Removed optionality from valueFormatter where appropriate

Source/Charts/Charts/ChartViewBase.swift

@@ -40,8 +40,8 @@ open class ChartViewBase: NSUIView, ChartDataProvider, AnimatorDelegate
     // MARK: - Properties
 
     /// The default IValueFormatter that has been determined by the chart considering the provided minimum and maximum values.
-    internal var _defaultValueFormatter: ValueFormatter? = DefaultValueFormatter(decimals: 0)
-    
+    internal lazy var defaultValueFormatter: ValueFormatter = DefaultValueFormatter(decimals: 0)
+
     /// The data for the chart
     @objc open var data: ChartData?
         {
@@ -56,9 +56,9 @@ open class ChartViewBase: NSUIView, ChartDataProvider, AnimatorDelegate
 
             for set in data.dataSets
             {
-                if set.needsFormatter || set.valueFormatter === _defaultValueFormatter
+                if set.valueFormatter === defaultValueFormatter
                 {
-                    set.valueFormatter = _defaultValueFormatter
+                    set.valueFormatter = defaultValueFormatter
                 }
             }
 
@@ -251,12 +251,12 @@ open class ChartViewBase: NSUIView, ChartDataProvider, AnimatorDelegate
         }
 
 
-        if _defaultValueFormatter is DefaultValueFormatter
+        if defaultValueFormatter is DefaultValueFormatter
         {
             // setup the formatter with a new number of digits
             let digits = reference.decimalPlaces
 
-            (_defaultValueFormatter as? DefaultValueFormatter)?.decimals
+            (defaultValueFormatter as? DefaultValueFormatter)?.decimals
              = digits
         }
     }

Source/Charts/Components/AxisBase.swift

@@ -22,7 +22,7 @@ open class AxisBase: ComponentBase
     }
 
     /// Custom formatter that is used instead of the auto-formatter if set
-    private var _axisValueFormatter: AxisValueFormatter?
+    private lazy var _axisValueFormatter: AxisValueFormatter = DefaultAxisValueFormatter(decimals: decimals)
 
     @objc open var labelFont = NSUIFont.systemFont(ofSize: 10.0)
     @objc open var labelTextColor = NSUIColor.black
@@ -161,10 +161,9 @@ open class AxisBase: ComponentBase
     {
         get
         {
-            if _axisValueFormatter == nil ||
-                (_axisValueFormatter is DefaultAxisValueFormatter &&
-                    (_axisValueFormatter as! DefaultAxisValueFormatter).hasAutoDecimals &&
-                    (_axisValueFormatter as! DefaultAxisValueFormatter).decimals != decimals)
+            if _axisValueFormatter is DefaultAxisValueFormatter,
+                (_axisValueFormatter as! DefaultAxisValueFormatter).hasAutoDecimals,
+                (_axisValueFormatter as! DefaultAxisValueFormatter).decimals != decimals
             {
                 _axisValueFormatter = DefaultAxisValueFormatter(decimals: decimals)
             }

Source/Charts/Data/Implementations/ChartBaseDataSet.swift

@@ -268,35 +268,10 @@ open class ChartBaseDataSet: NSObject, ChartDataSetProtocol
 
     /// - returns: `true` if value highlighting is enabled for this dataset
     open var isHighlightEnabled: Bool { return highlightEnabled }
-
-    /// Custom formatter that is used instead of the auto-formatter if set
-    internal var _valueFormatter: ValueFormatter?
-
+
     /// Custom formatter that is used instead of the auto-formatter if set
-    open var valueFormatter: ValueFormatter?
-    {
-        get
-        {
-            if needsFormatter
-            {
-                return ChartUtils.defaultValueFormatter()
-            }
-
-            return _valueFormatter
-        }
-        set
-        {
-            if newValue == nil { return }
-
-            _valueFormatter = newValue
-        }
-    }
-
-    open var needsFormatter: Bool
-    {
-        return _valueFormatter == nil
-    }
-
+    open lazy var valueFormatter: ValueFormatter = ChartUtils.defaultValueFormatter()
+
     /// Sets/get a single color for value text.
     /// Setting the color clears the colors array and adds a single color.
     /// Getting will return the first color in the array.

