fix: remove UIColors which caused CI build errors

* feat: add linechart interaction point

* feat: add ability to show current data point on linechart

.swiftpm/xcode/xcuserdata/samuandras.xcuserdatad/xcschemes/xcschememanagement.plist

@@ -0,0 +1,14 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<!DOCTYPE plist PUBLIC "-//Apple//DTD PLIST 1.0//EN" "http://www.apple.com/DTDs/PropertyList-1.0.dtd">
+<plist version="1.0">
+<dict>
+	<key>SchemeUserState</key>
+	<dict>
+		<key>SwiftUICharts.xcscheme_^#shared#^_</key>
+		<dict>
+			<key>orderHint</key>
+			<integer>2</integer>
+		</dict>
+	</dict>
+</dict>
+</plist>

.swiftpm/xcode/xcuserdata/samuandris.xcuserdatad/xcdebugger/Breakpoints_v2.xcbkptlist

@@ -0,0 +1,6 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<Bucket
+   uuid = "91E23D30-CB6C-44DA-BEFC-9D39A1DA2242"
+   type = "1"
+   version = "2.0">
+</Bucket>

.swiftpm/xcode/xcuserdata/samuandris.xcuserdatad/xcschemes/xcschememanagement.plist

@@ -7,7 +7,20 @@
 		<key>SwiftUICharts.xcscheme_^#shared#^_</key>
 		<dict>
 			<key>orderHint</key>
-			<integer>2</integer>
+			<integer>0</integer>
+		</dict>
+	</dict>
+	<key>SuppressBuildableAutocreation</key>
+	<dict>
+		<key>SwiftUICharts</key>
+		<dict>
+			<key>primary</key>
+			<true/>
+		</dict>
+		<key>SwiftUIChartsTests</key>
+		<dict>
+			<key>primary</key>
+			<true/>
 		</dict>
 	</dict>
 </dict>

Sources/SwiftUICharts/Base/CardView/CardView.swift

@@ -26,9 +26,9 @@ public struct CardView<Content: View>: View, ChartBase {
             if showShadow {
                 RoundedRectangle(cornerRadius: 20)
                     .fill(Color.white)
-                    .shadow(color: Color.gray, radius: 8)
+                    .shadow(color: Color(white: 0.9, opacity: 1), radius: 8)
             }
-            VStack {
+            VStack (alignment: .leading) {
                 self.content()
             }
             .clipShape(RoundedRectangle(cornerRadius: showShadow ? 20 : 0))

Sources/SwiftUICharts/Base/Chart/ChartData.swift

@@ -2,11 +2,36 @@ import SwiftUI
 
 /// An observable wrapper for an array of data for use in any chart
 public class ChartData: ObservableObject {
-    @Published public var data: [Double] = []
+    @Published public var data: [(String, Double)] = []
 
-	/// Initialize with data array
-	/// - Parameter data: Array of `Double`
+    var points: [Double] {
+        data.map { $0.1 }
+    }
+
+    var values: [String] {
+        data.map { $0.0 }
+    }
+
+    var normalisedPoints: [Double] {
+        let absolutePoints = points.map { abs($0) }
+        return points.map { $0 / (absolutePoints.max() ?? 1.0) }
+    }
+
+    var normalisedRange: Double {
+        (normalisedPoints.max() ?? 0.0) - (normalisedPoints.min() ?? 0.0)
+    }
+
+    var isInNegativeDomain: Bool {
+        (points.min() ?? 0.0) < 0
+    }
+
+    /// Initialize with data array
+    /// - Parameter data: Array of `Double`
     public init(_ data: [Double]) {
+        self.data = data.map { ("", $0) }
+    }
+
+    public init(_ data: [(String, Double)]) {
         self.data = data
     }
 

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

@@ -8,7 +8,7 @@ extension CGPoint {
 	///   - data: array of `Double`
 	/// - Returns: X and Y delta as a `CGPoint`
     static func getStep(frame: CGRect, data: [Double]) -> CGPoint {
-        let padding: CGFloat = 30.0
+        let padding: CGFloat = 0
 
         // stepWidth
         var stepWidth: CGFloat = 0.0
@@ -38,4 +38,10 @@ extension CGPoint {
 
         return CGPoint(x: stepWidth, y: stepHeight)
     }
+    
+    func denormalize(with geometry: GeometryProxy) -> CGPoint {
+        let width = geometry.frame(in: .local).width
+        let height = geometry.frame(in: .local).height
+        return CGPoint(x: self.x * width, y: self.y * height)
+    }
 }

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

@@ -6,6 +6,13 @@ extension View where Self: ChartBase {
 	/// - Parameter data: array of `Double`
 	/// - Returns: modified `View` with data attached
     public func data(_ data: [Double]) -> some View {
+        chartData.data = data.map { ("", $0) }
+        return self
+            .environmentObject(chartData)
+            .environmentObject(ChartValue())
+    }
+
+    public func data(_ data: [(String, Double)]) -> some View {
         chartData.data = data
         return self
             .environmentObject(chartData)

Sources/SwiftUICharts/Base/Grid/ChartGrid.swift

@@ -1,25 +1,52 @@
 import SwiftUI
 
-/// <#Description#>
 public struct ChartGrid<Content: View>: View, ChartBase {
     public var chartData = ChartData()
     let content: () -> Content
+    let numberOfHorizontalLines = 4
 
