Question

I am trying to set the AVFoundation camera size based on my UIImageView (selectedImage) size like this:

    self.sess = [AVCaptureSession new];
    self.snapper = [AVCaptureStillImageOutput new];
    self.snapper.outputSettings = @{AVVideoCodecKey: AVVideoCodecJPEG};
    self.sess.sessionPreset = AVCaptureSessionPresetPhoto;
    [self.sess addOutput:self.snapper];
    AVCaptureDevice* cam = [AVCaptureDevice defaultDeviceWithMediaType:AVMediaTypeVideo];
    AVCaptureDeviceInput* input = [AVCaptureDeviceInput deviceInputWithDevice:cam error:nil];
    [self.sess addInput:input];
    AVCaptureVideoPreviewLayer* lay = [[AVCaptureVideoPreviewLayer alloc] initWithSession:self.sess];
    lay.videoGravity = AVLayerVideoGravityResizeAspectFill;
    lay.frame = selectedImage.frame;
   [self.view.layer addSublayer:lay];

In the app, it shows it just fine – 320X320 size, but when I look in the photo gallery, the saved image is longer than a square.

I also tried to remove lay.videoGravity = AVLayerVideoGravityResizeAspectFill; but then the image in the app is not filling the screen.

How can I set also the shot image size to be what the user sees in the camera with no extra tails?

This is the code that saves the image to gallery:

AVCaptureConnection *vc = [self.snapper connectionWithMediaType:AVMediaTypeVideo];
// deal with image when it arrives
typedef void(^MyBufBlock)(CMSampleBufferRef, NSError*);
MyBufBlock h = ^(CMSampleBufferRef buf, NSError *err) {
    NSData* data = [AVCaptureStillImageOutput jpegStillImageNSDataRepresentation:buf];
    UIImage* im = [UIImage imageWithData:data];
    dispatch_async(dispatch_get_main_queue(), ^{
        selectedImage.hidden = NO;
        selectedImage.contentMode = UIViewContentModeScaleAspectFill;
        selectedImage.clipsToBounds = YES;
        selectedImage.image = im;
        [self.previewLayer removeFromSuperlayer];
        self.previewLayer = nil;
        [self.sess stopRunning];
        ALAssetsLibrary *library = [[ALAssetsLibrary alloc] init];
        [library writeImageToSavedPhotosAlbum:[selectedImage.image CGImage] orientation:(ALAssetOrientation)[selectedImage.image imageOrientation] completionBlock:nil];

Answer 1

I believe you’ll need to crop the image yourself; the reduced size of your viewfinder only affected its visible shape, not the amount of data it would be processing.

An example on how to crop an image can be found at: How to properly crop an image taken on iPhone 4G (with EXIF rotation data)?