From 92216b85d0e022970328841d040d7c382adb50a5 Mon Sep 17 00:00:00 2001
From: Majid Jabrayilov <cmecid@gmail.com>
Date: Thu, 5 May 2022 18:38:38 +0400
Subject: [PATCH] Stacked horizontal bar chart view introduced

---
 .../StackedHorizontalBarChartView.swift       | 101 ++++++++++++++++++
 1 file changed, 101 insertions(+)
 create mode 100644 Sources/SwiftUICharts/StackedHorizontalBarChartView.swift

diff --git a/Sources/SwiftUICharts/StackedHorizontalBarChartView.swift b/Sources/SwiftUICharts/StackedHorizontalBarChartView.swift
new file mode 100644
index 0000000..1dd416a
--- /dev/null
+++ b/Sources/SwiftUICharts/StackedHorizontalBarChartView.swift
@@ -0,0 +1,101 @@
+//
+//  StackedHorizontalBarChartView.swift
+//  SwiftUICharts
+//
+//  Created by Majid Jabrayilov on 05.05.22.
+//
+import SwiftUI
+
+/// Type that defines horizontally stacked bar chart style.
+public struct StackedHorizontalBarChartStyle: ChartStyle {
+    /// Boolean value indicating whenever to show chart legend
+    public let showLegends: Bool
+    /// Spacing between stacked horizontal bars
+    public let spacing: CGFloat
+    /// Corner radius for the whole chart view
+    public let cornerRadius: CGFloat
+
+    /**
+     Creates a new stacked bar chart style with the following parameters.
+
+     - Parameters:
+        - showLegends: Bool value that controls whenever to show the legend.
+        - cornerRadius: Corner radius used to round chart corners.
+        - spacing: Spacing between stacked bars in the chart.
+     */
+    public init(
+        showLegends: Bool = true,
+        cornerRadius: CGFloat = 8,
+        spacing: CGFloat = 0
+    ) {
+        self.showLegends = showLegends
+        self.cornerRadius = cornerRadius
+        self.spacing = spacing
+    }
+}
+
+/// SwiftUI view that draws data points as horizontally stacked bars.
+public struct StackedHorizontalBarChartView: View {
+    /// An array of data points to draw
+    let dataPoints: [DataPoint]
+
+    @Environment(\.chartStyle) private var chartStyle
+    private var style: StackedHorizontalBarChartStyle {
+        (chartStyle as? StackedHorizontalBarChartStyle) ?? .init()
+    }
+
+    /**
+     Creates a new horizontally stacked bar chart view
+
+     - Parameters:
+        - dataPoints: An array of data points to draw
+    */
+    public init(dataPoints: [DataPoint]) {
+        self.dataPoints = dataPoints
+    }
+
+    public var body: some View {
+        VStack {
+            GeometryReader { geometry in
+                HStack(spacing: style.spacing) {
+                    ForEach(dataPoints, id: \.self) { dataPoint in
+                        Rectangle()
+                            .fill(dataPoint.legend.color)
+                            .frame(width: dataPoint.endValue / sum * geometry.size.width)
+                            .accessibilityValue(Text(String(dataPoint.endValue)) + Text(dataPoint.label))
+                            .accessibilityLabel(dataPoint.legend.label)
+                    }
+                }
+                .clipShape(RoundedRectangle(cornerRadius: style.cornerRadius, style: .continuous))
+            }
+
+            LegendView(dataPoints: dataPoints)
+                .padding(.top)
+                .accessibility(hidden: true)
+        }
+    }
+
+    private var sum: CGFloat {
+        dataPoints.map(\.endValue).reduce(0.0, +)
+    }
+}
+
+struct StackedHorizontalBarChartView_Previews: PreviewProvider {
+    static var previews: some View {
+        let protein = Legend(color: .green, label: "Protein", order: 1)
+        let carbs = Legend(color: .blue, label: "Carbs", order: 2)
+        let fat = Legend(color: .red, label: "Fat", order: 3)
+
+        return List {
+            StackedHorizontalBarChartView(
+                dataPoints: [
+                    .init(value: 44, label: "Breast", legend: protein),
+                    .init(value: 77, label: "Couscous", legend: carbs),
+                    .init(value: 6, label: "Fats", legend: fat)
+                ]
+            )
+            .frame(minHeight: 100)
+            .padding(.vertical)
+        }
+    }
+}