QR Code Model 1 vs Model 2 Incorrect Printing

I’ve noticed that QRCode Model 1 is not readable. And Model 2 looks to be Model 1 when visually comparing the printed code with a Model 1 code printed via this pre ESC-POS implementation:

String text = "test";

printerBuffer[0] = 0x1d;
printerBuffer[1] = 0x28;
printerBuffer[2] = 0x6b;
printerBuffer[3] = 4;
printerBuffer[4] = 0;
printerBuffer[5] = 0x31;
printerBuffer[6] = 0x41;
printerBuffer[7] = 0x49; // 0x49 - model 1 / 0x50 - model 2
printerBuffer[8] = 0x00;
serialPort.Write(printerBuffer, 0, 9);

printerBuffer[0] = 0x1d;
printerBuffer[1] = 0x28;
printerBuffer[2] = 0x6b;
printerBuffer[3] = 3;
printerBuffer[4] = 0;
printerBuffer[5] = 0x31;
printerBuffer[6] = 0x45;
printerBuffer[7] = 0x33; // 0x33 - Error correction level H (30% recovery capacity)
serialPort.Write(printerBuffer, 0, 8);

int len = 3 + text.Length;

printerBuffer[0] = 0x1d;
printerBuffer[1] = 0x28;
printerBuffer[2] = 0x6b;
printerBuffer[3] = (byte)(len % 256);
printerBuffer[4] = (byte)(len / 256);
printerBuffer[5] = 0x31;
printerBuffer[6] = 0x50;
printerBuffer[7] = 0x30;

char[] strChars = text.ToCharArray();
for (int i = 0; i < text.Length; i++) {
    printerBuffer[8 + i] = (byte)strChars[i];
}
serialPort.Write(printerBuffer, 0, 8 + text.Length);

printerBuffer[0] = 0x1d;
printerBuffer[1] = 0x28;
printerBuffer[2] = 0x6b;
printerBuffer[3] = 3;
printerBuffer[4] = 0;
printerBuffer[5] = 0x31;
printerBuffer[6] = 0x51;
printerBuffer[7] = 0x30;
serialPort.Write(printerBuffer, 0, 8);

This is the equivalent ESC-POS call:

printer.Write(E.Print2DCode(TwoDimensionCodeType.QRCODE_MODEL2, text, Size2DCode.SMALL, CorrectionLevel2DCode.PERCENT_30));

[igorocampos]

Please read some more about this in #79

[neon-dev]

Don’t trust this legacy code I posted too much. It was never used in production and I just inherited the project, so no guarantees for correctness. Now that you say it, to me it looks like the byte stream is incorrect and 0x49 should in fact be 49 / 0x31, since all other codes for commands I’ve seen were decimals.

I cannot test anything right now, so the only thing I can assure is that codes with QRCODE_MODEL1 failed to scan but QRCODE_MODEL2 can be scanned successfully. Whoever else has access to a printer should verify first.