Prepare charts to display x and y values souch as a value for a given point

* Dark/Light mode fixes (#148)

Fix for making text work with both Dark/Light mode.

Also solves line chart background to appear white in dark mode

* Add custom string format for ChartLabel when interactionInProgress = true

Co-authored-by: Sagar Patel <s.72427patel@gmail.com>

.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"

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

@@ -10,5 +10,18 @@
 			<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>
 </plist>

.swiftpm/xcode/xcuserdata/samuandris.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>

LICENSE

@@ -0,0 +1,21 @@
+MIT License
+
+Copyright (c) 2019 Andras Samu
+
+Permission is hereby granted, free of charge, to any person obtaining a copy
+of this software and associated documentation files (the "Software"), to deal
+in the Software without restriction, including without limitation the rights
+to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+copies of the Software, and to permit persons to whom the Software is
+furnished to do so, subject to the following conditions:
+
+The above copyright notice and this permission notice shall be included in all
+copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+SOFTWARE.

Package.swift

@@ -6,13 +6,13 @@ import PackageDescription
 let package = Package(
     name: "SwiftUICharts",
     platforms: [
-        .iOS(.v13),
+        .iOS(.v13), .watchOS(.v6), .macOS(.v10_15)
     ],
     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"])
     ]
 )

README.md

@@ -2,17 +2,18 @@
 
 Swift package for displaying charts effortlessly.
 
-![SwiftUI Charts](./chartview.gif "SwiftUI Charts")
+![SwiftUI Charts](./Resources/showcase1.gif "SwiftUI Charts")
 
-It supports currently:
-* barcharts
-* piecharts
+It supports:
+* Line charts
+* Bar charts
+* Pie charts
 
 ### Installation:
 
-It requires iOS 13 and xCode 11!
+It requires iOS 13 and Xcode 11!
 
-In xCode got to `File -> Swift Packages -> Add Package Dependency` and paste inthe repo's url: `https://github.com/AppPear/ChartView`
+In Xcode got to `File -> Swift Packages -> Add Package Dependency` and paste inthe repo's url: `https://github.com/AppPear/ChartView`
 
 ### Usage:
 
@@ -20,23 +21,172 @@ import the package in the file you would like to use it: `import SwiftUICharts`
 
 You can display a Chart by adding a chart view to your parent view: 
 
-Barchart:
+### Demo
+
+Added an example project, with **iOS, watchOS** target: https://github.com/AppPear/ChartViewDemo
+
+## Line charts
+
+**LineChartView with multiple lines!**
+First release of this feature, interaction is disabled for now, I'll figure it out how could be the best to interact with multiple lines with a single touch.
+![Multiine Charts](./Resources/multiline1.gif "Multiine Charts")
+
+Usage:
 ```swift
-ChartView(data: [8,23,54,32,12,37,7,23,43], title: "Barchart")
+MultiLineChartView(data: [([8,32,11,23,40,28], GradientColors.green), ([90,99,78,111,70,60,77], GradientColors.purple), ([34,56,72,38,43,100,50], GradientColors.orngPink)], title: "Title")
+```
+Gradient colors are now under the `GradientColor` struct you can create your own gradient by `GradientColor(start: Color, end: Color)`
+
+Available preset gradients: 
+* orange 
+* blue
+* green
+* blu 
+* bluPurpl
+* purple
+* prplPink 
+* prplNeon
+* orngPink
+
+**Full screen view called LineView!!!**
+
+![Line Charts](./Resources/fullscreen2.gif "Line Charts")
+
+```swift
+ LineView(data: [8,23,54,32,12,37,7,23,43], title: "Line chart", legend: "Full screen") // legend is optional, use optional .padding()
 ```
 
-Piechart:
+Adopts to dark mode automatically 
+
+![Line Charts](./Resources/showcase3.gif "Line Charts")
+
+You can add your custom darkmode style by specifying:
+
 ```swift
-PieChartView(data:[43,56,78,34], title: "Piechart")
+let myCustomStyle = ChartStyle(...)
+let myCutsomDarkModeStyle = ChartStyle(...)
+myCustomStyle.darkModeStyle = myCutsomDarkModeStyle
 ```
 
-You can optionally configure:
-* legend
+**Line chart is interactive, so you can drag across to reveal the data points**
+
+You can add a line chart with the following code: 
+
+```swift
+ LineChartView(data: [8,23,54,32,12,37,7,23,43], title: "Title", legend: "Legendary") // legend is optional
+```
+
+**Turn drop shadow off by adding to the Initialiser: `dropShadow: false`**
+
+
+## Bar charts
+![Bar Charts](./Resources/showcase2.gif "Bar Charts")
+
+**[New feature] you can display labels also along values and points for each bar to descirbe your data better!**
+**Bar chart is interactive, so you can drag across to reveal the data points**
+
+You can add a bar chart with the following code: 
+
+Labels and points:
+
+```swift
+ BarChartView(data: ChartData(values: [("2018 Q4",63150), ("2019 Q1",50900), ("2019 Q2",77550), ("2019 Q3",79600), ("2019 Q4",92550)]), title: "Sales", legend: "Quarterly") // legend is optional
+```
+Only points:
+
+```swift
+ BarChartView(data: ChartData(points: [8,23,54,32,12,37,7,23,43]), title: "Title", legend: "Legendary") // legend is optional
+```
+
+**ChartData** structure
+Stores values in data pairs (actually tuple): `(String,Double)`
+* you can have duplicate values
+* keeps the data order
+
+You can initialise ChartData multiple ways:
+* For integer values: `ChartData(points: [8,23,54,32,12,37,7,23,43])`
+* For floating point values: `ChartData(points: [2.34,3.14,4.56])`
+* For label,value pairs: `ChartData(values: [("2018 Q4",63150), ("2019 Q1",50900)])`
+
+
+You can add different formats: 
+* Small `ChartForm.small`
+* Medium  `ChartForm.medium`
+* Large `ChartForm.large` 
+
+```swift
+BarChartView(data: ChartData(points: [8,23,54,32,12,37,7,23,43]), title: "Title", form: ChartForm.small)
+```
+
+For floating point numbers, you can set a custom specifier: 
+
+```swift
+BarChartView(data: ChartData(points:[1.23,2.43,3.37]) ,title: "A", valueSpecifier: "%.2f")
+```
+For integers you can disable by passing: `valueSpecifier: "%.0f"`
+
+
+You can set your custom image in the upper right corner by passing in the initialiser: `cornerImage:Image(systemName: "waveform.path.ecg")` 
+
+
+ **Turn drop shadow off by adding to the Initialiser: `dropShadow: false`**
+
+ ### You can customize styling of the chart with a ChartStyle object: 
+
+Customizable: 
 * background color
 * accent color
+* second gradient color
+* text color
+* legend text color
 
 ```swift
-ChartView(data: [12,17,24,33,36,31,27,23,14], title: "Title", legend: "Legend", backgroundColor:Color(red: 226.0/255.0, green: 250.0/255.0, blue: 231.0/255.0) , accentColor:Color(red: 114.0/255.0, green: 191.0/255.0, blue: 130.0/255.0))
+ let chartStyle = ChartStyle(backgroundColor: Color.black, accentColor: Colors.OrangeStart, secondGradientColor: Colors.OrangeEnd, chartFormSize: ChartForm.medium, textColor: Color.white, legendTextColor: Color.white )
+ ...
+ BarChartView(data: [8,23,54,32,12,37,7,23,43], title: "Title", style: chartStyle)
 ```
 
+You can access built-in styles: 
+```swift
+ BarChartView(data: [8,23,54,32,12,37,7,23,43], title: "Title", style: Styles.barChartMidnightGreen)
+```
+#### All styles available as a preset: 
+* barChartStyleOrangeLight
+* barChartStyleOrangeDark
+* barChartStyleNeonBlueLight
+* barChartStyleNeonBlueDark
+* barChartMidnightGreenLight
+* barChartMidnightGreenDark
+
+![Midnightgreen](./Resources/midnightgreen.gif "Midnightgreen")
+
+![Custom Charts](./Resources/showcase5.png "Custom Charts")
+
+
+### You can customize the size of the chart with a ChartForm object: 
+
+**ChartForm**
+* `.small`
+* `.medium`
+* `.large`
+* `.detail`
+
+```swift
+BarChartView(data: [8,23,54,32,12,37,7,23,43], title: "Title", form: ChartForm.small)
+```
+
+### WatchOS support for Bar charts: 
+
+![Pie Charts](./Resources/watchos1.png "Pie Charts")
+
+## Pie charts
+![Pie Charts](./Resources/showcase4.png "Pie Charts")
+
+You can add a pie chart with the following code: 
+
+```swift
+ PieChartView(data: [8,23,54,32], title: "Title", legend: "Legendary") // legend is optional
+```
+
+**Turn drop shadow off by adding to the Initialiser: `dropShadow: false`**
 

Sources/SwiftUICharts/Base/CardView/CardView.swift

@@ -0,0 +1,37 @@
+import SwiftUI
+
+/// View containing data and some kind of chart content
+public struct CardView<Content: View>: View, ChartBase {
+    public var chartData = ChartData()
+    let content: () -> Content
+
+    private var showShadow: Bool
+
+    @EnvironmentObject var style: ChartStyle
+
+	/// Initialize with view options and a nested `ViewBuilder`
+	/// - Parameters:
+	///   - showShadow: should card have a rounded-rectangle shadow around it
+	///   - content: <#content description#>
+    public init(showShadow: Bool = true, @ViewBuilder content: @escaping () -> Content) {
+        self.showShadow = showShadow
+        self.content = content
+    }
+
+	/// The content and behavior of the `CardView`.
+	///
+	///
+    public var body: some View {
+        ZStack{
+            if showShadow {
+                RoundedRectangle(cornerRadius: 20)
+                    .fill(Color.white)
+                    .shadow(color: Color.gray, radius: 8)
+            }
+            VStack {
+                self.content()
+            }
+            .clipShape(RoundedRectangle(cornerRadius: showShadow ? 20 : 0))
+        }
+    }
+}