     @EnvironmentObject var data: ChartData
     @EnvironmentObject var style: ChartStyle
 
-	/// <#Description#>
-	/// - Parameter content: <#content description#>
     public init(@ViewBuilder content: @escaping () -> Content) {
         self.content = content
     }
 
-	/// The content and behavior of the `ChartGrid`.
-	///
-	/// TODO: Explain why this is in a `ZStack`
     public var body: some View {
-        ZStack{
-            self.content()
+        HStack {
+            ZStack {
+                VStack {
+                    ForEach(0..<numberOfHorizontalLines) { _ in 
+                        GridElement()
+                        Spacer()
+                    }
+                }
+                self.content()
+            }
+        }
+    }
+}
+
+struct GridElement: View {
+    var body: some View {
+        DashedLine()
+            .frame(maxHeight: 2, alignment: .center)
+    }
+}
+
+struct DashedLine: View {
+    func line(frame: CGRect) -> Path {
+        let baseLine: CGFloat = CGFloat(frame.height / 2)
+        var hLine = Path()
+        hLine.move(to: CGPoint(x:0, y: baseLine))
+        hLine.addLine(to: CGPoint(x: frame.width, y: baseLine))
+        return hLine
+    }
+
+    var body: some View {
+        GeometryReader { geometry in
+            line(frame: geometry.frame(in: .local))
+                .stroke(Color(white: 0.85), style: StrokeStyle(lineWidth: 1, lineCap: .round, dash: [5, 10]))
         }
     }
 }

Sources/SwiftUICharts/Base/Label/ChartLabel.swift

@@ -12,7 +12,8 @@ public enum ChartLabelType {
 /// A chart may contain any number of labels in pre-set positions based on their `ChartLabelType`
 public struct ChartLabel: View {
     @EnvironmentObject var chartValue: ChartValue
-    @State private var textToDisplay:String = ""
+    @State var textToDisplay:String = ""
+    var format: String = "%.01f"
 
     private var title: String
 
@@ -38,13 +39,13 @@ public struct ChartLabel: View {
     private var labelPadding: EdgeInsets {
         switch labelType {
         case .title:
-            return EdgeInsets(top: 16.0, leading: 8.0, bottom: 0.0, trailing: 8.0)
+            return EdgeInsets(top: 16.0, leading: 0, bottom: 0.0, trailing: 8.0)
         case .legend:
-            return EdgeInsets(top: 4.0, leading: 8.0, bottom: 0.0, trailing: 8.0)
+            return EdgeInsets(top: 4.0, leading: 0, bottom: 0.0, trailing: 8.0)
         case .subTitle:
-            return EdgeInsets(top: 8.0, leading: 8.0, bottom: 0.0, trailing: 8.0)
+            return EdgeInsets(top: 8.0, leading: 0, bottom: 0.0, trailing: 8.0)
         case .largeTitle:
-            return EdgeInsets(top: 24.0, leading: 8.0, bottom: 0.0, trailing: 8.0)
+            return EdgeInsets(top: 24.0, leading: 0, bottom: 0.0, trailing: 8.0)
         case .custom(_, let padding, _):
             return padding
         }
@@ -58,13 +59,13 @@ public struct ChartLabel: View {
     private var labelColor: Color {
         switch labelType {
         case .title:
-            return Color(UIColor.label)
+            return Color.primary
         case .legend:
-            return Color(UIColor.secondaryLabel)
+            return Color.secondary
         case .subTitle:
-            return Color(UIColor.label)
+            return Color.primary
         case .largeTitle:
-            return Color(UIColor.label)
+            return Color.primary
         case .custom(_, _, let color):
             return color
         }
@@ -74,10 +75,12 @@ public struct ChartLabel: View {
 	/// - Parameters:
 	///   - title: Any `String`
 	///   - type: Which `ChartLabelType` to use
-    public init(_ title: String,
-                 type: ChartLabelType = .title) {
+    public init (_ title: String,
+                 type: ChartLabelType = .title,
+                 format: String = "%.01f") {
         self.title = title
         labelType = type
+        self.format = format
     }
 
 	/// The content and behavior of the `ChartLabel`.
@@ -94,7 +97,7 @@ public struct ChartLabel: View {
                     self.textToDisplay = self.title
                 }
                 .onReceive(self.chartValue.objectWillChange) { _ in
-                    self.textToDisplay = self.chartValue.interactionInProgress ? String(format: "%.01f", self.chartValue.currentValue) : self.title
+                    self.textToDisplay = self.chartValue.interactionInProgress ? String(format: format, self.chartValue.currentValue) : self.title
                 }
             if !self.chartValue.interactionInProgress {
                 Spacer()

Sources/SwiftUICharts/Charts/BarChart/BarChartCell.swift

@@ -4,27 +4,17 @@ import SwiftUI
 public struct BarChartCell: View {
     var value: Double
     var index: Int = 0
-    var width: Float
-    var numberOfDataPoints: Int
     var gradientColor: ColorGradient
     var touchLocation: CGFloat
 
