Generate QR Code with CIQRCodeDescriptor initWithPayload: symbolVersion: maskPattern errorCorrectionLevel: - qr-code

Question

I am trying to generate a QR Code using CoreImage.
I want to be able to control the symbol version, the masking pattern, and the error correction level.
Using the simple "CIFilter filterWithName:" does not give you the ability to set the symbol version or the mask pattern.
The only way it seems possible is to use a CIQRCodeDescriptor - using "CIQRCodeDesciptor initWithPayload: symbolVersion: maskPattern: errorCorrectionLevel:"
Has anyone been able to use this method to successfully generate a QR Code image?
If so, can you please post a simple complete example?

Answer 1

To be able to use CIQRCodeDescriptor you need
codewords (mode + character count + data + terminator + padding)
correct symbol version (version for the character count; 1-40)
correct mask pattern (mask with minimum penalty; 0-7)
Follows example of "Think Different".
Notice the extra bits in codeword
Think Different: 54 68 69 6E 6B 20 44 69 66 66 65 72 65 6E 74
Codeword: 40 F5 46 86 96 E6 B2 04 46 96 66 66 57 26 56 E7 40 EC 11
The codeword construction is explained at nayuiki or at the bottom.
let codeword : [UInt8] = [0x40, 0xf5, 0x46, 0x86, 0x96, 0xe6, 0xb2, 0x04, 0x46, 0x96, 0x66, 0x66, 0x57, 0x26, 0x56, 0xe7, 0x40, 0xec, 0x11]
let data = Data(bytes: codeword, count: codeword.count)
if let descriptor = CIQRCodeDescriptor(payload: data, symbolVersion: 1, maskPattern: 4, errorCorrectionLevel: .levelL) {
if let image = imageFromBarcodeCodeDescriptor(descriptor)?.transformed(by: .init(scaleX: 10, y: 10)) {
let newImage = NSImage()
newImage.addRepresentation(NSCIImageRep(ciImage: image))
imageView1.image = newImage
}
}
func imageFromBarcodeCodeDescriptor(_ descriptor: CIBarcodeDescriptor) -> CIImage? {
let filter = CIFilter(name: "CIBarcodeGenerator", parameters: ["inputBarcodeDescriptor" : descriptor])
return filter?.outputImage
}
Concatenate segments, add padding, make codewords
Notes:
The segment mode is always a 4-bit field.
The character count’s field width depends on the mode and version.
The terminator is normally four “0” bits, but fewer if the data
codeword capacity is reached.
The bit padding is between zero to seven “0” bits, to fill all unused
bits in the last byte.
The byte padding consists of alternating (hexadecimal) EC and 11 until
the capacity is reached.
The entire sequence of data bits:
01000000111101010100011010000110100101101110011010110010000001000100011010010110011001100110011001010111001001100101011011100111010000001110110000010001
The entire sequence of data codeword bytes (by splitting the bit
string into groups of 8 bits), displayed in hexadecimal: 40 F5 46 86
96 E6 B2 04 46 96 66 66 57 26 56 E7 40 EC 11

Answer 2

It seems CIQRCodeGenerator doesn't support those parameters.
Maybe you can find what you are looking for in this library.

Answer 3

You need to use "CIBarcodeGenerator" CIFilter with the CIQRCodeDescriptor as input:
let data = ... // error corrected payload data
if let barcode = CIQRCodeDescriptor(payload: data,
symbolVersion: 1, // 1...40
maskPattern: 0, // 0..7
errorCorrectionLevel: .levelL) // Any of the available enum values
{
let filter = CIFilter(name: "CIBarcodeGenerator",
parameters: ["inputBarcodeDescriptor": barcode])
let image = filter?.outputImage
}
The caveat though is that you need to obtain somehow the errorCorrectedPayload data for the message you are trying to encode. One of the ways to do this would be to use "CIQRCodeGenerator" to encode the message, parse the resulting image with Vision to extract the barcode descriptor from it, and then get the errorCorrectedPayload data from that descriptor.

Answer 4

A simple working example is:
// Create the CIFilter (CIQRCodeGenerator)
CIFilter *ciFilter = [CIFilter filterWithName:#"CIQRCodeGenerator"];
[ciFilter setDefaults];
NSData *data = [#"123456" dataUsingEncoding:NSUTF8StringEncoding];// QR code value
[ciFilter setValue:data forKey:#"inputMessage"];
[ciFilter setValue:#"L" forKey:#"inputCorrectionLevel"];// L: low, M: Medium, Q: Quartile, H: High
// Create the image at the desired size
CGSize size = CGSizeMake(280, 280);// Desired QR code size
CGRect rect = CGRectIntegral(ciFilter.outputImage.extent);
CIImage *ciImage = [ciFilter.outputImage imageByApplyingTransform:CGAffineTransformMakeScale(size.width/CGRectGetWidth(rect), size.height/CGRectGetHeight(rect))];
// Create a UIImage (if needed)
UIImage *image = [UIImage imageWithCIImage:ciImage];
_imageView.image = image;