Merge pull request #131 from willdale/feature/add-number-formatter-fo…

…r-y-axis-labels Add number formatter for Y axis labels.
willdale · Nov 6, 2021 · 21f4db1 · 21f4db1
2 parents 9f2fc83 + e1fc96e
commit 21f4db1
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Showing 3 changed files with 29 additions and 5 deletions.
diff --git a/Sources/SwiftUICharts/SharedLineAndBar/Models/ChartViewData.swift b/Sources/SwiftUICharts/SharedLineAndBar/Models/ChartViewData.swift
@@ -65,6 +65,9 @@ public struct ChartViewData {
      */
     var yAxisSpecifier: String = "%.0f"
 
+    /// Optional number formatter for the y axis labels when they are `.numeric`.
+    var yAxisNumberFormatter: NumberFormatter? = nil
+
     /**
      Width of the y axis title label once
      it has been rotated.

diff --git a/Sources/SwiftUICharts/SharedLineAndBar/Models/Protocols/LineAndBarProtocolsExtentions.swift b/Sources/SwiftUICharts/SharedLineAndBar/Models/Protocols/LineAndBarProtocolsExtentions.swift
@@ -73,7 +73,10 @@ extension CTLineBarChartDataProtocol where Self: GetDataProtocol {
      They are either auto calculated numbers
      or array of strings.
      */
-    internal var labelsArray: [String] { self.generateYLabels(self.viewData.yAxisSpecifier) }
+    internal var labelsArray: [String] {
+        self.generateYLabels(self.viewData.yAxisSpecifier,
+                             numberFormatter: self.viewData.yAxisNumberFormatter)
+    }
 
     /**
      Labels to display on the Y axis
@@ -89,14 +92,29 @@ extension CTLineBarChartDataProtocol where Self: GetDataProtocol {
         - specifier: Decimal precision of the labels.
      - Returns: Array of labels.
      */
-    private func generateYLabels(_ specifier: String) -> [String] {
+    private func generateYLabels(_ specifier: String, numberFormatter: NumberFormatter?) -> [String] {
         switch self.chartStyle.yAxisLabelType {
         case .numeric:
             let dataRange: Double = self.range
             let minValue: Double = self.minValue
             let range: Double = dataRange / Double(self.chartStyle.yAxisNumberOfLabels-1)
-            let firstLabel = [String(format: specifier, minValue)]
-            let otherLabels = (1...self.chartStyle.yAxisNumberOfLabels-1).map { String(format: specifier, minValue + range * Double($0)) }
+            let firstLabel: [String] = {
+                if let formatter = numberFormatter,
+                   let formattedNumber = formatter.string(from: NSNumber(value:minValue)) {
+                    return [formattedNumber]
+                } else {
+                    return [String(format: specifier, minValue)]
+                }
+            }()
+            let otherLabels: [String] = (1...self.chartStyle.yAxisNumberOfLabels-1).map {
+                let value = minValue + range * Double($0)
+                if let formatter = numberFormatter,
+                   let formattedNumber = formatter.string(from: NSNumber(value: value)) {
+                    return formattedNumber
+                } else {
+                    return String(format: specifier, value)
+                }
+            }
             let labels = firstLabel + otherLabels
             return labels
         case .custom:

diff --git a/Sources/SwiftUICharts/SharedLineAndBar/ViewModifiers/YAxisLabels.swift b/Sources/SwiftUICharts/SharedLineAndBar/ViewModifiers/YAxisLabels.swift
@@ -19,13 +19,15 @@ internal struct YAxisLabels<T>: ViewModifier where T: CTLineBarChartDataProtocol
     internal init(
         chartData: T,
         specifier: String,
+        formatter: NumberFormatter?,
         colourIndicator: AxisColour
     ) {
         self.chartData = chartData
         self.specifier = specifier
         self.colourIndicator = colourIndicator
         chartData.viewData.hasYAxisLabels = true
         chartData.viewData.yAxisSpecifier = specifier
+        chartData.viewData.yAxisNumberFormatter = formatter
     }
 
     internal func body(content: Content) -> some View {
@@ -81,8 +83,9 @@ extension View {
     public func yAxisLabels<T: CTLineBarChartDataProtocol>(
         chartData: T,
         specifier: String = "%.0f",
+        formatter: NumberFormatter? = nil,
         colourIndicator: AxisColour = .none
     ) -> some View {
-        self.modifier(YAxisLabels(chartData: chartData, specifier: specifier, colourIndicator: colourIndicator))
+        self.modifier(YAxisLabels(chartData: chartData, specifier: specifier, formatter: formatter, colourIndicator: colourIndicator))
     }
 }