/// <summary>
/// Creates a QR code representing the specified segments with the specified encoding parameters.
/// <para>
/// The smallest possible QR code version (size) is used. The range of versions can be
/// restricted by the <paramref name="minVersion"/> and <paramref name="maxVersion"/> parameters.
/// </para>
/// <para>
/// If <paramref name="boostEcl"/> is <c>true</c>, the resulting ECC level will be higher than the
/// one specified if it can be achieved without increasing the size (version).
/// </para>
/// <para>
/// The QR code mask is usually automatically chosen. It can be explicitly set with the <paramref name="mask"/>
/// parameter by using a value between 0 to 7 (inclusive). -1 is for automatic mode (which may be slow).
/// </para>
/// <para>
/// This function allows the user to create a custom sequence of segments that switches
/// between modes (such as alphanumeric and byte) to encode text in less space and gives full control over all
/// encoding paramters.
/// </para>
/// </summary>
/// <remarks>
/// This is a mid-level API; the high-level APIs are <see cref="EncodeText(string, Ecc)"/>
/// and <see cref="EncodeBinary(byte[], Ecc)"/>.
/// </remarks>
/// <param name="segments">The segments to encode.</param>
/// <param name="ecl">The minimal or fixed error correction level to use .</param>
/// <param name="minVersion">The minimum version (size) of the QR code (between 1 and 40).</param>
/// <param name="maxVersion">The maximum version (size) of the QR code (between 1 and 40).</param>
/// <param name="mask">The mask number to use (between 0 and 7), or -1 for automatic mask selection.</param>
/// <param name="boostEcl">If <c>true</c> the ECC level wil be increased if it can be achieved without increasing the size (version).</param>
/// <returns>The created QR code representing the segments.</returns>
/// <exception cref="ArgumentNullException"><paramref name="segments"/>, any list element, or <paramref name="ecl"/> is <c>null</c>.</exception>
/// <exception cref="ArgumentOutOfRangeException">1 ≤ minVersion ≤ maxVersion ≤ 40
/// or -1 ≤ mask ≤ 7 is violated.</exception>
/// <exception cref="DataTooLongException">The segments are too long to fit in the largest QR code size (version)
/// at the specified error correction level.</exception>
public static QrCode EncodeSegments(List <QrSegment> segments, Ecc ecl, int minVersion = MinVersion, int maxVersion = MaxVersion, int mask = -1, bool boostEcl = true)
{
Objects.RequireNonNull(segments);
Objects.RequireNonNull(ecl);
if (minVersion < MinVersion || minVersion > maxVersion)
{
throw new ArgumentOutOfRangeException(nameof(minVersion), "Invalid value");
}
if (maxVersion > MaxVersion)
{
throw new ArgumentOutOfRangeException(nameof(maxVersion), "Invalid value");
}
if (mask < -1 || mask > 7)
{
throw new ArgumentOutOfRangeException(nameof(mask), "Invalid value");
}
// Find the minimal version number to use
int version, dataUsedBits;
for (version = minVersion; ; version++)
{
int numDataBits = GetNumDataCodewords(version, ecl) * 8; // Number of data bits available
dataUsedBits = QrSegment.GetTotalBits(segments, version);
if (dataUsedBits != -1 && dataUsedBits <= numDataBits)
{
break; // This version number is found to be suitable
}
if (version >= maxVersion)
{ // All versions in the range could not fit the given data
string msg = "Segment too long";
if (dataUsedBits != -1)
{
msg = $"Data length = {dataUsedBits} bits, Max capacity = {numDataBits} bits";
}
throw new DataTooLongException(msg);
}
}
Debug.Assert(dataUsedBits != -1);
// Increase the error correction level while the data still fits in the current version number
foreach (Ecc newEcl in Ecc.AllValues)
{ // From low to high
if (boostEcl && dataUsedBits <= GetNumDataCodewords(version, newEcl) * 8)
{
ecl = newEcl;
}
}
// Concatenate all segments to create the data bit string
BitArray ba = new BitArray(0);
foreach (QrSegment seg in segments)
{
ba.AppendBits(seg.EncodingMode.ModeBits, 4);
ba.AppendBits((uint)seg.NumChars, seg.EncodingMode.NumCharCountBits(version));
ba.AppendData(seg.GetData());
}
Debug.Assert(ba.Length == dataUsedBits);
// Add terminator and pad up to a byte if applicable
int dataCapacityBits = GetNumDataCodewords(version, ecl) * 8;
Debug.Assert(ba.Length <= dataCapacityBits);
ba.AppendBits(0, Math.Min(4, dataCapacityBits - ba.Length));
ba.AppendBits(0, (8 - ba.Length % 8) % 8);
Debug.Assert(ba.Length % 8 == 0);
// Pad with alternating bytes until data capacity is reached
for (uint padByte = 0xEC; ba.Length < dataCapacityBits; padByte ^= 0xEC ^ 0x11)
{
ba.AppendBits(padByte, 8);
}
// Pack bits into bytes in big endian
byte[] dataCodewords = new byte[ba.Length / 8];
for (int i = 0; i < ba.Length; i++)
{
if (ba.Get(i))
{
dataCodewords[i >> 3] |= (byte)(1 << (7 - (i & 7)));
}
}
// Create the QR code object
return(new QrCode(version, ecl, dataCodewords, mask));
}