Sources/SwiftUICharts/Base/Chart/ChartBase.swift

@@ -0,0 +1,6 @@
+import SwiftUI
+
+/// Protocol for any type of chart, to get access to underlying data
+public protocol ChartBase {
+    var chartData: ChartData { get }
+}

Sources/SwiftUICharts/Base/Chart/ChartData.swift

@@ -0,0 +1,28 @@
+import SwiftUI
+
+/// An observable wrapper for an array of data for use in any chart
+public class ChartData: ObservableObject {
+    @Published public var data: [(String, Double)] = []
+
+    var points: [Double] {
+        data.map { $0.1 }
+    }
+
+    var values: [String] {
+        data.map { $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
+    }
+
+    public init() {
+        self.data = []
+    }
+}

Sources/SwiftUICharts/Base/Chart/ChartValue.swift

@@ -0,0 +1,7 @@
+import SwiftUI
+
+/// Representation of a single data point in a chart that is being observed
+public class ChartValue: ObservableObject {
+    @Published var currentValue: Double = 0
+    @Published var interactionInProgress: Bool = false
+}

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

@@ -0,0 +1,19 @@
+import Foundation
+
+extension Array where Element == ColorGradient {
+	
+	/// <#Description#>
+	/// - Parameter index: offset in data table
+	/// - Returns: <#description#>
+    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/Extensions/CGPoint+Extension.swift

@@ -0,0 +1,41 @@
+import SwiftUI
+
+extension CGPoint {
+	
+	/// Calculate X and Y delta for each data point, based on data min/max and enclosing frame.
+	/// - Parameters:
+	///   - frame: Rectangle of enclosing frame
+	///   - 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
+
+        // stepWidth
+        var stepWidth: CGFloat = 0.0
+        if data.count < 2 {
+            stepWidth = 0.0
+        }
+        stepWidth = frame.size.width / CGFloat(data.count - 1)
+
+        // stepHeight
+        var stepHeight: CGFloat = 0.0
+
+        var min: Double?
+        var max: Double?
+        if let minPoint = data.min(), let maxPoint = data.max(), minPoint != maxPoint {
+            min = minPoint
+            max = maxPoint
+        } else {
+            return .zero
+        }
+        if let min = min, let max = max, min != max {
+            if min <= 0 {
+                stepHeight = (frame.size.height - padding) / CGFloat(max - min)
+            } else {
+                stepHeight = (frame.size.height - padding) / CGFloat(max + min)
+            }
+        }
+
+        return CGPoint(x: stepWidth, y: stepHeight)
+    }
+}

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

@@ -0,0 +1,11 @@
+import Foundation
+import SwiftUI
+
+extension CGRect {
+
+	/// Midpoint of rectangle
+	/// - Returns: the coordinate for a rectangle center
+    public var mid: CGPoint {
+        return CGPoint(x: self.midX, y: self.midY)
+    }
+}

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

@@ -0,0 +1,21 @@
+import SwiftUI
+
+extension View where Self: ChartBase {
+	
+	/// Set data for a chart
+	/// - 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)
+            .environmentObject(ChartValue())
+    }
+}

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

@@ -0,0 +1,25 @@
+import SwiftUI
+
+extension Color {
+	/// Create a `Color` from a hexadecimal representation
+	/// - Parameter hexString: 3, 6, or 8-character string, with optional (ignored) punctuation such as "#"
+    init(hexString: String) {
+        let hex = hexString.trimmingCharacters(in: CharacterSet.alphanumerics.inverted)
+        var int = UInt64()
+        Scanner(string: hex).scanHexInt64(&int)
+        let red, green, blue: UInt64
+        switch hex.count {
+        case 3: // RGB (12-bit)
+            (red, green, blue) = ((int >> 8) * 17, (int >> 4 & 0xF) * 17, (int & 0xF) * 17)
+        case 6: // RGB (24-bit)
+            (red, green, blue) = (int >> 16, int >> 8 & 0xFF, int & 0xFF)
+        case 8: // ARGB (32-bit)
+            // FIXME: I think we need an an alpha value on this one. See link below.
+            // https://stackoverflow.com/a/56874327/4475605
+            (red, green, blue) = (int >> 16 & 0xFF, int >> 8 & 0xFF, int & 0xFF)
+        default:
+            (red, green, blue) = (0, 0, 0)
+        }
+        self.init(red: Double(red) / 255, green: Double(green) / 255, blue: Double(blue) / 255)
+    }
+}