-    var cellWidth: Double {
-        return Double(width)/(Double(numberOfDataPoints) * 1.5)
-    }
-
-    @State private var firstDisplay: Bool = true
+    @State private var didCellAppear: Bool = false
 
     public init( value: Double,
                  index: Int = 0,
-                 width: Float,
-                 numberOfDataPoints: Int,
                  gradientColor: ColorGradient,
                  touchLocation: CGFloat) {
         self.value = value
         self.index = index
-        self.width = width
-        self.numberOfDataPoints = numberOfDataPoints
         self.gradientColor = gradientColor
         self.touchLocation = touchLocation
     }
@@ -33,20 +23,15 @@ public struct BarChartCell: View {
 	///
 	/// Animated when first displayed, using the `firstDisplay` variable, with an increasing delay through the data set.
     public var body: some View {
-        ZStack {
-            RoundedRectangle(cornerRadius: 4)
-                .fill(gradientColor.linearGradient(from: .bottom, to: .top))
-        }
-        .frame(width: CGFloat(self.cellWidth))
-        .scaleEffect(CGSize(width: 1, height: self.firstDisplay ? 0.0 : self.value), anchor: .bottom)
-        .onAppear {
-            self.firstDisplay = false
+        BarChartCellShape(value: didCellAppear ? value : 0.0)
+        .fill(gradientColor.linearGradient(from: .bottom, to: .top))        .onAppear {
+            self.didCellAppear = true
         }
         .onDisappear {
-            self.firstDisplay = true
+            self.didCellAppear = false
         }
         .transition(.slide)
-        .animation(Animation.spring().delay(self.touchLocation < 0 || !firstDisplay ? Double(self.index) * 0.04 : 0))
+        .animation(Animation.spring().delay(self.touchLocation < 0 || !didCellAppear ? Double(self.index) * 0.04 : 0))
     }
 }
 
@@ -54,17 +39,17 @@ struct BarChartCell_Previews: PreviewProvider {
     static var previews: some View {
         Group {
             Group {
-                BarChartCell(value: 0, width: 50, numberOfDataPoints: 1, gradientColor: ColorGradient.greenRed, touchLocation: CGFloat())
+                BarChartCell(value: 0, gradientColor: ColorGradient.greenRed, touchLocation: CGFloat())
 
-                BarChartCell(value: 1, width: 50, numberOfDataPoints: 1, gradientColor: ColorGradient.greenRed, touchLocation: CGFloat())
-                BarChartCell(value: 1, width: 50, numberOfDataPoints: 1, gradientColor: ColorGradient.whiteBlack, touchLocation: CGFloat())
-                BarChartCell(value: 1, width: 50, numberOfDataPoints: 1, gradientColor: ColorGradient(.purple), touchLocation: CGFloat())
+                BarChartCell(value: 0.5, gradientColor: ColorGradient.greenRed, touchLocation: CGFloat())
+                BarChartCell(value: 0.75, gradientColor: ColorGradient.whiteBlack, touchLocation: CGFloat())
+                BarChartCell(value: 1, gradientColor: ColorGradient(.purple), touchLocation: CGFloat())
             }
 
             Group {
-                BarChartCell(value: 1, width: 50, numberOfDataPoints: 1, gradientColor: ColorGradient.greenRed, touchLocation: CGFloat())
-                BarChartCell(value: 1, width: 50, numberOfDataPoints: 1, gradientColor: ColorGradient.whiteBlack, touchLocation: CGFloat())
-                BarChartCell(value: 1, width: 50, numberOfDataPoints: 1, gradientColor: ColorGradient(.purple), touchLocation: CGFloat())
+                BarChartCell(value: 1, gradientColor: ColorGradient.greenRed, touchLocation: CGFloat())
+                BarChartCell(value: 1, gradientColor: ColorGradient.whiteBlack, touchLocation: CGFloat())
+                BarChartCell(value: 1, gradientColor: ColorGradient(.purple), touchLocation: CGFloat())
             }.environment(\.colorScheme, .dark)
         }
     }

Sources/SwiftUICharts/Charts/BarChart/BarChartCellShape.swift

@@ -0,0 +1,49 @@
+import SwiftUI
+
+struct BarChartCellShape: Shape, Animatable {
+    var value: Double
+    var cornerRadius: CGFloat = 6.0
+    
+    var animatableData: CGFloat {
+        get { CGFloat(value) }
+        set { value = Double(newValue) }
+    }
+
+    func path(in rect: CGRect) -> Path {
+        let adjustedOriginY = rect.height - (rect.height * CGFloat(value))
+        var path = Path()
+        path.move(to: CGPoint(x: 0.0 , y: rect.height))
+        path.addLine(to: CGPoint(x: 0.0, y: adjustedOriginY + cornerRadius))
+        path.addArc(center: CGPoint(x: cornerRadius, y: adjustedOriginY +  cornerRadius),
+                    radius: cornerRadius,
+                    startAngle: Angle(radians: Double.pi),
+                    endAngle: Angle(radians: value < 0 ? Double.pi/2 : -Double.pi/2),
+                    clockwise: value < 0 ? true : false)
+        path.addLine(to: CGPoint(x: rect.width - cornerRadius, y: value < 0 ? adjustedOriginY + 2 * cornerRadius : adjustedOriginY))
+        path.addArc(center: CGPoint(x: rect.width - cornerRadius, y: adjustedOriginY + cornerRadius),
+                    radius: cornerRadius,
+                    startAngle: Angle(radians: value < 0 ? Double.pi/2 : -Double.pi/2),
+                    endAngle: Angle(radians: 0),
+                    clockwise: value < 0 ? true : false)
+        path.addLine(to: CGPoint(x: rect.width, y: rect.height))
+        path.closeSubpath()
+
+        return path
+    }
+}
+
+struct BarChartCellShape_Previews: PreviewProvider {
+    static var previews: some View {
+        Group {
+            BarChartCellShape(value: 0.75)
+                .fill(Color.red)
+
+            BarChartCellShape(value: 0.3)
+                .fill(Color.blue)
+            
+            BarChartCellShape(value: -0.3)
+                .fill(Color.blue)
+                .offset(x: 0, y: -600)
+        }
+    }
+}

