Rotating the pie chart about piecharts

[ivnsch]

Implemented! You can now rotate the chart after initialization.

Example:

func onSelected(slice: PieSlice, selected: Bool) {
    chartView.referenceAngle = 270 - slice.view.midAngle.radiansToDegrees + chartView.referenceAngle
}

extension FloatingPoint {
    var radiansToDegrees: Self {
        return self * 180 / .pi
    }
}

Where 270 is the top center, the angle you want to rotate the slice to.

While this doesn't affect the calculations, it's worth to note that the slice's mid angle is not necessarily in [0, 2π] range. If you want to have it in this range, e.g. to debug you can do slice.view.midAngle.radiansToDegrees.truncatingRemainder(dividingBy: 360).

You'll have to use 0 as selectedOffset for now. To support both selectedOffset and rotation change it's necessary to do a little more work. You can try to do this if you want! The most simple way to achieve this would be to add a delegate method for termination of rotate animation and also allow to select slices programmatically, such that you can do this when the rotation finishes. Or the other way around, depending on what you need.

The change is in master, to use it:

pod 'PieCharts', :git => 'https://github.com/i-schuetz/PieCharts.git'

[ivnsch]

It's not possible right now. I will take a look into this in the next days, thanks!

[Brandon-316]

Awesome thanks!

[Brandon-316]

Great thank you!