我在应用程序中使用下面的代码，它适用于 6+。
代码启动一个 AVCaptureSession，从设备的摄像头中提取视频输入。
当它这样做时，它会不断更新来自 captureOutput 委托函数的 runImage 变量。
当用户想要拍照时，会调用 takePhoto 方法。此方法创建一个临时 UIImageview 并将 runImage 输入其中。然后使用这个临时 UIImageView 将另一个名为 currentImage 的变量绘制到设备的比例。
在我的例子中，currentImage 是方形的，与 previewHolder 框架相匹配，但我想你可以制作任何你想要的东西。
声明这些：
AVCaptureDevice * device;
AVCaptureDeviceInput * input;
AVCaptureVideoDataOutput * output;
AVCaptureSession * session;
AVCaptureVideoPreviewLayer * preview;
AVCaptureConnection * connection;
UIImage * runImage;
加载扫描仪：
-(void)loadScanner
{
device = [AVCaptureDevice defaultDeviceWithMediaType:AVMediaTypeVideo];
input = [AVCaptureDeviceInput deviceInputWithDevice:device error:nil];
output = [AVCaptureVideoDataOutput new];
session = [AVCaptureSession new];
[session setSessionPreset:AVCaptureSessionPresetPhoto];
[session addInput:input];
[session addOutput:output];
[output setSampleBufferDelegate:self queue:dispatch_get_main_queue()];
[output setVideoSettings:[NSDictionary dictionaryWithObject:[NSNumber numberWithInt:kCVPixelFormatType_32BGRA] forKey:(id)kCVPixelBufferPixelFormatTypeKey]];
preview = [AVCaptureVideoPreviewLayer layerWithSession:session];
preview.videoGravity = AVLayerVideoGravityResizeAspectFill;
preview.frame = previewHolder.bounds;
connection = preview.connection;
[connection setVideoOrientation:AVCaptureVideoOrientationPortrait];
[previewHolder.layer insertSublayer:preview atIndex:0];
}
正在进行的图像捕获，更新 runImage var。
-(void)captureOutput:(AVCaptureOutput *)captureOutput didOutputSampleBuffer:(CMSampleBufferRef)sampleBuffer fromConnection:(AVCaptureConnection *)connection
{
runImage = [self imageForBuffer:sampleBuffer];
}
与上述有关。
-(UIImage *)imageForBuffer:(CMSampleBufferRef)sampleBuffer
{
CVImageBufferRef imageBuffer = CMSampleBufferGetImageBuffer(sampleBuffer);
CVPixelBufferLockBaseAddress(imageBuffer, 0);
void *baseAddress = CVPixelBufferGetBaseAddress(imageBuffer);
size_t bytesPerRow = CVPixelBufferGetBytesPerRow(imageBuffer);
size_t width = CVPixelBufferGetWidth(imageBuffer);
size_t height = CVPixelBufferGetHeight(imageBuffer);
CGColorSpaceRef colorSpace = CGColorSpaceCreateDeviceRGB();
CGContextRef context = CGBitmapContextCreate(baseAddress, width, height, 8, bytesPerRow, colorSpace, kCGBitmapByteOrder32Little | kCGImageAlphaPremultipliedFirst);
CGImageRef quartzImage = CGBitmapContextCreateImage(context);
CVPixelBufferUnlockBaseAddress(imageBuffer,0);
CGContextRelease(context);
CGColorSpaceRelease(colorSpace);
UIImage *image = [UIImage imageWithCGImage:quartzImage];
CGImageRelease(quartzImage);
UIImage * rotated = [[UIImage alloc] initWithCGImage:image.CGImage scale:1.0 orientation:UIImageOrientationRight];
return rotated;
}
拍照时：
-(void)takePhoto
{
UIImageView * temp = [UIImageView new];
temp.frame = previewHolder.frame;
temp.image = runImage;
temp.contentMode = UIViewContentModeScaleAspectFill;
temp.clipsToBounds = true;
[self.view addSubview:temp];
UIGraphicsBeginImageContextWithOptions(temp.bounds.size, NO, [UIScreen mainScreen].scale);
[temp drawViewHierarchyInRect:temp.bounds afterScreenUpdates:YES];
currentImage = UIGraphicsGetImageFromCurrentImageContext();
UIGraphicsEndImageContext();
[temp removeFromSuperview];
//further code...
}