LineChart with optional Y parameter swift - ios

Require a LineChart where in it allows y value as nil. As when no data for that particular day(x) is there the line should just go forward.
Currently I have researched on SwiftChart & Charts but both doesn't provide that functionality.
Please refer below image for more understanding.
As you can see Sunday, Monday & Wednesday there is data Tuesday there is no data so the line just continues from Monday to Wednesday.
How can I achieve this or if there is any library that can help me achieve this.


You can just skip some X value in https://github.com/danielgindi/Charts
private func setupChart() {
let leftAxis = chart.leftAxis
leftAxis.axisMinimum = 0
leftAxis.axisMaximum = 100
leftAxis.granularity = 10
let rightAxis = chart.rightAxis
rightAxis.enabled = false
let xAxis = chart.xAxis
xAxis.axisMinimum = 0
xAxis.axisMaximum = 7
xAxis.labelPosition = .bottom
xAxis.granularity = 1
}
private func setupChartData() {
var dataEntries: [ChartDataEntry] = []
for i in 0...7 {
if i % 2 == 0 {
let value = arc4random_uniform(100) + 1
if value != 0 {
let dataEntry = ChartDataEntry(x: Double(i), y: Double(value))
dataEntries.append(dataEntry)
}
}
}
let dataSet = LineChartDataSet(entries: dataEntries, label: "")
let data = LineChartData(dataSet: dataSet)
chart.data = data
}

Related

Not to start xAxis at zero in LineChart iOS Swift

I have created lineChartView. Below xAxis values are displayed hours with 1 hour time interval. My graph starts at 0 and I am not able to show proper xAxis label value.
I want to put extra space in xAxis starting so that the xAxis label can proper visible.
Here is my code:
func setChart(yValues: [Double], xValues: [String]) {
chartView.noDataText = "You need to provide data for the chart."
var dataEntries: [ChartDataEntry] = []
for i in 0..<yValues.count {
let dataEntry = ChartDataEntry(x: Double(i), y: yValues[i])
dataEntries.append(dataEntry)
}
let chartDataSet = LineChartDataSet(entries: dataEntries, label: "")
chartDataSet.colors = [.black]
chartDataSet.drawFilledEnabled = true
let chartData = LineChartData(dataSet: chartDataSet)
let chartFormatter = LineChartFormatter(labels: xValues)
chartView.xAxis.valueFormatter = chartFormatter
chartView.xAxis.labelCount = dataEntries.count
chartView.data = chartData
chartView.xAxis.granularity = 1.0
chartView.xAxis.granularityEnabled = true
chartView.xAxis.centerAxisLabelsEnabled = false
chartView.xAxis.axisMinimum = 0
chartView.xAxis.axisMaximum = Double(dataEntries.count)
chartView.setVisibleXRange(minXRange: 1.0, maxXRange: 3.0)
}

iOS Charts not showing all xAxis Value

I am writing an iOS App in Swift 4.2
I am using Charts library to display Horizontal Bar Chart. I need to set its xAxis Values. Only last value is being displayed.
Issue Screenshot:
Code Snippet:
#IBOutlet var chartView: HorizontalBarChartView!
override func viewDidLoad() {
super.viewDidLoad()
let xAxis = chartView.xAxis
xAxis.labelPosition = .bottom
xAxis.labelFont = .systemFont(ofSize: 10)
xAxis.drawAxisLineEnabled = false
xAxis.drawGridLinesEnabled = false
xAxis.granularity = 1
xAxis.enabled=true
xAxis.setLabelCount(3, force: false) //Not working as per expectations
xAxis.valueFormatter=IndexAxisValueFormatter(values: ["A","B","C"]) //Not working as per expectations
self.setDataCount(3,values:[142000,122400,100110])
chartView.animate(yAxisDuration: 2.5)
}
func setDataCount(_ count: Int, values:[Double]) {
let barWidth = 2.0
let spaceForBar = 4.0
var n=0
let yVals = (0..<count).map { (i) -> BarChartDataEntry in
let val = values[n]
n+=1
return BarChartDataEntry(x: Double(i)*spaceForBar, y: val)
}
let set1 = BarChartDataSet(entries: yVals, label: "DataSet")
set1.drawIconsEnabled = false
let data = BarChartData(dataSet: set1)
data.setValueFont(UIFont(name:"HelveticaNeue-Light", size:10)!)
data.barWidth = barWidth
chartView.data = data
//let xAxis = chartView.xAxis
//xAxis.setLabelCount(3, force: false)
//xAxis.valueFormatter=IndexAxisValueFormatter(values: ["A","B","C"])
}
I tried to find solutions:
xAxis.valueFormatter=IndexAxisValueFormatter(values: ["A","B","C"])
but these are not working.

