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Dynamsoft Barcode Reader, FAQ, tech basic, enable DPM |
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This page helps to you modify the barcode results when non-printable characters exists in the barcode text you decoded.
You always get 2 values that stands for the barcode decoding result from the textResult object:
barcodeBytesbarcodeText
Since barcodeText is a string value that generated from the barcodeBytes, is might be decoded into different characters based on different character encoding formats. When there exists a non-printable ASCII value (0 ~ 31 or 127) in the barcodeBytes array, the value is decoded into a messy code. Currently, the library doesn't provide methods to remove the non-printable characters nor convert them into printable characters, you have to add your own code to recognize the non-printable characters and replace or remove them. The following code snippet is an example for how to create a method for processing the barcodeBytes into a string you want.
Code Snippet
>- JavaScript >- Android >- Objective-C >- Swift >- Python >- Java >- C# >- C++ > > ```javascript const ProcessNonPrintingCharsMode = { PNPCM_KEEP: 0, PNPCM_REMOVE: 1, PNPCM_CONVERT: 2}; class ProcessBarcodeBytesUtil { #__non_printing_ascii_chars_value_to_string_dict = new Map([ [0, '{NUL}'], [1, '{SOH}'], [2, '{STX}'], [3, '{ETX}'], [4, '{EOT}'], [5, '{ENQ}'], [6, '{ACK}'], [7, '{BEL}'], [8, '{BS}'], [9, '{HT}'], [10, '{LF}'], [11, '{VT}'], [12, '{FF}'], [13, '{CR}'], [14, '{SO}'], [15, '{SI}'], [16, '{DLE}'], [17, '{DC1}'], [18, '{DC2}'], [19, '{DC3}'], [20, '{DC4}'], [21, '{NAK}'], [22, '{SYN}'], [23, '{ETB}'], [24, '{CAN}'], [25, '{EM}'], [26, '{SUB}'], [27, '{ESC}'], [28, '{FS}'], [29, '{GS}'], [30, '{RS}'], [31, '{US}'], [127, '{DEL}'] ]) process_barcode_bytes(bytes, mode, keepLineBreak = true) { // Process the non-printing chars of barcode bytes to obtain desired text. // Parameters // ---------- // bytes : bytearray // The barcode content in a byte array. // mode : ProcessNonPrintingCharsMode // The mode indicates how to processing non-printing chars. // keepLineBreak : bool // The flag indicates whether to preserve the original line breaks in the resulting text. It is only valid when mode is PNPCM_REMOVE or PNPCM_CONVERT. // Returns // ------- // result : str // Returns The text result after processing barcode bytes. let result = ""; for (let _byte in bytes) { if (this.#__non_printing_ascii_chars_value_to_string_dict.has(_byte) || mode == ProcessNonPrintingCharsMode.PNPCM_KEEP || keepLineBreak && (_byte == 10 || _byte == 13)) { result += String.fromCharCode(_byte); } else if (mode == ProcessNonPrintingCharsMode.PNPCM_CONVERT) { result += this.#__non_printing_ascii_chars_value_to_string_dict.get(_byte); } } return result; } } let barcode_bytes = text_result.barcode_bytes; let util = new ProcessBarcodeBytesUtil(); let origin_str = util.process_barcode_bytes(barcode_bytes, ProcessNonPrintingCharsMode.PNPCM_KEEP); console.log('original text:\n' + origin_str); let removed_str = util.process_barcode_bytes(barcode_bytes, ProcessNonPrintingCharsMode.PNPCM_REMOVE); console.log('2.text after removing non-printing chars except line break:\n' + removed_str); let removed_str2 = util.process_barcode_bytes(barcode_bytes, ProcessNonPrintingCharsMode.PNPCM_REMOVE, false); console.log('3.text after removing non-printing chars:\n' + removed_str2); let converted_str = util.process_barcode_bytes(barcode_bytes, ProcessNonPrintingCharsMode.PNPCM_CONVERT); console.log('4.text after converting non-printing chars except line break:\n' + converted_str); let converted_str2 = util.process_barcode_bytes(barcode_bytes, ProcessNonPrintingCharsMode.PNPCM_CONVERT, false); console.log('5.text after converting non-printing chars:\n' + converted_str2); ``` > ```java mReader.setTextResultListener(new TextResultListener() { // Obtain the recognized barcode results and display. @Override public void textResultCallback(int id, ImageData imageData, TextResult[] textResults) { process = new ProcessBarcodeResultUtil(); if (textResults!