Source/Charts/Data/Interfaces/ChartDataSetProtocol.swift

@@ -187,10 +187,7 @@ public protocol ChartDataSetProtocol
     var isHighlightEnabled: Bool { get }
 
     /// Custom formatter that is used instead of the auto-formatter if set
-    var valueFormatter: ValueFormatter? { get set }
-
-    /// - returns: `true` if the valueFormatter object of this DataSet is null.
-    var needsFormatter: Bool { get }
+    var valueFormatter: ValueFormatter { get set }
 
     /// Sets/get a single color for value text.
     /// Setting the color clears the colors array and adds a single color.

Source/Charts/Renderers/BarChartRenderer.swift

@@ -333,7 +333,7 @@ open class BarChartRenderer: BarLineScatterCandleBubbleRenderer
 
                 let buffer = _buffers[dataSetIndex]
 
-                guard let formatter = dataSet.valueFormatter else { continue }
+                let formatter = dataSet.valueFormatter
 
                 let trans = dataProvider.getTransformer(forAxis: dataSet.axisDependency)
 

Source/Charts/Renderers/BubbleChartRenderer.swift

@@ -137,11 +137,9 @@ open class BubbleChartRenderer: BarLineScatterCandleBubbleRenderer
         {
             let dataSet = dataSets[i]
 
-            guard
-                shouldDrawValues(forDataSet: dataSet),
-                let formatter = dataSet.valueFormatter
-                else { continue }
+            guard shouldDrawValues(forDataSet: dataSet) else { continue }
 
+            let formatter = dataSet.valueFormatter
             let alpha = phaseX == 1 ? phaseY : phaseX
 
             _xBounds.set(chart: dataProvider, dataSet: dataSet, animator: animator)

Source/Charts/Renderers/CandleStickChartRenderer.swift

@@ -260,7 +260,7 @@ open class CandleStickChartRenderer: LineScatterCandleRadarRenderer
 
                 let valueFont = dataSet.valueFont
 
-                guard let formatter = dataSet.valueFormatter else { continue }
+                let formatter = dataSet.valueFormatter
 
                 let trans = dataProvider.getTransformer(forAxis: dataSet.axisDependency)
                 let valueToPixelMatrix = trans.valueToPixelMatrix

Source/Charts/Renderers/HorizontalBarChartRenderer.swift

@@ -328,7 +328,7 @@ open class HorizontalBarChartRenderer: BarChartRenderer
                 let valueFont = dataSet.valueFont
                 let yOffset = -valueFont.lineHeight / 2.0
 
-                guard let formatter = dataSet.valueFormatter else { continue }
+                let formatter = dataSet.valueFormatter
 
                 let trans = dataProvider.getTransformer(forAxis: dataSet.axisDependency)
 

Source/Charts/Renderers/LineChartRenderer.swift

@@ -521,7 +521,7 @@ open class LineChartRenderer: LineRadarRenderer
 
                 let valueFont = dataSet.valueFont
 
-                guard let formatter = dataSet.valueFormatter else { continue }
+                let formatter = dataSet.valueFormatter
 
                 let trans = dataProvider.getTransformer(forAxis: dataSet.axisDependency)
                 let valueToPixelMatrix = trans.valueToPixelMatrix

Source/Charts/Renderers/PieChartRenderer.swift

@@ -321,7 +321,7 @@ open class PieChartRenderer: NSObject, DataRenderer
             let entryLabelFont = dataSet.entryLabelFont
             let lineHeight = valueFont.lineHeight
 
-            guard let formatter = dataSet.valueFormatter else { continue }
+            let formatter = dataSet.valueFormatter
 
             for j in 0 ..< dataSet.entryCount
             {

Source/Charts/Renderers/RadarChartRenderer.swift

@@ -173,7 +173,7 @@ open class RadarChartRenderer: LineRadarRenderer
 
                 let valueFont = dataSet.valueFont
 
-                guard let formatter = dataSet.valueFormatter else { continue }
+                let formatter = dataSet.valueFormatter
 
                 if dataSet.isDrawValuesEnabled
                 {

Source/Charts/Renderers/ScatterChartRenderer.swift

@@ -125,7 +125,7 @@ open class ScatterChartRenderer: LineScatterCandleRadarRenderer
 
                 let valueFont = dataSet.valueFont
 
-                guard let formatter = dataSet.valueFormatter else { continue }
+                let formatter = dataSet.valueFormatter
 
                 let trans = dataProvider.getTransformer(forAxis: dataSet.axisDependency)
                 let valueToPixelMatrix = trans.valueToPixelMatrix