This is happening because the default functionality of IndexAxisValueFormatter
You have to code your own custom IAxisValueFormatter like this
final class CustomFormatter: IAxisValueFormatter {
var labels: [String] = []
func stringForValue(_ value: Double, axis: AxisBase?) -> String {
let count = self.labels.count
guard let axis = axis, count > 0 else {
return ""
}
let factor = axis.axisMaximum / Double(count)
let index = Int((value / factor).rounded())
if index >= 0 && index < count {
return self.labels[index]
}
return ""
}
}
Then use it like
let customFormater = CustomFormater()
customFormater.labels = ["A","B","C"]
chartView.xAxis.valueFormatter = customFormater
Make sure the size/count of the data and labels is the same or it wont give you the desired results.

I updated your given code please check changes.
I hope its work for you.
class ViewController: UIViewController {
#IBOutlet var chartView: HorizontalBarChartView!
override func viewDidLoad() {
super.viewDidLoad()
let xAxis = chartView.xAxis
xAxis.labelPosition = .bottom
xAxis.labelFont = .systemFont(ofSize: 10)
xAxis.drawAxisLineEnabled = false
xAxis.drawGridLinesEnabled = false
xAxis.granularity = 1
xAxis.enabled=true
xAxis.setLabelCount(3, force: false) //Not working as per expectations
xAxis.valueFormatter = IndexAxisValueFormatter(values: ["A","B","C"])//AxisValueFormatter(values: ["A","B","C"]) //Not working as per expectations
self.setDataCount(3,values:[142000,122400,100110])
chartView.animate(yAxisDuration: 2.5)
}
func setDataCount(_ count: Int, values:[Double]) {
let yVals = (0..<count).map { (i) -> BarChartDataEntry in
let val = values[i]
return BarChartDataEntry(x: Double(i), y: val)
}
let set1 = BarChartDataSet(values: yVals, label: "DataSet")
set1.drawIconsEnabled = false
let data = BarChartData(dataSet: set1)
data.setValueFont(UIFont(name:"HelveticaNeue-Light", size:10)!)
//data.barWidth = barWidth
chartView.data = data
//let xAxis = chartView.xAxis
//xAxis.setLabelCount(3, force: false)
//xAxis.valueFormatter=IndexAxisValueFormatter(values: ["A","B","C"])
}
}

How to add string labels( xAxis labels) to horizontal bar in Charts framework

I am using charts framework for drawing charts. I need to add some strings in left of every bars. In my code always there are two bars, one for Income and one for Expense. I want to show these string aside of every bar.
Below you can see my codes:
let ys1 = [model.totalIncome, abs(model.totalExpense)]
var yse1 = ys1.enumerated().map { x, y -> BarChartDataEntry in
return BarChartDataEntry(x: Double(x), y: y)
}
let count = 2
let data = BarChartData()
let ds1 = BarChartDataSet(values: yse1, label: "")
ds1.colors = [UIColor.red, UIColor.blue]
// Number formatting of Values
ds1.valueFormatter = YAxisValueFormatter()
ds1.valueFont = UIFont(fontType: .H6)!
ds1.valueTextColor = UIColor.dark_text
// Data set
data.addDataSet(ds1)
horizontalBarChartView.data = data
// General setting
horizontalBarChartView.xAxis.drawLabelsEnabled = false
horizontalBarChartView.setScaleEnabled(false)
// Grid
horizontalBarChartView.xAxis.drawGridLinesEnabled = false
horizontalBarChartView.leftAxis.gridLineDashLengths = [15.0, 15.0]
horizontalBarChartView.leftAxis.gridColor = UIColor.palette_28
horizontalBarChartView.rightAxis.drawGridLinesEnabled = false
// Disable number formatting of leftAxis and rightAxis
horizontalBarChartView.leftAxis.enabled = false
horizontalBarChartView.rightAxis.enabled = false
horizontalBarChartView.xAxis.valueFormatter =
IndexAxisValueFormatter(values: ["Income","Expense"])
horizontalBarChartView.xAxis.granularityEnabled = true
horizontalBarChartView.xAxis.granularity = 1
// setViewPortOffsets
let digitCount = Int(data.yMax).digitCount
let leftOffcet: CGFloat = digitCount > 2 ? CGFloat((digitCount - 1) * 10) : 10.0
horizontalBarChartView.setViewPortOffsets(left: leftOffcet, top: 0, right: 0, bottom: 50)
horizontalBarChartView.leftAxis.axisMinimum = 0
And my view:
lazy var horizontalBarChartView: HorizontalBarChartView = {
let chartView = HorizontalBarChartView()
chartView.contentMode = .scaleAspectFit
chartView.drawBordersEnabled = false
chartView.drawGridBackgroundEnabled = false
chartView.gridBackgroundColor = UIColor.clear
chartView.legend.enabled = false
chartView.chartDescription = nil
chartView.highlighter = nil
chartView.clipsToBounds = true
chartView.translatesAutoresizingMaskIntoConstraints = false
return chartView
}()
I guess below code should add these labels, however, it is not working
horizontalBarChartView.xAxis.valueFormatter = IndexAxisValueFormatter(values: ["Income","Expense"])
horizontalBarChartView.xAxis.granularityEnabled = true
horizontalBarChartView.xAxis.granularity = 1
Update
See orange rectangle. I need these labels.