Sources/SwiftUICharts/Base/Extensions/Path+QuadCurve.swift

@@ -0,0 +1,476 @@
+import SwiftUI
+
+extension Path {
+
+	/// Returns a tiny segment of path based on percentage along the path
+	///
+	/// TODO: Explain why more than 1 gets 0 and why less than 0 gets 1
+	/// - Parameter percent: fraction along data set, between 0.0 and 1.0 (underflow and overflow are handled)
+	/// - Returns: tiny path right around the requested fraction
+    func trimmedPath(for percent: CGFloat) -> Path {
+        let boundsDistance: CGFloat = 0.001
+        let completion: CGFloat = 1 - boundsDistance
+        
+        let pct = percent > 1 ? 0 : (percent < 0 ? 1 : percent)
+
+		// Start/end points centered around given percentage, but capped if right at the very end
+        let start = pct > completion ? completion : pct - boundsDistance
+        let end = pct > completion ? 1 : pct + boundsDistance
+        return trimmedPath(from: start, to: end)
+    }
+
+	/// Find the `CGPoint` for the given fraction along the path.
+	///
+	/// This works by requesting a very tiny trimmed section of the path, then getting the center of the bounds rectangle
+	/// - Parameter percent: fraction along data set, between 0.0 and 1.0 (underflow and overflow are handled)
+	/// - Returns: a `CGPoint` representing the location of that section of the path
+    func point(for percent: CGFloat) -> CGPoint {
+        let path = trimmedPath(for: percent)
+        return CGPoint(x: path.boundingRect.midX, y: path.boundingRect.midY)
+    }
+
+	/// <#Description#>
+	/// - Parameter maxX: <#maxX description#>
+	/// - Returns: <#description#>
+    func point(to maxX: CGFloat) -> CGPoint {
+        let total = length
+        let sub = length(to: maxX)
+        let percent = sub / total
+        return point(for: percent)
+    }
+    
+	/// <#Description#>
+	/// - Returns: <#description#>
+   var length: CGFloat {
+        var ret: CGFloat = 0.0
+        var start: CGPoint?
+        var point = CGPoint.zero
+        
+        forEach { ele in
+            switch ele {
+            case .move(let to):
+                if start == nil {
+                    start = to
+                }
+                point = to
+            case .line(let to):
+                ret += point.line(to: to)
+                point = to
+            case .quadCurve(let to, let control):
+                ret += point.quadCurve(to: to, control: control)
+                point = to
+            case .curve(let to, let control1, let control2):
+                ret += point.curve(to: to, control1: control1, control2: control2)
+                point = to
+            case .closeSubpath:
+                if let to = start {
+                    ret += point.line(to: to)
+                    point = to
+                }
+                start = nil
+            }
+        }
+        return ret
+    }
+
+	/// <#Description#>
+	/// - Parameter maxX: <#maxX description#>
+	/// - Returns: <#description#>
+    func length(to maxX: CGFloat) -> CGFloat {
+        var ret: CGFloat = 0.0
+        var start: CGPoint?
+        var point = CGPoint.zero
+        var finished = false
+        
+        forEach { ele in
+            if finished {
+                return
+            }
+            switch ele {
+            case .move(let to):
+                if to.x > maxX {
+                    finished = true
+                    return
+                }
+                if start == nil {
+                    start = to
+                }
+                point = to
+            case .line(let to):
+                if to.x > maxX {
+                    finished = true
+                    ret += point.line(to: to, x: maxX)
+                    return
+                }
+                ret += point.line(to: to)
+                point = to
+            case .quadCurve(let to, let control):
+                if to.x > maxX {
+                    finished = true
+                    ret += point.quadCurve(to: to, control: control, x: maxX)
+                    return
+                }
+                ret += point.quadCurve(to: to, control: control)
+                point = to
+            case .curve(let to, let control1, let control2):
+                if to.x > maxX {
+                    finished = true
+                    ret += point.curve(to: to, control1: control1, control2: control2, x: maxX)
+                    return
+                }
+                ret += point.curve(to: to, control1: control1, control2: control2)
+                point = to
+            case .closeSubpath:
+                fatalError("Can't include closeSubpath")
+            }
+        }
+        return ret
+    }
+
+	/// <#Description#>
+	/// - Parameters:
+	///   - points: <#points description#>
+	///   - step: <#step description#>
+	///   - globalOffset: <#globalOffset description#>
+	/// - Returns: <#description#>
+    static func quadCurvedPathWithPoints(points: [Double], step: CGPoint, globalOffset: Double? = nil) -> Path {
+        var path = Path()
+        if points.count < 2 {
+            return path
+        }
+        let offset = globalOffset ?? points.min()!
+//        guard let offset = points.min() else { return path }
+        var point1 = CGPoint(x: 0, y: CGFloat(points[0]-offset)*step.y)
+        path.move(to: point1)
+        for pointIndex in 1..<points.count {
+            let point2 = CGPoint(x: step.x * CGFloat(pointIndex), y: step.y*CGFloat(points[pointIndex]-offset))
+            let midPoint = CGPoint.midPointForPoints(firstPoint: point1, secondPoint: point2)
+            path.addQuadCurve(to: midPoint, control: CGPoint.controlPointForPoints(firstPoint: midPoint, secondPoint: point1))
+            path.addQuadCurve(to: point2, control: CGPoint.controlPointForPoints(firstPoint: midPoint, secondPoint: point2))
+            point1 = point2
+        }
+        return path
+    }
+
+	/// <#Description#>
+	/// - Parameters:
+	///   - points: <#points description#>
+	///   - step: <#step description#>
+	///   - globalOffset: <#globalOffset description#>
+	/// - Returns: <#description#>
+    static func quadClosedCurvedPathWithPoints(points: [Double], step: CGPoint, globalOffset: Double? = nil) -> Path {
+        var path = Path()
+        if points.count < 2 {
+            return path
+        }
+        let offset = globalOffset ?? points.min()!
+
+//        guard let offset = points.min() else { return path }
+        path.move(to: .zero)
+        var point1 = CGPoint(x: 0, y: CGFloat(points[0]-offset)*step.y)
+        path.addLine(to: point1)
+        for pointIndex in 1..<points.count {
+            let point2 = CGPoint(x: step.x * CGFloat(pointIndex), y: step.y*CGFloat(points[pointIndex]-offset))
+            let midPoint = CGPoint.midPointForPoints(firstPoint: point1, secondPoint: point2)
+            path.addQuadCurve(to: midPoint, control: CGPoint.controlPointForPoints(firstPoint: midPoint, secondPoint: point1))
+            path.addQuadCurve(to: point2, control: CGPoint.controlPointForPoints(firstPoint: midPoint, secondPoint: point2))
+            point1 = point2
+        }
+        path.addLine(to: CGPoint(x: point1.x, y: 0))
+        path.closeSubpath()
+        return path
+    }
+
+	/// <#Description#>
+	/// - Parameters:
+	///   - points: <#points description#>
+	///   - step: <#step description#>
+	/// - Returns: <#description#>
+    static func linePathWithPoints(points: [Double], step: CGPoint) -> Path {
+        var path = Path()
+        if points.count < 2 {
+            return path
+        }
+        guard let offset = points.min() else {
+            return path
+        }
+        let point1 = CGPoint(x: 0, y: CGFloat(points[0]-offset)*step.y)
+        path.move(to: point1)
+        for pointIndex in 1..<points.count {
+            let point2 = CGPoint(x: step.x * CGFloat(pointIndex), y: step.y*CGFloat(points[pointIndex]-offset))
+            path.addLine(to: point2)
+        }
+        return path
+    }
+
+	/// <#Description#>
+	/// - Parameters:
+	///   - points: <#points description#>
+	///   - step: <#step description#>
+	/// - Returns: <#description#>
+    static func closedLinePathWithPoints(points: [Double], step: CGPoint) -> Path {
+        var path = Path()
+        if points.count < 2 {
+            return path
+        }
+        guard let offset = points.min() else {
+            return path
+        }
+        var point1 = CGPoint(x: 0, y: CGFloat(points[0]-offset)*step.y)
+        path.move(to: point1)
+        for pointIndex in 1..<points.count {
+            point1 = CGPoint(x: step.x * CGFloat(pointIndex), y: step.y*CGFloat(points[pointIndex]-offset))
+            path.addLine(to: point1)
+        }
+        path.addLine(to: CGPoint(x: point1.x, y: 0))
+        path.closeSubpath()
+        return path
+    }
+    
+}
+
+extension CGPoint {
+
+	/// <#Description#>
+	/// - Parameters:
+	///   - to: <#to description#>
+	///   - x: <#x description#>
+	/// - Returns: <#description#>
+    func point(to: CGPoint, x: CGFloat) -> CGPoint {
+        let a = (to.y - self.y) / (to.x - self.x)
+        let y = self.y + (x - self.x) * a
+        return CGPoint(x: x, y: y)
+    }
+
+	/// <#Description#>
+	/// - Parameter to: <#to description#>
+	/// - Returns: <#description#>
+    func line(to: CGPoint) -> CGFloat {
+        dist(to: to)
+    }
+
+	/// <#Description#>
+	/// - Parameters:
+	///   - to: <#to description#>
+	///   - x: <#x description#>
+	/// - Returns: <#description#>
+    func line(to: CGPoint, x: CGFloat) -> CGFloat {
+        dist(to: point(to: to, x: x))
+    }
+
+	/// <#Description#>
+	/// - Parameters:
+	///   - to: <#to description#>
+	///   - control: <#control description#>
+	/// - Returns: <#description#>
+    func quadCurve(to: CGPoint, control: CGPoint) -> CGFloat {
+        var dist: CGFloat = 0
+        let steps: CGFloat = 100
+        
+        for i in 0..<Int(steps) {
+            let t0 = CGFloat(i) / steps
+            let t1 = CGFloat(i+1) / steps
+            let a = point(to: to, t: t0, control: control)
+            let b = point(to: to, t: t1, control: control)
+            
+            dist += a.line(to: b)
+        }
+        return dist
+    }
+
+	/// <#Description#>
+	/// - Parameters:
+	///   - to: <#to description#>
+	///   - control: <#control description#>
+	///   - x: <#x description#>
+	/// - Returns: <#description#>
+    func quadCurve(to: CGPoint, control: CGPoint, x: CGFloat) -> CGFloat {
+        var dist: CGFloat = 0
+        let steps: CGFloat = 100
+        
+        for i in 0..<Int(steps) {
+            let t0 = CGFloat(i) / steps
+            let t1 = CGFloat(i+1) / steps
+            let a = point(to: to, t: t0, control: control)
+            let b = point(to: to, t: t1, control: control)
+            
+            if a.x >= x {
+                return dist
+            } else if b.x > x {
+                dist += a.line(to: b, x: x)
+                return dist
+            } else if b.x == x {
+                dist += a.line(to: b)
+                return dist
+            }
+            
+            dist += a.line(to: b)
+        }
+        return dist
+    }
+
+	/// <#Description#>
+	/// - Parameters:
+	///   - to: <#to description#>
+	///   - t: <#t description#>
+	///   - control: <#control description#>
+	/// - Returns: <#description#>
+    func point(to: CGPoint, t: CGFloat, control: CGPoint) -> CGPoint {
+        let x = CGPoint.value(x: self.x, y: to.x, t: t, c: control.x)
+        let y = CGPoint.value(x: self.y, y: to.y, t: t, c: control.y)
+        
+        return CGPoint(x: x, y: y)
+    }
+
+	/// <#Description#>
+	/// - Parameters:
+	///   - to: <#to description#>
+	///   - control1: <#control1 description#>
+	///   - control2: <#control2 description#>
+	/// - Returns: <#description#>
+    func curve(to: CGPoint, control1: CGPoint, control2: CGPoint) -> CGFloat {
+        var dist: CGFloat = 0
+        let steps: CGFloat = 100
+        
+        for i in 0..<Int(steps) {
+            let t0 = CGFloat(i) / steps
+            let t1 = CGFloat(i+1) / steps
+            
+            let a = point(to: to, t: t0, control1: control1, control2: control2)
+            let b = point(to: to, t: t1, control1: control1, control2: control2)
+            
+            dist += a.line(to: b)
+        }
+        
+        return dist
+    }
+
+	/// <#Description#>
+	/// - Parameters:
+	///   - to: <#to description#>
+	///   - control1: <#control1 description#>
+	///   - control2: <#control2 description#>
+	///   - x: <#x description#>
+	/// - Returns: <#description#>
+    func curve(to: CGPoint, control1: CGPoint, control2: CGPoint, x: CGFloat) -> CGFloat {
+        var dist: CGFloat = 0
+        let steps: CGFloat = 100
+        
+        for i in 0..<Int(steps) {
+            let t0 = CGFloat(i) / steps
+            let t1 = CGFloat(i+1) / steps
+            
+            let a = point(to: to, t: t0, control1: control1, control2: control2)
+            let b = point(to: to, t: t1, control1: control1, control2: control2)
+            
+            if a.x >= x {
+                return dist
+            } else if b.x > x {
+                dist += a.line(to: b, x: x)
+                return dist
+            } else if b.x == x {
+                dist += a.line(to: b)
+                return dist
+            }
+            
+            dist += a.line(to: b)
+        }
+        
+        return dist
+    }
+
+	/// <#Description#>
+	/// - Parameters:
+	///   - to: <#to description#>
+	///   - t: <#t description#>
+	///   - control1: <#control1 description#>
+	///   - control2: <#control2 description#>
+	/// - Returns: <#description#>
+    func point(to: CGPoint, t: CGFloat, control1: CGPoint, control2: CGPoint) -> CGPoint {
+        let x = CGPoint.value(x: self.x, y: to.x, t: t, control1: control1.x, control2: control2.x)
+        let y = CGPoint.value(x: self.y, y: to.y, t: t, control1: control1.y, control2: control2.x)
+        
+        return CGPoint(x: x, y: y)
+    }
+
+	/// <#Description#>
+	/// - Parameters:
+	///   - x: <#x description#>
+	///   - y: <#y description#>
+	///   - t: <#t description#>
+	///   - c: <#c description#>
+	/// - Returns: <#description#>
+    static func value(x: CGFloat, y: CGFloat, t: CGFloat, c: CGFloat) -> CGFloat {
+        var value: CGFloat = 0.0
+        // (1-t)^2 * p0 + 2 * (1-t) * t * c1 + t^2 * p1
+        value += pow(1-t, 2) * x
+        value += 2 * (1-t) * t * c
+        value += pow(t, 2) * y
+        return value
+    }
+
+	/// <#Description#>
+	/// - Parameters:
+	///   - x: <#x description#>
+	///   - y: <#y description#>
+	///   - t: <#t description#>
+	///   - control1: <#control1 description#>
+	///   - control2: <#control2 description#>
+	/// - Returns: <#description#>
+    static func value(x: CGFloat, y: CGFloat, t: CGFloat, control1: CGFloat, control2: CGFloat) -> CGFloat {
+        var value: CGFloat = 0.0
+        // (1-t)^3 * p0 + 3 * (1-t)^2 * t * c1 + 3 * (1-t) * t^2 * c2 + t^3 * p1
+        value += pow(1-t, 3) * x
+        value += 3 * pow(1-t, 2) * t * control1
+        value += 3 * (1-t) * pow(t, 2) * control2
+        value += pow(t, 3) * y
+        return value
+    }
+
+	/// <#Description#>
+	/// - Parameters:
+	///   - point1: <#point1 description#>
+	///   - point2: <#point2 description#>
+	/// - Returns: <#description#>
+    static func getMidPoint(point1: CGPoint, point2: CGPoint) -> CGPoint {
+        return CGPoint(
+            x: point1.x + (point2.x - point1.x) / 2,
+            y: point1.y + (point2.y - point1.y) / 2
+        )
+    }
+
+	/// <#Description#>
+	/// - Parameter to: <#to description#>
+	/// - Returns: <#description#>
+    func dist(to: CGPoint) -> CGFloat {
+        return sqrt((pow(self.x - to.x, 2) + pow(self.y - to.y, 2)))
+    }
+
+	/// <#Description#>
+	/// - Parameters:
+	///   - firstPoint: <#firstPoint description#>
+	///   - secondPoint: <#secondPoint description#>
+	/// - Returns: <#description#>
+    static func midPointForPoints(firstPoint: CGPoint, secondPoint: CGPoint) -> CGPoint {
+        return CGPoint(
+            x: (firstPoint.x + secondPoint.x) / 2,
+            y: (firstPoint.y + secondPoint.y) / 2)
+    }
+
+	/// <#Description#>
+	/// - Parameters:
+	///   - firstPoint: <#firstPoint description#>
+	///   - secondPoint: <#secondPoint description#>
+	/// - Returns: <#description#>
+    static func controlPointForPoints(firstPoint: CGPoint, secondPoint: CGPoint) -> CGPoint {
+        var controlPoint = CGPoint.midPointForPoints(firstPoint: firstPoint, secondPoint: secondPoint)
+        let diffY = abs(secondPoint.y - controlPoint.y)
+        
+        if firstPoint.y < secondPoint.y {
+            controlPoint.y += diffY
+        } else if firstPoint.y > secondPoint.y {
+            controlPoint.y -= diffY
+        }
+        return controlPoint
+    }
+}

