Add breakdown chart support

This also cleans up the bar chart code slightly and fixes
some minor bugs that were detected in related code.

Closes #244

src/Spectre.Console/Widgets/Charts/BarChart.cs

@@ -0,0 +1,99 @@
+using System;
+using System.Collections.Generic;
+using System.Globalization;
+using System.Linq;
+using Spectre.Console.Rendering;
+
+namespace Spectre.Console
+{
+    /// <summary>
+    /// A renderable (horizontal) bar chart.
+    /// </summary>
+    public sealed class BarChart : Renderable, IHasCulture
+    {
+        /// <summary>
+        /// Gets the bar chart data.
+        /// </summary>
+        public List<IBarChartItem> Data { get; }
+
+        /// <summary>
+        /// Gets or sets the width of the bar chart.
+        /// </summary>
+        public int? Width { get; set; }
+
+        /// <summary>
+        /// Gets or sets the bar chart label.
+        /// </summary>
+        public string? Label { get; set; }
+
+        /// <summary>
+        /// Gets or sets the bar chart label alignment.
+        /// </summary>
+        public Justify? LabelAlignment { get; set; } = Justify.Center;
+
+        /// <summary>
+        /// Gets or sets a value indicating whether or not
+        /// values should be shown next to each bar.
+        /// </summary>
+        public bool ShowValues { get; set; } = true;
+
+        /// <summary>
+        /// Gets or sets the culture that's used to format values.
+        /// </summary>
+        /// <remarks>Defaults to invariant culture.</remarks>
+        public CultureInfo? Culture { get; set; }
+
+        /// <summary>
+        /// Initializes a new instance of the <see cref="BarChart"/> class.
+        /// </summary>
+        public BarChart()
+        {
+            Data = new List<IBarChartItem>();
+        }
+
+        /// <inheritdoc/>
+        protected override Measurement Measure(RenderContext context, int maxWidth)
+        {
+            var width = Math.Min(Width ?? maxWidth, maxWidth);
+            return new Measurement(width, width);
+        }
+
+        /// <inheritdoc/>
+        protected override IEnumerable<Segment> Render(RenderContext context, int maxWidth)
+        {
+            var width = Math.Min(Width ?? maxWidth, maxWidth);
+            var maxValue = Data.Max(item => item.Value);
+
+            var grid = new Grid();
+            grid.Collapse();
+            grid.AddColumn(new GridColumn().PadRight(2).RightAligned());
+            grid.AddColumn(new GridColumn().PadLeft(0));
+            grid.Width = width;
+
+            if (!string.IsNullOrWhiteSpace(Label))
+            {
+                grid.AddRow(Text.Empty, new Markup(Label).Alignment(LabelAlignment));
+            }
+
+            foreach (var item in Data)
+            {
+                grid.AddRow(
+                    new Markup(item.Label),
+                    new ProgressBar()
+                    {
+                        Value = item.Value,
+                        MaxValue = maxValue,
+                        ShowRemaining = false,
+                        CompletedStyle = new Style().Foreground(item.Color ?? Color.Default),
+                        FinishedStyle = new Style().Foreground(item.Color ?? Color.Default),
+                        UnicodeBar = '█',
+                        AsciiBar = '█',
+                        ShowValue = ShowValues,
+                        Culture = Culture,
+                    });
+            }
+
+            return ((IRenderable)grid).Render(context, width);
+        }
+    }
+}

src/Spectre.Console/Widgets/Charts/BarChartItem.cs

@@ -0,0 +1,38 @@
+using System;
+
+namespace Spectre.Console
+{
+    /// <summary>
+    /// An item that's shown in a bar chart.
+    /// </summary>
+    public sealed class BarChartItem : IBarChartItem
+    {
+        /// <summary>
+        /// Gets the item label.
+        /// </summary>
+        public string Label { get; }
+
+        /// <summary>
+        /// Gets the item value.
+        /// </summary>
+        public double Value { get; }
+
+        /// <summary>
+        /// Gets the item color.
+        /// </summary>
+        public Color? Color { get; }
+
+        /// <summary>
+        /// Initializes a new instance of the <see cref="BarChartItem"/> class.
+        /// </summary>
+        /// <param name="label">The item label.</param>
+        /// <param name="value">The item value.</param>
+        /// <param name="color">The item color.</param>
+        public BarChartItem(string label, double value, Color? color = null)
+        {
+            Label = label ?? throw new ArgumentNullException(nameof(label));
+            Value = value;
+            Color = color;
+        }
+    }
+}

