Bitonal images are now encoded using CCITTFaxDecode - fix #691

[eroux]

Fixes #691

I couldn't run the tests through pytest for some reason:

pytest
ERROR: usage: pytest [options] [file_or_dir] [file_or_dir] [...]
pytest: error: unrecognized arguments: --cov=fpdf --cov-report=xml
  inifile: /home/eroux/BUDA/softs/fpdf2/setup.cfg
  rootdir: /home/eroux/BUDA/softs/fpdf2

Checklist:

• The GitHub pipeline is OK (green),
  meaning that both pylint (static code analyzer) and black (code formatter) are happy with the changes of this PR.

• A unit test is covering the code added / modified by this PR

• This PR is ready to be merged

• [Not Applicable] In case of a new feature, docstrings have been added, with also some documentation in the docs/ folder

• A mention of the change is present in CHANGELOG.md

By submitting this pull request, I confirm that my contribution is made under the terms of the GNU LGPL 3.0 license.

[Lucas-C]

Thank you for the PR @eroux!

For reference, basic support for monochromatic images was initially introduced on september last year: #527

Some minor issues were spotted by Pylint in the GitHub Actions pipeline, could you please fix them?

fpdf/image_parsing.py:136:0: C0303: Trailing whitespace (trailing-whitespace)
fpdf/image_parsing.py:73:12: W0105: String statement has no effect (pointless-string-statement)
fpdf/image_parsing.py:200:12: C0209: Formatting a regular string which could be a f-string (consider-using-f-string)

[eroux]

I've addressed your comments (all of them I think?)

[Lucas-C]

I've addressed your comments (all of them I think?)

I think there are a few ones left 😊
But thank you for your diligence and the improvements you already made!

I couldn't run the tests through pytest for some reason:

Have you checked our documentation regarding development on the project?
https://pyfpdf.github.io/fpdf2/Development.html

I think you just need to pip install -r test/requirements.txt 😊

[Lucas-C]

Could you please format the code with black?
This will allow the GitHub Actions pipeline to execute the unit tests suite.

Run black --check .
would reformat /home/runner/work/fpdf2/fpdf2/fpdf/image_parsing.py

Oh no! 💥 💔 💥
1 file would be reformatted, 144 files would be left unchanged.

[eroux]

I did reformat it with black, thanks! There's an issue when I try to install the test dependencies so I still can't run the unit tests, but I'll try on another system

[eroux]

@Lucas-C I finally managed to launch the tests, the only that fails on my machine is the performance comparison, I don't know what the value of 0.3s is computed, but on my computer fpdf is too fast to pass the test(!), is that a problem?

[Lucas-C]

@Lucas-C I finally managed to launch the tests, the only that fails on my machine is the performance comparison, I don't know what the value of 0.3s is computed, but on my computer fpdf is too fast to pass the test(!), is that a problem?

It's OK, don't worry, as long as the unit tests pass in the GitHub Actions pipelines that's fine 😊
Thank you for taking the time to run the tests on your machine.

I think this PR is close to be ready to be merged!
Thank your for your work on this.
I have one last question: why are the PDF reference files in test/template/ impacted by your change?

[eroux]

Great, thanks! The impact is that all bitonal images are now encoded in CCITT by default and these contain some bitonal images

[codecov]

Codecov Report

Base: 93.93% // Head: 93.77% // Decreases project coverage by -0.17% ⚠️

Coverage data is based on head (aff4b21) compared to base (61348c5).
Patch coverage: 76.47% of modified lines in pull request are covered.

❗ Current head aff4b21 differs from pull request most recent head 513276f. Consider uploading reports for the commit 513276f to get more accurate results

Additional details and impacted files

@@            Coverage Diff             @@
##           master     #695      +/-   ##
==========================================
- Coverage   93.93%   93.77%   -0.17%     
==========================================
  Files          26       26              
  Lines        6780     6829      +49     
  Branches     1206     1216      +10     
==========================================
+ Hits         6369     6404      +35     
- Misses        242      251       +9     
- Partials      169      174       +5     

Impacted Files	Coverage Δ
fpdf/image_parsing.py	83.33% <76.47%> (-5.17%)	⬇️

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[Lucas-C]

@allcontributors please add @eroux for code

[allcontributors]

@Lucas-C

I've put up a pull request to add @eroux! 🎉

[Lucas-C]

Merged!
Thank you for your contribution 😊