Issue while setting LinearDataSet

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* [ ] I've read, understood, and done my best to follow the [*CONTRIBUTING guidelines](https://github.com/jjatie/Charts/blob/master/CONTRIBUTING.md).

## What did you do?
func configure() {

chartView.clear()
guard let rows = self.rows, let rowDataItem = self.rowDataItem else { return }

if(/rows.count == 1){
var dataPoints = [String]()
var max : Int = 0
rows.forEach({ model in
if(Int(/Double(model.value ?? "")) > max){
max = Int(/Double(model.value ?? ""))
}
dataPoints.append(/model.date)
})

setChartViewProperties(max)

var values = (0 ..< /dataPoints.count).map { (i) -> ChartDataEntry in
if(i == /rows.count){
return(ChartDataEntry(x: /Double(i), y: /Double(0)))
}
return ChartDataEntry(x: /Double(i), y: /Double(rows[i].value ?? ""))
}

if(rows.count == 1){
values.removeAll()
dataPoints.removeAll()
values.append(ChartDataEntry(x: /Double(0), y: /Double(0)))
values.append(ChartDataEntry(x: /Double(1), y: /Double(rows[0].value ?? "")))
values.append(ChartDataEntry(x: /Double(2), y: /Double(0)))
dataPoints.append("")
dataPoints.append(rows[0].date ?? "")
dataPoints.append("")
}

let set1 = LineChartDataSet(entries: values, label:"")
set1.drawIconsEnabled = false
setup(set1)

let gradientColors = [UIColor.AppThemeGreenColor().cgColor,
#colorLiteral(red: 0.3019607843, green: 0.662745098, blue: 0.8156862745, alpha: 1).cgColor]
let gradient = CGGradient(colorsSpace: nil, colors: gradientColors as CFArray, locations: nil)!

set1.fillAlpha = 1
set1.drawFilledEnabled = false
let data = LineChartData(dataSet: set1)
chartView.data = data

}
else if(/rows.count > 0) {
var dataPoints = [String]()
var max : Int = 0
rows.forEach({ model in
if(Int(/Double(model.value ?? "")) > max){
max = Int(/Double(model.value ?? ""))
}
dataPoints.append(/model.date)
})

self.setChartViewProperties(max)

var values = (0 ..< /dataPoints.count).map { (i) -> ChartDataEntry in
if(i == /rows.count){
return(ChartDataEntry(x: /Double(i), y: /Double(0)))
}
return ChartDataEntry(x: /Double(i), y: /Double(rows[i].value ?? ""))
}

if(rows.count == 1){
values.removeAll()
dataPoints.removeAll()
values.append(ChartDataEntry(x: /Double(0), y: /Double(0)))
values.append(ChartDataEntry(x: /Double(1), y: /Double(rows[0].value ?? "")))
values.append(ChartDataEntry(x: /Double(2), y: /Double(0)))
dataPoints.append("")
dataPoints.append(rowDataItem.date ?? "")
dataPoints.append("")
}

let set1 = LineChartDataSet(entries: values, label:"")
set1.drawIconsEnabled = false

setup(set1)

let gradientColors = [UIColor.AppThemeGreenColor().cgColor,
#colorLiteral(red: 0.3019607843, green: 0.662745098, blue: 0.8156862745, alpha: 1).cgColor]
let gradient = CGGradient(colorsSpace: nil, colors: gradientColors as CFArray, locations: nil)!