src/Spectre.Console/Widgets/Charts/BreakdownBar.cs

@@ -0,0 +1,42 @@
+using System;
+using System.Collections.Generic;
+using System.Linq;
+using Spectre.Console.Rendering;
+
+namespace Spectre.Console
+{
+    internal sealed class BreakdownBar : Renderable
+    {
+        private readonly List<IBreakdownChartItem> _data;
+
+        public int? Width { get; set; }
+
+        public BreakdownBar(List<IBreakdownChartItem> data)
+        {
+            _data = data ?? throw new ArgumentNullException(nameof(data));
+        }
+
+        protected override Measurement Measure(RenderContext context, int maxWidth)
+        {
+            var width = Math.Min(Width ?? maxWidth, maxWidth);
+            return new Measurement(width, width);
+        }
+
+        protected override IEnumerable<Segment> Render(RenderContext context, int maxWidth)
+        {
+            var width = Math.Min(Width ?? maxWidth, maxWidth);
+
+            // Chart
+            var maxValue = _data.Sum(i => i.Value);
+            var items = _data.ToArray();
+            var bars = Ratio.Distribute(width, items.Select(i => Math.Max(0, (int)(width * (i.Value / maxValue)))).ToArray());
+
+            for (var index = 0; index < items.Length; index++)
+            {
+                yield return new Segment(new string('█', bars[index]), new Style(items[index].Color));
+            }
+
+            yield return Segment.LineBreak;
+        }
+    }
+}

src/Spectre.Console/Widgets/Charts/BreakdownChart.cs

@@ -0,0 +1,102 @@
+using System;
+using System.Collections.Generic;
+using System.Globalization;
+using Spectre.Console.Rendering;
+
+namespace Spectre.Console
+{
+    /// <summary>
+    /// A renderable breakdown chart.
+    /// </summary>
+    public sealed class BreakdownChart : Renderable, IHasCulture
+    {
+        /// <summary>
+        /// Gets the breakdown chart data.
+        /// </summary>
+        public List<IBreakdownChartItem> Data { get; }
+
+        /// <summary>
+        /// Gets or sets the width of the breakdown chart.
+        /// </summary>
+        public int? Width { get; set; }
+
+        /// <summary>
+        /// Gets or sets a value indicating whether or not
+        /// to show values as percentages or not.
+        /// </summary>
+        public bool ShowAsPercentages { get; set; }
+
+        /// <summary>
+        /// Gets or sets a value indicating whether or not to show tags.
+        /// </summary>
+        public bool ShowTags { get; set; } = true;
+
+        /// <summary>
+        /// Gets or sets a value indicating whether or not to show tag values.
+        /// </summary>
+        public bool ShowTagValues { get; set; } = true;
+
+        /// <summary>
+        /// Gets or sets a value indicating whether or not the
+        /// chart and tags should be rendered in compact mode.
+        /// </summary>
+        public bool Compact { get; set; } = true;
+
+        /// <summary>
+        /// Gets or sets the <see cref="CultureInfo"/> to use
+        /// when rendering values.
+        /// </summary>
+        /// <remarks>Defaults to invariant culture.</remarks>
+        public CultureInfo? Culture { get; set; }
+
+        /// <summary>
+        /// Initializes a new instance of the <see cref="BreakdownChart"/> class.
+        /// </summary>
+        public BreakdownChart()
+        {
+            Data = new List<IBreakdownChartItem>();
+            Culture = CultureInfo.InvariantCulture;
+        }
+
+        /// <inheritdoc/>
+        protected override Measurement Measure(RenderContext context, int maxWidth)
+        {
+            var width = Math.Min(Width ?? maxWidth, maxWidth);
+            return new Measurement(width, width);
+        }
+
+        /// <inheritdoc/>
+        protected override IEnumerable<Segment> Render(RenderContext context, int maxWidth)
+        {
+            var width = Math.Min(Width ?? maxWidth, maxWidth);
+
+            var grid = new Grid().Width(width);
+            grid.AddColumn(new GridColumn().NoWrap());
+
+            // Bar
+            grid.AddRow(new BreakdownBar(Data)
+            {
+                Width = width,
+            });
+
+            if (ShowTags)
+            {
+                if (!Compact)
+                {
+                    grid.AddEmptyRow();
+                }
+
+                // Tags
+                grid.AddRow(new BreakdownTags(Data)
+                {
+                    Width = width,
+                    Culture = Culture,
+                    ShowPercentages = ShowAsPercentages,
+                    ShowTagValues = ShowTagValues,
+                });
+            }
+
+            return ((IRenderable)grid).Render(context, width);
+        }
+    }
+}

