Add rounded border

src/Sample/Program.cs

@@ -87,7 +87,7 @@ namespace Sample
             table.AddRow("Hej 👋", "[green]Världen[/]");
             AnsiConsole.Render(table);
 
-            table = new Table(BorderKind.Ascii);
+            table = new Table(BorderKind.Rounded);
             table.AddColumns("[red underline]Foo[/]", "Bar");
             table.AddRow("[blue][underline]Hell[/]o[/]", "World 🌍");
             table.AddRow("[yellow]Patrik [green]\"Lol[/]\" Svensson[/]", "Was [underline]here[/]!");

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

@@ -12,6 +12,7 @@ namespace Spectre.Console.Tests.Unit.Composition
             [Theory]
             [InlineData(BorderKind.Ascii, typeof(AsciiBorder))]
             [InlineData(BorderKind.Square, typeof(SquareBorder))]
+            [InlineData(BorderKind.Rounded, typeof(RoundedBorder))]
             public void Should_Return_Correct_Border_For_Specified_Kind(BorderKind kind, Type expected)
             {
                 // Given, When

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

@@ -111,7 +111,7 @@ namespace Spectre.Console.Tests.Unit.Composition
         }
 
         [Fact]
-        public void Should_Render_Table_With_Specified_Border_Correctly()
+        public void Should_Render_Table_With_Ascii_Border_Correctly()
         {
             // Given
             var console = new PlainConsole(width: 80);
@@ -132,6 +132,28 @@ namespace Spectre.Console.Tests.Unit.Composition
             console.Lines[5].ShouldBe("+-------------------------+");
         }
 
+        [Fact]
+        public void Should_Render_Table_With_Rounded_Border_Correctly()
+        {
+            // Given
+            var console = new PlainConsole(width: 80);
+            var table = new Table(BorderKind.Rounded);
+            table.AddColumns("Foo", "Bar", "Baz");
+            table.AddRow("Qux", "Corgi", "Waldo");
+            table.AddRow("Grault", "Garply", "Fred");
+
+            // When
+            console.Render(table);
+
+            // Then
+            console.Lines[0].ShouldBe("╭────────┬────────┬───────╮");
+            console.Lines[1].ShouldBe("│ Foo    │ Bar    │ Baz   │");
+            console.Lines[2].ShouldBe("├────────┼────────┼───────┤");
+            console.Lines[3].ShouldBe("│ Qux    │ Corgi  │ Waldo │");
+            console.Lines[4].ShouldBe("│ Grault │ Garply │ Fred  │");
+            console.Lines[5].ShouldBe("╰────────┴────────┴───────╯");
+        }
+
         [Fact]
         public void Should_Render_Table_With_No_Border_Correctly()
         {

src/Spectre.Console/Composition/Border.cs

@@ -17,6 +17,7 @@ namespace Spectre.Console.Composition
             { BorderKind.None, new NoBorder() },
             { BorderKind.Ascii, new AsciiBorder() },
             { BorderKind.Square, new SquareBorder() },
+            { BorderKind.Rounded, new RoundedBorder() },
         };
 
         /// <summary>

src/Spectre.Console/Composition/BorderKind.cs

@@ -19,5 +19,10 @@ namespace Spectre.Console
         /// An old school ASCII border.
         /// </summary>
         Ascii = 2,
+
+        /// <summary>
+        /// A rounded border.
+        /// </summary>
+        Rounded = 3,
     }
 }

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

@@ -0,0 +1,37 @@
+using System;
+
+namespace Spectre.Console.Composition
+{
+    /// <summary>
+    /// Represents a rounded border.
+    /// </summary>
+    public sealed class RoundedBorder : Border
+    {
+        /// <inheritdoc/>
+        protected override string GetBoxPart(BorderPart part)
+        {
+            return part switch
+            {
+                BorderPart.HeaderTopLeft => "╭",
+                BorderPart.HeaderTop => "─",
+                BorderPart.HeaderTopSeparator => "┬",
+                BorderPart.HeaderTopRight => "╮",
+                BorderPart.HeaderLeft => "│",
+                BorderPart.HeaderSeparator => "│",
+                BorderPart.HeaderRight => "│",
+                BorderPart.HeaderBottomLeft => "├",
+                BorderPart.HeaderBottom => "─",
+                BorderPart.HeaderBottomSeparator => "┼",
+                BorderPart.HeaderBottomRight => "┤",
+                BorderPart.CellLeft => "│",
+                BorderPart.CellSeparator => "│",
+                BorderPart.ColumnRight => "│",
+                BorderPart.FooterBottomLeft => "╰",
+                BorderPart.FooterBottom => "─",
+                BorderPart.FooterBottomSeparator => "┴",
+                BorderPart.FooterBottomRight => "╯",
+                _ => throw new InvalidOperationException("Unknown box part."),
+            };
+        }
+    }
+}