Add PieChart + multicolor (#98)

* Add ColorGradient example
Add ColorGradient single color constructor
Add preview for BarChart

* Add PieChart
Allow multi color for Pie and Bar
Add linter

.swiftlint.yml

@@ -0,0 +1,64 @@
+disabled_rules:
+- explicit_acl
+- trailing_whitespace
+- force_cast
+- unused_closure_parameter
+- multiple_closures_with_trailing_closure
+opt_in_rules:
+- anyobject_protocol
+- array_init
+- attributes
+- collection_alignment
+- colon
+- conditional_returns_on_newline
+- convenience_type
+- empty_count
+- empty_string
+- empty_collection_literal
+- enum_case_associated_values_count
+- function_default_parameter_at_end
+- fatal_error_message
+- file_name
+- first_where
+- modifier_order
+- toggle_bool
+- unused_private_declaration
+- yoda_condition
+excluded:
+- Carthage
+- Pods
+- SwiftLint/Common/3rdPartyLib
+identifier_name:
+  excluded:
+    - a
+    - b
+    - c
+    - i
+    - id
+    - t
+    - to
+    - x
+    - y
+line_length:
+    warning: 150
+    error: 200
+    ignores_function_declarations: true
+    ignores_comments: true
+    ignores_urls: true
+function_body_length:
+    warning: 300
+    error: 500
+function_parameter_count:
+    warning: 6
+    error: 8
+type_body_length:
+    warning: 300
+    error: 400
+file_length:
+    warning: 500
+    error: 1200
+    ignore_comment_only_lines: true
+cyclomatic_complexity:
+    warning: 15
+    error: 21
+reporter: "xcode"

Package.swift

@@ -6,13 +6,13 @@ import PackageDescription
 let package = Package(
     name: "SwiftUICharts",
     platforms: [
-        .iOS(.v13),.watchOS(.v6)
+        .iOS(.v13), .watchOS(.v6)
     ],
     products: [
         // Products define the executables and libraries produced by a package, and make them visible to other packages.
         .library(
             name: "SwiftUICharts",
-            targets: ["SwiftUICharts"]),
+            targets: ["SwiftUICharts"])
     ],
     dependencies: [
         // Dependencies declare other packages that this package depends on.
@@ -26,6 +26,6 @@ let package = Package(
             dependencies: []),
         .testTarget(
             name: "SwiftUIChartsTests",
-            dependencies: ["SwiftUICharts"]),
+            dependencies: ["SwiftUICharts"])
     ]
 )

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

@@ -0,0 +1,16 @@
+//
+//  CGRect+Extension.swift
+//  SwiftUICharts
+//
+//  Created by Nicolas Savoini on 2020-05-24.
+//
+
+import Foundation
+import SwiftUI
+
+extension CGRect {
+    // Return the coordinate for a rectangle center
+    public var mid: CGPoint {
+        return CGPoint(x: self.midX, y: self.midY)
+    }
+}

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

@@ -5,17 +5,17 @@ extension Color {
         let hex = hexString.trimmingCharacters(in: CharacterSet.alphanumerics.inverted)
         var int = UInt64()
         Scanner(string: hex).scanHexInt64(&int)
-        let r, g, b: UInt64
+        let red, green, blue: UInt64
         switch hex.count {
         case 3: // RGB (12-bit)
-            (r, g, b) = ((int >> 8) * 17, (int >> 4 & 0xF) * 17, (int & 0xF) * 17)
+            (red, green, blue) = ((int >> 8) * 17, (int >> 4 & 0xF) * 17, (int & 0xF) * 17)
         case 6: // RGB (24-bit)
-            (r, g, b) = (int >> 16, int >> 8 & 0xFF, int & 0xFF)
+            (red, green, blue) = (int >> 16, int >> 8 & 0xFF, int & 0xFF)
         case 8: // ARGB (32-bit)
-            (r, g, b) = (int >> 16 & 0xFF, int >> 8 & 0xFF, int & 0xFF)
+            (red, green, blue) = (int >> 16 & 0xFF, int >> 8 & 0xFF, int & 0xFF)
         default:
-            (r, g, b) = (0, 0, 0)
+            (red, green, blue) = (0, 0, 0)
         }
-        self.init(red: Double(r) / 255, green: Double(g) / 255, blue: Double(b) / 255)
+        self.init(red: Double(red) / 255, green: Double(green) / 255, blue: Double(blue) / 255)
     }
 }

Sources/SwiftUICharts/Base/Style/ChartStyle.swift

@@ -1,11 +1,28 @@
 import SwiftUI
 
 public struct ChartStyle {
-    public let backgroundColor: Color
-    public let foregroundColor: ColorGradient
 