Sources/SwiftUICharts/Charts/BarChart/BarChartRow.swift

@@ -6,14 +6,10 @@ public struct BarChartRow: View {
     @ObservedObject var chartData: ChartData
     @State private var touchLocation: CGFloat = -1.0
 
-    enum Constant {
-        static let spacing: CGFloat = 16.0
-    }
-
     var style: ChartStyle
     
     var maxValue: Double {
-        guard let max = chartData.data.max() else {
+        guard let max = chartData.points.max() else {
             return 1
         }
         return max != 0 ? max : 1
@@ -27,20 +23,18 @@ public struct BarChartRow: View {
     public var body: some View {
         GeometryReader { geometry in
             HStack(alignment: .bottom,
-                   spacing: (geometry.frame(in: .local).width - Constant.spacing) / CGFloat(self.chartData.data.count * 3)) {
-                    ForEach(0..<self.chartData.data.count, id: \.self) { index in
-                        BarChartCell(value: self.normalizedValue(index: index),
+                   spacing: geometry.frame(in: .local).width / CGFloat(chartData.data.count * 3)) {
+                    ForEach(0..<chartData.data.count, id: \.self) { index in
+                        BarChartCell(value: chartData.normalisedPoints[index],
                                      index: index,
-                                     width: Float(geometry.frame(in: .local).width - Constant.spacing),
-                                     numberOfDataPoints: self.chartData.data.count,
                                      gradientColor: self.style.foregroundColor.rotate(for: index),
                                      touchLocation: self.touchLocation)
                             .scaleEffect(self.getScaleSize(touchLocation: self.touchLocation, index: index), anchor: .bottom)
                             .animation(Animation.easeIn(duration: 0.2))
                     }
-//                   .drawingGroup()
+//                    .drawingGroup()
             }
-            .padding([.top, .leading, .trailing], 10)
+            .frame(maxHeight: chartData.isInNegativeDomain ? geometry.size.height / 2 : geometry.size.height)
             .gesture(DragGesture()
                 .onChanged({ value in
                     let width = geometry.frame(in: .local).width
@@ -58,13 +52,6 @@ public struct BarChartRow: View {
         }
     }
 
-	/// Value relative to maximum value
-	/// - Parameter index: index into array of data
-	/// - Returns: data value at given index, divided by data maximum
-    func normalizedValue(index: Int) -> Double {
-        return Double(chartData.data[index])/Double(maxValue)
-    }
-
 	/// Size to scale the touch indicator
 	/// - Parameters:
 	///   - touchLocation: fraction of width where touch is happening
@@ -84,6 +71,14 @@ public struct BarChartRow: View {
     func getCurrentValue(width: CGFloat) -> Double? {
         guard self.chartData.data.count > 0 else { return nil}
             let index = max(0,min(self.chartData.data.count-1,Int(floor((self.touchLocation*width)/(width/CGFloat(self.chartData.data.count))))))
-            return self.chartData.data[index]
+            return self.chartData.points[index]
         }
 }
+
+struct BarChartRow_Previews: PreviewProvider {
+    static let chartData = ChartData([6, 2, 5, 8, 6])
+    static let chartStyle = ChartStyle(backgroundColor: .white, foregroundColor: .orangeBright)
+    static var previews: some View {
+        BarChartRow(chartData: chartData, style: chartStyle)
+    }
+}

Sources/SwiftUICharts/Charts/LineChart/IndicatorPoint.swift

@@ -1,11 +1,3 @@
-//
-//  IndicatorPoint.swift
-//  LineChart
-//
-//  Created by András Samu on 2019. 09. 03..
-//  Copyright © 2019. András Samu. All rights reserved.
-//
-
 import SwiftUI
 
 /// A dot representing a single data point as user moves finger over line in `LineChart`

Sources/SwiftUICharts/Charts/LineChart/Line.swift

@@ -3,94 +3,58 @@ import SwiftUI
 /// A single line of data, a view in a `LineChart`
 public struct Line: View {
     @EnvironmentObject var chartValue: ChartValue
-    @State private var frame: CGRect = .zero
     @ObservedObject var chartData: ChartData
 