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

@@ -0,0 +1,11 @@
+import SwiftUI
+
+extension View {
+
+	/// Attach chart style to a View
+	/// - Parameter style: chart style
+	/// - Returns: `View` with chart style attached
+    public func chartStyle(_ style: ChartStyle) -> some View {
+        self.environmentObject(style)
+    }
+}

Sources/SwiftUICharts/Base/Grid/ChartGrid.swift

@@ -0,0 +1,26 @@
+import SwiftUI
+
+/// <#Description#>
+public struct ChartGrid<Content: View>: View, ChartBase {
+    public var chartData = ChartData()
+    let content: () -> Content
+
+    @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()
+        }
+    }
+}
+

Sources/SwiftUICharts/Base/Label/ChartLabel.swift

@@ -0,0 +1,107 @@
+import SwiftUI
+
+/// What kind of label - this affects color, size, position of the label
+public enum ChartLabelType {
+    case title
+    case subTitle
+    case largeTitle
+    case custom(size: CGFloat, padding: EdgeInsets, color: Color)
+    case legend
+}
+
+/// 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 var textToDisplay:String = ""
+    var format: String = "%.01f"
+
+    private var title: String
+
+	/// Label font size
+	/// - Returns: the font size of the label
+    private var labelSize: CGFloat {
+        switch labelType {
+        case .title:
+            return 32.0
+        case .legend:
+            return 14.0
+        case .subTitle:
+            return 24.0
+        case .largeTitle:
+            return 38.0
+        case .custom(let size, _, _):
+            return size
+        }
+    }
+
+	/// Padding around label
+	/// - Returns: the edge padding to use based on position of the label
+    private var labelPadding: EdgeInsets {
+        switch labelType {
+        case .title:
+            return EdgeInsets(top: 16.0, leading: 8.0, bottom: 0.0, trailing: 8.0)
+        case .legend:
+            return EdgeInsets(top: 4.0, leading: 8.0, bottom: 0.0, trailing: 8.0)
+        case .subTitle:
+            return EdgeInsets(top: 8.0, leading: 8.0, bottom: 0.0, trailing: 8.0)
+        case .largeTitle:
+            return EdgeInsets(top: 24.0, leading: 8.0, bottom: 0.0, trailing: 8.0)
+        case .custom(_, let padding, _):
+            return padding
+        }
+    }
+
+	/// Which type (color, size, position) for label
+    private let labelType: ChartLabelType
+
+	/// Foreground color for this label
+	/// - Returns: Color of label based on its `ChartLabelType`
+    private var labelColor: Color {
+        switch labelType {
+        case .title:
+            return Color(UIColor.label)
+        case .legend:
+            return Color(UIColor.secondaryLabel)
+        case .subTitle:
+            return Color(UIColor.label)
+        case .largeTitle:
+            return Color(UIColor.label)
+        case .custom(_, _, let color):
+            return color
+        }
+    }
+
+	/// Initialize
+	/// - Parameters:
+	///   - title: Any `String`
+	///   - type: Which `ChartLabelType` to use
+    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`.
+	///
+	/// Displays current value if chart is currently being touched along a data point, otherwise the specified text.
+    public var body: some View {
+        HStack {
+            Text(textToDisplay)
+                .font(.system(size: labelSize))
+                .bold()
+                .foregroundColor(self.labelColor)
+                .padding(self.labelPadding)
+                .onAppear {
+                    self.textToDisplay = self.title
+                }
+                .onReceive(self.chartValue.objectWillChange) { _ in
+                    self.textToDisplay = self.chartValue.interactionInProgress ? String(format: format, self.chartValue.currentValue) : self.title
+                }
+            if !self.chartValue.interactionInProgress {
+                Spacer()
+            }
+        }
+    }
+}

Sources/SwiftUICharts/Base/Style/ChartStyle.swift

@@ -0,0 +1,47 @@
+import SwiftUI
+
+/// Descripton of colors/styles for any kind of chart
+public class ChartStyle: ObservableObject {
+
+	/// colors for background are of chart
+	public let backgroundColor: ColorGradient
+	/// colors for foreground fill of chart
+    public let foregroundColor: [ColorGradient]
+
+	/// Initialize with a single background color and an array of `ColorGradient` for the foreground
+	/// - Parameters:
+	///   - backgroundColor: a `Color`
+	///   - foregroundColor: array of `ColorGradient`
+    public init(backgroundColor: Color, foregroundColor: [ColorGradient]) {
+        self.backgroundColor = ColorGradient.init(backgroundColor)
+        self.foregroundColor = foregroundColor
+    }
+
+	/// Initialize with a single background color and a single `ColorGradient` for the foreground
+	/// - Parameters:
+	///   - backgroundColor: a `Color`
+	///   - foregroundColor: a `ColorGradient`
+    public init(backgroundColor: Color, foregroundColor: ColorGradient) {
+        self.backgroundColor = ColorGradient.init(backgroundColor)
+        self.foregroundColor = [foregroundColor]
+    }
+
+	/// Initialize with a single background `ColorGradient` and a single `ColorGradient` for the foreground
+	/// - Parameters:
+	///   - backgroundColor: a `ColorGradient`
+	///   - foregroundColor: a `ColorGradient`
+    public init(backgroundColor: ColorGradient, foregroundColor: ColorGradient) {
+        self.backgroundColor = backgroundColor
+        self.foregroundColor = [foregroundColor]
+    }
+
+	/// Initialize with a  single background `ColorGradient` and an array of `ColorGradient` for the foreground
+	/// - Parameters:
+	///   - backgroundColor: a `ColorGradient`
+	///   - foregroundColor: array of `ColorGradient`
+    public init(backgroundColor: ColorGradient, foregroundColor: [ColorGradient]) {
+        self.backgroundColor = backgroundColor
+        self.foregroundColor = foregroundColor
+    }
+    
+}

Sources/SwiftUICharts/Base/Style/ColorGradient.swift

@@ -0,0 +1,47 @@
+import SwiftUI
+
+/// An encapsulation of a simple gradient between one color and another
+public struct ColorGradient: Equatable {
+	public let startColor: Color
+    public let endColor: Color
+
+	/// Initialize as a solid color
+	/// - Parameter color: a  single `Color` (no gradient effect visible)
+    public init(_ color: Color) {
+        self.startColor = color
+        self.endColor = color
+    }
+
+	/// Initialize a color gradient from two specified colors
+	/// - Parameters:
+	///   - startColor: starting color
+	///   - endColor: ending color
+    public init(_ startColor: Color, _ endColor: Color) {
+        self.startColor = startColor
+        self.endColor = endColor
+    }
+
+	/// Convert to a  `Gradient` object (more complicated than just two colors)
+	/// - Returns: a `Gradient` between the specified start and end colors
+    public var gradient: Gradient {
+        return Gradient(colors: [startColor, endColor])
+    }
+}
+
+extension ColorGradient {
+    /// Convenience method to return a SwiftUI LinearGradient view 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/Base/Style/Colors.swift

@@ -0,0 +1,11 @@
+import SwiftUI
+
+/// Some predefined colors, used for demos, defaults if color is missing, and data indicator point
+public enum ChartColors {
+    // Orange
+    public static let orangeBright = Color(hexString: "#FF782C")
+    public static let orangeDark = Color(hexString: "#EC2301")
+
+    public static let legendColor: Color = Color(hexString: "#E8E7EA")
+    public static let indicatorKnob: Color = Color(hexString: "#FF57A6")
+}

