Method Details

• calculateMaskPenalty

  private static int calculateMaskPenalty(ByteMatrix matrix)

  Scores a mask pattern by applying the four penalty rules and summing them; see Table 21 of JISX0510:2004 (p.45) for the details.

  Parameters:

  matrix - the masked symbol

  Returns:

  the penalty, lower is better

• encode

  public static QRCode encode(String content, ErrorCorrectionLevel ecLevel) throws WriterException

  Encode the given content into a QR Code.

  Parameters:

  content - text to encode

  ecLevel - error correction level to use

  Returns:

  QRCode representing the encoded QR code

  Throws:

  WriterException - if encoding can't succeed, because of for example invalid content or configuration

• encode

  public static QRCode encode(String content, ErrorCorrectionLevel ecLevel, Map<EncodeHintType, ?> hints) throws WriterException

  Encode content into a QR Code with hints for encoding options.

  Parameters:

  content - text to encode

  ecLevel - error correction level

  hints - optional hints (character set, version, mask pattern, GS1 format)

  Returns:

  QRCode representing the encoded QR code

  Throws:

  WriterException - if encoding fails

• recommendVersion

  private static Version recommendVersion(ErrorCorrectionLevel ecLevel, Mode mode, BitArray headerBits, BitArray dataBits) throws WriterException

  Decides the smallest version of QR code that will contain all of the provided data.

  Parameters:

  ecLevel - the required error-correction level

  mode - the data encoding mode

  headerBits - the header bits counted against the version capacity

  dataBits - the encoded data bits that must fit

  Returns:

  the smallest version whose capacity holds header and data bits

  Throws:

  WriterException - if the data cannot fit in any version

• calculateBitsNeeded

  private static int calculateBitsNeeded(Mode mode, BitArray headerBits, BitArray dataBits, Version version)

  Counts the bits needed to encode the content at a version.

  Parameters:

  mode - the encoding mode

  headerBits - the mode and length header

  dataBits - the encoded content

  version - the version to size for

  Returns:

  the number of bits

• getAlphanumericCode

  static int getAlphanumericCode(int code)

  -1 if there is no corresponding code in the table.

  Parameters:

  code - the code point of the single character to look up in the alphanumeric table

  Returns:

  the code point of the table used in alphanumeric mode or

• chooseMode

  public static Mode chooseMode(String content)

  Selects the mode that encodes the given text in the fewest bits.

  Parameters:

  content - the text to encode, examined character by character to decide the mode

  Returns:

  the mode that encodes content in the fewest bits

• chooseMode

  private static Mode chooseMode(String content, String encoding)

  Choose the best mode by examining the content. Note that 'encoding' is used as a hint; if it is Shift_JIS, and the input is only double-byte Kanji, then we return Mode.KANJI.

  Parameters:

  content - the text to examine

  encoding - the character-set hint, may be null

  Returns:

  the most compact encoding mode for the content

• isOnlyDoubleByteKanji

  private static boolean isOnlyDoubleByteKanji(String content)

  Checks whether the content is all double-byte Kanji.

  Parameters:

  content - the text to check

  Returns:

  true if Kanji encoding is the only option

• chooseMaskPattern

  private static int chooseMaskPattern(BitArray bits, ErrorCorrectionLevel ecLevel, Version version, ByteMatrix matrix) throws WriterException

  Picks the mask pattern with the lowest penalty.

  Parameters:

  bits - the encoded data

  ecLevel - the level in use

  version - the symbol version

  matrix - the symbol being built

  Returns:

  the pattern number to use

  Throws:

  WriterException - if a mask cannot be applied

• chooseVersion

  private static Version chooseVersion(int numInputBits, ErrorCorrectionLevel ecLevel) throws WriterException

  Picks the smallest version that fits the data.

  Parameters:

  numInputBits - the bits to encode

  ecLevel - the level to fit within

  Returns:

  the version, null if none is large enough

  Throws:

  WriterException - if no version can hold the data

• willFit

  private static boolean willFit(int numInputBits, Version version, ErrorCorrectionLevel ecLevel)

  Whether the data fits in the version at this error-correction level.

  Parameters:

  numInputBits - the number of data bits to fit

  version - the QR code version to test

  ecLevel - the error-correction level the code uses

  Returns:

  true if the number of input bits will fit in a code with the specified version and error correction level.

• terminateBits

  static void terminateBits(int numDataBytes, BitArray bits) throws WriterException

  Terminate bits as described in 8.4.8 and 8.4.9 of JISX0510:2004 (p.24).

