private static BitList GenerateModeMessage(bool compact, int layers, int messageSizeInWords)
{
var modeMessage = new BitList();
if (compact)
{
modeMessage.AddBits((uint)layers - 1, 2);
modeMessage.AddBits((uint)messageSizeInWords - 1, 6);
modeMessage = ErrorCorrection.GenerateCheckWords(modeMessage, 28, 4);
}
else
{
modeMessage.AddBits((uint)layers - 1, 5);
modeMessage.AddBits((uint)messageSizeInWords - 1, 11);
modeMessage = ErrorCorrection.GenerateCheckWords(modeMessage, 40, 4);
}
return(modeMessage);
}
public static IBarcode Encode(string content, int minimumEccPercentage = 23, int userSpecifiedLayers = 0)
{
BitList bits = HighLevelEncoding.Encode(content.Select(x => (byte)x).ToArray());
int eccBits = ((bits.Length * minimumEccPercentage) / 100) + 11;
int totalSizeBits = bits.Length + eccBits;
int layers, totalBitsInLayer, wordSize;
bool compact;
BitList stuffedBits;
if (userSpecifiedLayers != 0)
{
compact = userSpecifiedLayers < 0;
layers = compact ? -userSpecifiedLayers : userSpecifiedLayers;
if ((compact && layers > MaximumNumberOfCompactBits) || (!compact && layers > MaximumNumberOfBits))
{
throw new InvalidOperationException($"Illegal value {userSpecifiedLayers} for layers");
}
totalBitsInLayer = GetTotalBitsInLayer(layers, compact);
wordSize = WordSize[layers];
int usableBitsInLayer = totalBitsInLayer - (totalBitsInLayer % wordSize);
stuffedBits = StuffBits(bits, wordSize);
if (stuffedBits.Length + eccBits > usableBitsInLayer)
{
throw new InvalidOperationException("Data too large for user specified layer");
}
if (compact && stuffedBits.Length > wordSize * 64)
{
throw new InvalidOperationException("Data too large for user specified layer");
}
}
else
{
stuffedBits = new BitList();
wordSize = 0;
// We look at the possible table sizes in the order Compact1, Compact2, Compact3,
// Compact4, Normal4,... Normal(i) for i < 4 isn't typically used since Compact(i+1)
// is the same size, but has more data.
for (int i = 0; ; i++)
{
if (i > MaximumNumberOfBits)
{
throw new InvalidOperationException("Data too large for an aztec code");
}
compact = i <= 3;
layers = compact ? i + 1 : i;
totalBitsInLayer = GetTotalBitsInLayer(layers, compact);
if (totalSizeBits > totalBitsInLayer)
{
continue;
}
// [Re]stuff the bits if this is the first opportunity, or if the
// wordSize has changed
if (wordSize != WordSize[layers])
{
wordSize = WordSize[layers];
stuffedBits = StuffBits(bits, wordSize);
}
int usableBitsInLayers = totalBitsInLayer - (totalBitsInLayer % wordSize);
if (compact && stuffedBits.Length > wordSize * 64)
{
continue; // Compact format only allows 64 data words, though C4 can hold more words than that
}
if (stuffedBits.Length + eccBits <= usableBitsInLayers)
{
break;
}
}
}
BitList messageBits = ErrorCorrection.GenerateCheckWords(stuffedBits, totalBitsInLayer, wordSize);
int messageSizeInWords = stuffedBits.Length / wordSize;
BitList modeMessage = GenerateModeMessage(compact, layers, messageSizeInWords);
// allocate symbol
int baseMatrixSize = compact
? 11 + layers * 4
: 14 + layers * 4;
var alignmentMap = new int[baseMatrixSize];
int matrixSize;
if (compact)
{
// no alignment marks in compact mode, alignmentMap is a no-op
matrixSize = baseMatrixSize;
for (int i = 0; i < alignmentMap.Length; i++)
{
alignmentMap[i] = i;
}
}
else
{
matrixSize = baseMatrixSize + 1 + 2 * ((baseMatrixSize / 2 - 1) / 15);
int origCenter = baseMatrixSize / 2;
int center = matrixSize / 2;
for (int i = 0; i < origCenter; i++)
{
int newOffset = i + i / 15;
alignmentMap[origCenter - i - 1] = center - newOffset - 1;
alignmentMap[origCenter + i] = center + newOffset + 1;
}
}
var code = new AztecCode(matrixSize);
code.Content = content;
// draw data bits
for (int i = 0, rowOffset = 0; i < layers; i++)
{
int rowSize = (layers - i) * 4;
if (compact)
{
rowSize += 9;
}
else
{
rowSize += 12;
}
for (int j = 0; j < rowSize; j++)
{
int columnOffset = j * 2;
for (int k = 0; k < 2; k++)
{
if (messageBits.GetBit(rowOffset + columnOffset + k))
{
code.Set(alignmentMap[i * 2 + k], alignmentMap[i * 2 + j]);
}
if (messageBits.GetBit(rowOffset + rowSize * 2 + columnOffset + k))
{
code.Set(alignmentMap[i * 2 + j], alignmentMap[baseMatrixSize - 1 - i * 2 - k]);
}
if (messageBits.GetBit(rowOffset + rowSize * 4 + columnOffset + k))
{
code.Set(alignmentMap[baseMatrixSize - 1 - i * 2 - k], alignmentMap[baseMatrixSize - 1 - i * 2 - j]);
}
if (messageBits.GetBit(rowOffset + rowSize * 6 + columnOffset + k))
{
code.Set(alignmentMap[baseMatrixSize - 1 - i * 2 - j], alignmentMap[i * 2 + k]);
}
}
}
rowOffset += rowSize * 8;
}
// draw mode message
DrawModeMessage(code, compact, matrixSize, modeMessage);
// draw alignment marks
if (compact)
{
DrawBullsEye(code, matrixSize / 2, 5);
}
else
{
DrawBullsEye(code, matrixSize / 2, 7);
for (int i = 0, j = 0; i < baseMatrixSize / 2 - 1; i += 15, j += 16)
{
for (int k = (matrixSize / 2) & 1; k < matrixSize; k += 2)
{
code.Set(matrixSize / 2 - j, k);
code.Set(matrixSize / 2 + j, k);
code.Set(k, matrixSize / 2 - j);
code.Set(k, matrixSize / 2 + j);
}
}
}
return(code);
}