I am using an extension for this
extension BarChartView {
private class BarChartFormatter: NSObject, IAxisValueFormatter {
var labels: [String] = []
func stringForValue(_ value: Double, axis: AxisBase?) -> String {
return labels[Int(value)]
}
init(labels: [String]) {
super.init()
self.labels = labels
}
}
func setBarChartData(xValues: [String], yValues: [Double], label: String) {
var dataEntries: [BarChartDataEntry] = []
for i in 0..<yValues.count {
let dataEntry = BarChartDataEntry(x: Double(i), y: yValues[i])
dataEntries.append(dataEntry)
}
let chartDataSet = BarChartDataSet(values: dataEntries, label: label)
let chartData = BarChartData(dataSet: chartDataSet)
let chartFormatter = BarChartFormatter(labels: xValues)
let xAxis = XAxis()
xAxis.valueFormatter = chartFormatter
self.xAxis.valueFormatter = xAxis.valueFormatter
self.data = chartData
}
}
you can use this in code like this
chartView.setBarChartData(xValues: xEntries, yValues: yEntries, label: "Income")
where,
//You need to add values dynamically
var yEntries: [Double] = [1000, 200, 500]
var xEntries: [String] = ["Income1", "Income2", "Income3"]
Hope this works.

Charts framework is a great tool for drawing charts. You should study it perfectly. I used an old code in our project (copy/paste), so it caused some problems for drawing xAxis labels in my chart.
Just comment below line:
horizontalBarChartView.xAxis.drawLabelsEnabled = false

When you create your BarChartDataSet you can pass the label.
let data = BarChartData()
let ds1 = BarChartDataSet(values: yse1, label: "Income")
ds1.colors = [UIColor.red, UIColor.blue]
Hope this helps.

self.ChartObj.xAxis.valueFormatter = DefaultAxisValueFormatter(block: {(index, _) in
print(index)
return YourArray.object(at: Int(index)) as! String
})
self.ChartObj.xAxis.setLabelCount(YourArray.count, force: true)
Try this code

How to format xAxis labels iOS charts

Im implementing a barchart and I've managed to assign the data and labels. However, when i load the barchart, it only shows 3/7 of my labels and I'm not sure why.
the labels show up when i interact with the chart but they go glitchy.
I'm sorry if i haven't explained myself well but i have uploaded a .gif showing my problem.
I really need some help with the formatting of the labels on the xAxis. it would be much appreciated.
Thanks in advance.
gif of problem