+    public let backgroundColor: ColorGradient
+    public let foregroundColor: [ColorGradient]
+
+    public init(backgroundColor: Color, foregroundColor: [ColorGradient]) {
+        self.backgroundColor = ColorGradient.init(backgroundColor)
+        self.foregroundColor = foregroundColor
+    }
+
     public init(backgroundColor: Color, foregroundColor: ColorGradient) {
+        self.backgroundColor = ColorGradient.init(backgroundColor)
+        self.foregroundColor = [foregroundColor]
+    }
+
+    public init(backgroundColor: ColorGradient, foregroundColor: ColorGradient) {
+        self.backgroundColor = backgroundColor
+        self.foregroundColor = [foregroundColor]
+    }
+
+    public init(backgroundColor: ColorGradient, foregroundColor: [ColorGradient]) {
         self.backgroundColor = backgroundColor
         self.foregroundColor = foregroundColor
     }
+
 }

Sources/SwiftUICharts/Base/Style/ColorGradient.swift

@@ -4,6 +4,11 @@ public struct ColorGradient {
     public let startColor: Color
     public let endColor: Color
 
+    public init(_ color: Color) {
+        self.startColor = color
+        self.endColor = color
+    }
+
     public init (_ startColor: Color, _ endColor: Color) {
         self.startColor = startColor
         self.endColor = endColor
@@ -13,3 +18,21 @@ public struct ColorGradient {
         return Gradient(colors: [startColor, endColor])
     }
 }
+
+extension ColorGradient {
+    /// Convenience method to return a LinearGradient from the ColorGradient
+    /// - Parameters:
+    ///   - startPoint: starting point
+    ///   - endPoint: ending point
+    /// - Returns: a Linear gradient
+    public func linearGradient(from startPoint: UnitPoint, to endPoint: UnitPoint) -> LinearGradient {
+        return LinearGradient(gradient: self.gradient, startPoint: startPoint, endPoint: endPoint)
+    }
+}
+
+extension ColorGradient {
+    public static let orangeBright = ColorGradient(ChartColors.orangeBright)
+    public static let redBlack = ColorGradient(.red, .black)
+    public static let greenRed = ColorGradient(.green, .red)
+    public static let whiteBlack = ColorGradient(.white, .black)
+}

Sources/SwiftUICharts/Charts/BarChart/BarChart.swift

@@ -2,8 +2,26 @@ import SwiftUI
 
 public struct BarChart: ChartType {
     public func makeChart(configuration: Self.Configuration, style: Self.Style) -> some View {
-        BarChartRow(data: configuration.data, gradientColor: style.foregroundColor)
+        BarChartRow(data: configuration.data, style: style)
     }
-
     public init() {}
 }
+
+struct BarChart_Previews: PreviewProvider {
+    static var previews: some View {
+        Group {
+            Group {
+                BarChart().makeChart(
+                    configuration: .init(data: [1, 2, 3, 5, 1]),
+                    style: .init(backgroundColor: .white, foregroundColor: ColorGradient.redBlack))
+            }.environment(\.colorScheme, .light)
+
+            Group {
+                BarChart().makeChart(
+                configuration: .init(data: [1, 2, 3]),
+                style: .init(backgroundColor: .white, foregroundColor: ColorGradient.redBlack))
+            }.environment(\.colorScheme, .dark)
+
+        }
+    }
+}

Sources/SwiftUICharts/Charts/BarChart/BarChartCell.swift

@@ -1,6 +1,6 @@
 import SwiftUI
 
-public struct BarChartCell : View {
+public struct BarChartCell: View {
     @State var value: Double
     @State var index: Int = 0
     @State var width: Float
@@ -13,16 +13,36 @@ public struct BarChartCell : View {
 
     @State var scaleValue: Double = 0
     @Binding var touchLocation: CGFloat
+
     public var body: some View {
         ZStack {
             RoundedRectangle(cornerRadius: 4)
-                .fill(LinearGradient(gradient: gradientColor.gradient, startPoint: .bottom, endPoint: .top))
+                .fill(gradientColor.linearGradient(from: .bottom, to: .top))
             }
             .frame(width: CGFloat(self.cellWidth))
             .scaleEffect(CGSize(width: 1, height: self.scaleValue), anchor: .bottom)
-            .onAppear(){
+            .onAppear {
                 self.scaleValue = self.value
             }
         .animation(Animation.spring().delay(self.touchLocation < 0 ?  Double(self.index) * 0.04 : 0))
     }
 }
+
+struct BarChartCell_Previews: PreviewProvider {
+    static var previews: some View {
+        Group {
+            Group {
+                BarChartCell(value: 1, width: 50, numberOfDataPoints: 1, gradientColor: ColorGradient.greenRed, touchLocation: .constant(CGFloat()))
+                BarChartCell(value: 1, width: 50, numberOfDataPoints: 1, gradientColor: ColorGradient.whiteBlack, touchLocation: .constant(CGFloat()))
+                BarChartCell(value: 1, width: 50, numberOfDataPoints: 1, gradientColor: ColorGradient(.purple), touchLocation: .constant(CGFloat()))
+            }
+
+            Group {
+                BarChartCell(value: 1, width: 50, numberOfDataPoints: 1, gradientColor: ColorGradient.greenRed, touchLocation: .constant(CGFloat()))
+                BarChartCell(value: 1, width: 50, numberOfDataPoints: 1, gradientColor: ColorGradient.whiteBlack, touchLocation: .constant(CGFloat()))
+                BarChartCell(value: 1, width: 50, numberOfDataPoints: 1, gradientColor: ColorGradient(.purple), touchLocation: .constant(CGFloat()))
+            }.environment(\.colorScheme, .dark)
+        }
+
+    }
+}

