public QRCode()
{
mode = null;
ecLevel = null;
version = -1;
matrixWidth = -1;
maskPattern = -1;
numTotalBytes = -1;
numDataBytes = -1;
numECBytes = -1;
numRSBlocks = -1;
matrix = null;
}
private static int ChooseMaskPattern(BitVector bits, ErrorCorrectionLevel ecLevel, int version,
ByteMatrix matrix)
{
int minPenalty = int.MaxValue; // Lower penalty is better.
int bestMaskPattern = -1;
// We try all mask patterns to choose the best one.
for (int maskPattern = 0; maskPattern < QRCode.NUM_MASK_PATTERNS; maskPattern++)
{
MatrixUtil.BuildMatrix(bits, ecLevel, version, maskPattern, matrix);
int penalty = CalculateMaskPenalty(matrix);
if (penalty < minPenalty)
{
minPenalty = penalty;
bestMaskPattern = maskPattern;
}
}
return(bestMaskPattern);
}
/**
* Initialize "qrCode" according to "numInputBytes", "ecLevel", and "mode". On success,
* modify "qrCode".
*/
private static void InitQRCode(int numInputBytes, ErrorCorrectionLevel ecLevel, Mode mode,
QRCode qrCode)
{
qrCode.SetECLevel(ecLevel);
qrCode.SetMode(mode);
// In the following comments, we use numbers of Version 7-H.
for (int versionNum = 1; versionNum <= 40; versionNum++)
{
Version version = Version.GetVersionForNumber(versionNum);
// numBytes = 196
int numBytes = version.GetTotalCodewords();
// getNumECBytes = 130
Version.ECBlocks ecBlocks = version.GetECBlocksForLevel(ecLevel);
int numEcBytes = ecBlocks.GetTotalECCodewords();
// getNumRSBlocks = 5
int numRSBlocks = ecBlocks.GetNumBlocks();
// getNumDataBytes = 196 - 130 = 66
int numDataBytes = numBytes - numEcBytes;
// We want to choose the smallest version which can contain data of "numInputBytes" + some
// extra bits for the header (mode info and length info). The header can be three bytes
// (precisely 4 + 16 bits) at most. Hence we do +3 here.
if (numDataBytes >= numInputBytes + 3)
{
// Yay, we found the proper rs block info!
qrCode.SetVersion(versionNum);
qrCode.SetNumTotalBytes(numBytes);
qrCode.SetNumDataBytes(numDataBytes);
qrCode.SetNumRSBlocks(numRSBlocks);
// getNumECBytes = 196 - 66 = 130
qrCode.SetNumECBytes(numEcBytes);
// matrix width = 21 + 6 * 4 = 45
qrCode.SetMatrixWidth(version.GetDimensionForVersion());
return;
}
}
throw new WriterException("Cannot find proper rs block info (input data too big?)");
}
// Make bit vector of type information. On success, store the result in "bits" and return true.
// Encode error correction level and mask pattern. See 8.9 of
// JISX0510:2004 (p.45) for details.
public static void MakeTypeInfoBits(ErrorCorrectionLevel ecLevel, int maskPattern, BitVector bits)
{
if (!QRCode.IsValidMaskPattern(maskPattern))
{
throw new WriterException("Invalid mask pattern");
}
int typeInfo = (ecLevel.GetBits() << 3) | maskPattern;
bits.AppendBits(typeInfo, 5);
int bchCode = CalculateBCHCode(typeInfo, TYPE_INFO_POLY);
bits.AppendBits(bchCode, 10);
BitVector maskBits = new BitVector();
maskBits.AppendBits(TYPE_INFO_MASK_PATTERN, 15);
bits.Xor(maskBits);
if (bits.Size() != 15)
{ // Just in case.
throw new WriterException("should not happen but we got: " + bits.Size());
}
}
public void SetECLevel(ErrorCorrectionLevel value)
{
ecLevel = value;
}
public static void Encode(String content, ErrorCorrectionLevel ecLevel, IDictionary <EncodeHintType, Object> hints,
QRCode qrCode)
{
String encoding = null;
if (hints != null && hints.ContainsKey(EncodeHintType.CHARACTER_SET))
{
encoding = (string)hints[EncodeHintType.CHARACTER_SET];
}
if (encoding == null)
{
encoding = DEFAULT_BYTE_MODE_ENCODING;
}
// Step 1: Choose the mode (encoding).
Mode mode = ChooseMode(content, encoding);
// Step 2: Append "bytes" into "dataBits" in appropriate encoding.
BitVector dataBits = new BitVector();
AppendBytes(content, mode, dataBits, encoding);
// Step 3: Initialize QR code that can contain "dataBits".
int numInputBytes = dataBits.SizeInBytes();
InitQRCode(numInputBytes, ecLevel, mode, qrCode);
// Step 4: Build another bit vector that contains header and data.
BitVector headerAndDataBits = new BitVector();
// Step 4.5: Append ECI message if applicable
if (mode == Mode.BYTE && !DEFAULT_BYTE_MODE_ENCODING.Equals(encoding))
{
CharacterSetECI eci = CharacterSetECI.GetCharacterSetECIByName(encoding);
if (eci != null)
{
AppendECI(eci, headerAndDataBits);
}
}
AppendModeInfo(mode, headerAndDataBits);
int numLetters = mode.Equals(Mode.BYTE) ? dataBits.SizeInBytes() : content.Length;
AppendLengthInfo(numLetters, qrCode.GetVersion(), mode, headerAndDataBits);
headerAndDataBits.AppendBitVector(dataBits);
// Step 5: Terminate the bits properly.
TerminateBits(qrCode.GetNumDataBytes(), headerAndDataBits);
// Step 6: Interleave data bits with error correction code.
BitVector finalBits = new BitVector();
InterleaveWithECBytes(headerAndDataBits, qrCode.GetNumTotalBytes(), qrCode.GetNumDataBytes(),
qrCode.GetNumRSBlocks(), finalBits);
// Step 7: Choose the mask pattern and set to "qrCode".
ByteMatrix matrix = new ByteMatrix(qrCode.GetMatrixWidth(), qrCode.GetMatrixWidth());
qrCode.SetMaskPattern(ChooseMaskPattern(finalBits, qrCode.GetECLevel(), qrCode.GetVersion(),
matrix));
// Step 8. Build the matrix and set it to "qrCode".
MatrixUtil.BuildMatrix(finalBits, qrCode.GetECLevel(), qrCode.GetVersion(),
qrCode.GetMaskPattern(), matrix);
qrCode.SetMatrix(matrix);
// Step 9. Make sure we have a valid QR Code.
if (!qrCode.IsValid())
{
throw new WriterException("Invalid QR code: " + qrCode.ToString());
}
}
/**
* Encode "bytes" with the error correction level "ecLevel". The encoding mode will be chosen
* internally by ChooseMode(). On success, store the result in "qrCode".
*
* We recommend you to use QRCode.EC_LEVEL_L (the lowest level) for
* "getECLevel" since our primary use is to show QR code on desktop screens. We don't need very
* strong error correction for this purpose.
*
* Note that there is no way to encode bytes in MODE_KANJI. We might want to add EncodeWithMode()
* with which clients can specify the encoding mode. For now, we don't need the functionality.
*/
public static void Encode(String content, ErrorCorrectionLevel ecLevel, QRCode qrCode)
{
Encode(content, ecLevel, null, qrCode);
}
public ECBlocks GetECBlocksForLevel(ErrorCorrectionLevel ecLevel)
{
return(ecBlocks[ecLevel.Ordinal()]);
}
