ENH: Accelerate image list keys generation

[pubpub-zz]

closes #1987

[pubpub-zz]

@MartinThoma
I've got 2 mypy errors I do not understand Can you have a look please 😘

[codecov]

Codecov Report

Patch coverage: 100.00% and project coverage change: -0.02% ⚠️

Comparison is base (890c93a) 94.03% compared to head (88c8bb2) 94.01%.
Report is 6 commits behind head on main.

❗ Current head 88c8bb2 differs from pull request most recent head c756267. Consider uploading reports for the commit c756267 to get more accurate results

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #2014      +/-   ##
==========================================
- Coverage   94.03%   94.01%   -0.02%     
==========================================
  Files          33       33              
  Lines        7076     7090      +14     
  Branches     1413     1418       +5     
==========================================
+ Hits         6654     6666      +12     
- Misses        263      264       +1     
- Partials      159      160       +1     

Files Changed	Coverage Δ
pypdf/_page.py	93.61% <100.00%> (-0.15%)	⬇️
pypdf/_utils.py	99.17% <100.00%> (+<0.01%)	⬆️

... and 1 file with indirect coverage changes

☔ View full report in Codecov by Sentry.
📢 Have feedback on the report? Share it here.

[pubpub-zz]

@MartinThoma
I've found a nice fix. Now it's all your 😀

[MartinThoma]

I've tested it with https://github.com/py-pdf/pypdf/files/12160419/table_redacted.pdf and now I get:

Traceback (most recent call last):
  File "/home/moose/Github/py-pdf/pypdf/sample-files/foo.py", line 20, in <module>
    run("table_redacted.pdf")
  File "/home/moose/Github/py-pdf/pypdf/sample-files/foo.py", line 13, in run
    for image in page.images:
  File "/home/moose/Github/py-pdf/pypdf/pypdf/_page.py", line 2633, in __iter__
    yield self[i]
          ~~~~^^^
  File "/home/moose/Github/py-pdf/pypdf/pypdf/_page.py", line 2629, in __getitem__
    return self.get_function(lst[index])
           ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/home/moose/Github/py-pdf/pypdf/pypdf/_page.py", line 532, in _get_image
    return self.inline_images[id]
           ~~~~~~~~~~~~~~~~~~^^^^
KeyError: '~0~'

[stefan6419846]

Which code did you use for testing? Did you remove page.inline_images = dict()?

[MartinThoma]

Thank you - I forgot that 🙈

[MartinThoma]

Before (current main):

• 4.24s: 009-pdflatex-geotopo/GeoTopo.pdf
• 2.88s: 009-pdflatex-geotopo/GeoTopo-komprimiert.pdf

With this PR:

• 2.01s: 009-pdflatex-geotopo/GeoTopo.pdf
• 0.44s: 009-pdflatex-geotopo/GeoTopo-komprimiert.pdf

Good work 🎉

[pubpub-zz]

I've tested it with https://github.com/py-pdf/pypdf/files/12160419/table_redacted.pdf and now I get:

Traceback (most recent call last):
  File "/home/moose/Github/py-pdf/pypdf/sample-files/foo.py", line 20, in <module>
    run("table_redacted.pdf")
  File "/home/moose/Github/py-pdf/pypdf/sample-files/foo.py", line 13, in run
    for image in page.images:
  File "/home/moose/Github/py-pdf/pypdf/pypdf/_page.py", line 2633, in __iter__
    yield self[i]
          ~~~~^^^
  File "/home/moose/Github/py-pdf/pypdf/pypdf/_page.py", line 2629, in __getitem__
    return self.get_function(lst[index])
           ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/home/moose/Github/py-pdf/pypdf/pypdf/_page.py", line 532, in _get_image
    return self.inline_images[id]
           ~~~~~~~~~~~~~~~~~~^^^^
KeyError: '~0~'

can you clarify the code you are using ? page.inline_images = dict() is normally not required

[MartinThoma]

Yes, I was adding page.inline_images = dict(). That was leading to the error. However, I would not consider this a blocker as this is modifying pypdf behavior in an unexpected way.

I want to have a final look after work, but so far it seems like a great improvement. I'll likely merge it as it is :-)