Sources/SwiftUICharts/ChartCell.swift

@@ -1,41 +0,0 @@
-//
-//  ChartCell.swift
-//  ChartView
-//
-//  Created by András Samu on 2019. 06. 12..
-//  Copyright © 2019. András Samu. All rights reserved.
-//
-
-import SwiftUI
-
-public struct ChartCell : View {
-    var value: Double
-    var index: Int = 0
-    var width: Float
-    var numberOfDataPoints: Int
-    var cellWidth: Double {
-        return Double(width)/(Double(numberOfDataPoints) * 1.5)
-    }
-    @State var scaleValue: Double = 0
-    public var body: some View {
-        ZStack {
-            Rectangle()
-                .cornerRadius(4)
-            }
-            .frame(width: CGFloat(self.cellWidth))
-            .scaleEffect(CGSize(width: 1, height: self.scaleValue), anchor: .bottom)
-            .onAppear(){
-                self.scaleValue = self.value
-            }
-            .animation(Animation.spring().delay(Double(self.index) * 0.04))
-      
-    }
-}
-
-#if DEBUG
-struct ChartCell_Previews : PreviewProvider {
-    static var previews: some View {
-        ChartCell(value: Double(0.75), width: 320, numberOfDataPoints: 12)
-    }
-}
-#endif

Sources/SwiftUICharts/ChartRow.swift

@@ -1,33 +0,0 @@
-//
-//  ChartRow.swift
-//  ChartView
-//
-//  Created by András Samu on 2019. 06. 12..
-//  Copyright © 2019. András Samu. All rights reserved.
-//
-
-import SwiftUI
-
-public struct ChartRow : View {
-    var data: [Int]
-    var maxValue: Int {
-        data.max() ?? 0
-    }
-    public var body: some View {
-        GeometryReader { geometry in
-            HStack(alignment: .bottom, spacing: (geometry.frame(in: .local).width-22)/CGFloat(self.data.count * 3)){
-                ForEach(0..<self.data.count) { i in
-                    ChartCell(value: Double(self.data[i])/Double(self.maxValue), index: i, width: Float(geometry.frame(in: .local).width - 22), numberOfDataPoints: self.data.count)
-                }
-                }.padding([.trailing,.leading], 13)
-        }
-    }
-}
-
-#if DEBUG
-struct ChartRow_Previews : PreviewProvider {
-    static var previews: some View {
-        ChartRow(data: [8,23,54,32,12,37,7])
-    }
-}
-#endif

Sources/SwiftUICharts/ChartView.swift

@@ -1,60 +0,0 @@
-//
-//  ChartView.swift
-//  ChartView
-//
-//  Created by András Samu on 2019. 06. 12..
-//  Copyright © 2019. András Samu. All rights reserved.
-//
-
-import SwiftUI
-
-public struct ChartView : View {
-    public var data: [Int]
-    public var title: String
-    public var legend: String?
-    public var backgroundColor:Color
-    public var accentColor:Color
-    
-    public init(data: [Int], title: String, legend: String? = nil,backgroundColor:Color = Color(red: 238.0/255.0, green: 241.0/255.0, blue: 254.0/255.0),accentColor:Color = Color(red: 66.0/255.0, green: 102.0/255.0, blue: 232.0/255.0) ){
-        self.data = data
-        self.title = title
-        self.legend = legend
-        self.backgroundColor = backgroundColor
-        self.accentColor = accentColor
-    }
-    
-    public var body: some View {
-        ZStack{
-            Rectangle()
-            .fill(self.backgroundColor)
-            .cornerRadius(20)
-            VStack(alignment: .leading){
-                HStack{
-                    Text(self.title)
-                    .font(.headline)
-                    Spacer()
-                    Image(systemName: "waveform.path.ecg")
-                    .imageScale(.large)
-                    .foregroundColor(self.accentColor)
-                }.padding()
-                ChartRow(data: data)
-                .foregroundColor(self.accentColor)
-                .clipped()
-                if self.legend != nil {
-                    Text(self.legend!)
-                        .font(.headline)
-                        .foregroundColor(self.accentColor)
-                        .padding()
-                }
-            }
-            }.frame(width: 180, height: 240)
-    }
-}
-
-#if DEBUG
-struct ChartView_Previews : PreviewProvider {
-    static var previews: some View {
-        ChartView(data: [8,23,54,32,12,37,7,23,43], title: "Title")
-    }
-}
-#endif

Sources/SwiftUICharts/Charts/BarChart/BarChart.swift

@@ -0,0 +1,18 @@
+import SwiftUI
+
+/// A type of chart that displays vertical bars for each data point
+public struct BarChart: View, ChartBase {
+    public var chartData = ChartData()
+
+    @EnvironmentObject var data: ChartData
+    @EnvironmentObject var style: ChartStyle
+
+	/// The content and behavior of the `BarChart`.
+	///
+	///
+    public var body: some View {
+        BarChartRow(chartData: data, style: style)
+    }
+
+    public init() {}
+}

Sources/SwiftUICharts/Charts/BarChart/BarChartCell.swift

@@ -0,0 +1,71 @@
+import SwiftUI
+
+/// A single vertical bar in a `BarChart`
+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
+
+    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
+    }
+
+	/// The content and behavior of the `BarChartCell`.
+	///
+	/// 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
+        }
+        .onDisappear {
+            self.firstDisplay = true
+        }
+        .transition(.slide)
+        .animation(Animation.spring().delay(self.touchLocation < 0 || !firstDisplay ? Double(self.index) * 0.04 : 0))
+    }
+}
+
+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: 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())
+            }
+
+            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())
+            }.environment(\.colorScheme, .dark)
+        }
+    }
+}

Sources/SwiftUICharts/Charts/BarChart/BarChartRow.swift

@@ -0,0 +1,89 @@
+import SwiftUI
+
+/// A single row of data, a view in a `BarChart`
+public struct BarChartRow: View {
+    @EnvironmentObject var chartValue: ChartValue
+    @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.points.max() else {
+            return 1
+        }
+        return max != 0 ? max : 1
+    }
+
+	/// The content and behavior of the `BarChartRow`.
+	///
+	/// Shows each `BarChartCell` in an `HStack`; may be scaled up if it's the one currently being touched.
+	/// Not using a drawing group for optimizing animation.
+	/// As touched (dragged) the `touchLocation` is updated and the current value is highlighted.
+    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),
+                                     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()
+            }
+            .padding([.top, .leading, .trailing], 10)
+            .gesture(DragGesture()
+                .onChanged({ value in
+                    let width = geometry.frame(in: .local).width
+                    self.touchLocation = value.location.x/width
+                    if let currentValue = self.getCurrentValue(width: width) {
+                        self.chartValue.currentValue = currentValue
+                        self.chartValue.interactionInProgress = true
+                    }
+                })
+                .onEnded({ value in
+                    self.chartValue.interactionInProgress = false
+                    self.touchLocation = -1
+                })
+            )
+        }
+    }
+
+	/// 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.points[index])/Double(maxValue)
+    }
+
+	/// Size to scale the touch indicator
+	/// - Parameters:
+	///   - touchLocation: fraction of width where touch is happening
+	///   - index: index into data array
+	/// - Returns: a scale larger than 1.0 if in bounds; 1.0 (unscaled) if not in bounds
+    func getScaleSize(touchLocation: CGFloat, index: Int) -> CGSize {
+        if touchLocation > CGFloat(index)/CGFloat(chartData.data.count) &&
+           touchLocation < CGFloat(index+1)/CGFloat(chartData.data.count) {
+            return CGSize(width: 1.4, height: 1.1)
+        }
+        return CGSize(width: 1, height: 1)
+    }
+
+	/// Get data value where touch happened
+	/// - Parameter width: width of chart
+	/// - Returns: value as `Double` if chart has data
+    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.points[index]
+        }
+}

Sources/SwiftUICharts/Charts/LineChart/IndicatorPoint.swift

@@ -0,0 +1,24 @@
+import SwiftUI
+
+/// A dot representing a single data point as user moves finger over line in `LineChart`
+struct IndicatorPoint: View {
+	/// The content and behavior of the `IndicatorPoint`.
+	///
+	/// A filled circle with a thick white outline and a shadow
+    public var body: some View {
+        ZStack {
+            Circle()
+                .fill(ChartColors.indicatorKnob)
+            Circle()
+                .stroke(Color.white, style: StrokeStyle(lineWidth: 4))
+        }
+        .frame(width: 14, height: 14)
+        .shadow(color: ChartColors.legendColor, radius: 6, x: 0, y: 6)
+    }
+}
+
+struct IndicatorPoint_Previews: PreviewProvider {
+    static var previews: some View {
+        IndicatorPoint()
+    }
+}

Sources/SwiftUICharts/Charts/LineChart/Line.swift

@@ -0,0 +1,183 @@
+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
+    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.points)
+    }
+
+	/// Path of line graph
+	/// - Returns: A path for stroking representing the data, either curved or jagged.
+    var path: Path {
+        let points = chartData.points
+
+        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.points
+
+        if curvedLines {
+            return Path.quadClosedCurvedPathWithPoints(points: points,
+                                            step: step,
+                                            globalOffset: nil)
+        }
+
+        return Path.closedLinePathWithPoints(points: points, step: step)
+    }
+
+    // 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.
+    let orientationChanged = NotificationCenter.default.publisher(for: UIDevice.orientationDidChangeNotification)
+        .makeConnectable()
+        .autoconnect()
+    
+	/// 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 {
+        GeometryReader { geometry in
+            ZStack {
+                if self.showFull && self.showBackground {
+                    self.getBackgroundPathView()
+                }
+                self.getLinePathView()
+                if self.showIndicator {
+                    IndicatorPoint()
+                        .position(self.getClosestPointOnPath(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)
+
+            }
+			.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.chartValue.interactionInProgress = true
+                })
+                .onEnded({ value in
+                    self.touchLocation = .zero
+                    self.showIndicator = false
+                    self.chartValue.interactionInProgress = false
+                })
+            )
+        }
+    }
+}
+
+// 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
+    }
+
+	/// 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))
+        if (index >= 0 && index < self.chartData.data.count){
+            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 {
+    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, 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/LineChart.swift

