Add fallback for unicode borders

src/Sample/Program.cs

@@ -13,6 +13,7 @@ namespace Sample
             AnsiConsole.WriteLine("Hello World!");
             AnsiConsole.Reset();
             AnsiConsole.MarkupLine("Capabilities: [yellow underline]{0}[/]", AnsiConsole.Capabilities);
+            AnsiConsole.MarkupLine("Encoding: [yellow underline]{0}[/]", AnsiConsole.Console.Encoding.EncodingName);
             AnsiConsole.MarkupLine("Width=[yellow]{0}[/], Height=[yellow]{1}[/]", AnsiConsole.Width, AnsiConsole.Height);
             AnsiConsole.MarkupLine("[white on red]Good[/] [red]bye[/]!");
             AnsiConsole.WriteLine();
@@ -51,6 +52,7 @@ namespace Sample
             console.ResetColors();
             console.ResetDecoration();
             console.MarkupLine("Capabilities: [yellow underline]{0}[/]", console.Capabilities);
+            console.MarkupLine("Encoding: [yellow underline]{0}[/]", AnsiConsole.Console.Encoding.EncodingName);
             console.MarkupLine("Width=[yellow]{0}[/], Height=[yellow]{1}[/]", console.Width, console.Height);
             console.MarkupLine("[white on red]Good[/] [red]bye[/]!");
             console.WriteLine();

src/Spectre.Console.Tests/Fixtures/PlainConsole.cs

@@ -7,7 +7,7 @@ namespace Spectre.Console.Tests
 {
     public sealed class PlainConsole : IAnsiConsole, IDisposable
     {
-        public Capabilities Capabilities => throw new NotSupportedException();
+        public Capabilities Capabilities { get; }
         public Encoding Encoding { get; }
 
         public int Width { get; }
@@ -21,11 +21,15 @@ namespace Spectre.Console.Tests
         public string Output => Writer.ToString().TrimEnd('\n');
         public IReadOnlyList<string> Lines => Output.Split(new char[] { '\n' });
 
-        public PlainConsole(int width = 80, int height = 9000, Encoding encoding = null)
+        public PlainConsole(
+            int width = 80, int height = 9000, Encoding encoding = null,
+            bool supportsAnsi = true, ColorSystem colorSystem = ColorSystem.Standard,
+            bool legacyConsole = false)
         {
+            Capabilities = new Capabilities(supportsAnsi, colorSystem, legacyConsole);
+            Encoding = encoding ?? Encoding.UTF8;
             Width = width;
             Height = height;
-            Encoding = encoding ?? Encoding.UTF8;
             Writer = new StringWriter();
         }
 

src/Spectre.Console.Tests/Unit/Composition/BorderTests.cs

@@ -10,13 +10,18 @@ namespace Spectre.Console.Tests.Unit.Composition
         public sealed class TheGetBorderMethod
         {
             [Theory]
-            [InlineData(BorderKind.Ascii, typeof(AsciiBorder))]
+            [InlineData(BorderKind.None, false, typeof(NoBorder))]
-            [InlineData(BorderKind.Square, typeof(SquareBorder))]
+            [InlineData(BorderKind.Ascii, false, typeof(AsciiBorder))]
-            [InlineData(BorderKind.Rounded, typeof(RoundedBorder))]
+            [InlineData(BorderKind.Square, false, typeof(SquareBorder))]
-            public void Should_Return_Correct_Border_For_Specified_Kind(BorderKind kind, Type expected)
+            [InlineData(BorderKind.Rounded, false, typeof(RoundedBorder))]
+            [InlineData(BorderKind.None, true, typeof(NoBorder))]
+            [InlineData(BorderKind.Ascii, true, typeof(AsciiBorder))]
+            [InlineData(BorderKind.Square, true, typeof(SquareBorder))]
+            [InlineData(BorderKind.Rounded, true, typeof(SquareBorder))]
+            public void Should_Return_Correct_Border_For_Specified_Kind(BorderKind kind, bool safe, Type expected)
             {
                 // Given, When
-                var result = Border.GetBorder(kind);
+                var result = Border.GetBorder(kind, safe);
 
                 // Then
                 result.ShouldBeOfType(expected);
@@ -26,7 +31,7 @@ namespace Spectre.Console.Tests.Unit.Composition
             public void Should_Throw_If_Unknown_Border_Kind_Is_Specified()
             {
                 // Given, When
-                var result = Record.Exception(() => Border.GetBorder((BorderKind)int.MaxValue));
+                var result = Record.Exception(() => Border.GetBorder((BorderKind)int.MaxValue, false));
 
