add ICC profiles to PDFs

[eroux]

Fixes #697

• 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

• 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.

[eroux]

@Lucas-C I don't have a Winows machine so I couldn't update test/image/image_types/image_types_insert_png_alpha_dctdecode_windows.pdf, is there any way you could do it? Thanks!

[Lucas-C]

Hey @eroux
Thank you for taking the time to work on this!
That's a very valuable addition for fpdf2 🥳😀

[Lucas-C]

@Lucas-C I don't have a Winows machine so I couldn't update test/image/image_types/image_types_insert_png_alpha_dctdecode_windows.pdf, is there any way you could do it? Thanks!

Sure, but I just ran unit test test_insert_png_alpha_dctdecode() on my Windows environment, and it passed!

By the way, you may want to get rid of PYTHONMALLOCSTATS as part of thi PR to avoid the GitHub Actions logs being bloated, cf. #657 (comment)

[Lucas-C]

Sure, but I just ran unit test test_insert_png_alpha_dctdecode() on my Windows environment, and it passed!

My bad, I did not run the test correctly... 🤦‍♂️

I generated a reference PDF file, but I got this error when performing git push on your branch:

ERROR: Permission to buda-base/fpdf2.git denied to Lucas-C.

You can either allow me push to your fork: https://docs.github.com/en/pull-requests/collaborating-with-pull-requests/working-with-forks/allowing-changes-to-a-pull-request-branch-created-from-a-fork

Or use the PDF file included with this comment:
image_types_insert_png_alpha_dctdecode_windows.pdf

[Lucas-C]

Apart from the nice mention you already added in CHANGELOG.md, I think this feature would be worth a section in docs/images.md! 😊

In order to mention this automatic inclusion of ICC profiles from images, and also how to remove /alter ICC profiles:
simply by modifying .info["icc_profile"] with Pillow before passing PIL.Image instances to FPDF.image()!

[eroux]

thanks for the PDF, I've pushed it. I'm working on the two changes but I just wanted to say that updating docs/images.md is a good idea.

I'm thinking also that perhaps releasing a new version with those changes could be a good option? The changes since the last version are pretty significant for use cases involving images

[Lucas-C]

I'm thinking also that perhaps releasing a new version with those changes could be a good option? The changes since the last version are pretty significant for use cases involving images

I agree.
Given the maturity of the 4 current open PRs, I'm currently planning to perform a release once they are all merged.
If ever any of them is delayed, I may publish a new version of fpdf2 beforehand, we'll see.

In the meantime, you can still use the latest fpdf2 version from the master branch of this repository:

pip install git+https://github.com/PyFPDF/fpdf2.git@master

[eroux]

I think it should be ok now

[Lucas-C]

Merged!
Thank you @eroux for this contribution 👍

[eroux]

amazing, thanks!