     var style: ChartStyle
 
     @State private var showIndicator: Bool = false
     @State private var touchLocation: CGPoint = .zero
-    @State private var showFull: Bool = false
     @State private var showBackground: Bool = true
+    @State private var didCellAppear: Bool = false
+
     var curvedLines: Bool = true
-
-	/// Step for plotting through data
-	/// - Returns: X and Y delta between each data point based on data and view's frame
-	var step: CGPoint {
-        return CGPoint.getStep(frame: frame, data: chartData.data)
-    }
-
-	/// Path of line graph
-	/// - Returns: A path for stroking representing the data, either curved or jagged.
     var path: Path {
-        let points = chartData.data
-
-        if curvedLines {
-            return Path.quadCurvedPathWithPoints(points: points,
-                                                 step: step,
-                                                 globalOffset: nil)
-        }
-
-        return Path.linePathWithPoints(points: points, step: step)
-    }
-    
-	/// Path of linegraph, but also closed at the bottom side
-	/// - Returns: A path for filling representing the data, either curved or jagged
-    var closedPath: Path {
-        let points = chartData.data
-
-        if curvedLines {
-            return Path.quadClosedCurvedPathWithPoints(points: points,
-                                            step: step,
-                                            globalOffset: nil)
-        }
-
-        return Path.closedLinePathWithPoints(points: points, step: step)
+        Path.quadCurvedPathWithPoints(points: chartData.normalisedPoints,
+                                      step: CGPoint(x: 1.0, y: 1.0))
     }
     
 	/// The content and behavior of the `Line`.
-	///
 	/// Draw the background if showing the full line (?) and the `showBackground` option is set. Above that draw the line, and then the data indicator if the graph is currently being touched.
 	/// On appear, set the frame so that the data graph metrics can be calculated. On a drag (touch) gesture, highlight the closest touched data point.
 	/// TODO: explain rotation
     public var body: some View {
-
-		let orientationChanged = NotificationCenter.default.publisher(for: UIDevice.orientationDidChangeNotification)
-			.makeConnectable()
-			.autoconnect()	// see https://stackoverflow.com/a/62370919
-		// This lets geometry be recalculated when device rotates. However it doesn't cover issue of app changing
-		// from full screen to split view. Not possible in SwiftUI? Feedback submitted to apple FB8451194.
-
         GeometryReader { geometry in
             ZStack {
-                if self.showFull && self.showBackground {
-                    self.getBackgroundPathView()
+                if self.didCellAppear && self.showBackground {
+                    LineBackgroundShapeView(chartData: chartData,
+                                            geometry: geometry,
+                                            style: style)
                 }
-                self.getLinePathView()
+                LineShapeView(chartData: chartData,
+                              geometry: geometry,
+                              style: style,
+                              trimTo: didCellAppear ? 1.0 : 0.0)
+                    .animation(.easeIn)
                 if self.showIndicator {
                     IndicatorPoint()
-                        .position(self.getClosestPointOnPath(touchLocation: self.touchLocation))
+                        .position(self.getClosestPointOnPath(geometry: geometry,
+                                                             touchLocation: self.touchLocation))
                         .rotationEffect(.degrees(180), anchor: .center)
                         .rotation3DEffect(.degrees(180), axis: (x: 0, y: 1, z: 0))
                 }
             }
             .onAppear {
-                self.frame = geometry.frame(in: .local)
-
+                didCellAppear = true
+            }
+            .onDisappear() {
+                didCellAppear = false
             }
-			.onReceive(orientationChanged) { _ in
-				// When we receive notification here, the geometry is still the old value
-				// so delay evaluation to get the new frame!
-				DispatchQueue.main.async {
-					self.frame = geometry.frame(in: .local)	// recalculate layout with new frame
-				}
-			}
 			
             .gesture(DragGesture()
                 .onChanged({ value in
                     self.touchLocation = value.location
                     self.showIndicator = true
-                    self.getClosestDataPoint(point: self.getClosestPointOnPath(touchLocation: value.location))
+                    self.getClosestDataPoint(geometry: geometry, touchLocation: value.location)
                     self.chartValue.interactionInProgress = true
                 })
                 .onEnded({ value in
@@ -106,79 +70,42 @@ public struct Line: View {
 // MARK: - Private functions
 
 extension Line {
-
 	/// Calculate point closest to where the user touched
 	/// - Parameter touchLocation: location in view where touched
 	/// - Returns: `CGPoint` of data point on chart
-    private func getClosestPointOnPath(touchLocation: CGPoint) -> CGPoint {
-        let closest = self.path.point(to: touchLocation.x)
-        return closest
+    private func getClosestPointOnPath(geometry: GeometryProxy, touchLocation: CGPoint) -> CGPoint {
+        let geometryWidth = geometry.frame(in: .local).width
+        let normalisedTouchLocationX = (touchLocation.x / geometryWidth) * CGFloat(chartData.normalisedPoints.count - 1)
+        let closest = self.path.point(to: normalisedTouchLocationX)
+        var denormClosest = closest.denormalize(with: geometry)
+        denormClosest.x = denormClosest.x / CGFloat(chartData.normalisedPoints.count - 1)
+        denormClosest.y = denormClosest.y / CGFloat(chartData.normalisedRange)
+        return denormClosest
     }
 