                 // Then
                 result.ShouldBeOfType<InvalidOperationException>();

src/Spectre.Console/Capabilities.cs

@@ -25,7 +25,13 @@ namespace Spectre.Console
         /// </remarks>
         public bool LegacyConsole { get; }
 
-        internal Capabilities(bool supportsAnsi, ColorSystem colorSystem, bool legacyConsole)
+        /// <summary>
+        /// Initializes a new instance of the <see cref="Capabilities"/> class.
+        /// </summary>
+        /// <param name="supportsAnsi">Whether or not ANSI escape sequences are supported.</param>
+        /// <param name="colorSystem">The color system that is supported.</param>
+        /// <param name="legacyConsole">Whether or not this is a legacy console.</param>
+        public Capabilities(bool supportsAnsi, ColorSystem colorSystem, bool legacyConsole)
         {
             SupportsAnsi = supportsAnsi;
             ColorSystem = colorSystem;

src/Spectre.Console/Composition/Border.cs

@@ -20,6 +20,11 @@ namespace Spectre.Console.Composition
             { BorderKind.Rounded, new RoundedBorder() },
         };
 
+        private static readonly Dictionary<BorderKind, BorderKind> _safeLookup = new Dictionary<BorderKind, BorderKind>
+        {
+            { BorderKind.Rounded, BorderKind.Square },
+        };
+
         /// <summary>
         /// Initializes a new instance of the <see cref="Border"/> class.
         /// </summary>
@@ -32,9 +37,15 @@ namespace Spectre.Console.Composition
         /// Gets a <see cref="Border"/> represented by the specified <see cref="BorderKind"/>.
         /// </summary>
         /// <param name="kind">The kind of border to get.</param>
+        /// <param name="safe">Whether or not to get a "safe" border that can be rendered in a legacy console.</param>
         /// <returns>A <see cref="Border"/> instance representing the specified <see cref="BorderKind"/>.</returns>
-        public static Border GetBorder(BorderKind kind)
+        public static Border GetBorder(BorderKind kind, bool safe)
         {
+            if (safe && _safeLookup.TryGetValue(kind, out var safeKind))
+            {
+                kind = safeKind;
+            }
+
             if (!_borders.TryGetValue(kind, out var border))
             {
                 throw new InvalidOperationException("Unknown border kind");

src/Spectre.Console/Composition/Borders/NoBorder.cs

@@ -1,7 +1,11 @@
 namespace Spectre.Console.Composition
 {
-    internal sealed class NoBorder : Border
+    /// <summary>
+    /// Represents an invisible border.
+    /// </summary>
+    public sealed class NoBorder : Border
     {
+        /// <inheritdoc/>
         protected override string GetBoxPart(BorderPart part)
         {
             return " ";

src/Spectre.Console/Composition/Grid.cs

@@ -1,6 +1,5 @@
 using System;
 using System.Collections.Generic;
-using System.Text;
 using Spectre.Console.Composition;
 
 namespace Spectre.Console
@@ -25,15 +24,15 @@ namespace Spectre.Console
         }
 
         /// <inheritdoc/>
-        public Measurement Measure(Encoding encoding, int maxWidth)
+        public Measurement Measure(RenderContext context, int maxWidth)
         {
-            return ((IRenderable)_table).Measure(encoding, maxWidth);
+            return ((IRenderable)_table).Measure(context, maxWidth);
         }
 
         /// <inheritdoc/>
-        public IEnumerable<Segment> Render(Encoding encoding, int width)
+        public IEnumerable<Segment> Render(RenderContext context, int width)
         {
-            return ((IRenderable)_table).Render(encoding, width);
+            return ((IRenderable)_table).Render(context, width);
         }
 
         /// <summary>

src/Spectre.Console/Composition/IRenderable.cs

@@ -1,5 +1,4 @@
 using System.Collections.Generic;
-using System.Text;
 
 namespace Spectre.Console.Composition
 {
@@ -11,17 +10,17 @@ namespace Spectre.Console.Composition
         /// <summary>
         /// Measures the renderable object.
         /// </summary>
-        /// <param name="encoding">The encoding to use.</param>
+        /// <param name="context">The render context.</param>
         /// <param name="maxWidth">The maximum allowed width.</param>
         /// <returns>The minimum and maximum width of the object.</returns>
-        Measurement Measure(Encoding encoding, int maxWidth);
+        Measurement Measure(RenderContext context, int maxWidth);
 
