Fix scatter collapse after repeated box zoom

[FarhanAliRaza]

Motivation

Repeated anisotropic box zoom followed by Zoom Out could collapse a scatter plot into a horizontal band.

A box zoom can narrow X and Y by very different factors. Zoom Out previously expanded both axes geometrically without respecting each axis's original range, so the less-zoomed axis could grow far beyond its home span while the other axis was still zoomed in. That extreme aspect-ratio mismatch visually flattened the point cloud.

Description

• Cap each axis independently at its original span during zoom-out. Once an axis reaches its home span it stops expanding, while a more deeply zoomed axis can continue zooming out. (js/src/53_interaction.js)
• Add the exact repeated box-zoom reproduction to examples/demo-advance.ipynb.
• Add a Chromium regression that performs three anisotropic box zooms and four zoom-outs, then verifies X remains zoomed while Y stops exactly at its home domain. (tests/test_zoom_precision.py)
• Regenerate the tracked anywidget and standalone browser bundles from the JS source. (python/xy/static/index.js, python/xy/static/standalone.js)

The earlier GPU-coordinate precision workaround was removed because it was not needed for this failure.

Testing

• node js/build.mjs --check — generated static bundles are fresh.
• uv run ruff check tests/test_zoom_precision.py — passed.
• uv run ruff format --check tests/test_zoom_precision.py — passed.
• uv run pytest tests/test_zoom_precision.py tests/test_static_client_security.py tests/test_scatter.py tests/test_components.py -q — 187 passed.
• Chrome verification using the 20,000-point notebook reproduction:
  • after three anisotropic box zooms: X 125×, Y 1.953×
  • after four zoom-outs: X 7.8125×, Y 1×
  • before the fix, Y reached 0.122×—eight times wider than its home span
  • the point cloud remained two-dimensional and no console errors were emitted

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Closes #87

[codspeed-hq]

Merging this PR will not alter performance

✅ 97 untouched benchmarks
⏩ 1 skipped benchmark¹

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_{Comparing codex/fix-scatter-view-collapse-on-zoom (1dfaeda) with main (09b5873)}

Footnotes

1. 1 benchmark was skipped, so the baseline result was used instead. If it was deleted from the codebase, click here and archive it to remove it from the performance reports. ↩

[masenf]

when zooming out, if the zoom level is already at 100%, the pan is reset as well. when this happens, it leaves the previous selection in place including the dot and tooltip.

Screen.Recording.2026-07-20.at.2.54.03.PM.mov

probably a task for another PR, but i'm wondering if we should let the outer page scroll when the chart is already zoomed out to mitigate ENG-10492 which is a bit annoying when browsing the docs. idk if it would be more jarring for a user actively zooming out to hit 100% and then suddenly scroll down the page.

[greptile-apps]

Greptile Summary

This PR fixes scatter collapse after repeated anisotropic box zooms. The main changes are:

• Independent home-span limits for each axis during zoom-out.
• Data-space tooltip positioning across view changes.
• A browser test for repeated box zoom and zoom-out.
• Cleaner Chromium shutdown and regenerated browser bundles.
• Updated examples and interaction documentation.

Confidence Score: 5/5

This looks safe to merge.

No blocking issues found in the changed code.

T-Rex Logs

What T-Rex did

• Executed the general-contract-validation-proof to compare the current and final domains for X and Y.
• The final Y domain is [-1.0388, 1.0387999999999995], confirming the expected y-range after validation.
• The final X domain is [-0.2713599999999998, 0.2713599999999998], showing the narrowed horizontal range.
• Recorded before-and-after videos demonstrating the complete repeated box-zoom and zoom-out sequence on the standalone HTML, client code, and styles.
• Reached the maximum agent steps and noted that substantive validation tasks are complete; artifacts should be retained for review.

_{Ran code and verified through T-Rex}

Important Files Changed

Filename	Overview
js/src/53_interaction.js	Limits each axis to its home span during zoom-out and clears tooltip state on explicit dismissal paths.
tests/test_zoom_precision.py	Adds browser coverage for repeated anisotropic box zoom followed by zoom-out.
js/src/52_tooltip.js	Stores tooltip positions in data space and reprojects them when the view changes.
js/src/50_chartview.js	Repositions visible tooltips after chart redraws.
js/src/54_kernel.js	Updates tooltip positions with exact coordinates returned by the kernel.
python/xy/_chromium.py	Requests orderly browser shutdown before falling back to process termination.
python/xy/static/index.js	Regenerates the anywidget bundle with the zoom and tooltip changes.
python/xy/static/standalone.js	Regenerates the standalone bundle with the zoom and tooltip changes.

_{Reviews (6): Last reviewed commit: "fix(export): shut Chromium down via CDP ..." | Re-trigger Greptile}

[masenf]

i busted a test try to merge origin/main, will push a patch to this branch