i think you have used this library(https://github.com/danielgindi/Charts) ... i have set x-Axis using delegate method of chart
func ChartView()
{
xAxis.drawGridLinesEnabled = false
xAxis.drawLabelsEnabled = true
xAxis.labelPosition = .Bottom
xAxis.axisMinimum = 0.0
xAxis.labelCount = ITEM_COUNT
xAxis.granularity = 1.0
xAxis.valueFormatter = self
self.updateChartData()
}
func updateChartData()
{
self.chartView.data = nil
self.setChartData()
}
func generateLineData() -> LineChartData
{
let d = LineChartData()
let entries = NSMutableArray()
var weightstr = String()
var datestr = String()
entries.addObject(ChartDataEntry(x: Double(index), y: ( Double(dic[setvalue]as! String)!)))
let set = LineChartDataSet(values: entries as? [ChartDataEntry] , label: "X-title")
set.setColor(colorWithHexString("#FE1643"))
set.lineWidth = 2.5
set.setCircleColor( UIColor.whiteColor())
set.circleHoleColor = NSUIColor.greenColor()
set.circleRadius = 5.0
set.circleHoleRadius = 2.5
set.fillColor = UIColor.redColor()
set.mode = .HorizontalBezier
set.valueTextColor = UIColor.lightGrayColor()
set.drawValuesEnabled = true
set.valueFont = UIFont(name: "Exo-Regular", size: FOntSIZE(10.0))!
set.axisDependency = .Left
d.addDataSet(set)
return d
}
func setChartData()
{
let data = CombinedChartData()
data.lineData = self.generateLineData()
self.chartView.xAxis.axisMaximum = Double(months.count)-1
self.chartView.data = data
}
func chartValueSelected(chartView: ChartViewBase, entry: ChartDataEntry, highlight: Highlight)
{
print("chartValueSelected")
}
func chartValueNothingSelected(chartView: ChartViewBase)
{
print("chartValueNothingSelected")
}
func stringForValue(value: Double, axis: AxisBase?) -> String
{
return months[Int(round(value)) % months.count] as! String
}

How to make a grouped BarChart with ios-charts?