@@ -0,0 +1,18 @@
+import SwiftUI
+
+/// A type of chart that displays a line connecting the data points
+public struct LineChart: View, ChartBase {
+    public var chartData = ChartData()
+
+    @EnvironmentObject var data: ChartData
+    @EnvironmentObject var style: ChartStyle
+
+	/// The content and behavior of the `LineChart`.
+	///
+	///
+    public var body: some View {
+        Line(chartData: data, style: style)
+    }
+    
+    public init() {}
+}

Sources/SwiftUICharts/Charts/PieChart/PieChart.swift

@@ -0,0 +1,18 @@
+import SwiftUI
+
+/// A type of chart that displays a slice of "pie" for each data point
+public struct PieChart: View, ChartBase {
+    public var chartData = ChartData()
+
+    @EnvironmentObject var data: ChartData
+    @EnvironmentObject var style: ChartStyle
+
+	/// The content and behavior of the `PieChart`.
+	///
+	///
+    public var body: some View {
+        PieChartRow(chartData: data, style: style)
+    }
+
+    public init() {}
+}

Sources/SwiftUICharts/Charts/PieChart/PieChartCell.swift

@@ -0,0 +1,116 @@
+import SwiftUI
+
+/// One slice of a `PieChartRow`
+struct PieSlice: Identifiable {
+    var id = UUID()
+    var startDeg: Double
+    var endDeg: Double
+    var value: Double
+}
+
+/// A single row of data, a view in a `PieChart`
+public struct PieChartCell: View {
+    @State private var show: Bool = false
+    var rect: CGRect
+    var radius: CGFloat {
+        return min(rect.width, rect.height)/2
+    }
+    var startDeg: Double
+	var endDeg: Double
+
+	/// Path representing this slice
+    var path: Path {
+        var path = Path()
+        path.addArc(
+            center: rect.mid,
+            radius: self.radius,
+            startAngle: Angle(degrees: self.startDeg),
+            endAngle: Angle(degrees: self.endDeg),
+            clockwise: false)
+        path.addLine(to: rect.mid)
+        path.closeSubpath()
+        return path
+    }
+    var index: Int
+    
+    // Section line border color
+    var backgroundColor: Color
+    
+    // Section color
+    var accentColor: ColorGradient
+    
+	/// The content and behavior of the `PieChartCell`.
+	///
+	/// Fills and strokes with 2-pixel line (unless start/end degrees not yet set). Animates by scaling up to 100% when first appears.
+    public var body: some View {
+        Group {
+            path
+                .fill(self.accentColor.linearGradient(from: .bottom, to: .top))
+                .overlay(path.stroke(self.backgroundColor, lineWidth: (startDeg == 0 && endDeg == 0 ? 0 : 2)))
+                .scaleEffect(self.show ? 1 : 0)
+                .animation(Animation.spring().delay(Double(self.index) * 0.04))
+                .onAppear {
+                    self.show = true
+            }
+            
+        }
+    }
+}
+
+struct PieChartCell_Previews: PreviewProvider {
+    static var previews: some View {
+        Group {
+            
+            GeometryReader { geometry in
+                PieChartCell(
+                    rect: geometry.frame(in: .local),
+                    startDeg: 00.0,
+                    endDeg: 90.0,
+                    index: 0,
+                    backgroundColor: Color.red,
+                    accentColor: ColorGradient.greenRed)
+                }.frame(width: 100, height: 100)
+            
+            GeometryReader { geometry in
+            PieChartCell(
+                rect: geometry.frame(in: .local),
+                startDeg: 0.0,
+                endDeg: 90.0,
+                index: 0,
+                backgroundColor: Color.green,
+                accentColor: ColorGradient.redBlack)
+            }.frame(width: 100, height: 100)
+            
+            GeometryReader { geometry in
+            PieChartCell(
+                rect: geometry.frame(in: .local),
+                startDeg: 100.0,
+                endDeg: 135.0,
+                index: 0,
+                backgroundColor: Color.black,
+                accentColor: ColorGradient.whiteBlack)
+            }.frame(width: 100, height: 100)
+            
+            GeometryReader { geometry in
+            PieChartCell(
+                rect: geometry.frame(in: .local),
+                startDeg: 185.0,
+                endDeg: 290.0,
+                index: 1,
+                backgroundColor: Color.purple,
+                accentColor: ColorGradient(.purple))
+            }.frame(width: 100, height: 100)
+            
+            GeometryReader { geometry in
+            PieChartCell(
+                rect: geometry.frame(in: .local),
+                startDeg: 0,
+                endDeg: 0,
+                index: 0,
+                backgroundColor: Color.purple,
+                accentColor: ColorGradient(.purple))
+            }.frame(width: 100, height: 100)
+            
+        }.previewLayout(.fixed(width: 125, height: 125))
+    }
+}

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

@@ -0,0 +1,69 @@
+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.points.reduce(0, +)
+        
+        for slice in chartData.points {
+            let normalized: Double = Double(slice) / (maxValue == 0 ? 1 : maxValue)
+            let startDeg = lastEndDeg
+            let endDeg = lastEndDeg + (normalized * 360)
+            lastEndDeg = endDeg
+            tempSlices.append(PieSlice(startDeg: startDeg, endDeg: endDeg, value: slice))
+        }
+        
+        return tempSlices
+    }
+
+    @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)
+                    )
+                    .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
+                        })
+            )
+        }
+    }
+}

Sources/SwiftUICharts/Charts/RingsChart/Ring.swift

@@ -0,0 +1,187 @@
+//
+//  Ring.swift
+//  ChartViewV2Demo
+//
+//  Created by Dan Wood on 8/20/20.
+//	Based on article and playground code by Frank Jia
+//	https://medium.com/@frankjia/creating-activity-rings-in-swiftui-11ef7d336676
+
+import SwiftUI
+
+
+extension Double {
+	func toRadians() -> Double {
+		return self * Double.pi / 180
+	}
+	func toCGFloat() -> CGFloat {
+		return CGFloat(self)
+	}
+}
+
+struct RingShape: Shape {
+	/// Helper function to convert percent values to angles in degrees
+	/// - Parameters:
+	///   - percent: percent, greater than 100 is OK
+	///   - startAngle: angle to add after converting
+	/// - Returns: angle in degrees
+	static func percentToAngle(percent: Double, startAngle: Double) -> Double {
+		(percent / 100 * 360) + startAngle
+	}
+	private var percent: Double
+	private var startAngle: Double
+	private let drawnClockwise: Bool
+
+	// This allows animations to run smoothly for percent values
+	var animatableData: Double {
+		get {
+			return percent
+		}
+		set {
+			percent = newValue
+		}
+	}
+
+	init(percent: Double = 100, startAngle: Double = -90, drawnClockwise: Bool = false) {
+		self.percent = percent
+		self.startAngle = startAngle
+		self.drawnClockwise = drawnClockwise
+	}
+
+	/// This draws a simple arc from the start angle to the end angle
+	///
+	/// - Parameter rect: The frame of reference for describing this shape.
+	/// - Returns: A path that describes this shape.
+	func path(in rect: CGRect) -> Path {
+		let width = rect.width
+		let height = rect.height
+		let radius = min(width, height) / 2
+		let center = CGPoint(x: width / 2, y: height / 2)
+		let endAngle = Angle(degrees: RingShape.percentToAngle(percent: self.percent, startAngle: self.startAngle))
+		return Path { path in
+			path.addArc(center: center, radius: radius, startAngle: Angle(degrees: startAngle), endAngle: endAngle, clockwise: drawnClockwise)
+		}
+	}
+}
+
+struct Ring: View {
+
+	private static let ShadowColor: Color = Color.black.opacity(0.2)
+	private static let ShadowRadius: CGFloat = 5
+	private static let ShadowOffsetMultiplier: CGFloat = ShadowRadius + 2
+
+	private let ringWidth: CGFloat
+	private let percent: Double
+	private let foregroundColor: ColorGradient
+	private let startAngle: Double = -90
+
+	private let touchLocation: CGFloat
+
+
+
+	private var gradientStartAngle: Double {
+		self.percent >= 100 ? relativePercentageAngle - 360 : startAngle
+	}
+	private var absolutePercentageAngle: Double {
+		RingShape.percentToAngle(percent: self.percent, startAngle: 0)
+	}
+	private var relativePercentageAngle: Double {
+		// Take into account the startAngle
+		absolutePercentageAngle + startAngle
+	}
+	private var lastGradientColor: Color {
+		self.foregroundColor.endColor
+	}
+
+	private var ringGradient: AngularGradient {
+		AngularGradient(
+			gradient: self.foregroundColor.gradient,
+			center: .center,
+			startAngle: Angle(degrees: self.gradientStartAngle),
+			endAngle: Angle(degrees: relativePercentageAngle)
+		)
+	}
+
+	init(ringWidth: CGFloat, percent: Double, foregroundColor: ColorGradient, touchLocation:CGFloat) {
+		self.ringWidth = ringWidth
+		self.percent = percent
+		self.foregroundColor = foregroundColor
+		self.touchLocation = touchLocation
+	}
+
+	var body: some View {
+		GeometryReader { geometry in
+			ZStack {
+				// Background for the ring. Use the final color with reduced opacity
+				RingShape()
+					.stroke(style: StrokeStyle(lineWidth: self.ringWidth))
+					.fill(lastGradientColor.opacity(0.142857))
+				// Foreground
+				RingShape(percent: self.percent, startAngle: self.startAngle)
+					.stroke(style: StrokeStyle(lineWidth: self.ringWidth, lineCap: .round))
+					.fill(self.ringGradient)
+				// End of ring with drop shadow
+				if self.getShowShadow(frame: geometry.size) {
+					Circle()
+						.fill(self.lastGradientColor)
+						.frame(width: self.ringWidth, height: self.ringWidth, alignment: .center)
+						.offset(x: self.getEndCircleLocation(frame: geometry.size).0,
+								y: self.getEndCircleLocation(frame: geometry.size).1)
+						.shadow(color: Ring.ShadowColor,
+								radius: Ring.ShadowRadius,
+								x: self.getEndCircleShadowOffset().0,
+								y: self.getEndCircleShadowOffset().1)
+				}
+			}
+		}
+		// Padding to ensure that the entire ring fits within the view size allocated
+		.padding(self.ringWidth / 2)
+	}
+
+	private func getEndCircleLocation(frame: CGSize) -> (CGFloat, CGFloat) {
+		// Get angle of the end circle with respect to the start angle
+		let angleOfEndInRadians: Double = relativePercentageAngle.toRadians()
+		let offsetRadius = min(frame.width, frame.height) / 2
+		return (offsetRadius * cos(angleOfEndInRadians).toCGFloat(), offsetRadius * sin(angleOfEndInRadians).toCGFloat())
+	}
+
+	private func getEndCircleShadowOffset() -> (CGFloat, CGFloat) {
+		let angleForOffset = absolutePercentageAngle + (self.startAngle + 90)
+		let angleForOffsetInRadians = angleForOffset.toRadians()
+		let relativeXOffset = cos(angleForOffsetInRadians)
+		let relativeYOffset = sin(angleForOffsetInRadians)
+		let xOffset = relativeXOffset.toCGFloat() * Ring.ShadowOffsetMultiplier
+		let yOffset = relativeYOffset.toCGFloat() * Ring.ShadowOffsetMultiplier
+		return (xOffset, yOffset)
+	}
+
+	private func getShowShadow(frame: CGSize) -> Bool {
+		if self.percent >= 100 {
+			return true
+		}
+		let circleRadius = min(frame.width, frame.height) / 2
+		let remainingAngleInRadians = (360 - absolutePercentageAngle).toRadians().toCGFloat()
+
+		return circleRadius * remainingAngleInRadians <= self.ringWidth
+	}
+}
+
+struct Ring_Previews: PreviewProvider {
+	static var previews: some View {
+		VStack {
+			Ring(
+				ringWidth: 50, percent: 5 ,
+				foregroundColor: ColorGradient(.green, .blue), touchLocation: -1.0
+			)
+			.frame(width: 200, height: 200)
+
+			Ring(
+				ringWidth: 20, percent: 110 ,
+				foregroundColor: ColorGradient(.red, .blue), touchLocation: -1.0
+			)
+			.frame(width: 200, height: 200)
+
+
+
+		}
+	}
+}