=null && textResults.length!=0){ for (int i=0; i< textResults.length; i++){ String processedResult = process.processBarcodeByte(textResults[i].barcodeBytes,ProcessBarcodeResultUtil.ProcessNonPrintingCharsMode.PNPCM_REMOVE,true); Log.i("ProcessByte", "textResultCallback: processeResult = "+processedResult); textResults[i].barcodeText = processedResult; } } } } // Create a ProcessBarcodeResultUtil class public class ProcessBarcodeResultUtil { enum ProcessNonPrintingCharsMode{ PNPCM_KEEP, PNPCM_REMOVE, PNPCM_CONVERT } final HashMap charValueToStringDict = new HashMap(); ProcessBarcodeResultUtil(){ final int[] NonPrintingAsciiCharsValue = {0,1,2,3,4,5,6,7,8,9,10,11,12,13,14,15,16,17,18,19,20,21,22,23,24,25,26,27,28,29,30,31,127}; final String[] NonPrintingAsciiCharsString = { "{NUL}","{SOH}","{STX}","{ETX}","{EOT}","{ENQ}","{ACK}","{BEL}","{BS}","{HT}","{LF}","{VT}","{FF}","{CR}","{SO}","{SI}", "{DLE}","{DC1}","{DC2}","{DC3}","{DC4}","{NAK}","{SYN}","{ETB}","{CAN}","{EM}","{SUB}","{ESC}","{FS}","{GS}","{RS}","{US}","{DEL}" }; for (int i = 0; i < 33; ++i){ charValueToStringDict.put(NonPrintingAsciiCharsValue[i], NonPrintingAsciiCharsString[i]); } } public String processBarcodeByte(byte[] barcodeByte, ProcessNonPrintingCharsMode mode, boolean keepLineBreak){ StringBuilder processedResult = new StringBuilder(); for (int i=0; i ```objc typedef NS_ENUM(NSInteger,EnumResultProcessMode) { RPM_KEEP = 0, RPM_CONVERT = 1, RPM_REMOVE = 2 }; ... - (void)textResultCallback:(NSInteger)frameId imageData:(iImageData *)imageData results:(NSArray *)results{ if (results) { for (NSInteger i = 0; i< [results count]; i++) { results[i].barcodeText = [self processResult:results[i].barcodeBytes mode:RPM_CONVERT isBreaklineKept:NO]; msgText = [msgText stringByAppendingString:[NSString stringWithFormat:@"\nFormat: %@\nText: %@\n", results[i].barcodeFormatString, results[i].barcodeText]]; } } } - (NSString *)processBarcodeBytes:(NSData *)byte mode:(EnumResultProcessMode)mode isBreaklineKept:(BOOL)isKept{ NSArray* _nonPrintingAsciiCharsKey = @[@0,@1,@2,@3,@4,@5,@6,@7,@8,@9,@10,@11,@12,@13,@14,@15,@16,@17,@18,@19,@20,@21,@22,@23,@24,@25,@26,@27,@28,@29,@30,@31,@127]; NSArray* _nonPrintingAsciiCharsString = @[@"{NUL}",@"{SOH}",@"{STX}",@"{ETX}",@"{EOT}",@"{ENQ}",@"{ACK}",@"{BEL}",@"{BS}",@"{HT}",@"{LF}",@"{VT}",@"{FF}",@"{CR}",@"{SO}",@"{SI}",@"{DLE}",@"{DC1}",@"{DC2}",@"{DC3}",@"{DC4}",@"{NAK}",@"{SYN}",@"{ETB}",@"{CAN}",@"{EM}",@"{SUB}",@"{ESC}",@"{FS}",@"{GS}",@"{RS}",@"{US}",@"{DEL}"]; NSMapTable * _charValueToStringDict = [NSMapTable strongToStrongObjectsMapTable]; for (int i=0; i<_nonPrintingAsciiCharsKey.count;i++){ [_charValueToStringDict setObject:_nonPrintingAsciiCharsString[i] forKey:_nonPrintingAsciiCharsKey[i]]; } const char* _Nonnull barcodeByteChar = byte.bytes; NSString *processedText = @""; for (int i=0;i31 && (int)barcodeByteChar[i]!=127 && (int)barcodeByteChar[i]!