I am using ios-charts library.
I would like to group my inverter values so that each year is one group. Unfortunately, the number of monthly values per year may vary.
My data json looks like this:
{"monthlyData":[{"ERTRAG":"30.2989999055862","MONAT":"2","JAHR":"2016"},{"ERTRAG":"154.897000223398","MONAT":"1","JAHR":"2016"},{"ERTRAG":"141.996000155807","MONAT":"12","JAHR":"2015"},{"ERTRAG":"135.449000149965","MONAT":"11","JAHR":"2015"},{"ERTRAG":"319.437000751495","MONAT":"10","JAHR":"2015"},{"ERTRAG":"483.369997739792","MONAT":"9","JAHR":"2015"},{"ERTRAG":"698.112997770309","MONAT":"8","JAHR":"2015"},{"ERTRAG":"771.764000892639","MONAT":"7","JAHR":"2015"},{"ERTRAG":"736.611003398895","MONAT":"6","JAHR":"2015"},{"ERTRAG":"737.237999916077","MONAT":"5","JAHR":"2015"},{"ERTRAG":"720.181995391846","MONAT":"4","JAHR":"2015"},{"ERTRAG":"484.979001283646","MONAT":"3","JAHR":"2015"},{"ERTRAG":"249.974001646042","MONAT":"2","JAHR":"2015"},{"ERTRAG":"92.8830004036427","MONAT":"1","JAHR":"2015"},{"ERTRAG":"52.7970000207424","MONAT":"12","JAHR":"2014"},{"ERTRAG":"181.025999426842","MONAT":"11","JAHR":"2014"},{"ERTRAG":"332.789002537727","MONAT":"10","JAHR":"2014"},{"ERTRAG":"482.244999885559","MONAT":"9","JAHR":"2014"},{"ERTRAG":"602.811999320984","MONAT":"8","JAHR":"2014"},{"ERTRAG":"699.872003316879","MONAT":"7","JAHR":"2014"},{"ERTRAG":"828.212007522583","MONAT":"6","JAHR":"2014"},{"ERTRAG":"679.010004997253","MONAT":"5","JAHR":"2014"},{"ERTRAG":"635.115998744965","MONAT":"4","JAHR":"2014"},{"ERTRAG":"559.617002010345","MONAT":"3","JAHR":"2014"},{"ERTRAG":"265.135001063347","MONAT":"2","JAHR":"2014"},{"ERTRAG":"165.272998273373","MONAT":"1","JAHR":"2014"},{"ERTRAG":"134.578999936581","MONAT":"12","JAHR":"2013"},{"ERTRAG":"153.774000287056","MONAT":"11","JAHR":"2013"},{"ERTRAG":"321.733997344971","MONAT":"10","JAHR":"2013"},{"ERTRAG":"482.768000483513","MONAT":"9","JAHR":"2013"},{"ERTRAG":"692.864000797272","MONAT":"8","JAHR":"2013"},{"ERTRAG":"846.429007053375","MONAT":"7","JAHR":"2013"},{"ERTRAG":"709.758005619049","MONAT":"6","JAHR":"2013"},{"ERTRAG":"532.493996858597","MONAT":"5","JAHR":"2013"},{"ERTRAG":"462.539998054504","MONAT":"4","JAHR":"2013"},{"ERTRAG":"419.105004012585","MONAT":"3","JAHR":"2013"},{"ERTRAG":"143.189998820424","MONAT":"2","JAHR":"2013"},{"ERTRAG":"78.720000628382","MONAT":"1","JAHR":"2013"},{"ERTRAG":"90.1430006623268","MONAT":"12","JAHR":"2012"},{"ERTRAG":"155.483000457287","MONAT":"11","JAHR":"2012"},{"ERTRAG":"348.231998205185","MONAT":"10","JAHR":"2012"},{"ERTRAG":"598.037001848221","MONAT":"9","JAHR":"2012"},{"ERTRAG":"729.740003108978","MONAT":"8","JAHR":"2012"},{"ERTRAG":"676.923998832703","MONAT":"7","JAHR":"2012"},{"ERTRAG":"694.879002094269","MONAT":"6","JAHR":"2012"},{"ERTRAG":"811.281997680664","MONAT":"5","JAHR":"2012"},{"ERTRAG":"489.765002369881","MONAT":"4","JAHR":"2012"},{"ERTRAG":"538.866001605988","MONAT":"3","JAHR":"2012"},{"ERTRAG":"277.856996208429","MONAT":"2","JAHR":"2012"},{"ERTRAG":"155.854999214411","MONAT":"1","JAHR":"2012"},{"ERTRAG":"148.157999750227","MONAT":"12","JAHR":"2011"},{"ERTRAG":"230.409998774529","MONAT":"11","JAHR":"2011"}]}
I tried the following:
var months = Array<String>()
var years = Array<String>()
var dataEntries: [BarChartDataEntry] = []
var dataSets: [BarChartDataSet] = []
var overallSum = 0.0
var year = 2010 //monthlyValues[0].year
var count = 0
var chartDataSet: BarChartDataSet?
for i in 0..<monthlyValues.count {
// if year is different, create new barchartdataset
if monthlyValues[i].year != year {
years.append("\(monthlyValues[i].year)")
chartDataSet = BarChartDataSet(yVals: dataEntries, label: "\(year)")
chartDataSet!.colors = [UIColor.whiteColor()]
dataSets.append(chartDataSet!)
year = monthlyValues[i].year
dataEntries = []
//months = []
count = 0
}
months.append("\(monthlyValues[i].month)")
overallSum += monthlyValues[i].amount
let dataEntry = BarChartDataEntry(value: monthlyValues[i].amount, xIndex: count)
count++
dataEntries.append(dataEntry)
}
let chartData = BarChartData(xVals: months, dataSets: dataSets)
self.barChartView.data = chartData
This results in five series with the right year labels in the legend but there is no group separator in the chart and also the number of bars per year is either 4 or 5 (expected = 12).
Thanks for any hint on this!

