iOS Charts: Determine the positioning and color of the highlighted entry - ios-charts

Question

I have a pie chart implemented with the Charts library. Now when an entry is tapped and becomes highlighted, I would like to show a tooltip that shows the value of the selected entry, positioned in the middle of the entry, and outlined in the same color of the selected piece of the pie.
In the delegate function chartValueSelected(_ chartView: ChartViewBase, entry: ChartDataEntry, highlight: Highlight) I can obtain the highlight's xPx and yPx, but this is the touch point where the user tapped to highlight this entry, not the center point of the entry itself, so centering the tooltip on these values results in the tooltip jumping around depending on where you tap the entry. And I don't see any way to get the color of the highlighted entry.
I am trying to obtain the following, and outline it in that pink color:

Answer 1

:: 1 :: Position of the Popup
Hmm... I've been looking and I don't think the ChartDataEntry has an available frame to use as a reference point for setting your popup's position.
I think doing it based on the tap location is a decent alternative, though. That at least gets the popup to show in the same general region as the pie segment. It should still be a good user experience, in my opinion. :)
:: 2 :: Color of the Currently Selected Segment
PieChartDataSet has a values property that has your ChartDataEntry objects in it. So you could find the index of the matching one since the chartValueSelected delegate method passes you the current ChartDataEntry object (entry).

Answer 2

PieChartView has the marker property which you can use for display marker when a value is clicked on the chart. In my opinion, using marker property and creating the custom marker class it is a preferred way of resolving your task.
The custom marker class must conform to IMarker protocol and can be instantiated from MarkerImage class. Pay attention to two functions:
draw(context: CGContext, point: CGPoint) function with two input params which pass position and context for drawing. So you have information about the position for your balloon.
refreshContent(entry: ChartDataEntry, highlight: Highlight). In this function, you can choose a color for the balloon. MarkerImage class has chartView property so you have access to datasets. If you use more than one dataset, you can use a value of highlight.dataSetIndex to define dataset which was clicked. When the dataset is chosen you can get a color from dataSet.colors property using index obtained by dataSet.entryIndex(entry: entry).
Example of color choosing:
open override func refreshContent(entry: ChartDataEntry, highlight: Highlight)
{
let dataSet = chartView!.data!.dataSets[highlight.dataSetIndex]
let colorIndex = dataSet.entryIndex(entry: entry) % dataSet.colors.count
color = dataSet.colors[colorIndex]
super.refreshContent(entry: entry, highlight: highlight)
}