[Feature] add new function same as api.currentSeriesIndices with pie chart legend select, eg. currentDataIndices in custom chart

[Ling310]

What problem does this feature solve?

i need a new function same as api.currentSeriesIndices when pie chart legend active changed(eg. api.currentDataIndices) in custom chart. I want to draw some extra graphic elements to pie chart, when legend active is changed,I wish my custom element colud show or hide at same time.

What does the proposed API look like?

if I have three data, draw a pie chart, and this function I wish(api.currentDataIndices):

• do nothing, return [0, 1, 2]
• click first legend item make it unselect, return [1, 2]

[github-actions[bot]]

This issue has been automatically marked as stale because it did not have recent activity. It will be closed in 7 days if no further activity occurs. If you wish not to mark it as stale, please leave a comment in this issue.

[github-actions[bot]]

This issue has been automatically closed because it did not have recent activity. If this remains to be a problem with the latest version of Apache ECharts, please open a new issue and link this to it. Thanks!