         /// <summary>
         /// Renders the object.
         /// </summary>
-        /// <param name="encoding">The encoding to use.</param>
+        /// <param name="context">The render context.</param>
-        /// <param name="width">The width of the render area.</param>
+        /// <param name="maxWidth">The maximum allowed width.</param>
         /// <returns>A collection of segments.</returns>
-        IEnumerable<Segment> Render(Encoding encoding, int width);
+        IEnumerable<Segment> Render(RenderContext context, int maxWidth);
     }
 }

src/Spectre.Console/Composition/Panel.cs

@@ -1,6 +1,5 @@
 using System.Collections.Generic;
 using System.Linq;
-using System.Text;
 using Spectre.Console.Composition;
 
 namespace Spectre.Console
@@ -13,7 +12,14 @@ namespace Spectre.Console
         private readonly IRenderable _child;
         private readonly bool _fit;
         private readonly Justify _content;
-        private readonly Border _border;
+        private readonly BorderKind _border;
+
+        /// <summary>
+        /// Gets or sets a value indicating whether or not to use
+        /// a "safe" border on legacy consoles that might not be able
+        /// to render non-ASCII characters. Defaults to <c>true</c>.
+        /// </summary>
+        public bool SafeBorder { get; set; } = true;
 
         /// <summary>
         /// Initializes a new instance of the <see cref="Panel"/> class.
@@ -31,47 +37,49 @@ namespace Spectre.Console
             _child = child ?? throw new System.ArgumentNullException(nameof(child));
             _fit = fit;
             _content = content;
-            _border = Border.GetBorder(border);
+            _border = border;
         }
 
         /// <inheritdoc/>
-        Measurement IRenderable.Measure(Encoding encoding, int maxWidth)
+        Measurement IRenderable.Measure(RenderContext context, int maxWidth)
         {
-            var childWidth = _child.Measure(encoding, maxWidth);
+            var childWidth = _child.Measure(context, maxWidth);
             return new Measurement(childWidth.Min + 4, childWidth.Max + 4);
         }
 
         /// <inheritdoc/>
-        IEnumerable<Segment> IRenderable.Render(Encoding encoding, int width)
+        IEnumerable<Segment> IRenderable.Render(RenderContext context, int width)
         {
+            var border = Border.GetBorder(_border, (context.LegacyConsole || !context.Unicode) && SafeBorder);
+
             var childWidth = width - 4;
             if (!_fit)
             {
-                var measurement = _child.Measure(encoding, width - 2);
+                var measurement = _child.Measure(context, width - 2);
                 childWidth = measurement.Max;
             }
 
             var result = new List<Segment>();
             var panelWidth = childWidth + 2;
 
-            result.Add(new Segment(_border.GetPart(BorderPart.HeaderTopLeft)));
+            result.Add(new Segment(border.GetPart(BorderPart.HeaderTopLeft)));
-            result.Add(new Segment(_border.GetPart(BorderPart.HeaderTop, panelWidth)));
+            result.Add(new Segment(border.GetPart(BorderPart.HeaderTop, panelWidth)));
-            result.Add(new Segment(_border.GetPart(BorderPart.HeaderTopRight)));
+            result.Add(new Segment(border.GetPart(BorderPart.HeaderTopRight)));
             result.Add(new Segment("\n"));
 
             // Render the child.
-            var childSegments = _child.Render(encoding, childWidth);
+            var childSegments = _child.Render(context, childWidth);
 
             // Split the child segments into lines.
             var lines = Segment.SplitLines(childSegments, childWidth);
             foreach (var line in lines)
             {
-                result.Add(new Segment(_border.GetPart(BorderPart.CellLeft)));
+                result.Add(new Segment(border.GetPart(BorderPart.CellLeft)));
                 result.Add(new Segment(" ")); // Left padding
 
                 var content = new List<Segment>();
 
-                var length = line.Sum(segment => segment.CellLength(encoding));
+                var length = line.Sum(segment => segment.CellLength(context.Encoding));
                 if (length < childWidth)
                 {
                     // Justify right side
@@ -116,13 +124,13 @@ namespace Spectre.Console
                 result.AddRange(content);
 
                 result.Add(new Segment(" "));
-                result.Add(new Segment(_border.GetPart(BorderPart.CellRight)));
+                result.Add(new Segment(border.GetPart(BorderPart.CellRight)));
                 result.Add(new Segment("\n"));
             }
 