  Parameters:

  numDataBytes - the data section size in bytes, which sets the capacity at 8 bits each

  bits - the bit buffer the terminator and padding bits are appended to

  Throws:

  WriterException - if bits already exceeds that capacity, or does not end at it

• getNumDataBytesAndNumECBytesForBlockID

  static void getNumDataBytesAndNumECBytesForBlockID(int numTotalBytes, int numDataBytes, int numRSBlocks, int blockID, int[] numDataBytesInBlock, int[] numECBytesInBlock) throws WriterException

  Get number of data bytes and number of error correction bytes for block id "blockID". Store the result in "numDataBytesInBlock", and "numECBytesInBlock". See table 12 in 8.5.1 of JISX0510:2004 (p.30)

  Parameters:

  numTotalBytes - the total codeword count for the version and error correction level

  numDataBytes - the codeword count left after the error correction codewords

  numRSBlocks - the number of Reed-Solomon blocks the codewords are split into

  blockID - the zero-based index of the block to compute, below numRSBlocks

  numDataBytesInBlock - a one-element array receiving the data codeword count

  numECBytesInBlock - a one-element array receiving the error correction codeword count

  Throws:

  WriterException - if blockID is out of range, or the block geometry implied by the other counts is inconsistent

• interleaveWithECBytes

  static BitArray interleaveWithECBytes(BitArray bits, int numTotalBytes, int numDataBytes, int numRSBlocks) throws WriterException

  Interleave "bits" with corresponding error correction bytes. On success, store the result in "result". The interleave rule is complicated. See 8.6 of JISX0510:2004 (p.37) for details.

  Parameters:

  bits - the data codewords, which must hold exactly numDataBytes

  numTotalBytes - the total codeword count including error correction

  numDataBytes - the data codeword count within numTotalBytes

  numRSBlocks - the number of Reed-Solomon blocks to split the data across

  Returns:

  a buffer holding the data and error correction codewords interleaved

  Throws:

  WriterException - if the supplied counts disagree, or the result is not numTotalBytes long

• generateECBytes

  static byte[] generateECBytes(byte[] dataBytes, int numEcBytesInBlock)

  Generate the error correction bytes for one block of data, appending them to a copy of the block and running Reed-Solomon encoding over the result.

  Parameters:

  dataBytes - data to encode

  numEcBytesInBlock - number of parity bytes to produce; must be positive

  Returns:

  the trailing numEcBytesInBlock parity bytes computed over the data

• appendModeInfo

  static void appendModeInfo(Mode mode, BitArray bits)

  Append mode info. On success, store the result in "bits".

  Parameters:

  mode - the encoding mode, whose four-bit indicator is written

  bits - the bit buffer the mode indicator is appended to

• appendLengthInfo

  static void appendLengthInfo(int numLetters, Version version, Mode mode, BitArray bits) throws WriterException

  Append length info. On success, store the result in "bits".

  Parameters:

  numLetters - the character count, which must fit the mode and version's count field

  version - the QR version, which fixes the width of the character count field

  mode - the encoding mode, which fixes that width as well

  bits - the bit buffer the character count is appended to

  Throws:

  WriterException - if numLetters does not fit in the character count field

• appendBytes

  static void appendBytes(String content, Mode mode, BitArray bits, String encoding) throws WriterException

  Append "bytes" in "mode" mode (encoding) into "bits". On success, store the result in "bits".

  Parameters:

  content - the text whose characters are encoded, read in whatever units the mode needs

  mode - the encoding mode to apply, which selects one of the append methods below

  bits - the bit buffer the encoded characters are appended to

  encoding - the charset name used by the modes that fall back to bytes

  Throws:

  WriterException - if mode is not one of the four encodable modes, or the content cannot be represented in it

• appendNumericBytes

  static void appendNumericBytes(CharSequence content, BitArray bits)

  Append numeric mode bytes

  Parameters:

  content - the digits to encode, packed three at a time wherever a run allows it

  bits - the bit buffer the packed digits are appended to

• appendAlphanumericBytes

  static void appendAlphanumericBytes(CharSequence content, BitArray bits) throws WriterException

  Append alphanumeric mode bytes

  Parameters:

  content - the alphanumeric characters to encode, packed in pairs where a run allows

  bits - the bit buffer the packed characters are appended to

  Throws:

  WriterException - if any character has no alphanumeric table entry

• append8BitBytes

  static void append8BitBytes(String content, BitArray bits, String encoding) throws WriterException

  Append 8-bit byte mode bytes

  Parameters:

  content - the text to encode, first converted using encoding

  bits - the bit buffer the resulting bytes are appended to

  encoding - the charset name to convert the text with

  Throws:

  WriterException - if the JVM does not support encoding

• appendKanjiBytes

  static void appendKanjiBytes(String content, BitArray bits) throws WriterException

  Append Kanji mode bytes

  Parameters:

  content - the Kanji text to encode, read as Shift_JIS

  bits - the bit buffer the encoded characters are appended to

  Throws:

  WriterException - if the text does not convert to an even number of Shift_JIS bytes, or a byte pair is outside the two ranges Kanji mode defines

• appendECI

  private static void appendECI(CharacterSetECI eci, BitArray bits)

  Appends the ECI header naming the character set.

  Parameters:

  eci - the character set to name

  bits - the bits to append to