=0)){ NSString *nextString = [NSString stringWithFormat:@"%c",barcodeByteChar[i]]; processedText = [processedText stringByAppendingString:nextString]; } else if (mode == RPM_CONVERT){ NSNumber *keyValue = [[NSNumber alloc] initWithInt:(int)barcodeByteChar[i]]; NSString *nextString = [_charValueToStringDict objectForKey:@2]; processedText = [processedText stringByAppendingString:nextString]; } } return processedText; } ``` > ```swift enum EnumResultProcessMode{ case keep case convert case remove } func textResultCallback(_ frameId: Int, imageData: iImageData, results: [iTextResult]?) { if (results != nil){ for item in results! { let processedBarcodeText = processBarcodeBytes(byte: item.barcodeBytes!, processMode: EnumResultProcessMode.convert, isKeep: true) item.barcodeText = processedBarcodeText } } } private func processBarcodeBytes(byte:Data, processMode:EnumResultProcessMode, isKeep:Bool) -> String{ let charValueToStringDict:NSDictionary = [0:"{NUL}",1:"{SOH}",2:"{STX}",3:"{ETX}",4:"{EOT}",5:"{ENQ}",6:"{ACK}",7:"{BEL}",8:"{BS}",9:"{HT}",10:"{LF}",11:"{VT}",12:"{FF}",13:"{CR}",14:"{SO}",15:"{SI}",16:"{DLE}",17:"{DC1}",18:"{DC2}",19:"{DC3}",20:"{DC4}",21:"{NAK}",22:"{SYN}",23:"{ETB}",24:"{CAN}",25:"{EM}",26:"{SUB}",27:"{ESC}",28:"{FS}",29:"{GS}",30:"{RS}",31:"{US}",127:"{DEL}"] var processedString = "" for i in 0...byte.count-1{ if ((isKeep && ((byte[i]==10) || (byte[i]==13))) || (processMode == EnumResultProcessMode.keep) || ((byte[i]>31) && (byte[i] != 127) && (byte[i] != 0))){ let nextText:String = String(bytes: [byte[i]], encoding: String.Encoding.utf8)! processedString += nextText as String } else if (processMode == EnumResultProcessMode.convert){ let nextText:NSString = charValueToStringDict.object(forKey: byte[i]) as! NSString processedString += nextText as String } } return processedString } ``` > ```python class ProcessNonPrintingCharsMode: PNPCM_KEEP = 0 PNPCM_REMOVE = 1 PNPCM_CONVERT = 2 class ProcessBarcodeBytesUtil: def __init__(self): self.__non_printing_ascii_chars_value_to_string_dict:dict = dict({ (0,'{NUL}'),(1,'{SOH}'),(2,'{STX}'),(3,'{ETX}'),(4,'{EOT}'),(5,'{ENQ}'),(6,'{ACK}'),(7,'{BEL}'), (8,'{BS}'),(9,'{HT}'),(10,'{LF}'),(11,'{VT}'),(12,'{FF}'),(13,'{CR}'),(14,'{SO}'),(15,'{SI}'), (16,'{DLE}'),(17,'{DC1}'),(18,'{DC2}'),(19,'{DC3}'),(20,'{DC4}'),(21,'{NAK}'),(22,'{SYN}'),(23,'{ETB}'), (24,'{CAN}'),(25,'{EM}'),(26,'{SUB}'),(27,'{ESC}'),(28,'{FS}'),(29,'{GS}'),(30,'{RS}'),(31,'{US}'),(127,'{DEL}') }) def process_barcode_bytes(self, bytes:bytearray, mode:ProcessNonPrintingCharsMode, keepLineBreak:bool = True)->str: """ Process the non-printing chars of barcode bytes to obtain desired text. Parameters ---------- bytes : bytearray The barcode content in a byte array. mode : ProcessNonPrintingCharsMode The mode indicates how to processing non-printing chars. keepLineBreak : bool The flag indicates whether to preserve the original line breaks in the resulting text. It is only valid when mode is PNPCM_REMOVE or PNPCM_CONVERT. Returns ------- result : str Returns The text result after processing barcode bytes. """ result:str = '' for _byte in bytes: if not self.__non_printing_ascii_chars_value_to_string_dict.__contains__(_byte) \ or mode == ProcessNonPrintingCharsMode.PNPCM_KEEP \ or keepLineBreak and (_byte == 10 or _byte == 13): result += chr(_byte) elif mode == ProcessNonPrintingCharsMode.PNPCM_CONVERT: result += self.__non_printing_ascii_chars_value_to_string_dict.get(_byte) return result if __name__ == '__main__': barcode_bytes = text_result.barcode_bytes util = ProcessBarcodeBytesUtil() origin_str = util.process_barcode_bytes(barcode_bytes, ProcessNonPrintingCharsMode.PNPCM_KEEP) print('original text:\n' + origin_str) removed_str = util.process_barcode_bytes(barcode_bytes, ProcessNonPrintingCharsMode.PNPCM_REMOVE) print('\n2.text after removing non-printing chars except line break:\n' + removed_str) removed_str2 = util.process_barcode_bytes(barcode_bytes, ProcessNonPrintingCharsMode.PNPCM_REMOVE, False) print('\n3.text after removing non-printing chars:\n' + removed_str2) converted_str = util.process_barcode_bytes(barcode_bytes, ProcessNonPrintingCharsMode.PNPCM_CONVERT) print('\n4.text after converting non-printing chars except line break:\n' + converted_str) converted_str2 = util.process_barcode_bytes(barcode_bytes, ProcessNonPrintingCharsMode.PNPCM_CONVERT, False) print('\n5.text after converting non-printing chars:\n' + converted_str2) ``` > ```java public class ProcessBarcodeBytesUtil { enum ProcessNonPrintingCharsMode { PNPCM_KEEP, PNPCM_REMOVE, PNPCM_CONVERT } final HashMap charValueToStringDict = new HashMap(); ProcessBarcodeBytesUtil() { final int[] NonPrintingAsciiCharsValue = {0,1,2,3,4,5,6,7,8,9,10,11,12,13,14,15,16,17,18,19,20,21,22,23,24,25,26,27,28,29,30,31,127}; final String[] NonPrintingAsciiCharsString = {"{NUL}","{SOH}","{STX}","{ETX}","{EOT}","{ENQ}","{ACK}","{BEL}","{BS}","{HT}","{LF}","{VT}","{FF}","{CR}","{SO}","{SI}","{DLE}","{DC1}","{DC2}","{DC3}","{DC4}","{NAK}","{SYN}","{ETB}","{CAN}","{EM}","{SUB}","{ESC}","{FS}","{GS}","{RS}","{US}","{DEL}" }; for (int i = 0; i < 33; ++i) charValueToStringDict.put(NonPrintingAsciiCharsValue[i], NonPrintingAsciiCharsString[i]); } /** * Process the non-printing chars of barcode bytes to obtain desired text. * * @param bytes The barcode content in a byte array. * @param mode The mode indicates how to processing non-printing chars. * @param keepLineBreak The flag indicates whether to preserve the original line breaks in the resulting text. It is only valid when mode is PNPCM_REMOVE or PNPCM_CONVERT. * @return Returns The text result after processing barcode bytes. * */ public String processBarcodeBytes(byte[] bytes, ProcessNonPrintingCharsMode mode, boolean keepLineBreak) { StringBuilder result = new StringBuilder(); for (int i = 0; i < bytes.length; ++i) { int byteValue = (int)bytes[i]; if (!charValueToStringDict.containsKey(byteValue) || mode == ProcessNonPrintingCharsMode.PNPCM_KEEP || keepLineBreak && (byteValue == 10 || byteValue == 13)) { result.append((char)bytes[i]); } else if (mode == ProcessNonPrintingCharsMode.PNPCM_CONVERT) { result.append(charValueToStringDict.get(byteValue)); } } return result.toString(); } public static void main(String[] args) throws InterruptedException { byte[] barcodeBytes = textResult.barcodeBytes; ProcessBarcodeBytesUtil util = new ProcessBarcodeBytesUtil(); String s0 = util.ProcessBarcodeBytes(barcodeBytes, ProcessNonPrintingCharsMode.PNPCM_KEEP, true); String s1 = util.ProcessBarcodeBytes(barcodeBytes, ProcessNonPrintingCharsMode.PNPCM_REMOVE, true); String s2 = util.ProcessBarcodeBytes(barcodeBytes, ProcessNonPrintingCharsMode.PNPCM_REMOVE, false); String s3 = util.ProcessBarcodeBytes(barcodeBytes, ProcessNonPrintingCharsMode.PNPCM_CONVERT, true); String s4 = util.ProcessBarcodeBytes(barcodeBytes, ProcessNonPrintingCharsMode.PNPCM_CONVERT, false); System.out.println("1.original text:\n" + s0); System.out.println("\n2.text after removing non-printing chars except line break:\n" + s1); System.out.println("\n3.text after removing non-printing chars:\n" + s2); System.out.println("\n4.text after converting non-printing chars except line break:\n" + s3); System.out.println("\n5.text after converting non-printing chars:\n" + s4); } } ``` > ```csharp class ProcessBarcodeBytesUtil { internal enum ProcessNonPrintingCharsMode { PNPCM_KEEP, PNPCM_REMOVE, PNPCM_CONVERT } Hashtable charValueToStringDict = new Hashtable(); ProcessBarcodeBytesUtil() { int[] NonPrintingAsciiCharsValue = { 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 127 }; string[] NonPrintingAsciiCharsString = { "{NUL}","{SOH}","{STX}","{ETX}","{EOT}","{ENQ}","{ACK}","{BEL}","{BS}","{HT}","{LF}","{VT}","{FF}","{CR}","{SO}","{SI}", "{DLE}","{DC1}","{DC2}","{DC3}","{DC4}","{NAK}","{SYN}","{ETB}","{CAN}","{EM}","{SUB}","{ESC}","{FS}","{GS}","{RS}","{US}","{DEL}" }; for (int i = 0; i < 33; ++i) charValueToStringDict.Add(NonPrintingAsciiCharsValue[i], NonPrintingAsciiCharsString[i]); } ///