Restore rotating index for multicolor (#102)

Sources/SwiftUICharts/Base/Extensions/Array+Extension.swift

@@ -0,0 +1,22 @@
+//
+//  File.swift
+//  
+//
+//  Created by Nicolas Savoini on 2020-05-25.
+//
+
+import Foundation
+
+extension Array where Element == ColorGradient {
+    func rotate(for index: Int) -> ColorGradient {
+        if self.isEmpty {
+            return ColorGradient.orangeBright
+        }
+        
+        if self.count <= index {
+            return self[index % self.count]
+        }
+        
+        return self[index]
+    }
+}

Sources/SwiftUICharts/Base/Style/ColorGradient.swift

@@ -1,6 +1,6 @@
 import SwiftUI
 
-public struct ColorGradient {
+public struct ColorGradient: Equatable {
     public let startColor: Color
     public let endColor: Color
 

Sources/SwiftUICharts/Charts/BarChart/BarChartRow.swift

@@ -23,7 +23,7 @@ public struct BarChartRow: View {
                                  index: index,
                                  width: Float(geometry.frame(in: .local).width - Constant.spacing),
                                  numberOfDataPoints: self.data.count,
-                                 gradientColor: self.style.foregroundColor.first!,
+                                 gradientColor: self.style.foregroundColor.rotate(for: index),
                                  touchLocation: self.$touchLocation)
                         .scaleEffect(self.getScaleSize(touchLocation: self.touchLocation, index: index), anchor: .bottom)
                         .animation(.spring())

Sources/SwiftUICharts/PieChart/PieChartRow.swift

@@ -38,7 +38,7 @@ public struct PieChartRow: View {
                             endDeg: self.slices[index].endDeg,
                             index: index,
                             backgroundColor: self.style.backgroundColor.startColor,
-                            accentColor: self.style.foregroundColor.first!
+                            accentColor: self.style.foregroundColor.rotate(for: index)
                         )
                 }
                 
@@ -56,6 +56,12 @@ struct PieChartRow_Previews: PreviewProvider {
                 data: [8, 23, 32, 7, 23, 43],
                 style: defaultMultiColorChartStyle)
                 .frame(width: 100, height: 100)
+            
+            PieChartRow(
+                data: [8, 23, 32, 7, 23, 43],
+                style: multiColorChartStyle)
+            .   frame(width: 100, height: 100)
+            
         }.previewLayout(.fixed(width: 125, height: 125))
         
     }
@@ -64,3 +70,7 @@ struct PieChartRow_Previews: PreviewProvider {
 private let defaultMultiColorChartStyle = ChartStyle(
     backgroundColor: Color.white,
     foregroundColor: [ColorGradient]())
+
+private let multiColorChartStyle = ChartStyle(
+backgroundColor: Color.purple,
+foregroundColor: [ColorGradient.greenRed, ColorGradient.whiteBlack])

Tests/SwiftUIChartsTests/ArrayExtensionTests.swift

@@ -0,0 +1,45 @@
+//
+//  File.swift
+//  
+//
+//  Created by Nicolas Savoini on 2020-05-25.
+//
+
+@testable import SwiftUICharts
+import XCTest
+
+class ArrayExtensionTests: XCTestCase {
+
+    func testArrayRotatingIndexEmpty() {
+        let colors = [ColorGradient]()
+        XCTAssertEqual(colors.rotate(for: 0), ColorGradient.orangeBright)
+    }
+    
+    func testArrayRotatingIndexOneValue() {
+        let colors = [ColorGradient.greenRed]
+        
+        XCTAssertEqual(colors.rotate(for: 0), ColorGradient.greenRed)
+        XCTAssertEqual(colors.rotate(for: 1), ColorGradient.greenRed)
+        XCTAssertEqual(colors.rotate(for: 2), ColorGradient.greenRed)
+    }
+    
+    func testArrayRotatingIndexLessValues() {
+        let colors = [ColorGradient.greenRed, ColorGradient.whiteBlack]
+        
+        XCTAssertEqual(colors.rotate(for: 0), ColorGradient.greenRed)
+        XCTAssertEqual(colors.rotate(for: 1), ColorGradient.whiteBlack)
+        XCTAssertEqual(colors.rotate(for: 2), ColorGradient.greenRed)
+        XCTAssertEqual(colors.rotate(for: 3), ColorGradient.whiteBlack)
+        XCTAssertEqual(colors.rotate(for: 4), ColorGradient.greenRed)
+    }
+    
+    func testArrayRotatingIndexMoreValues() {
+        let colors = [ColorGradient.greenRed, ColorGradient.whiteBlack, ColorGradient.orangeBright]
+        
+        XCTAssertEqual(colors.rotate(for: 0), ColorGradient.greenRed)
+        XCTAssertEqual(colors.rotate(for: 1), ColorGradient.whiteBlack)
+
+    }
+  
+}
+