src/Spectre.Console/Widgets/Charts/BreakdownChartItem.cs

@@ -0,0 +1,38 @@
+using System;
+
+namespace Spectre.Console
+{
+    /// <summary>
+    /// An item that's shown in a breakdown chart.
+    /// </summary>
+    public sealed class BreakdownChartItem : IBreakdownChartItem
+    {
+        /// <summary>
+        /// Gets the item label.
+        /// </summary>
+        public string Label { get; }
+
+        /// <summary>
+        /// Gets the item value.
+        /// </summary>
+        public double Value { get; }
+
+        /// <summary>
+        /// Gets the item color.
+        /// </summary>
+        public Color Color { get; }
+
+        /// <summary>
+        /// Initializes a new instance of the <see cref="BreakdownChartItem"/> class.
+        /// </summary>
+        /// <param name="label">The item label.</param>
+        /// <param name="value">The item value.</param>
+        /// <param name="color">The item color.</param>
+        public BreakdownChartItem(string label, double value, Color color)
+        {
+            Label = label ?? throw new ArgumentNullException(nameof(label));
+            Value = value;
+            Color = color;
+        }
+    }
+}

src/Spectre.Console/Widgets/Charts/BreakdownTags.cs

@@ -0,0 +1,69 @@
+using System;
+using System.Collections.Generic;
+using System.Globalization;
+using Spectre.Console.Rendering;
+
+namespace Spectre.Console
+{
+    internal sealed class BreakdownTags : Renderable
+    {
+        private readonly List<IBreakdownChartItem> _data;
+
+        public int? Width { get; set; }
+        public CultureInfo? Culture { get; set; }
+        public bool ShowPercentages { get; set; }
+        public bool ShowTagValues { get; set; } = true;
+
+        public BreakdownTags(List<IBreakdownChartItem> data)
+        {
+            _data = data ?? throw new ArgumentNullException(nameof(data));
+        }
+
+        protected override Measurement Measure(RenderContext context, int maxWidth)
+        {
+            var width = Math.Min(Width ?? maxWidth, maxWidth);
+            return new Measurement(width, width);
+        }
+
+        protected override IEnumerable<Segment> Render(RenderContext context, int maxWidth)
+        {
+            var culture = Culture ?? CultureInfo.InvariantCulture;
+
+            var panels = new List<Panel>();
+            foreach (var item in _data)
+            {
+                var panel = new Panel(GetTag(item, culture));
+                panel.Inline = true;
+                panel.Padding = new Padding(0, 0);
+                panel.NoBorder();
+
+                panels.Add(panel);
+            }
+
+            foreach (var segment in ((IRenderable)new Columns(panels).Padding(0, 0)).Render(context, maxWidth))
+            {
+                yield return segment;
+            }
+        }
+
+        private string GetTag(IBreakdownChartItem item, CultureInfo culture)
+        {
+            return string.Format(
+                culture, "[{0}]■[/] {1}",
+                item.Color.ToMarkup() ?? "default",
+                FormatValue(item, culture)).Trim();
+        }
+
+        private string FormatValue(IBreakdownChartItem item, CultureInfo culture)
+        {
+            if (ShowTagValues)
+            {
+                return string.Format(culture, "{0} [grey]{1}{2}[/]",
+                    item.Label.EscapeMarkup(), item.Value,
+                    ShowPercentages ? "%" : string.Empty);
+            }
+
+            return item.Label.EscapeMarkup();
+        }
+    }
+}

src/Spectre.Console/Widgets/Charts/IBarChartItem.cs

@@ -0,0 +1,23 @@
+namespace Spectre.Console
+{
+    /// <summary>
+    /// Represents a bar chart item.
+    /// </summary>
+    public interface IBarChartItem
+    {
+        /// <summary>
+        /// Gets the item label.
+        /// </summary>
+        string Label { get; }
+
+        /// <summary>
+        /// Gets the item value.
+        /// </summary>
+        double Value { get; }
+
+        /// <summary>
+        /// Gets the item color.
+        /// </summary>
+        Color? Color { get; }
+    }
+}

src/Spectre.Console/Widgets/Charts/IBreakdownChartItem.cs

@@ -0,0 +1,23 @@
+namespace Spectre.Console
+{
+    /// <summary>
+    /// Represents a breakdown chart item.
+    /// </summary>
+    public interface IBreakdownChartItem
+    {
+        /// <summary>
+        /// Gets the item label.
+        /// </summary>
+        string Label { get; }
+
+        /// <summary>
+        /// Gets the item value.
+        /// </summary>
+        double Value { get; }
+
+        /// <summary>
+        /// Gets the item color.
+        /// </summary>
+        Color Color { get; }
+    }
+}