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PieChart: Custom labels outside of segments

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Hi guys,

I have some troubles with piecharts in swift. I want to provide custom labels outside of the piecharts segments. I found a screenshot of a nested piechart attached to an issue in your issue tracker. Thats what I want to do in swift, but I couldn’t find out a way to do so. Could you please provide an example code?

Thanks a lot in advance!

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Hi, Alexander.

The easiest way to achieve this without overriding the drawing engine is to add second donut series with clear color and the same segments as your pieSeries has.

let pieSeries = SCIPieRenderableSeries()
    pieSeries.segmentsCollection.add(segmentWithValue(segmentValue: 40, title: "Green", centerColor: 0xff84BC3D, edgeColor: 0xff5B8829))

    let donutSeries = SCIDonutRenderableSeries()
    donutSeries.segmentsCollection.add(segmentWithValue(segmentValue: 40, title: "Green", centerColor: 0x00000000, edgeColor: 0x00000000))


    surface.seriesSpacing = 0

    pieSeries.drawLabels = false

func segmentWithValue(segmentValue: Double, title: String, centerColor: UInt32, edgeColor: UInt32) -> SCIPieSegment {
    let segment = SCIPieSegment()
    segment.value = segmentValue
    segment.title = title
    segment.fillStyle = SCIRadialGradientBrushStyle(centerColorCode: centerColor, edgeColorCode: edgeColor)
    segment.titleStyle = SCIFontStyle(textColor: .white)

    segment.strokeStyle = SCISolidPenStyle(color: .clear, thickness: 0)

    return segment

I hope, that helped.

  • Alexander Frankenhauser
    Hi Andriy, thanks a lot for your fast response! That seems to be a pragmatic way to place value labels next to the segments of a pie chart. But to add the titles of the segments as well I assume there is no other way than to use an override func within a custom label provider class. And I can’t find a solution for this problem in the developer documentation for pie charts/donut charts. Using a custom label provider for a numerical axis of a column series for example was not a problem. May be you have a sample code for this purpose as well? Thank you very much in advance! Alex
  • Alexander Frankenhauser
    Did it! It works using the LabelFormatter protocol and the „formatLabel“ function. A bit complicated but combined with the suggestion of Andriy I have what I wanted!
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