fix(tools): read ProbeTool value on stack images other than the first

[jisuzzzz]

Context

Fixes #2967

On a StackViewport, ProbeTool draws the handle but no text box on any image other than the first one: cachedStats[targetId].value is undefined.

_calculateCachedStats overwrites ijk[2] with viewport.getCurrentImageIdIndex() (for display) and then reads the value with voxelManager.getAtIJKPoint(ijk). For a stack, getImageData().voxelManager holds a single image ([w, h, 1]), so any k ≥ 1 is out of range. This is a regression from 7c91439 (#2621); up to 83608ba the value was read before ijk[2] was overwritten.

Changes & Results

• ProbeTool: read the value (US and default branches) with the image-space index; ijk[2] is still replaced with the stack index for display, so cachedStats.index is unchanged.
• ProbeTool_test.js: new case that sets a two-image stack at index 1 and expects the value on the bar (255) and index[2] === 1. All existing Probe tests use setStack([imageId], 0), which is why this was not caught.

Before: the new test fails with Expected undefined to be 255. After: all 7 Probe tests pass.

Testing

KARMA_PACKAGE=tools KARMA_GREP="Probe Tool" npx karma start --single-run

Or manually: load a multi-image series in a stack viewport, scroll past the first image and place a probe — the text box now shows the index and value.

Checklist

PR

• My Pull Request title is descriptive, accurate and follows the
  semantic-release format and guidelines.

Code

• My code has been well-documented (function documentation, inline comments,
  etc.)

Public Documentation Updates

• The documentation page has been updated as necessary for any public API
  additions or removals. (no public API change)

Tested Environment

• "OS: Windows 11 (10.0.26200)"
• "Node version: 24.14.1"
• "Browser: Chrome Headless (karma)"

Summary by CodeRabbit

• Bug Fixes
  • Corrected voxel-value lookups for non-ECG stack images so Probe annotations report the value from the selected image while preserving the displayed stack index.
• Tests
  • Added coverage for Probe annotations on the second image in a stack, including the reported value and stack index.

[coderabbitai]

No actionable comments were generated in the recent review. 🎉

ℹ️ Recent review info

⚙️ Run configuration

• Configuration used: defaults
• Review profile: CHILL
• Plan: Advanced
• Run ID: b61b349f-0fe5-4f87-b58c-4bc6978cff38

📥 Commits

Reviewing files that changed from the base of the PR and between 5f2af21 and 52eb3b4.

📒 Files selected for processing (2)

• packages/tools/src/tools/annotation/ProbeTool.ts
• packages/tools/test/ProbeTool_test.js

Included review availability: This review used your included allowance. Your plan provides up to 4 included reviews per hour; 3 remain after this review.

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📝 Walkthrough

Walkthrough

ProbeTool now preserves the rounded image-space voxel index for non-ECG voxel lookups on stack viewports. A new test checks the probe value and stack index on the second image in a two-image stack.

Changes

Stack Probe Voxel Lookup

Layer / File(s)	Summary
Voxel lookup and stack test packages/tools/src/tools/annotation/ProbeTool.ts, packages/tools/test/ProbeTool_test.js	ProbeTool uses the preserved voxel index for non-ECG voxel lookups while retaining the adjusted index for display and enhanced-region calibration. The stack viewport test checks that the annotation references the second image, samples value 255, and reports stack index 1.

Priority: ➖ Normal

Estimated code review effort: 2 (Simple) | ~10 minutes

Change: Bug fix · Severity of issue fixed: Medium

Suggested reviewers: sedghi

Merge Risk: ⚪ Minimal · up to 52eb3

The change addresses Probe values on later stack images, and no actionable merge-blocking issue remains after normal checks.

🚥 Pre-merge checks | ✅ 5

✅ Passed checks (5 passed)

Check name	Status	Explanation
Title check	✅ Passed	The title clearly describes the fix for ProbeTool values on stack images beyond the first and follows the semantic-release format.
Description check	✅ Passed	The description covers the context, changes, results, testing steps, checklist, and tested environment. It provides enough detail to understand and verify the fix.
Linked Issues check	✅ Passed	Issue #2967 requires ProbeTool to show voxel values on stack images after the first while retaining the displayed stack index. ProbeTool.ts now copies the image-space IJK before replacing ijk[2], and …
Out of Scope Changes check	✅ Passed	The changes are limited to the ProbeTool value lookup and a regression test for issue #2967. The test directly verifies the requested stack behavior. No unrelated changes appear in the whole-PR diff.
Docstring Coverage	✅ Passed	No functions found in the changed files to evaluate docstring coverage. Skipping docstring coverage check. Docstring coverage is scoped to functions touched by this diff. Analyzed 0 functions across 2…

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