-	/// Figure out where closest touch point was
-	/// - Parameter point: location of data point on graph, near touch location
-    private func getClosestDataPoint(point: CGPoint) {
-        let index = Int(round((point.x)/step.x))
+//	/// Figure out where closest touch point was
+//	/// - Parameter point: location of data point on graph, near touch location
+    private func getClosestDataPoint(geometry: GeometryProxy, touchLocation: CGPoint) {
+        let geometryWidth = geometry.frame(in: .local).width
+        let index = Int(round((touchLocation.x / geometryWidth) * CGFloat(chartData.points.count - 1)))
         if (index >= 0 && index < self.chartData.data.count){
-            self.chartValue.currentValue = self.chartData.data[index]
+            self.chartValue.currentValue = self.chartData.points[index]
         }
     }
-
-	/// Get the view representing the filled in background below the chart, filled with the foreground color's gradient
-	///
-	/// TODO: explain rotations
-	/// - Returns: SwiftUI `View`
-    private func getBackgroundPathView() -> some View {
-        self.closedPath
-            .fill(LinearGradient(gradient: Gradient(colors: [
-                                                        style.foregroundColor.first?.startColor ?? .white,
-                                                        style.foregroundColor.first?.endColor ?? .white,
-                                                        .clear]),
-                                 startPoint: .bottom,
-                                 endPoint: .top))
-            .rotationEffect(.degrees(180), anchor: .center)
-            .rotation3DEffect(.degrees(180), axis: (x: 0, y: 1, z: 0))
-            .opacity(0.2)
-            .transition(.opacity)
-            .animation(.easeIn(duration: 1.6))
-    }
-
-	/// Get the view representing the line stroked in the `foregroundColor`
-	///
-	/// TODO: Explain how `showFull` works
-	/// TODO: explain rotations
-	/// - Returns: SwiftUI `View`
-    private func getLinePathView() -> some View {
-        self.path
-            .trim(from: 0, to: self.showFull ? 1:0)
-            .stroke(LinearGradient(gradient: style.foregroundColor.first?.gradient ?? ColorGradient.orangeBright.gradient,
-                                   startPoint: .leading,
-                                   endPoint: .trailing),
-                    style: StrokeStyle(lineWidth: 3, lineJoin: .round))
-            .rotationEffect(.degrees(180), anchor: .center)
-            .rotation3DEffect(.degrees(180), axis: (x: 0, y: 1, z: 0))
-            .animation(Animation.easeOut(duration: 1.2))
-            .onAppear {
-                self.showFull = true
-            }
-            .onDisappear {
-                self.showFull = false
-            }
-            .drawingGroup()
-    }
 }
 
 struct Line_Previews: PreviewProvider {
+    /// Predefined style, black over white, for preview
+    static let blackLineStyle = ChartStyle(backgroundColor: ColorGradient(.white), foregroundColor: ColorGradient(.black))
+
+    /// Predefined style red over white, for preview
+    static let redLineStyle = ChartStyle(backgroundColor: .whiteBlack, foregroundColor: ColorGradient(.red))
+
     static var previews: some View {
         Group {
-            Line(chartData:  ChartData([8, 23, 32, 7, 23, 43]), style: blackLineStyle)
+            Line(chartData:  ChartData([8, 23, 32, 7, 23, -4]), style: blackLineStyle)
             Line(chartData:  ChartData([8, 23, 32, 7, 23, 43]), style: redLineStyle)
         }
     }
 }
 
-/// Predefined style, black over white, for preview
-private let blackLineStyle = ChartStyle(backgroundColor: ColorGradient(.white), foregroundColor: ColorGradient(.black))
-
-/// Predefined stylem red over white, for preview
-private let redLineStyle = ChartStyle(backgroundColor: .whiteBlack, foregroundColor: ColorGradient(.red))

Sources/SwiftUICharts/Charts/LineChart/LineBackgroundShape.swift

@@ -0,0 +1,31 @@
+import SwiftUI
+
+struct LineBackgroundShape: Shape {
+    var data: [Double]
+    func path(in rect: CGRect) -> Path {
+        let path = Path.quadClosedCurvedPathWithPoints(points: data, step: CGPoint(x: 1.0, y: 1.0))
+        return path
+    }
+}
+
+struct LineBackgroundShape_Previews: PreviewProvider {
+    static var previews: some View {
+        Group {
+            GeometryReader { geometry in
+                LineBackgroundShape(data: [0, 0.5, 0.8, 0.6, 1])
+                    .transform(CGAffineTransform(scaleX: geometry.size.width / 4.0, y: geometry.size.height))
+                    .fill(Color.red)
+                    .rotationEffect(.degrees(180), anchor: .center)
+                    .rotation3DEffect(.degrees(180), axis: (x: 0, y: 1, z: 0))
+            }
+            GeometryReader { geometry in
+                LineBackgroundShape(data: [0, -0.5, 0.8, -0.6, 1])
+                    .transform(CGAffineTransform(scaleX: geometry.size.width / 4.0, y: geometry.size.height / 1.6))
+                    .fill(Color.blue)
+                    .rotationEffect(.degrees(180), anchor: .center)
+                    .rotation3DEffect(.degrees(180), axis: (x: 0, y: 1, z: 0))
+            }
+        }
+    }
+}
+

Sources/SwiftUICharts/Charts/LineChart/LineBackgroundShapeView.swift

@@ -0,0 +1,19 @@
+import SwiftUI
+
+struct LineBackgroundShapeView: View {
+    var chartData: ChartData
+    var geometry: GeometryProxy
+    var style: ChartStyle
+
+    var body: some View {
+        LineBackgroundShape(data: chartData.normalisedPoints)
+            .transform(CGAffineTransform(scaleX: geometry.size.width / CGFloat(chartData.normalisedPoints.count - 1),
+                                         y: geometry.size.height / CGFloat(chartData.normalisedRange)))
+            .fill(LinearGradient(gradient: Gradient(colors: [style.foregroundColor.first?.startColor ?? .white,
+                                                             style.backgroundColor.startColor]),
+                                 startPoint: .bottom,
+                                 endPoint: .top))
+            .rotationEffect(.degrees(180), anchor: .center)
+            .rotation3DEffect(.degrees(180), axis: (x: 0, y: 1, z: 0))
+    }
+}