let months = ["Jan", "Feb", "Mar", "Apr", "May"]
let unitsSold = [20.0, 4.0, 6.0, 3.0, 12.0]
let unitsBought = [10.0, 14.0, 60.0, 13.0, 2.0]
override func viewDidLoad() {
super.viewDidLoad()
// Do any additional setup after loading the view, typically from a nib.
barChartView.delegate = self
barChartView.noDataText = "You need to provide data for the chart."
barChartView.chartDescription?.text = "sales vs bought "
//legend
let legend = barChartView.legend
legend.enabled = true
legend.horizontalAlignment = .right
legend.verticalAlignment = .top
legend.orientation = .vertical
legend.drawInside = true
legend.yOffset = 10.0;
legend.xOffset = 10.0;
legend.yEntrySpace = 0.0;
let xaxis = barChartView.xAxis
xaxis.valueFormatter = axisFormatDelegate
xaxis.drawGridLinesEnabled = true
xaxis.labelPosition = .bottom
xaxis.centerAxisLabelsEnabled = true
xaxis.valueFormatter = IndexAxisValueFormatter(values:self.months)
xaxis.granularity = 1
let leftAxisFormatter = NumberFormatter()
leftAxisFormatter.maximumFractionDigits = 1
let yaxis = barChartView.leftAxis
yaxis.spaceTop = 0.35
yaxis.axisMinimum = 0
yaxis.drawGridLinesEnabled = false
barChartView.rightAxis.enabled = false
//axisFormatDelegate = self
setChart()
}
func setChart() {
barChartView.noDataText = "You need to provide data for the chart."
var dataEntries: [BarChartDataEntry] = []
var dataEntries1: [BarChartDataEntry] = []
for i in 0..<self.months.count {
let dataEntry = BarChartDataEntry(x: Double(i) , y: self.unitsSold[i])
dataEntries.append(dataEntry)
let dataEntry1 = BarChartDataEntry(x: Double(i) , y: self.self.unitsBought[i])
dataEntries1.append(dataEntry1)
//stack barchart
//let dataEntry = BarChartDataEntry(x: Double(i), yValues: [self.unitsSold[i],self.unitsBought[i]], label: "groupChart")
}
let chartDataSet = BarChartDataSet(values: dataEntries, label: "Unit sold")
let chartDataSet1 = BarChartDataSet(values: dataEntries1, label: "Unit Bought")
let dataSets: [BarChartDataSet] = [chartDataSet,chartDataSet1]
chartDataSet.colors = [UIColor(red: 230/255, green: 126/255, blue: 34/255, alpha: 1)]
//chartDataSet.colors = ChartColorTemplates.colorful()
//let chartData = BarChartData(dataSet: chartDataSet)
let chartData = BarChartData(dataSets: dataSets)
let groupSpace = 0.3
let barSpace = 0.05
let barWidth = 0.3
// (0.3 + 0.05) * 2 + 0.3 = 1.00 -> interval per "group"
let groupCount = self.months.count
let startYear = 0
chartData.barWidth = barWidth;
barChartView.xAxis.axisMinimum = Double(startYear)
let gg = chartData.groupWidth(groupSpace: groupSpace, barSpace: barSpace)
print("Groupspace: \(gg)")
barChartView.xAxis.axisMaximum = Double(startYear) + gg * Double(groupCount)
chartData.groupBars(fromX: Double(startYear), groupSpace: groupSpace, barSpace: barSpace)
//chartData.groupWidth(groupSpace: groupSpace, barSpace: barSpace)
barChartView.notifyDataSetChanged()
barChartView.data = chartData
//background color
barChartView.backgroundColor = UIColor(red: 189/255, green: 195/255, blue: 199/255, alpha: 1)
//chart animation
barChartView.animate(xAxisDuration: 1.5, yAxisDuration: 1.5, easingOption: .linear)
}

You got something wrong here. Right now you are creating a new DataSet for every year.
What you need to do is create as many DataSets as you want bars per group where one DataSet represents one bar in each group. (e.g. DataSet 1 represents every first bar of a group, DataSet 2 every second bar of a group, ...)
As an example, imagine a chart like this with 4 groups of 3 bars per group. Each group represents one year.
||| ||| ||| |||
The setup shown above requires 3 DataSets (one for each group)
Entries in the same group have the same x-index (e.g. in the first group all have x-index 0)
It consists of a total of 12 entries
Each DataSet contains 4 entries with Entry x-indices ranging from 0 to 3
Here you can find an example of the scenario described above and check out the documentation.

if you have noticed in above code in function chart. There is let
groupSpace = 0.3
let barSpace = 0.05
let barWidth = 0.3
// (0.3 + 0.05) * 2 + 0.3 = 1.00 -> interval per "group"
which will make equation
(groupSpace * barSpace) * n + groupSpace = 1
you need to play around this equation for n number of bars

I've tried Rajan Twanabashu solution, but it was almost the good one. Maybe it has changed since, I don't know.
Here's what I've done, after I found the groupWidth function in the BarDataChart file from Charts.
groupWidth function declaration
let groupSpace = 1 - n * (barWidth + barSpace)
Hope it could help

After diving in this equation "(0.3 + 0.05) * 2 + 0.3 = 1.00" to work on variant amount of grouping I got:
let n = Double(data.dataSets.count)
let groupSpace = 0.0031 * n
let barSpace = 0.002 * n
let barWidth = (1 - (n * barSpace) - groupSpace) / n
What is varying is barWidth.

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