Adds XML export method to DocumentBuilder

[felixdittrich92]

@fg-mindee
@charlesmindee
feat: adds the option to export the results in XML (hocr) format (like tesseract)

This request also offers the possibility to convert the documents into PDFs with a text layer
As with render(), the results depend on the correct division into blocks / lines and correct sorting of the boxes

Resolves: #512
Note:
#512 can be closed after adding an example/tutorial how to use this output to generate PDF Files with text layer

[fg-mindee]

Thanks for the PR! Looks good to me overall, I only think we should move everything into a Page.export_as_xml method which will be called by Document.export_as_xml

Let me know what you think 👌

[felixdittrich92]

@fg-mindee
btw. i have checked the parser this will only work if we set resolve_lines and resolve_blocks in builder.py to true :)

[fg-mindee]

Thanks! I added a few suggestions: would you mind adding more comment in your code please? So that people understand what the actual code is expected to do :)

[felixdittrich92]

@fg-mindee
@charlesmindee
i´m done from my side :)
What do you thing ?

[felixdittrich92]

@fg-mindee
any further changes needed ? 🤗

Have a nice day 😃

[codecov]

Codecov Report

Merging #544 (39460d0) into main (b27c3a6) will increase coverage by 0.03%.
The diff coverage is 97.36%.

@@            Coverage Diff             @@
##             main     #544      +/-   ##
==========================================
+ Coverage   96.04%   96.08%   +0.03%     
==========================================
  Files         109      109              
  Lines        4198     4236      +38     
==========================================
+ Hits         4032     4070      +38     
  Misses        166      166              

Flag	Coverage Δ
unittests	96.08% <97.36%> (+0.03%)	⬆️

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Impacted Files	Coverage Δ
doctr/io/elements.py	91.95% <97.36%> (+1.51%)	⬆️
...dels/detection/differentiable_binarization/base.py	91.82% <0.00%> (+0.62%)	⬆️

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[fg-mindee]

Thanks again! I added some comments, I think we're almost ready for merge

[felixdittrich92]

@fg-mindee
please let me know what you think about the skip_rotated_boxes part 🤗

[fg-mindee]

Last changes to do and we can merge :)

[felixdittrich92]

@fg-mindee
now i have found this damn blank line 😂
I was fixated on the last line the whole time 🙈

[fg-mindee]

A few typos left 😅

[fg-mindee]

Thanks for all the edits 🙏

[fg-mindee]

FYI @felixdittrich92
Not sure it was on purpose so I thought it's better to let you know: it looks like you're working with multiple Git accounts. Some of your commits come from felixdittrich92 but others are from felix (cf. https://github.com/mindee/doctr/pull/544/commits)

If that's not on purpose, I would suggest sticking to your main account ;)