Add structured append support to QR Code

[repolevedavaj]

Hello! I would like to use this library to generate QR codes, but need the structured append mode. I tried to stick to the style of the QrCode class and the structured append mode implementation of Pdf417, but the implementation could be optimized (e.g. I could move the automated structured append symbol generation of both symbol classes to a common place). Please let me know what you think.

[gredler]

Thanks for the contribution! It may be a few days before I'm able to review it, but I will get to it later this week.

[repolevedavaj]

I just saw that there is a Checkstyle violation. I will take care about it asap.

Update: I added the missing license header.

[gredler]

Starting to review, but can you add 7 test cases under src/test/resources/uk/org/okapibarcode/backend/qrcode?

• One series of 4 symbols which do not use ECI, duplicating the example included in the QR Code spec (see below)
• A series of 3 symbols which also uses ECI (maybe using some Japanese test text).

Here's the 4-symbol sequence in the standard which it would be nice to recreate for the first symbol sequence:

[repolevedavaj]

Sure, i will work on that on the weekend.

[repolevedavaj]

@gredler done. I detected an issue in the creation of the parity: I always used a fixed encoding. Now I use the same which will be used to encode the actual data (as defined in the spec).

[gredler]

Looks pretty good overall!

[repolevedavaj]

@gredler thank you very much for the review. I resolved or responded to all comments, except the ones regarding the additional error test cases (I am still working on that). The commit history got a bit messy, as I took over the suggestions one by one, but I assume you agree if I squash my commits after all comments have been resolved.

I will let you know as soon as I created the additional test cases.

[repolevedavaj]

@gredler I am done with my changes. Let me know what you think.

[gredler]

Did you regenerate the three ECI images after changing the parity? It looks like the tests are failing during the image comparison.

[repolevedavaj]

Did you regenerate the three ECI images after changing the parity? It looks like the tests are failing during the image comparison.

Ah, I was just wondering why the test fails... thanks!

[gredler]

Looks good! I may look at refactoring a few pieces to reduce duplication, but I need to check whether it makes sense or not. Thanks for the contribution!