[Draft] Allow underzoom and overpan of a single-copy world

[larsmaxfield]

Launch Checklist

Draft PR to check the implications of current underzoom design. I am not currently able to run local tests.

Fixes #4510, #4591 by allowing the map to be underzoomed and overpanned:

• [Feature] Allow "underzooming" to show entire map on non-square viewports when renderWorldCopies=false #4510
• How to zoomout without phone boundary limit #4591

Explanation of current design at #4510 (comment).

Demo:

^{https://larsmaxfield.github.io/swings/maplibre-underzoom/unbounded.html}

• Confirm your changes do not include backports from Mapbox projects (unless with compliant license) - if you are not sure about this, please ask!
• Briefly describe the changes in this PR.
• Link to related issues.
• Include before/after visuals or gifs if this PR includes visual changes.
• Write tests for all new functionality.
• Document any changes to public APIs.
• Post benchmark scores.
• Add an entry to CHANGELOG.md under the ## main section.

[codecov-commenter]

Codecov Report

Attention: Patch coverage is 39.80583% with 62 lines in your changes missing coverage. Please review.

Project coverage is 87.75%. Comparing base (ca4e603) to head (c12227c).
Report is 3 commits behind head on main.

Files with missing lines	Patch %	Lines
src/geo/transform.ts	44.44%	30 Missing and 5 partials ⚠️
src/ui/map.ts	32.50%	27 Missing ⚠️

Additional details and impacted files

@@           Coverage Diff           @@
##             main    #4733   +/-   ##
=======================================
  Coverage   87.75%   87.75%           
=======================================
  Files         247      247           
  Lines       33656    33747   +91     
  Branches     2201     2167   -34     
=======================================
+ Hits        29536    29616   +80     
- Misses       3132     3148   +16     
+ Partials      988      983    -5     

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[birkskyum]

I am not currently able to run local tests.

can you elaborate? unit tests? in case you need assistance, what do you see now when you run npm run test-unit?

The Build tests will pass if you update the expected build size to what it is now.

The Tests / Code Hygiene (pull_request), you can have it pass simply by dumping these in the docs/assets/examples folder, and name them so they match the example .html files

underzoom.png

underzoom-wide.png

underzoom-tall.png

[larsmaxfield]

The map visually freezes with overpan=50 when terrain is enabled and the map is panned such that it is in a corner of the bounds. The hash continues to update, though, and you can unfreeze the map by panning away from the corner whereby the map suddenly updates with the hash. Setting overpan=49 solves this. (Finally getting back to this PR and hope to tidy everything up in the coming weeks.)

[Ghosts]

Is this something that would be possible to merge if the tests are resolved? Would be happy to assist getting this moved forward.

[larsmaxfield]

Yes, I'd be happy if you helped — but it will be more work than just tests:

• My underzoom branch for this PR is still in v4 and cannot automatically merge the changes from v5. I'm not sure how much effort that will be.

• The corner bounds issue I noted above should also be fixed if it persists with the changes in v5.

• Based on some feedback in the underzoom feature request we may also need to better match the options and/or definitions with existing configurations. See [Feature] Allow "underzooming" to show entire map on non-square viewports when renderWorldCopies=false #4510