Sources/SwiftUICharts/Charts/RingsChart/RingsChart.swift

@@ -0,0 +1,22 @@
+//
+//  RingsChart.swift
+//  ChartViewV2Demo
+//
+//  Created by Dan Wood on 8/20/20.
+//
+
+import SwiftUI
+
+public struct RingsChart: View, ChartBase {
+	public var chartData = ChartData()
+
+	@EnvironmentObject var data: ChartData
+	@EnvironmentObject var style: ChartStyle
+
+	// TODO - should put background opacity, ring width & spacing as chart style values
+	
+	public var body: some View {
+		RingsChartRow(width:10.0, spacing:5.0, chartData: data, style: style)
+	}
+
+}

Sources/SwiftUICharts/Charts/RingsChart/RingsChartRow.swift

@@ -0,0 +1,133 @@
+//
+//  RingsChartRow.swift
+//  ChartViewV2Demo
+//
+//  Created by Dan Wood on 8/20/20.
+//
+
+import SwiftUI
+
+public struct RingsChartRow: View {
+
+	var width : CGFloat
+	var spacing : CGFloat
+
+	@EnvironmentObject var chartValue: ChartValue
+	@ObservedObject var chartData: ChartData
+	@State var touchRadius: CGFloat = -1.0
+
+	var style: ChartStyle
+
+	public var body: some View {
+		GeometryReader { geometry in
+
+			ZStack {
+
+				// FIXME: Why is background circle offset strangely when frame isn't specified? See Preview below. Related to the .animation somehow ????
+				Circle()
+					.fill(RadialGradient(gradient: self.style.backgroundColor.gradient, center: .center, startRadius: min(geometry.size.width, geometry.size.height)/2.0, endRadius: 1.0))
+
+				ForEach(0..<self.chartData.data.count, id: \.self) { index in
+
+					let scaleUp = isRingScaled(size:geometry.size, touchRadius: self.touchRadius, index: index)
+					let scaledWidth = scaleUp ? self.width * 2.0 : self.width
+
+					let normalPadding = (width + spacing) * CGFloat(index)
+					let scaledDiff = (scaledWidth - width) / 2.0
+					let padding = min(normalPadding - scaledDiff,
+									  min(geometry.size.width, geometry.size.height)/2.0 - width
+									  // make sure it doesn't get to crazy value
+					)
+
+					Ring(ringWidth:scaledWidth, percent: self.chartData.points[index], foregroundColor:self.style.foregroundColor.rotate(for: index),
+						 touchLocation: self.touchRadius)
+
+
+						.zIndex(scaleUp ? 1 : 0)	// make sure zoomed one is on top
+						.padding(padding)
+
+						.animation(Animation.easeIn(duration: 0.5))
+				}
+				//                   .drawingGroup()
+			}
+
+			.gesture(DragGesture()
+						.onChanged({ value in
+							let frame = geometry.frame(in: .local)
+							let radius = min(frame.width, frame.height) / 2.0
+							let deltaX = value.location.x - frame.midX
+							let deltaY = value.location.y - frame.midY
+							self.touchRadius = sqrt(deltaX*deltaX + deltaY*deltaY) // Pythagorean equation
+
+							if let currentValue = self.getCurrentValue(maxRadius: radius) {
+								self.chartValue.currentValue = currentValue
+								self.chartValue.interactionInProgress = true
+							}
+						})
+						.onEnded({ value in
+							self.chartValue.interactionInProgress = false
+							self.touchRadius = -1
+						})
+			)
+
+		}
+	}
+
+	/// should we scale up the touched ring?
+	/// - Parameters:
+	///   - size: size of the view
+	///   - touchRadius: distance from center where touched
+	///   - index: which ring is being drawn
+	/// - Returns: size to scale up or just scale of 1 if not scaled up
+	func isRingScaled(size: CGSize, touchRadius: CGFloat, index: Int) -> Bool {
+		let radius = min(size.width, size.height) / 2.0
+		return index == self.touchedCircleIndex(maxRadius: radius)
+	}
+
+	/// Find which circle has been touched
+	/// - Parameter maxRadius: radius of overall view circle
+	/// - Returns: which circle index was touched, if found. 0 = outer, 1 = next one in, etc.
+	func touchedCircleIndex(maxRadius: CGFloat) -> Int? {
+		guard self.chartData.data.count > 0 else { return nil }	// no data
+
+		// Pretend actual circle goes ½ the inter-ring spacing out, so that a touch
+		// is registered on either side of each ring
+		let radialDistanceFromEdge = (maxRadius + spacing/2) - self.touchRadius;
+		guard radialDistanceFromEdge >= 0 else { return nil }	// touched outside of ring
+
+		let touchIndex = Int(floor(radialDistanceFromEdge / (width + spacing)))
+
+		if touchIndex >= self.chartData.data.count { return nil }	// too far from outside, no ring
+
+		return touchIndex
+	}
+
+	/// Description
+	/// - Parameter maxRadius: radius of overall view circle
+	/// - Returns: percentage value of the touched circle, based on `touchRadius` if found
+	func getCurrentValue(maxRadius: CGFloat) -> Double? {
+
+		guard let index = self.touchedCircleIndex(maxRadius: maxRadius) else { return nil }
+		return self.chartData.points[index]
+	}
+}
+
+
+struct RingsChartRow_Previews: PreviewProvider {
+	static var previews: some View {
+
+		let multiStyle = ChartStyle(backgroundColor: ColorGradient(Color.black.opacity(0.05), Color.white),
+									foregroundColor:
+										[ColorGradient(.purple, .blue),
+										 ColorGradient(.orange, .red),
+										 ColorGradient(.green, .yellow),
+										])
+
+		return RingsChartRow(width:20.0, spacing:10.0, chartData: ChartData([25,50,75,100,125]), style: multiStyle)
+
+			// and why does this not get centered when frame isn't specified?
+			.frame(width:300, height:400)
+	}
+}
+
+

Sources/SwiftUICharts/PieChartCell.swift

@@ -1,65 +0,0 @@
-//
-//  PieChartCell.swift
-//  ChartView
-//
-//  Created by András Samu on 2019. 06. 12..
-//  Copyright © 2019. András Samu. All rights reserved.
-//
-
-import SwiftUI
-
-struct PieSlice: Identifiable {
-    var id = UUID()
-    var startDeg: Double
-    var endDeg: Double
-    var value: Int
-    var normalizedValue: Double
-}
-
-public struct PieChartCell : View {
-    @State private var show:Bool = false
-    var rect: CGRect
-    var radius: CGFloat {
-        return min(rect.width, rect.height)/2
-    }
-    var startDeg: Double
-    var endDeg: Double
-    var path: Path {
-        var path = Path()
-        path.addArc(center:rect.mid , radius:self.radius, startAngle: Angle(degrees: self.startDeg), endAngle: Angle(degrees: self.endDeg), clockwise: false)
-        path.addLine(to: rect.mid)
-        path.closeSubpath()
-        return path
-    }
-    var index: Int
-    var backgroundColor:Color
-    var accentColor:Color
-    public var body: some View {
-        path
-        .fill()
-        .foregroundColor(self.accentColor)
-        .overlay(path.stroke(self.backgroundColor, lineWidth: 2))
-        .scaleEffect(self.show ? 1 : 0)
-        .animation(Animation.spring().delay(Double(self.index) * 0.04))
-        .onAppear(){
-                self.show = true
-        }
-    }
-}
-
-extension CGRect {
-    var mid: CGPoint {
-        return CGPoint(x:self.midX, y: self.midY)
-    }
-}
-
-#if DEBUG
-struct PieChartCell_Previews : PreviewProvider {
-    static var previews: some View {
-        GeometryReader { geometry in
-            PieChartCell(rect: geometry.frame(in: .local),startDeg: 0.0,endDeg: 90.0, index: 0, backgroundColor: Color(red: 252.0/255.0, green: 236.0/255.0, blue: 234.0/255.0), accentColor: Color(red: 225.0/255.0, green: 97.0/255.0, blue: 76.0/255.0))
-        }.frame(width:100, height:100)
-        
-    }
-}
-#endif

