Issue with utf-8 about zbar-wasm HOT 13 CLOSED

@id1945 Your original qr code can be read correctly by configuring zbar-wasm to return binary data and delegating text decoding to the native TextDecoder e.g. like so:

import { ZBarConfigType, ZBarImage, ZBarScanner, ZBarSymbolType } ...;

const scanner = await ZBarScanner.create();
scanner.setConfig(ZBarSymbolType.ZBAR_NONE, ZBarConfigType.ZBAR_CFG_BINARY, 1); // <-- important
scanner.scan(image);
const symbols = scanner.getResults();

However, in order to read the code that I generated correctly, the scanner.config() statement has to be omitted.

Thus, with a particular setup, either one or the other QR code can be read correctly but not both.

This appears to be one of the peculiarities of the ZBar bar code reader on which zbar-wasm is based. Unfortunately, there is nothing that I can do about that.

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Thanks @pascalschoeni !
jschardet did help, although indirectly: it showed me that the raw data of one of my QR code test strings ('ÄÖÜ äöü ß ÁÉÍÓÚ áéíóú ÀÈÌÒÙ àéíóú') was not UTF-8 encoded (as it should have been) and therefore was not correctly decoded by the TextDecoder in UTF-8 mode.
I suspect that the online QR encoder that I used for the test image did not handle the test string properly. Encoding that string again here produced an image which zbar-wasm decodes correctly.

@id1945 :
The code snippet from my previous comment actually works not only for both variants of your QR code but also for all other barcodes in the unit tests of zbar-wasm.
Could you please provide me with an image of a QR code that is similar to your original one but does not contain personal data? Before closing this issue, I would like to include such an QR code in the unit tests if possible.
Also, please feel free to delete your original QR code image from this thread.

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Hmm... the raw bytes of the QR code are decoded by the browser's TextDecoder according to the selected character encoding, so there is not much that I can do about false decoding.

On the other hand, are you sure that the QR code is UTF-8 encoded? I googled and found several Vietnamese character encodings.

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I copied your expected text, pasted in into an online QR generator and obtained this QR code:

Scanning this QR code yields the following (correct) result:

This indicates that the text in your QR code is most likely not UTF-8-encoded.

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@undecaf jschardet (https://www.npmjs.com/package/jschardet) may help:

const detectedCharSet = jschardet.detect(Buffer.from(symbol.data))
const text = foundQr.decode(detectedCharSet.encoding)

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@undecaf 🥇 🥇
Luckily for me! 🙏
I found these websites that generate the error QRcode as we are discussed above. Below is the QRcode that I created. You can also create your own in Vietnamese language.

https://qrplanet.com/#text
https://qrcode.tec-it.com/en/Raw

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The image is confidential, so it should be removed

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Let me explain in more detail: zbar-wasm delegates decoding the raw bytes contained in the QR code to the text displayed as rawValue to the TextDecoder built into each browser. By default, the TextDecoder uses UTF-8 encoding, but a several other encodings are available.

If the text is not what is expected then I see two possible reasons:

1. A bug in the browser's TextDecoder -- unlikely but can be verified by trying whether a different browser produces the same text.
2. The text in the QR code is in an encoding different from UTF-8, so decoding the raw bytes as UTF-8 will likely yield a wrong result.
   Therefore I am kindly asking you again whether it can be confirmed that your QR code is actually UTF-8-encoded. The producer of the QR code should be able to provide this information.

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The image is confidential, so it should be removed

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Hmmm... the BarcodeDetector built into mobile Chrome also reads that code correctly.

Please give me some time to look into that.

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@undecaf

I really hope you get this fixed soon. Since I am developing a library for Angular ngx-scanner-qrcode based on yours.
And finally, please allow me to delete the photo of my citizenship card in the comment above.
Waiting to hear from you soon ^^!

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@undecaf Thank you very much. I've also tried and it doesn't work at all. It is still a headache for me.

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@undecaf 🥇
I will soon delete all the QR code containing my personal data here. I will give you another QR code image with the above error please wait for me. @@

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