-            result.Add(new Segment(_border.GetPart(BorderPart.FooterBottomLeft)));
+            result.Add(new Segment(border.GetPart(BorderPart.FooterBottomLeft)));
-            result.Add(new Segment(_border.GetPart(BorderPart.FooterBottom, panelWidth)));
+            result.Add(new Segment(border.GetPart(BorderPart.FooterBottom, panelWidth)));
-            result.Add(new Segment(_border.GetPart(BorderPart.FooterBottomRight)));
+            result.Add(new Segment(border.GetPart(BorderPart.FooterBottomRight)));
             result.Add(new Segment("\n"));
 
             return result;

src/Spectre.Console/Composition/RenderContext.cs

@@ -0,0 +1,37 @@
+using System.Text;
+
+namespace Spectre.Console.Composition
+{
+    /// <summary>
+    /// Represents a render context.
+    /// </summary>
+    public sealed class RenderContext
+    {
+        /// <summary>
+        /// Gets the console's output encoding.
+        /// </summary>
+        public Encoding Encoding { get; }
+
+        /// <summary>
+        /// Gets a value indicating whether or not this a legacy console (i.e. cmd.exe).
+        /// </summary>
+        public bool LegacyConsole { get; }
+
+        /// <summary>
+        /// Gets a value indicating whether or not unicode is supported.
+        /// </summary>
+        public bool Unicode { get; }
+
+        /// <summary>
+        /// Initializes a new instance of the <see cref="RenderContext"/> class.
+        /// </summary>
+        /// <param name="encoding">The console's output encoding.</param>
+        /// <param name="legacyConsole">A value indicating whether or not this a legacy console (i.e. cmd.exe).</param>
+        public RenderContext(Encoding encoding, bool legacyConsole)
+        {
+            Encoding = encoding ?? throw new System.ArgumentNullException(nameof(encoding));
+            LegacyConsole = legacyConsole;
+            Unicode = Encoding == Encoding.UTF8 || Encoding == Encoding.Unicode;
+        }
+    }
+}

src/Spectre.Console/Composition/Table.Calculations.cs

@@ -1,7 +1,6 @@
 using System;
 using System.Collections.Generic;
 using System.Linq;
-using System.Text;
 using Spectre.Console.Composition;
 using Spectre.Console.Internal;
 
@@ -15,9 +14,9 @@ namespace Spectre.Console
         // Calculate the widths of each column, including padding, not including borders.
         // Ported from Rich by Will McGugan, licensed under MIT.
         // https://github.com/willmcgugan/rich/blob/527475837ebbfc427530b3ee0d4d0741d2d0fc6d/rich/table.py#L394
-        private List<int> CalculateColumnWidths(Encoding encoding, int maxWidth)
+        private List<int> CalculateColumnWidths(RenderContext options, int maxWidth)
         {
-            var width_ranges = _columns.Select(column => MeasureColumn(column, encoding, maxWidth));
+            var width_ranges = _columns.Select(column => MeasureColumn(column, options, maxWidth));
             var widths = width_ranges.Select(range => range.Max).ToList();
 
             var tableWidth = widths.Sum();
@@ -132,7 +131,7 @@ namespace Spectre.Console
             return widths;
         }
 
-        private (int Min, int Max) MeasureColumn(TableColumn column, Encoding encoding, int maxWidth)
+        private (int Min, int Max) MeasureColumn(TableColumn column, RenderContext options, int maxWidth)
         {
             // Predetermined width?
             if (column.Width != null)
@@ -148,7 +147,7 @@ namespace Spectre.Console
             var maxWidths = new List<int>();
             foreach (var row in rows)
             {
-                var measure = ((IRenderable)row).Measure(encoding, maxWidth);
+                var measure = ((IRenderable)row).Measure(options, maxWidth);
                 minWidths.Add(measure.Min);
                 maxWidths.Add(measure.Max);
             }

src/Spectre.Console/Composition/Table.cs

@@ -1,7 +1,6 @@
 using System;
 using System.Collections.Generic;
 using System.Linq;
-using System.Text;
 using Spectre.Console.Composition;
 using Spectre.Console.Internal;
 
@@ -47,6 +46,13 @@ namespace Spectre.Console
         /// </summary>
         public int? Width { get; set; } = null;
 
+        /// <summary>
+        /// Gets or sets a value indicating whether or not to use
+        /// a "safe" border on legacy consoles that might not be able
+        /// to render non-ASCII characters. Defaults to <c>true</c>.
+        /// </summary>
+        public bool SafeBorder { get; set; } = true;
+
         /// <summary>
         /// Initializes a new instance of the <see cref="Table"/> class.
         /// </summary>
@@ -123,8 +129,13 @@ namespace Spectre.Console
         }
 
