des unterstützte Auflösung 1280x720 erreichen ist. Hat jemand Ideen, wie man eine einzelne Ausrichtung (nur im Quer- oder Hochformat) erreichen und das Seitenverhältnis beibehalten kann?

Mein aktueller Code für eine Kamera beginnt, ist

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

    // Initialize imageView to fullscreen 
    imageView = [[UIImageView alloc] initWithFrame:[UIScreen mainScreen].bounds]; 
    [self.view addSubview:imageView]; 
    [imageView setContentMode:UIViewContentModeScaleAspectFill]; 
    [imageView setClipsToBounds:YES]; 

    self.videoCamera = [[FixedCvVideoCamera alloc] initWithParentView:imageView]; 
    self.videoCamera.delegate = self; 
    self.videoCamera.defaultAVCaptureDevicePosition = AVCaptureDevicePositionBack; 
    self.videoCamera.defaultAVCaptureSessionPreset = AVCaptureSessionPresetHigh; 
    self.videoCamera.defaultAVCaptureVideoOrientation = AVCaptureVideoOrientationPortrait; 
    self.videoCamera.defaultFPS = 30; 
    [self.videoCamera start]; 
} 

Hinweis Ich verwende FixedCvVideoCamera statt die OpenCV CvVideoCamera Klasse. Der Grund ist, dass ich CvVideoCameras layoutPreviewLayer Funktion Unterklasse und überschreiben, um Portrait-Modus zu behalten.

- (void)layoutPreviewLayer; 
{ 
    if (self.parentView != nil) 
    { 
     CALayer* layer = self->customPreviewLayer; 
     CGRect bounds = self->customPreviewLayer.bounds; 
     int rotation_angle = 0; 

     switch (defaultAVCaptureVideoOrientation) { 
      case AVCaptureVideoOrientationLandscapeRight: 
       rotation_angle = 270; 
       break; 
      case AVCaptureVideoOrientationPortraitUpsideDown: 
       rotation_angle = 180; 
       break; 
      case AVCaptureVideoOrientationLandscapeLeft: 
       rotation_angle = 90; 
       break; 
      case AVCaptureVideoOrientationPortrait: 
      default: 
       break; 
     } 

     layer.position = CGPointMake(self.parentView.frame.size.width/2., self.parentView.frame.size.height/2.); 
     layer.affineTransform = CGAffineTransformMakeRotation(DEGREES_RADIANS(rotation_angle)); 
     layer.bounds = bounds; 
    } 
} 

Vielen Dank im Voraus.

Answer 1

Ich habe es selbst gelöst. Der Code unten hilft denjenigen, die nur einen festen Portrait-Modus wünschen und die Front- und Rückkamera unterstützen.

Viewcontroller

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

    // Initialize imageView to fullscreen 
    imageView = [[UIImageView alloc] initWithFrame:[UIScreen mainScreen].bounds]; 
    [self.view addSubview:imageView]; 
    [imageView setContentMode:UIViewContentModeScaleAspectFill]; 
    [imageView setClipsToBounds:YES]; 

    self.videoCamera = [[FixedCvVideoCamera alloc] initWithParentView:imageView]; 
    self.videoCamera.delegate = self; 
    self.videoCamera.defaultAVCaptureDevicePosition = AVCaptureDevicePositionBack; 
    self.videoCamera.defaultAVCaptureSessionPreset = AVCaptureSessionPresetHigh; 
    self.videoCamera.defaultAVCaptureVideoOrientation = AVCaptureVideoOrientationPortrait; 
    self.videoCamera.defaultFPS = 30; 
    self.videoCamera.grayscaleMode = NO; 

    [self.videoCamera start]; 
} 

FixedCvVideoCamera: CvVideoCamera

- (void)layoutPreviewLayer; 
{ 
    if (self.parentView != nil) 
    { 
     CALayer* layer = self->customPreviewLayer; 
     CGRect bounds = self->customPreviewLayer.bounds; 
     NSLog(@"[FixedCvVideoCamera]Custom Preview Layer bounds %fx%f", bounds.size.width, bounds.size.height); 

     float previewAspectRatio = bounds.size.height/bounds.size.width; 
     NSLog(@"[FixedCvVideoCamera]Preview aspect ratio %f", previewAspectRatio); 

     //int rotation_angle = 0; 

     layer.position = CGPointMake(self.parentView.frame.size.width/2., self.parentView.frame.size.height/2.); 
     //layer.affineTransform = CGAffineTransformMakeRotation(DEGREES_RADIANS(rotation_angle)); 

     // Get video feed's resolutions 
     NSArray* devices = [AVCaptureDevice devicesWithMediaType:AVMediaTypeVideo]; 
     AVCaptureDevice* device = nil; 
     for (AVCaptureDevice *d in devices) { 
      // Get the default camera device - should be either front of back camera device 
      if ([d position] == self.defaultAVCaptureDevicePosition) { 
       device = d; 
      } 
     } 

     // Set the default device if not found 
     if (!device) { 
      device = [AVCaptureDevice defaultDeviceWithMediaType:AVMediaTypeVideo]; 
     } 

     CMVideoDimensions dimensions = CMVideoFormatDescriptionGetDimensions(device.activeFormat.formatDescription); 
     CGSize resolution = CGSizeMake(dimensions.width, dimensions.height); 
     if (self.defaultAVCaptureVideoOrientation == AVCaptureVideoOrientationPortrait || self.defaultAVCaptureVideoOrientation == AVCaptureVideoOrientationPortraitUpsideDown) { 
      resolution = CGSizeMake(resolution.height, resolution.width); 
     } 
     NSLog(@"[FixedCvVideoCamera]Video feed resolution is %fx%f", resolution.width, resolution.height); 

     float videoFeedAspectRatio = resolution.height/resolution.width; 
     NSLog(@"[FixedCvVideoCamera]Video feed's aspect ratio is %f", videoFeedAspectRatio); 

     // Set layer bounds to ASPECT FILL by expanding either the width or the height 
     if (previewAspectRatio > videoFeedAspectRatio) { 
      NSLog(@"[FixedCvVideoCamera] Preview is more rectangular than the video feed aspect ratio. Expanding width to maintain aspect ratio."); 
      float newWidth = bounds.size.height/videoFeedAspectRatio; 
      layer.bounds = CGRectMake(0, 0, newWidth, bounds.size.height); 
     } else { 
      NSLog(@"[FixedCvVideoCamera] Preview is equally or less rectangular (wider) than the video feed's aspect ratio. Expanding height bound to maintain aspect ratio."); 
      float newHeight = bounds.size.width * videoFeedAspectRatio; 
      layer.bounds = CGRectMake(0, 0, bounds.size.width, newHeight); 
     } 
    } 
}