Sources/SwiftUICharts/Charts/LineChart/LineShape.swift

@@ -0,0 +1,30 @@
+import SwiftUI
+
+struct LineShape: Shape {
+    var data: [Double]
+    func path(in rect: CGRect) -> Path {
+        let path = Path.quadCurvedPathWithPoints(points: data, step: CGPoint(x: 1.0, y: 1.0))
+        return path
+    }
+}
+
+struct LineShape_Previews: PreviewProvider {
+    static var previews: some View {
+        Group {
+            GeometryReader { geometry in
+                LineShape(data: [0, 0.5, 0.8, 0.6, 1])
+                    .transform(CGAffineTransform(scaleX: geometry.size.width / 4.0, y: geometry.size.height))
+                    .stroke(Color.red)
+                    .rotationEffect(.degrees(180), anchor: .center)
+                    .rotation3DEffect(.degrees(180), axis: (x: 0, y: 1, z: 0))
+            }
+            GeometryReader { geometry in
+                LineShape(data: [0, -0.5, 0.8, -0.6, 1])
+                    .transform(CGAffineTransform(scaleX: geometry.size.width / 4.0, y: geometry.size.height / 1.6))
+                    .stroke(Color.blue)
+                    .rotationEffect(.degrees(180), anchor: .center)
+                    .rotation3DEffect(.degrees(180), axis: (x: 0, y: 1, z: 0))
+            }
+        }
+    }
+}

Sources/SwiftUICharts/Charts/LineChart/LineShapeView.swift

@@ -0,0 +1,26 @@
+import SwiftUI
+
+struct LineShapeView: View, Animatable {
+    var chartData: ChartData
+    var geometry: GeometryProxy
+    var style: ChartStyle
+    var trimTo: Double = 0
+
+    var animatableData: CGFloat {
+        get { CGFloat(trimTo) }
+        set { trimTo = Double(newValue) }
+    }
+
+    var body: some View {
+        LineShape(data: chartData.normalisedPoints)
+            .trim(from: 0, to: CGFloat(trimTo))
+            .transform(CGAffineTransform(scaleX: geometry.size.width / CGFloat(chartData.normalisedPoints.count - 1),
+                                         y: geometry.size.height / CGFloat(chartData.normalisedRange)))
+            .stroke(LinearGradient(gradient: style.foregroundColor.first?.gradient ?? ColorGradient.orangeBright.gradient,
+                                   startPoint: .leading,
+                                   endPoint: .trailing),
+                    style: StrokeStyle(lineWidth: 3, lineJoin: .round))
+            .rotationEffect(.degrees(180), anchor: .center)
+            .rotation3DEffect(.degrees(180), axis: (x: 0, y: 1, z: 0))
+    }
+}

Sources/SwiftUICharts/Charts/PieChart/PieChartCell.swift

@@ -1,10 +1,3 @@
-//
-//  PieChartCell.swift
-//  SwiftUICharts
-//
-//  Created by Nicolas Savoini on 2020-05-24.
-//
-
 import SwiftUI
 
 /// One slice of a `PieChartRow`

Sources/SwiftUICharts/Charts/PieChart/PieChartHelpers.swift

@@ -0,0 +1,34 @@
+import SwiftUI
+
+func isPointInCircle(point: CGPoint, circleRect: CGRect) -> Bool {
+    let r = min(circleRect.width, circleRect.height) / 2
+    let center = CGPoint(x: circleRect.midX, y: circleRect.midY)
+    let dx = point.x - center.x
+    let dy = point.y - center.y
+    let distance = sqrt(dx * dx + dy * dy)
+    return distance <= r
+}
+
+func degree(for point: CGPoint, inCircleRect circleRect: CGRect) -> Double {
+    let center = CGPoint(x: circleRect.midX, y: circleRect.midY)
+    let dx = point.x - center.x
+    let dy = point.y - center.y
+    let acuteDegree = Double(atan(dy / dx)) * (180 / .pi)
+    
+    let isInBottomRight = dx >= 0 && dy >= 0
+    let isInBottomLeft = dx <= 0 && dy >= 0
+    let isInTopLeft = dx <= 0 && dy <= 0
+    let isInTopRight = dx >= 0 && dy <= 0
+    
+    if isInBottomRight {
+        return acuteDegree
+    } else if isInBottomLeft {
+        return 180 - abs(acuteDegree)
+    } else if isInTopLeft {
+        return 180 + abs(acuteDegree)
+    } else if isInTopRight {
+        return 360 - abs(acuteDegree)
+    }
+    
+    return 0
+}

Sources/SwiftUICharts/Charts/PieChart/PieChartRow.swift

@@ -1,24 +1,18 @@
-//
-//  PieChartRow.swift
-//  SwiftUICharts
-//
-//  Created by Nicolas Savoini on 2020-05-24.
-//
-
 import SwiftUI
 
 /// A single "row" (slice) of data, a view in a `PieChart`
 public struct PieChartRow: View {
     @ObservedObject var chartData: ChartData
+    @EnvironmentObject var chartValue: ChartValue
 
     var style: ChartStyle
 
     var slices: [PieSlice] {
         var tempSlices: [PieSlice] = []
         var lastEndDeg: Double = 0
-        let maxValue: Double = chartData.data.reduce(0, +)
+        let maxValue: Double = chartData.points.reduce(0, +)
         
