Decoding fails for specific QR code generated by Powershell Modules.QRCodeGenerator
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Assessment
- Difficulty
- 4/5
- Estimated time
- Over a week
- Newbie friendliness
- 15/100
- Issue type
- Bug
- Clarity
- Mostly clear
- Activity status
- Stale
- Tech stack
- csharp, powershell
- Domain
- cli, developer-experience
Research direction
The report is about a QR code that the CommandLineDecoder fails to read unless --pure_barcode is passed, while phone scanners read it fine. Start from the decoder's QR detection path in the ZXing.Net source and reproduce with the two attached PNGs. Done would mean identifying why the detector misses the finder patterns for this input, which needs real familiarity with the QR detector.
Written by the indexing model from the issue text.
Description
I'm using https://github.com/TobiasPSP/Modules.QRCodeGenerator to generate some QR codes, however I'm finding that some of them (around 0.1%) are not recognized. I generate the code with the following command:
New-QRCodeText -Text "1668" -OutPath "code.png" -Width 14
...which gives the following file:
Scanning it with .\CommandLineDecoder.exe "code.png" gives "No barcode found"
Scaling, different dimensions, added text, crop, --try_harder all makes no difference. https://zxing.org/w/decode.jspx doesn't work either. Most other QR codes generated by same Powershell library are properly recognized. What does work for the above though, is --pure_barcode.
But, it again doesn't work with or without --try_harder (nor with scaling, --pure_barcode, etc) once I try the actual QR data I want to use, which looks like this:
However, scanning either of these off the screen with various different phone apps does work correctly. (including BinaryEye which uses ZXing C++). Other values than "1668" do work correctly, both in the source PNG (PNG with or without --pure_barcode) and in the actual data (without --pure_barcode)
Is this a bug in the library that it generates broken codes, or a problem in ZXing.NET, or I just need more error correction setting?
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