[bendichter]

When a selection touches one index along the first axis, apply the same row window along the next axis, and so on. arr[t, y0:y1, x0:x1] then fetches rows y0 to y1 of frame t instead of the whole frame, and a single item is fetched for a point.

The fetched block keeps the narrowed axes with length 1, so the shifted selection applies to it unchanged.

Summary

We have use-cases such as reading a small patch of a single frame of an image series, where it's possible and useful to extend the partial decode logic to inner dimensions. This identifies that specific indexing pattern and extends the current partial decode logic to efficiently read bytes in this case.

Author attestation

• I am a human, these are my changes, and I have reviewed and understood every change and can explain why each is correct.

TODO

• Add unit tests and/or doctests in docstrings
• Add docstrings and API docs for any new/modified user-facing classes and functions
• New/modified features documented in docs/user-guide/*.md
• Changes documented as a new file in changes/
• GitHub Actions have all passed
• Test coverage is 100% (Codecov passes)

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 94.90%. Comparing base (27f034e) to head (6e7d727).
⚠️ Report is 4 commits behind head on main.

Additional details and impacted files

@@           Coverage Diff           @@
##             main    #4611   +/-   ##
=======================================
  Coverage   94.90%   94.90%           
=======================================
  Files          96       96           
  Lines       14048    14063   +15     
=======================================
+ Hits        13332    13347   +15     
  Misses        716      716           

Files with missing lines	Coverage Δ
src/zarr/codecs/bytes.py	99.37% <100.00%> (+0.06%)	⬆️

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