Capture image with bounds? - ios

Question

I am able to capture images from the iOS rear facing camera. Everything is working flawlessly except I want it to take the picture as per the bounds in my UIView.
My code is below:
- (void)viewDidLoad
{
[super viewDidLoad];
// Do any additional setup after loading the view.
session = [[AVCaptureSession alloc] init];
session.sessionPreset = AVCaptureSessionPresetMedium;
captureVideoPreviewLayer = [[AVCaptureVideoPreviewLayer alloc] initWithSession:session];
captureVideoPreviewLayer.videoGravity = AVLayerVideoGravityResizeAspectFill;
captureVideoPreviewLayer.frame = vImagePreview.bounds;
[vImagePreview.layer addSublayer:captureVideoPreviewLayer];
AVCaptureDevice *device = [self backFacingCameraIfAvailable];
NSError *error = nil;
AVCaptureDeviceInput *input = [AVCaptureDeviceInput deviceInputWithDevice:device error:&error];
if (!input) {
// Handle the error appropriately.
NSLog(#"ERROR: trying to open camera: %#", error);
}
[session addInput:input];
stillImageOutput = [[AVCaptureStillImageOutput alloc] init];
NSDictionary *outputSettings = [[NSDictionary alloc] initWithObjectsAndKeys: AVVideoCodecJPEG, AVVideoCodecKey, nil];
[stillImageOutput setOutputSettings:outputSettings];
AVCaptureConnection *videoConnection = nil;
for (AVCaptureConnection *connection in stillImageOutput.connections) {
for (AVCaptureInputPort *port in [connection inputPorts]) {
if ([[port mediaType] isEqual:AVMediaTypeVideo] ) {
videoConnection = connection;
break;
}
}
if (videoConnection) {
break;
}
}
[session startRunning];
[session addOutput:stillImageOutput];
}
-(AVCaptureDevice *)backFacingCameraIfAvailable{
NSArray *videoDevices = [AVCaptureDevice devicesWithMediaType:AVMediaTypeVideo];
AVCaptureDevice *captureDevice = nil;
for (AVCaptureDevice *device in videoDevices){
if (device.position == AVCaptureDevicePositionBack){
captureDevice = device;
break;
}
}
// couldn't find one on the back, so just get the default video device.
if (!captureDevice){
captureDevice = [AVCaptureDevice defaultDeviceWithMediaType:AVMediaTypeVideo];
}
return captureDevice;
}
And below is the code to capture the image:
- (IBAction)captureTask {
AVCaptureConnection *videoConnection = nil;
for (AVCaptureConnection *connection in stillImageOutput.connections){
for (AVCaptureInputPort *port in [connection inputPorts]){
if ([[port mediaType] isEqual:AVMediaTypeVideo]){
videoConnection = connection;
break;
}
}
if (videoConnection) {
break;
}
}
NSLog(#"about to request a capture from: %#", stillImageOutput);
[stillImageOutput captureStillImageAsynchronouslyFromConnection:videoConnection completionHandler: ^(CMSampleBufferRef imageSampleBuffer, NSError *error)
{
CFDictionaryRef exifAttachments = CMGetAttachment(imageSampleBuffer, kCGImagePropertyExifDictionary, NULL);
if (exifAttachments) {
// Do something with the attachments.
NSLog(#"attachements: %#", exifAttachments);
} else {
NSLog(#"no attachments");
}
NSData *imageData = [AVCaptureStillImageOutput jpegStillImageNSDataRepresentation:imageSampleBuffer];
UIImage *image = [[UIImage alloc] initWithData:imageData];
stillImage = image;
}];
}
The issue i'm facing is that it's taking the picture, and saving to stillImage, however, the image is for the whole iPhone screen from what I can tell. It's not to the bounds of the UIView *vImagePreview I created. Is there a way to clip the bounds of the captured image??
[EDIT]
After reading the docs, I realized the image was proper resolution, as per here: session.sessionPreset = AVCaptureSessionPresetMedium;. Is there a way to make the image like a square? Like how Instagram makes their images? All of the session presets according to the docs are not at all squares :(
I tried with the below:
captureVideoPreviewLayer.videoGravity = AVLayerVideoGravityResize;
However, it only resizes the image to fit the current view, doesn't make a square image.

Answer 1

I understand your frustration, presets should be customizable or have more options! What I do with my images is crop them about the center, for which I wrote the following code:
- (UIImage *)crop:(UIImage *)image from:(CGSize)src to:(CGSize)dst
{
CGPoint cropCenter = CGPointMake((src.width/2), (src.height/2));
CGPoint cropStart = CGPointMake((cropCenter.x - (dst.width/2)), (cropCenter.y - (dst.height/2)));
CGRect cropRect = CGRectMake(cropStart.x, cropStart.y, dst.width, dst.height);
CGImageRef cropRef = CGImageCreateWithImageInRect(image.CGImage, cropRect);
UIImage* cropImage = [UIImage imageWithCGImage:cropRef];
CGImageRelease(cropRef);
return cropImage;
}
Where src represents the original dimensions and dst represents the cropped dimensions; and image is of course the image you want cropped.

Answer 2

If the device is retina display,
then this screenshot works like mentioned below:
if ([[UIScreen mainScreen] respondsToSelector:#selector(scale)] == YES && [[UIScreen mainScreen] scale] == 2.00)
{
CGPoint cropCenter = CGPointMake((src.width), (src.height));
CGPoint cropStart = CGPointMake((cropCenter.x - (dst.width)), (cropCenter.y - (dst.height)));
CGRect cropRect = CGRectMake(cropStart.x, cropStart.y, dst.width*2, dst.height*2);
CGImageRef cropRef = CGImageCreateWithImageInRect(image.CGImage, cropRect);
UIImage* cropImage = [UIImage imageWithCGImage:cropRef];
CGImageRelease(cropRef);
return cropImage;
}
else
{
CGPoint cropCenter = CGPointMake((src.width/2), (src.height/2));
CGPoint cropStart = CGPointMake((cropCenter.x - (dst.width/2)), (cropCenter.y - (dst.height/2)));
CGRect cropRect = CGRectMake(cropStart.x, cropStart.y, dst.width, dst.height);
CGImageRef cropRef = CGImageCreateWithImageInRect(image.CGImage, cropRect);
UIImage* cropImage = [UIImage imageWithCGImage:cropRef];
CGImageRelease(cropRef);
return cropImage;
}