Sources/SwiftUICharts/Charts/BarChart/BarChartRow.swift

@@ -1,14 +1,15 @@
 import SwiftUI
 
-public struct BarChartRow : View {
+public struct BarChartRow: View {
     @State var data: [Double] = []
     @State var touchLocation: CGFloat = -1.0
 
     enum Constant {
         static let spacing: CGFloat = 16.0
     }
 
-    var gradientColor: ColorGradient
+    var style: ChartStyle
+
     var maxValue: Double {
         data.max() ?? 0
     }
@@ -17,14 +18,14 @@ public struct BarChartRow : View {
         GeometryReader { geometry in
             HStack(alignment: .bottom,
                    spacing: (geometry.frame(in: .local).width - Constant.spacing) / CGFloat(self.data.count * 3)) {
-                ForEach(0..<self.data.count, id: \.self) { i in
-                    BarChartCell(value: self.normalizedValue(index: i),
-                                 index: i,
+                ForEach(0..<self.data.count, id: \.self) { index in
+                    BarChartCell(value: self.normalizedValue(index: index),
+                                 index: index,
                                  width: Float(geometry.frame(in: .local).width - Constant.spacing),
                                  numberOfDataPoints: self.data.count,
-                                 gradientColor: self.gradientColor,
+                                 gradientColor: self.style.foregroundColor.rotate(for: index),
                                  touchLocation: self.$touchLocation)
-                        .scaleEffect(self.getScaleSize(touchLocation: self.touchLocation, index: i), anchor: .bottom)
+                        .scaleEffect(self.getScaleSize(touchLocation: self.touchLocation, index: index), anchor: .bottom)
                         .animation(.spring())
 
                 }
@@ -52,4 +53,26 @@ public struct BarChartRow : View {
         }
         return CGSize(width: 1, height: 1)
     }
+
 }
+
+struct BarChartRow_Previews: PreviewProvider {
+    static var previews: some View {
+        Group {
+            Group {
+                BarChartRow(data: [1, 2, 3], style: styleGreenRed)
+                BarChartRow(data: [1, 2, 3], style: styleGreenRedWhiteBlack)
+            }
+            Group {
+                BarChartRow(data: [1, 2, 3], style: styleGreenRed)
+                BarChartRow(data: [1, 2, 3], style: styleGreenRedWhiteBlack)
+            }.environment(\.colorScheme, .dark)
+        }
+    }
+}
+
+private let styleGreenRed = ChartStyle(backgroundColor: .white, foregroundColor: .greenRed)
+
+private let styleGreenRedWhiteBlack = ChartStyle(
+    backgroundColor: ColorGradient.init(.white),
+    foregroundColor: [ColorGradient.redBlack, ColorGradient.whiteBlack])

Sources/SwiftUICharts/Charts/LineChart/Line.swift

@@ -3,7 +3,7 @@ import SwiftUI
 public struct Line: View {
     @State var frame: CGRect = .zero
     @State var data: [Double]
-    var gradientColor: ColorGradient
+    var style: ChartStyle
 
     @State var showIndicator: Bool = false
     @State var touchLocation: CGPoint = .zero
@@ -79,7 +79,7 @@ extension Line {
 
     private func getBackgroundPathView() -> some View {
         self.closedPath
-            .fill(LinearGradient(gradient: gradientColor.gradient, startPoint: .bottom, endPoint: .top))
+            .fill(style.backgroundColor.linearGradient(from: .bottom, to: .top))
             .rotationEffect(.degrees(180), anchor: .center)
             .rotation3DEffect(.degrees(180), axis: (x: 0, y: 1, z: 0))
             .transition(.opacity)
@@ -89,7 +89,7 @@ extension Line {
     private func getLinePathView() -> some View {
         self.path
             .trim(from: 0, to: self.showFull ? 1:0)
-            .stroke(LinearGradient(gradient: gradientColor.gradient,
+            .stroke(LinearGradient(gradient: style.foregroundColor.first?.gradient ?? ColorGradient.orangeBright.gradient,
                                    startPoint: .leading,
                                    endPoint: .trailing),
                     style: StrokeStyle(lineWidth: 3, lineJoin: .round))
@@ -105,3 +105,15 @@ extension Line {
             .drawingGroup()
     }
 }
+
+struct Line_Previews: PreviewProvider {
+    static var previews: some View {
+        Group {
+            Line(data: [1, 2, 3, 1, 2, 5, 7], style: blackLineStyle)
+            Line(data: [1, 2, 3, 1, 2, 5, 7], style: redLineStyle)
+        }
+    }
+}
+
+private let blackLineStyle = ChartStyle(backgroundColor: ColorGradient(.white), foregroundColor: ColorGradient(.black))
+private let redLineStyle = ChartStyle(backgroundColor: .whiteBlack, foregroundColor: ColorGradient(.red))