set1.fillAlpha = 1
set1.fill = LinearGradientFill(gradient: gradient, angle: 90)
set1.drawFilledEnabled = true


let data = LineChartData(dataSet: set1)

chartView.data = data

}
else {
chartView.clear()
chartView.data = nil
}
}

/*
Chart view to show the actual graph according to dataSet and the range
*/
func setChartViewProperties(_ max: Int) {

guard let rows = self.rows, let rowDataSet = self.rowDataItem else { return }
var numericMaxValue = "", numericMinValue = "", maxValue = 0.0, minRange = "", maxRange = ""

if !(/rowDataSet.minrange?.isEmpty) {
if let numericMinValueFromString = rowDataSet.minrange?.replacingOccurrences(of: "<", with: "") {
numericMaxValue = numericMinValueFromString
numericMinValue = "0.0"
} else {
numericMinValue = /rowDataSet.minrange
}
}
if !(/rowDataSet.maxrange?.isEmpty) {
if let numericMaxValueFromStrig = rowDataSet.maxrange?.replacingOccurrences(of: ">", with: "") {
numericMaxValue = "\(/Double(numericMaxValueFromStrig) * 2.0)"
numericMinValue = numericMaxValueFromStrig
} else {
numericMaxValue = /rowDataSet.maxrange
}
}

chartView.minOffset = 20
chartView.isUserInteractionEnabled = false
chartView.drawGridBackgroundEnabled = false
chartView.xAxis.drawGridLinesEnabled = false
chartView.chartDescription.enabled = false
chartView.dragEnabled = true
chartView.setScaleEnabled(true)
chartView.pinchZoomEnabled = true
chartView.noDataTextAlignment = .center

let leftAxis = chartView.leftAxis
leftAxis.removeAllLimitLines()
leftAxis.axisMaximum = /Double(max + 10)//Double(numericMaxValue) //Double(max + 10)
leftAxis.axisMinimum = 0 ///Double(numericMinValue)
let xAxis = chartView.xAxis
xAxis.labelPosition = .bottom
chartView.xAxis.centerAxisLabelsEnabled = true
chartView.xAxis.granularityEnabled = true

if(/rows.count > 1) {
xAxis.axisMinimum = 0
} else { xAxis.axisMinimum = 0 }

xAxis.granularity = 1
xAxis.labelRotationAngle = CGFloat(-25)
xAxis.valueFormatter = self

chartView.xAxis.valueFormatter = self
// chartView.xAxis.enabled = true
chartView.rightAxis.enabled = false
chartView.xAxis.gridColor = .clear
chartView.leftAxis.gridColor = .clear
chartView.rightAxis.gridColor = .clear
chartView.legend.enabled = false
chartView.animate(xAxisDuration: 0.0)
// chartView.animate(yAxisDuration: 1)

chartView.xAxis.drawAxisLineEnabled = true
}


func setup(_ dataSet: LineChartDataSet) {

dataSet.lineDashLengths = nil
dataSet.highlightLineDashLengths = nil
if(/rows?.count == 1){
dataSet.setColors(.black)
dataSet.setCircleColors(.black)
}
else {
dataSet.setColors(.black)
dataSet.setCircleColors(.black)
}
dataSet.gradientPositions = [0, 40, 100]
dataSet.lineWidth = (/rows?.count == 1) ? 0 : 2
dataSet.circleRadius = 4
dataSet.drawCircleHoleEnabled = false
dataSet.valueFont = .systemFont(ofSize: 9)
dataSet.formLineDashLengths = nil
dataSet.formLineWidth = 1
dataSet.formSize = 15
dataSet.valueFormatter = CustomIntFormatter1()
}
}
using the above i am getting the graph like this

## What did you expect to happen?
i want the graph like this
NOTE:- Do not go with the values inside the image
The green color area i want to show between the range the data points lie on

## What happened instead?

ℹ Please replace this with of what happened instead.

## DGCharts Environment

**DGCharts version/Branch/Commit Number:**
**Xcode version:**
**Swift version:**
**Platform(s) running DGCharts:**
**macOS version running Xcode:**

## Demo Project

ℹ Please link to or upload a project we can download that reproduces the issue.

Please provide the solution for this.

Start with the configure(), setChartViewProperties(), and setup() entry points shown in the issue, then compare their LineChartDataSet configuration with the two screenshots. Confirm the behavior using the supplied data and determine whether the chart fills the area between the relevant range and data points. Done means the rendered graph matches the requested green filled range without relying on the screenshot values.

Written by the indexing model from the issue text.