我目前正在使用AVCaptureSession和AVCaptureMetadataOutput.
它工作得很好,但我只是想知道如何指示仅在AVCaptureVideoPreviewLayer的特定区域扫描和分析元数据对象？
解决方法
以下是我所拥有的项目代码示例,可以帮助您走上正确的轨道
// where 'self.session' is prevIoUsly setup AVCaptureSession
// setup Metadata capture
AVCaptureMetadataOutput *MetadataOutput = [[AVCaptureMetadataOutput alloc] init];
[self.session addOutput:MetadataOutput];
[MetadataOutput setMetadataObjectsDelegate:self queue:dispatch_get_main_queue()];
[MetadataOutput setMetadataObjectTypes:@[AVMetadataObjectTypeEAN8Code,AVMetadataObjectTypeEAN13Code]];
// setup preview layer
AVCaptureVideoPreviewLayer *previewLayer = [[AVCaptureVideoPreviewLayer alloc] initWithSession:self.session];
previewLayer.frame = self.previewView.bounds;
previewLayer.videoGravity = AVLayerVideoGravityResizeAspectFill;
// we only want the visible area of the previewLayer to accept
// barcode input (ignore the rest)
// we need to convert rects coordinate system
CGRect visibleMetadataOutputRect = [previewLayer MetadataOutputRectOfInterestForRect:previewLayer.bounds];
MetadataOutput.rectOfInterest = visibleMetadataOutputRect;
// add the previewLayer as a sublayer of the displaying UIView
[self.previewView.layer addSublayer:previewLayer];