Decode Methods

Method	Description
`decodeBuffer`	Decode barcodes from raw buffer.
`decodeFileWithName`	Decode barcodes from a specified image file.
`decodeImage`	Decode barcodes from an image file in memory.
`decodeBase64`	Decode barcodes from a base64 encoded string.

decodeBuffer

Decode barcodes from the memory buffer containing image pixels in a defined format.

- (NSArray<iTextResult*>* _Nullable)decodeBuffer:(NSData* _Nonnull)buffer
                                       withWidth:(NSInteger)width
                                          height:(NSInteger)height
                                          stride:(NSInteger)stride
                                          format:(EnumImagePixelFormat)format
                                           error:(NSError* _Nullable * _Nullable)error
                                           NS_SWIFT_NAME(decodeBuffer(_:width:height:stride:format:));

Parameters

[in] buffer The array of bytes that contain the image data.
[in] width The width of the image in pixels.
[in] height The height of the image in pixels.
[in] stride The stride is measured by the byte length of each line in the buffer.
[in] format The image pixel format used in the image byte array.
[in,out] error Input a pointer to an error object. If an error occurs, this pointer is set to an actual error object containing the error information. You may specify nil for this parameter if you do not want the error information.

Return Value

The iTextResult of each successfully decoded barcode.

Get ImageData from DCEFrame

If you have imported DynamsoftCameraEnhancer.framework, you can get video frames from the frameOutputCallback. DCEFrame object contains all required parameters of decodeBuffer method.

Code Snippet

Objective-C
Swift

[_dce addListener:self];
//Get frames in callback methods.
- (void)frameOutPutCallback:(DCEFrame *)frame timeStamp:(NSTimeInterval)timeStamp{
   NSArray<iTextResult*>* barcodeResults = [barcodeReader decodeBuffer:frame.imageData withWidth:frame.width height:frame.height stride:frame.stride format:frame.pixelFormat error:nil];
}

func frameOutPutCallback(_ frame: DCEFrame, timeStamp: TimeInterval){
   let barcodeResults = try? barcodeReader.decodeBuffer(frame.imageData, withWidth: frame.width, height: frame.height, stride: frame.stride, format: EnumImagePixelFormat(rawValue: frame.pixelFormat) ?? EnumImagePixelFormat.ARGB_8888)
}

Get ImageData from CaptureOutput

If you are acquiring video frames from captureOutput callback, you can use the following code to extract the required parameters from sampleBuffer.

Code Snippet

Objective-C
Swift

- (void)captureOutput:(AVCaptureOutput *)captureOutput didOutputSampleBuffer:(CMSampleBufferRef)sampleBuffer fromConnection:(AVCaptureConnection *)connection;
{
   // Extract image data from sampleBuffer.
   CVImageBufferRef imageBuffer = CMSampleBufferGetImageBuffer(sampleBuffer);
   CVPixelBufferLockBaseAddress(imageBuffer, kCVPixelBufferLock_ReadOnly);
   int bufferSize = (int)CVPixelBufferGetDataSize(imageBuffer);
   int imgWidth = (int)CVPixelBufferGetWidth(imageBuffer);
   int imgHeight = (int)CVPixelBufferGetHeight(imageBuffer);
   size_t bpr = CVPixelBufferGetBytesPerRow(imageBuffer);
   void *baseAddress = CVPixelBufferGetBaseAddress(imageBuffer);
   CVPixelBufferUnlockBaseAddress(imageBuffer, kCVPixelBufferLock_ReadOnly);
   NSData * buffer = [NSData dataWithBytes:baseAddress length:bufferSize];
   startRecognitionDate = [NSDate date];
   NSArray* barcodeResults = [m_barcodeReader decodeBuffer:buffer withWidth:imgWidth height:imgHeight stride:bpr format: EnumImagePixelFormatARGB_8888 error:nil];
}

func captureOutput(_ output: AVCaptureOutput, didOutput sampleBuffer: CMSampleBuffer, from connection: AVCaptureConnection){
   let imageBuffer:CVImageBuffer = CMSampleBufferGetImageBuffer(sampleBuffer)!
   CVPixelBufferLockBaseAddress(imageBuffer, .readOnly)
   let baseAddress = CVPixelBufferGetBaseAddress(imageBuffer)
   let bufferSize = CVPixelBufferGetDataSize(imageBuffer)
   let width = CVPixelBufferGetWidth(imageBuffer)
   let height = CVPixelBufferGetHeight(imageBuffer)
   let bpr = CVPixelBufferGetBytesPerRow(imageBuffer)
   CVPixelBufferUnlockBaseAddress(imageBuffer, .readOnly)
   startRecognitionDate = NSDate()
   let buffer = Data(bytes: baseAddress!, count: bufferSize)
   guard let barcodeResults = try? barcodeReader.decodeBuffer(buffer, withWidth: width, height: height, stride: bpr, format: .ARGB_8888)
}

decodeFileWithName

Decode barcodes from a specified image file.

- (NSArray<iTextResult*>* _Nullable)decodeFileWithName:(NSString* _Nonnull)name
                                                 error:(NSError* _Nullable * _Nullable)error
                                                 NS_SWIFT_NAME(decodeFileWithName(_:));

Parameters

[in] name The local path of the file. It supports BMP, TIFF, JPG, PNG and PDF files.
[in,out] error Input a pointer to an error object. If an error occurs, this pointer is set to an actual error object containing the error information. You may specify nil for this parameter if you do not want the error information.

Return Value

The iTextResult of each successfully decoded barcode.

Code Snippet

Objective-C
Swift

NSArray<iTextResult*>* barcodeResults = [barcodeReader decodeFileWithName:@"your file path" error:&error];

let barcodeResults = try? barcodeReader.decodeFileWithName("your file path")

decodeImage

Decode barcodes from an image file in memory.

- (NSArray<iTextResult*>* _Nullable)decodeImage:(UIImage* _Nonnull)image
                                          error:(NSError* _Nullable * _Nullable)error
                                          NS_SWIFT_NAME(decodeImage(_:));

Parameters

[in] image The image file in memory.
[in, out] error Input a pointer to an error object. If an error occurs, this pointer is set to an actual error object containing the error information. You may specify nil for this parameter if you do not want the error information.

Return Value

The iTextResult of each successfully decoded barcode.

Code Snippet

Objective-C
Swift

UIImage *image = [[UIImage alloc] init];
NSError __autoreleasing * _Nullable error;
NSArray<iTextResult*>* barcodeResults = [_barcodeReader decodeImage:image error:&error];

let frameImage = dce.getFrameFromBuffer(true).toUIImage()
let barcodeResults = try? barcodeReader.decodeImage(frameImage)

decodeBase64

Decode barcodes from an image file encoded as a base64 string.

- (NSArray<iTextResult*>* _Nullable)decodeBase64:(NSString* _Nonnull)base64
                                           error:(NSError* _Nullable * _Nullable)error;

Parameters

[in] base64 A base64 encoded string that represents an image.
[in,out] error Input a pointer to an error object. If an error occurs, this pointer is set to an actual error object containing the error information. You may specify nil for this parameter if you do not want the error information.

Return Value

The iTextResult of each successfully decoded barcode.

Code Snippet

Objective-C
Swift

NSError __autoreleasing * _Nullable error;
NSArray<iTextResult*>* barcodeResults = [barcodeReader decodeBase64:@"file in base64 string" error:&error];

let barcodeResults = try? barcodeReader.decodeBase64("file in base64 string")