Sources/SwiftUICharts/PieChartRow.swift

@@ -1,46 +0,0 @@
-//
-//  PieChartRow.swift
-//  ChartView
-//
-//  Created by András Samu on 2019. 06. 12..
-//  Copyright © 2019. András Samu. All rights reserved.
-//
-
-import SwiftUI
-
-public struct PieChartRow : View {
-    var data: [Int]
-    var backgroundColor: Color
-    var accentColor: Color
-    var slices: [PieSlice] {
-        var tempSlices:[PieSlice] = []
-        var lastEndDeg:Double = 0
-        let maxValue = data.reduce(0, +)
-        for slice in data {
-            let normalized:Double = Double(slice)/Double(maxValue)
-            let startDeg = lastEndDeg
-            let endDeg = lastEndDeg + (normalized * 360)
-            lastEndDeg = endDeg
-            tempSlices.append(PieSlice(startDeg: startDeg, endDeg: endDeg, value: slice, normalizedValue: normalized))
-        }
-        return tempSlices
-    }
-    public var body: some View {
-        GeometryReader { geometry in
-            ZStack{
-                ForEach(0..<self.slices.count){ i in
-                    PieChartCell(rect: geometry.frame(in: .local), startDeg: self.slices[i].startDeg, endDeg: self.slices[i].endDeg, index: i, backgroundColor: self.backgroundColor,accentColor: self.accentColor)
-                }
-            }
-        }
-    }
-}
-
-#if DEBUG
-struct PieChartRow_Previews : PreviewProvider {
-    static var previews: some View {
-        PieChartRow(data:[8,23,54,32,12,37,7,23,43], backgroundColor: Color(red: 252.0/255.0, green: 236.0/255.0, blue: 234.0/255.0), accentColor: Color(red: 225.0/255.0, green: 97.0/255.0, blue: 76.0/255.0)).frame(width: 100, height: 100)
-        
-    }
-}
-#endif

Sources/SwiftUICharts/PieChartView.swift

@@ -1,60 +0,0 @@
-//
-//  PieChartView.swift
-//  ChartView
-//
-//  Created by András Samu on 2019. 06. 12..
-//  Copyright © 2019. András Samu. All rights reserved.
-//
-
-import SwiftUI
-
-public struct PieChartView : View {
-    public var data: [Int]
-    public var title: String
-    public var legend: String?
-    public var backgroundColor:Color
-    public var accentColor:Color
-    
-    public init(data: [Int], title: String, legend: String? = nil, backgroundColor:Color = Color(red: 252.0/255.0, green: 236.0/255.0, blue: 234.0/255.0),accentColor:Color = Color(red: 225.0/255.0, green: 97.0/255.0, blue: 76.0/255.0)){
-        self.data = data
-        self.title = title
-        self.legend = legend
-        self.backgroundColor = backgroundColor
-        self.accentColor = accentColor
-    }
-    
-    public var body: some View {
-        ZStack{
-            Rectangle()
-                .fill(self.backgroundColor)
-                .cornerRadius(20)
-            VStack(alignment: .leading){
-                HStack{
-                    Text(self.title)
-                        .font(.headline)
-                    Spacer()
-                    Image(systemName: "chart.pie.fill")
-                        .imageScale(.large)
-                        .foregroundColor(self.accentColor)
-                    }.padding()
-                PieChartRow(data: data, backgroundColor: self.backgroundColor, accentColor: self.accentColor)
-                    .foregroundColor(self.accentColor).padding(self.legend != nil ? 0 : 12).offset(y:self.legend != nil ? 0 : -10)
-                if(self.legend != nil) {
-                    Text(self.legend!)
-                        .font(.headline)
-                        .foregroundColor(self.accentColor)
-                        .padding()
-                }
-                
-            }
-            }.frame(width: 200, height: 240)
-    }
-}
-
-#if DEBUG
-struct PieChartView_Previews : PreviewProvider {
-    static var previews: some View {
-        PieChartView(data:[56,78,53], title: "Title", legend: "Legend")
-    }
-}
-#endif

Tests/SwiftUIChartsTests/ArrayExtensionTests.swift

@@ -0,0 +1,44 @@
+//
+//  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)
+
+    }
+  
+}

Tests/SwiftUIChartsTests/CGPointExtensionTests.swift

@@ -0,0 +1,32 @@
+//
+//  CGPointExtensionTests.swift
+//  SwiftUIChartsTests
+//
+//  Created by Adrian Bolinger on 5/24/20.
+//
+
+@testable import SwiftUICharts
+import XCTest
+
+class CGPointExtensionTests: XCTestCase {
+    static let twentyElementArray: [Double] = Array(repeating: Double.random(in: 1...100), count: 20)
+    
+    func testGetStepWithOneElementArray() {
+        let frame = CGRect(x: 0, y: 0, width: 300, height: 300)
+        let oneElementArray: [Double] = [0.0]
+        
+        XCTAssertEqual(CGPoint.getStep(frame: frame, data: oneElementArray), .zero)
+    }
+    
+    func testGetStepWithMultiElementArrayWithNegativeValues() {
+        let frame = CGRect(x: 0, y: 0, width: 300, height: 300)
+        let multiElementArray: [Double] = [-5.0, 0.0, 5.0]
+        XCTAssertEqual(CGPoint.getStep(frame: frame, data: multiElementArray), CGPoint(x: 150.0, y: 27.0))
+    }
+    
+    func testGetStepWithMultiElementArrayWithPositiveValues() {
+        let frame = CGRect(x: 0, y: 0, width: 300, height: 300)
+        let multiElementArray: [Double] = [5.0, 10.0, 15.0]
+        XCTAssertEqual(CGPoint.getStep(frame: frame, data: multiElementArray), CGPoint(x: 150.0, y: 13.5))
+    }
+}

Tests/SwiftUIChartsTests/ColorExtensionTests.swift

@@ -0,0 +1,56 @@
+//
+//  ColorExtensionTests.swift
+//  SwiftUIChartsTests
+//
+//  Created by Adrian Bolinger on 5/24/20.
+//
+
+@testable import SwiftUICharts
+import SwiftUI
+import XCTest
+
+class ColorExtensionTests: XCTestCase {
+    func testTwentyFourBitRGBColors() {
+        let actualWhite = Color(hexString: "FFFFFF")
+        let expectedWhite = Color(red: 1, green: 1, blue: 1)
+        XCTAssertEqual(actualWhite, expectedWhite)
+        
+        let actualBlack = Color(hexString: "000000")
+        let expectedBlack = Color(red: 0, green: 0, blue: 0)
+        XCTAssertEqual(actualBlack, expectedBlack)
+        
+        let actualRed = Color(hexString: "FF0000")
+        let expectedRed = Color(red: 255/255, green: 0, blue: 0)
+        XCTAssertEqual(actualRed, expectedRed)
+        
+        let actualGreen = Color(hexString: "00FF00")
+        let expectedGreen = Color(red: 0, green: 1, blue: 0)
+        XCTAssertEqual(actualGreen, expectedGreen)
+        
+        let actualBlue = Color(hexString: "0000FF")
+        let expectedBlue = Color(red: 0, green: 0, blue: 1)
+        XCTAssertEqual(actualBlue, expectedBlue)
+    }
+    
+    func testTwelveBitRGBColors() {
+        let actualWhite = Color(hexString: "FFF")
+        let expectedWhite = Color(red: 1, green: 1, blue: 1)
+        XCTAssertEqual(actualWhite, expectedWhite)
+        
+        let actualBlack = Color(hexString: "000")
+        let expectedBlack = Color(red: 0, green: 0, blue: 0)
+        XCTAssertEqual(actualBlack, expectedBlack)
+        
+        let actualRed = Color(hexString: "F00")
+        let expectedRed = Color(red: 255/255, green: 0, blue: 0)
+        XCTAssertEqual(actualRed, expectedRed)
+        
+        let actualGreen = Color(hexString: "0F0")
+        let expectedGreen = Color(red: 0, green: 1, blue: 0)
+        XCTAssertEqual(actualGreen, expectedGreen)
+        
+        let actualBlue = Color(hexString: "00F")
+        let expectedBlue = Color(red: 0, green: 0, blue: 1)
+        XCTAssertEqual(actualBlue, expectedBlue)
+    }
+}

Tests/SwiftUIChartsTests/SwiftUIChartsTests.swift

@@ -9,6 +9,6 @@ final class SwiftUIChartsTests: XCTestCase {
     }
 
     static var allTests = [
-        ("testExample", testExample),
+        ("testExample", testExample)
     ]
 }

Tests/SwiftUIChartsTests/XCTestManifests.swift

@@ -3,7 +3,7 @@ import XCTest
 #if !canImport(ObjectiveC)
 public func allTests() -> [XCTestCaseEntry] {
     return [
-        testCase(SwiftUIChartsTests.allTests),
+        testCase(SwiftUIChartsTests.allTests)
     ]
 }
 #endif