         /// <inheritdoc/>
-        Measurement IRenderable.Measure(Encoding encoding, int maxWidth)
+        Measurement IRenderable.Measure(RenderContext context, int maxWidth)
         {
+            if (context is null)
+            {
+                throw new ArgumentNullException(nameof(context));
+            }
+
             if (Width != null)
             {
                 maxWidth = Math.Min(Width.Value, maxWidth);
@@ -132,7 +143,7 @@ namespace Spectre.Console
 
             maxWidth -= GetExtraWidth(includePadding: true);
 
-            var measurements = _columns.Select(column => MeasureColumn(column, encoding, maxWidth)).ToList();
+            var measurements = _columns.Select(column => MeasureColumn(column, context, maxWidth)).ToList();
             var min = measurements.Sum(x => x.Min) + GetExtraWidth(includePadding: true);
             var max = Width ?? measurements.Sum(x => x.Max) + GetExtraWidth(includePadding: true);
 
@@ -140,9 +151,14 @@ namespace Spectre.Console
         }
 
         /// <inheritdoc/>
-        IEnumerable<Segment> IRenderable.Render(Encoding encoding, int width)
+        IEnumerable<Segment> IRenderable.Render(RenderContext context, int width)
         {
-            var border = Composition.Border.GetBorder(Border);
+            if (context is null)
+            {
+                throw new ArgumentNullException(nameof(context));
+            }
+
+            var border = Composition.Border.GetBorder(Border, (context.LegacyConsole || !context.Unicode) && SafeBorder);
 
             var showBorder = Border != BorderKind.None;
             var hideBorder = Border == BorderKind.None;
@@ -156,7 +172,7 @@ namespace Spectre.Console
             maxWidth -= GetExtraWidth(includePadding: true);
 
             // Calculate the column and table widths
-            var columnWidths = CalculateColumnWidths(encoding, maxWidth);
+            var columnWidths = CalculateColumnWidths(context, maxWidth);
 
             // Update the table width.
             width = columnWidths.Sum() + GetExtraWidth(includePadding: false);
@@ -181,7 +197,7 @@ namespace Spectre.Console
                 var cells = new List<List<SegmentLine>>();
                 foreach (var (rowWidth, cell) in columnWidths.Zip(row, (f, s) => (f, s)))
                 {
-                    var lines = Segment.SplitLines(((IRenderable)cell).Render(encoding, rowWidth));
+                    var lines = Segment.SplitLines(((IRenderable)cell).Render(context, rowWidth));
                     cellHeight = Math.Max(cellHeight, lines.Count);
                     cells.Add(lines);
                 }
@@ -234,7 +250,7 @@ namespace Spectre.Console
                         result.AddRange(cell[cellRowIndex]);
 
                         // Pad cell content right
-                        var length = cell[cellRowIndex].Sum(segment => segment.CellLength(encoding));
+                        var length = cell[cellRowIndex].Sum(segment => segment.CellLength(context.Encoding));
                         if (length < columnWidths[cellIndex])
                         {
                             result.Add(new Segment(new string(' ', columnWidths[cellIndex] - length)));

src/Spectre.Console/Composition/Text.cs

@@ -3,7 +3,6 @@ using System.Collections.Generic;
 using System.Diagnostics;
 using System.Diagnostics.CodeAnalysis;
 using System.Linq;
-using System.Text;
 using Spectre.Console.Composition;
 using Spectre.Console.Internal;
 
@@ -98,9 +97,9 @@ namespace Spectre.Console
         }
 
         /// <inheritdoc/>
-        Measurement IRenderable.Measure(Encoding encoding, int maxWidth)
+        Measurement IRenderable.Measure(RenderContext context, int maxWidth)
         {
-            var lines = Segment.SplitLines(((IRenderable)this).Render(encoding, maxWidth));
+            var lines = Segment.SplitLines(((IRenderable)this).Render(context, maxWidth));
             if (lines.Count == 0)
             {
                 return new Measurement(0, maxWidth);
@@ -113,7 +112,7 @@ namespace Spectre.Console
         }
 
         /// <inheritdoc/>
-        IEnumerable<Segment> IRenderable.Render(Encoding encoding, int width)
+        IEnumerable<Segment> IRenderable.Render(RenderContext context, int width)
         {
             if (string.IsNullOrWhiteSpace(_text))
             {

src/Spectre.Console/ConsoleExtensions.Rendering.cs

@@ -26,7 +26,9 @@ namespace Spectre.Console
                 throw new ArgumentNullException(nameof(renderable));
             }
 
-            foreach (var segment in renderable.Render(console.Encoding, console.Width))
+            var options = new RenderContext(console.Encoding, console.Capabilities.LegacyConsole);
+
+            foreach (var segment in renderable.Render(options, console.Width))
             {
                 if (!segment.Style.Equals(Style.Plain))
                 {