[英]How to capture camera only visible view in iPhone
我創建了一個視圖控制器,視圖的50%是攝影機視圖,另外50%是按鈕等。
我面臨的問題是,當我捕獲圖像時,會捕獲到更大的圖像,並且只想捕獲在那50%的視圖中看到的圖像。
所以看起來像這樣:
這是我所看到的:
這就是我捕獲后得到的圖像:
其背后的代碼是:
-(void) viewDidAppear:(BOOL)animated
{
AVCaptureSession *session = [[AVCaptureSession alloc] init];
session.sessionPreset = AVCaptureSessionPresetMedium;
CALayer *viewLayer = self.vImagePreview.view.layer;
NSLog(@"viewLayer = %@", viewLayer);
AVCaptureVideoPreviewLayer *captureVideoPreviewLayer = [[AVCaptureVideoPreviewLayer alloc] initWithSession:session];
[captureVideoPreviewLayer setVideoGravity:AVLayerVideoGravityResizeAspectFill];
captureVideoPreviewLayer.frame = self.vImagePreview.view.bounds;
[self.vImagePreview.view.layer addSublayer:captureVideoPreviewLayer];
NSLog(@"Rect of self.view: %@",NSStringFromCGRect(self.vImagePreview.view.frame));
AVCaptureDevice *device = [AVCaptureDevice defaultDeviceWithMediaType:AVMediaTypeVideo];
NSError *error = nil;
AVCaptureDeviceInput *input = [AVCaptureDeviceInput deviceInputWithDevice:device error:&error];
if (!input) {
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];
[session addOutput:stillImageOutput];
[session startRunning];
}
- (void)viewDidLoad
{
[super viewDidLoad];
// Load camera
vImagePreview = [[CameraViewController alloc]init];
vImagePreview.view.frame = CGRectMake(10, 10, 300, 500);
[self.view addSubview:vImagePreview.view];
vImage = [[UIImageView alloc]init];
vImage.frame = CGRectMake(10, 10, 300, 300);
[self.view addSubview:vImage];
}
這是我嘗試捕獲圖像時的事件:
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];
image = [[UIImage alloc] initWithData:imageData];
UIAlertView *successAlert = [[UIAlertView alloc] init];
successAlert.title = @"Review Picture";
successAlert.message = @"";
[successAlert addButtonWithTitle:@"Save"];
[successAlert addButtonWithTitle:@"Retake"];
[successAlert setDelegate:self];
UIImageView *_imageView = [[UIImageView alloc] initWithFrame:CGRectMake(220, 10, 40, 40)];
_imageView.image = image;
[successAlert addSubview:_imageView];
[successAlert show];
UIImage *_image = [self imageByScalingAndCroppingForSize:CGSizeMake(640,480) :_imageView.image];
NSData *idata = [NSData dataWithData:UIImagePNGRepresentation(_image)];
encodedImage = [self encodeBase64WithData:idata];
}];
為什么要獲得整個攝像機視圖,如何縮小攝像機捕獲的大小,以便僅捕獲攝像機視圖中看到的內容?
您可以在捕獲后裁剪圖像。 嘗試這個
CGImageRef imageRef = CGImageCreateWithImageInRect([largeImage CGImage], cropRect);
// or use the UIImage wherever you like
[UIImageView setImage:[UIImage imageWithCGImage:imageRef]];
CGImageRelease(imageRef);
或者試試這個
- (UIImage *)crop:(CGRect)rect {
if (self.scale > 1.0f) {
rect = CGRectMake(rect.origin.x * self.scale,
rect.origin.y * self.scale,
rect.size.width * self.scale,
rect.size.height * self.scale);
}
CGImageRef imageRef = CGImageCreateWithImageInRect(self.CGImage, rect);
UIImage *result = [UIImage imageWithCGImage:imageRef scale:self.scale orientation:self.imageOrientation];
CGImageRelease(imageRef);
return result;
}
另請參閱此鏈接: 裁剪UIImage
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