[Feature] Line style for varied segments and connectNulls

What problem does this feature solve?

Current API lacks the ability to control line style for varied segments. For example, if we want to make different styles for a line series, we have to mock it using many series, which is not an elegant way to do.

What does the proposed API look like?

The new option should give the developer the control over line styles for different line segments. The API could be:

{
  data: [{
    value: 10,
    lineStyle: {...}, // controls the line style after this data
    areaStyle: {...}
  }]
}

or something similar to visualMap.pieces:

{
  linePieces: [{
    index: [0, 2, 4], // the index of line segments
    lineStyle: {...},
    areaStyle: {...}
  }]
}

or callback rules:

{
  linePieces: [{
    rule: function(params) { return params.dataIndex % 4 === 1; },
    lineStyle: {...},
    areaStyle: {...}
  }]
}

We should also provide a way to set the lineStyle for the lines from connectNulls. The API may be

{
  nullLineStyle: {...},
  nullAreaStyle: {...}
}

or

{
  connectNullStyle: {
    lineStyle: {...},
    areaStyle: {...}
  }
}

or

{
  linePieces: [{
    rule: function(params) { return params.isConnectNulls },
    lineStyle: {...},
    areaStyle: {...}
  }]
}

This issue is a task for OSPP so it will probably be fixed by a student from the program. Discussion about the design and your own requirement is always welcomed.

[pe-2]

You’re welcome, It’s my pleasure. I will submit the application after I complete it. 😁

[Ovilia]

@pe-2 Thanks for your suggestion. Although we do not have something like this for other options, theoretically speeking, this could also be a solution. I would suggest comparing each of these solutions and getting to a conclusion which one is the best. The thinking behind the choice of API design is the most important thing for this task.

P.S. We don’t have any application on this task yet. Please make sure you submit the application on time.

Thanks!