-        for slice in chartData.data {
+        for slice in chartData.points {
             let normalized: Double = Double(slice) / (maxValue == 0 ? 1 : maxValue)
             let startDeg = lastEndDeg
             let endDeg = lastEndDeg + (normalized * 360)
@@ -29,59 +23,47 @@ public struct PieChartRow: View {
         return tempSlices
     }
 
-	/// The content and behavior of the `PieChartRow`.
-	///
-	///
+    @State private var currentTouchedIndex = -1 {
+        didSet {
+            if oldValue != currentTouchedIndex {
+                chartValue.interactionInProgress = currentTouchedIndex != -1
+                guard currentTouchedIndex != -1 else { return }
+                chartValue.currentValue = slices[currentTouchedIndex].value
+            }
+        }
+    }
+
     public var body: some View {
         GeometryReader { geometry in
             ZStack {
                 ForEach(0..<self.slices.count) { index in
                     PieChartCell(
-                            rect: geometry.frame(in: .local),
-                            startDeg: self.slices[index].startDeg,
-                            endDeg: self.slices[index].endDeg,
-                            index: index,
-                            backgroundColor: self.style.backgroundColor.startColor,
-                            accentColor: self.style.foregroundColor.rotate(for: index)
-                        )
+                        rect: geometry.frame(in: .local),
+                        startDeg: self.slices[index].startDeg,
+                        endDeg: self.slices[index].endDeg,
+                        index: index,
+                        backgroundColor: self.style.backgroundColor.startColor,
+                        accentColor: self.style.foregroundColor.rotate(for: index)
+                    )
+                    .scaleEffect(currentTouchedIndex == index ? 1.1 : 1)
+                    .animation(Animation.spring())
                 }
-                
             }
+            .gesture(DragGesture()
+                        .onChanged({ value in
+                            let rect = geometry.frame(in: .local)
+                            let isTouchInPie = isPointInCircle(point: value.location, circleRect: rect)
+                            if isTouchInPie {
+                                let touchDegree = degree(for: value.location, inCircleRect: rect)
+                                currentTouchedIndex = slices.firstIndex(where: { $0.startDeg < touchDegree && $0.endDeg > touchDegree }) ?? -1
+                            } else {
+                                currentTouchedIndex = -1
+                            }
+                        })
+                        .onEnded({ value in
+                            currentTouchedIndex = -1
+                        })
+            )
         }
     }
-
 }
-
-struct PieChartRow_Previews: PreviewProvider {
-    static var previews: some View {
-        Group {
-            //Empty Array - Default Colors.OrangeStart
-            PieChartRow(
-                chartData: ChartData([8, 23, 32, 7, 23, 43]),
-                style: defaultMultiColorChartStyle)
-            .frame(width: 100, height: 100)
-            
-            PieChartRow(
-                chartData:  ChartData([8, 23, 32, 7, 23, 43]),
-                style: multiColorChartStyle)
-            .frame(width: 100, height: 100)
-            
-            PieChartRow(
-                chartData:  ChartData([8, 23, 32, 7, 23, 43]),
-                style: multiColorChartStyle)
-            .frame(width: 100, height: 100)
-            
-        }.previewLayout(.fixed(width: 125, height: 125))
-        
-    }
-}
-
-/// Predefined color style, for preview
-private let defaultMultiColorChartStyle = ChartStyle(
-    backgroundColor: Color.white,
-    foregroundColor: [ColorGradient]())
-
-/// Predefined color style, for preview
-private let multiColorChartStyle = ChartStyle(
-backgroundColor: Color.purple,
-foregroundColor: [ColorGradient.greenRed, ColorGradient.whiteBlack])

Sources/SwiftUICharts/Charts/RingsChart/RingsChart.swift

@@ -19,4 +19,5 @@ public struct RingsChart: View, ChartBase {
 		RingsChartRow(width:10.0, spacing:5.0, chartData: data, style: style)
 	}
 
+    public init() {}
 }

Sources/SwiftUICharts/Charts/RingsChart/RingsChartRow.swift

@@ -39,7 +39,7 @@ public struct RingsChartRow: View {
 									  // make sure it doesn't get to crazy value
 					)
 
-					Ring(ringWidth:scaledWidth, percent: self.chartData.data[index], foregroundColor:self.style.foregroundColor.rotate(for: index),
+					Ring(ringWidth:scaledWidth, percent: self.chartData.points[index], foregroundColor:self.style.foregroundColor.rotate(for: index),
 						 touchLocation: self.touchRadius)
 
 
@@ -108,7 +108,7 @@ public struct RingsChartRow: View {
 	func getCurrentValue(maxRadius: CGFloat) -> Double? {
 
 		guard let index = self.touchedCircleIndex(maxRadius: maxRadius) else { return nil }
-		return self.chartData.data[index]
+		return self.chartData.points[index]
 	}
 }
 

Tests/SwiftUIChartsTests/ArrayExtensionTests.swift

@@ -1,10 +1,3 @@
-//
-//  File.swift
-//  
-//
-//  Created by Nicolas Savoini on 2020-05-25.
-//
-
 @testable import SwiftUICharts
 import XCTest