This is driving me crazy because I can't get it to work. I have the following scenario:
I'm using an AVCaptureSession
and an AVCaptureVideoPreviewLayer
to create my own camera interface. The interface shows a rectangle. Below is the AVCaptureVideoPreviewLayer
that fills the whole screen.
I want to the captured image to be cropped in a way, that the resulting image shows exactly the content seen in the rect on the display.
My setup looks like this:
_session = [[AVCaptureSession alloc] init];
AVCaptureSession *session = _session;
session.sessionPreset = AVCaptureSessionPresetPhoto;
AVCaptureDevice *camera = [AVCaptureDevice defaultDeviceWithMediaType:AVMediaTypeVideo];
if (camera == nil) {
[self showImagePicker];
_isSetup = YES;
return;
}
AVCaptureVideoPreviewLayer *captureVideoPreviewLayer = [[AVCaptureVideoPreviewLayer alloc] initWithSession:session];
captureVideoPreviewLayer.videoGravity = AVLayerVideoGravityResizeAspectFill;
captureVideoPreviewLayer.frame = self.liveCapturePlaceholderView.bounds;
[self.liveCapturePlaceholderView.layer addSublayer:captureVideoPreviewLayer];
NSError *error;
AVCaptureDeviceInput *input = [AVCaptureDeviceInput deviceInputWithDevice:camera error:&error];
if (error) {
HGAlertViewWrapper *av = [[HGAlertViewWrapper alloc] initWithTitle:kFailedConnectingToCameraAlertViewTitle message:kFailedConnectingToCameraAlertViewMessage cancelButtonTitle:kFailedConnectingToCameraAlertViewCancelButtonTitle otherButtonTitles:@[kFailedConnectingToCameraAlertViewRetryButtonTitle]];
[av showWithBlock:^(NSString *buttonTitle){
if ([buttonTitle isEqualToString:kFailedConnectingToCameraAlertViewCancelButtonTitle]) {
[self.delegate gloameCameraViewControllerDidCancel:self];
}
else {
[self setupAVSession];
}
}];
}
[session addInput:input];
NSDictionary *options = @{ AVVideoCodecKey : AVVideoCodecJPEG };
_stillImageOutput = [[AVCaptureStillImageOutput alloc] init];
[_stillImageOutput setOutputSettings:options];
[session addOutput:_stillImageOutput];
[session startRunning];
_isSetup = YES;
I'm capturing the image like this:
[_stillImageOutput captureStillImageAsynchronouslyFromConnection:videoConnection completionHandler: ^(CMSampleBufferRef imageSampleBuffer, NSError *error)
{
if (error) {
MWLogDebug(@"Error capturing image from camera. %@, %@", error, [error userInfo]);
_capturePreviewLayer.connection.enabled = YES;
}
else
{
NSData *imageData = [AVCaptureStillImageOutput jpegStillImageNSDataRepresentation:imageSampleBuffer];
UIImage *image = [[UIImage alloc] initWithData:imageData];
CGRect cropRect = [self createCropRectForImage:image];
UIImage *croppedImage;// = [self cropImage:image toRect:cropRect];
UIGraphicsBeginImageContext(cropRect.size);
[image drawAtPoint:CGPointMake(-cropRect.origin.x, -cropRect.origin.y)];
croppedImage = UIGraphicsGetImageFromCurrentImageContext();
UIGraphicsEndImageContext();
self.capturedImage = croppedImage;
[_session stopRunning];
}
}];
In the createCropRectForImage:
method I've tried various ways to calculate the rect to cut out of the image, but with no success so far.
- (CGRect)createCropRectForImage:(UIImage *)image
{
CGPoint maskTopLeftCorner = CGPointMake(self.maskRectView.frame.origin.x, self.maskRectView.frame.origin.y);
CGPoint maskBottomRightCorner = CGPointMake(self.maskRectView.frame.origin.x + self.maskRectView.frame.size.width, self.maskRectView.frame.origin.y + self.maskRectView.frame.size.height);
CGPoint maskTopLeftCornerInLayerCoords = [_capturePreviewLayer convertPoint:maskTopLeftCorner fromLayer:self.maskRectView.layer.superlayer];
CGPoint maskBottomRightCornerInLayerCoords = [_capturePreviewLayer convertPoint:maskBottomRightCorner fromLayer:self.maskRectView.layer.superlayer];
CGPoint maskTopLeftCornerInDeviceCoords = [_capturePreviewLayer captureDevicePointOfInterestForPoint:maskTopLeftCornerInLayerCoords];
CGPoint maskBottomRightCornerInDeviceCoords = [_capturePreviewLayer captureDevicePointOfInterestForPoint:maskBottomRightCornerInLayerCoords];
float x = maskTopLeftCornerInDeviceCoords.x * image.size.width;
float y = (1 - maskTopLeftCornerInDeviceCoords.y) * image.size.height;
float width = fabsf(maskTopLeftCornerInDeviceCoords.x - maskBottomRightCornerInDeviceCoords.x) * image.size.width;
float height = fabsf(maskTopLeftCornerInDeviceCoords.y - maskBottomRightCornerInDeviceCoords.y) * image.size.height;
return CGRectMake(x, y, width, height);
}
That is my current version but doesn't even get the proportions right. Could some one please help me!
I have also tried using this method to crop my image:
- (UIImage*)cropImage:(UIImage*)originalImage toRect:(CGRect)rect{
CGImageRef imageRef = CGImageCreateWithImageInRect([originalImage CGImage], rect);
CGBitmapInfo bitmapInfo = CGImageGetBitmapInfo(imageRef);
CGColorSpaceRef colorSpaceInfo = CGImageGetColorSpace(imageRef);
CGContextRef bitmap = CGBitmapContextCreate(NULL, rect.size.width, rect.size.height, CGImageGetBitsPerComponent(imageRef), CGImageGetBytesPerRow(imageRef), colorSpaceInfo, bitmapInfo);
if (originalImage.imageOrientation == UIImageOrientationLeft) {
CGContextRotateCTM (bitmap, radians(90));
CGContextTranslateCTM (bitmap, 0, -rect.size.height);
} else if (originalImage.imageOrientation == UIImageOrientationRight) {
CGContextRotateCTM (bitmap, radians(-90));
CGContextTranslateCTM (bitmap, -rect.size.width, 0);
} else if (originalImage.imageOrientation == UIImageOrientationUp) {
// NOTHING
} else if (originalImage.imageOrientation == UIImageOrientationDown) {
CGContextTranslateCTM (bitmap, rect.size.width, rect.size.height);
CGContextRotateCTM (bitmap, radians(-180.));
}
CGContextDrawImage(bitmap, CGRectMake(0, 0, rect.size.width, rect.size.height), imageRef);
CGImageRef ref = CGBitmapContextCreateImage(bitmap);
UIImage *resultImage=[UIImage imageWithCGImage:ref];
CGImageRelease(imageRef);
CGContextRelease(bitmap);
CGImageRelease(ref);
return resultImage;
}
Does anybody have the 'right combination' of methods to make this work? :)
have a look at this library, it could help you achieve what you want :)
I've solved this problem by using
metadataOutputRectOfInterestForRect
function.It works with any orientation.
The takenImage is still
imageOrientation
dependent image. You can delete orientation information for further image processing.AVMakeRectWithAspectRatioInsideRect this api is from AVFoundation, it will return the crop region for the image given the crop size.
In Swift 3: