[Feature] Add alternative behavior for select on legend

[winkyBrain]

What problem does this feature solve?

Now, when we select an item on legend, data of unselected chart element just fade out. How about alternative behavior, when unselected chart element just blurring, but still exists in the chart.
For example:

1. All items selected
   

2. Yellow item unselected(obviously points must be blurred too). Notice - this is what I suggest. There is no code for reproduce!
   

What does the proposed API look like?

legend.clearInactiveItem: boolean;
Default value is true, so true is current behavior.
legend.inactiveItemStyle: {
color?: someColor; // if you do not change the color, then the current color is used
opacity: number, form 0 to 1. default value is 0.5;
}
inactiveItemStyle working only if clearInactiveItem is false.

[helgasoft]

Normal behavior of legend uncheck is hiding the line, see official example.
Selecting ECharts elements is done by clicking on them, if selection is authorized.
So 1.All items selected and 2. Yellow item unselected cannot be reproduced. Please provide sample code.

That said, working on the issue, a bug pops out - line.select.lineStyle is nonfunctional.
It has been reported already in #16545. Turns out lines.select.lineStyle is the same - see #16981.

Conclusion:
line.select.lineStyle and lines.select.lineStyle should be removed from the API, as suggested by @susiwen8, since they are unlikely to be fixed in the foreseeable future.
My presentiment is that line and lines series code may need to be rewritten someday. Currently they behave more like customized scatter series.

disclaimer

opinions expressed in this post are strictly personal, as ECharts user, not a developer

[github-actions]

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]

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!