feat: add legend.groupdoubleclick to set group behavior on double-click

[rascal-sl]

Summary

layout.legend.groupdoubleclick sets the group behavior for a legend double-click. A figure can now toggle a whole legendgroup on a single click and isolate one trace on a double click.

Closes #6812

Why this shape

handleItemClick read groupclick for every action, so a double click could not differ from a single click.

groupdoubleclick takes the coerced groupclick value as its default. A figure that omits the attribute keeps the current behavior.

The isolation path now honors the resolved group value. This corrects one existing case. With groupclick: 'toggleitem' and the default itemdoubleclick: 'toggleothers', a double click now isolates the clicked trace instead of its whole legendgroup. The old output contradicted the description of toggleitem, which toggles "the individual item clicked on the graph". I flag that correction here for your judgment.

groupclick still drives the draw-time branches in get_legend_data.js and draw.js. A draw cannot depend on a later click.

Tests

Suite: test/jasmine/tests/legend_test.js

npm run test-jasmine -- legend --nowatch

Result on my machine, Chrome 151: TOTAL: 128 SUCCESS.

New specs:

• legend defaults - groupdoubleclick follows groupclick, and it also coerces on its own
• legend interaction - legendgroup visibility case of groupdoubleclick: "toggleitem", one spec for the double click and one for the single click

I put the old isolation line back and ran the suite again. That run reported TOTAL: 1 FAILED, 127 SUCCESS, so the new spec covers the change.

No new mock, and no baseline moves. The attribute changes no drawn output before a user double-clicks.

Rendered check

I loaded the local bundle and compared two figures that hold the same four traces. Trace 1 and trace 3 share legendgroup: 'foo'. Trace 0 is visible: false.

Figure	visible after a double click on trace 3
default	[false, true, "legendonly", true]
groupdoubleclick: 'toggleitem'	[false, "legendonly", "legendonly", true]

The two figures render the same before the double click. A second double click restores [false, true, true, true].

Checks

Command	Result
npm run lint	pass
npm run typecheck	pass
npm run test-syntax	pass
npm run schema-typegen-diff-check	pass

Note

traceIndicesInGroup in handle_click.js takes a value that no line reads. That predates this change, so I left it alone.

🐦

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Tisankan Jeyakumar