[py-tx] Create rotation helper functions in PhotoContent using Pillow

[haianhng31]

Summary

This is a part of the issue #1665
This has been discussed previously in PR #1669

• Create RotationType enum in content_base.py
  • Use StrEnum to make the enum’s values independent of the order
• Create 6 helper functions in PhotoContent
  • 5 functions are to rotate the image in different angles
  • 1 function is to try all different rotations

Test plan

@Dcallies said not to write a unittest at this stage.

However, I was able to show that the code is correct by writing a simple bit of python:

from threatexchange.content_type.photo import PhotoContent

file_path = pathlib.Path("threatexchange/tests/hashing/resources/LA.png")
with open(file_path, "rb") as f:
    image_data = f.read()

all_rotations = PhotoContent.all_simple_rotations(image_data)

for rotation_type, image_data in all_rotations.items():
    with open(f"image_{rotation_type}.png", "wb") as w:
        w.write(image_data)

Then I visually inspected all the files to confirm they were rotated as expected.

[Dcallies]

Looking good!

To test this, on your development environment, create a simple image, and then call, via Ipython the method and write the resultant bytes to files.

You may find that for some image types, you need to hint pillow on what the format is, which can be done via filename.

You can write the bytes to files and then visually inspect that you have all the rotations! You can include that code in your test plan.

[Dcallies]

Include a note on why we might want to do this :P

Namely, this is help for testing hash algorithms.

[Dcallies]

nit: Let's go with all_simple_rotations

[Dcallies]

nit: Something like

"""
Generate the 8 naive rotations of an image.

This can be helpful for testing, and for image algorithms that don't have
a native way to generate rotations during hashing, this can be a way to
brute force rotations. 

[haianhng31]

@Dcallies Thank you for your comments! I have included the docstring where necessary and also tested it on my development environment. If the code is ok, I can start moving to next step which is adding a new command line option (--rotations)

[Dcallies]

So close!

Can you:

1. Run black so CI passes
2. Confirm that you did something like the test plan?

[haianhng31]

Yes I have done the test plan and update the PR's description

[haianhng31]

@Dcallies it seems like StrEnum cannot be imported with py version before 3.11
Q: Would you like me to remove 3.9 from the workflow? Or would you want me to not use StrEnum and do something else instead?

[Dcallies]

Oh no! I totally missed that.

For now, use Enum, and then type out the names of the values that would be equivalent to auto(). It should just be lowercase

[haianhng31]

@Dcallies Fixed! Lmk if you have any other comment

[Dcallies]

Nice job!

[Dcallies]

nit: auto unused