Add method to get VT/ANSI codes for renderables

src/Spectre.Console.Tests/Unit/AnsiConsoleTests.Advanced.cs

@@ -5,7 +5,7 @@ using Xunit;
 
 namespace Spectre.Console.Tests.Unit
 {
-    public partial class AnsiConsoleTests
+    public sealed partial class AnsiConsoleTests
     {
         public sealed class Advanced
         {
@@ -42,6 +42,20 @@ namespace Spectre.Console.Tests.Unit
                 console.Output.NormalizeLineEndings()
                     .ShouldBeEmpty();
             }
+
+            [Fact]
+            public void Should_Return_Ansi_For_Renderable()
+            {
+                // Given
+                var console = new TestConsole().Colors(ColorSystem.TrueColor);
+                var markup = new Console.Markup("[yellow]Hello [blue]World[/]![/]");
+
+                // When
+                var result = console.ToAnsi(markup);
+
+                // Then
+                result.ShouldBe("Hello World!");
+            }
         }
     }
 }

src/Spectre.Console/Extensions/Advanced/AnsiConsoleExtensions.cs

@@ -1,4 +1,5 @@
 using System;
+using Spectre.Console.Rendering;
 
 namespace Spectre.Console.Advanced
 {
@@ -24,5 +25,16 @@ namespace Spectre.Console.Advanced
                 console.Write(new ControlCode(sequence));
             }
         }
+
+        /// <summary>
+        /// Gets the VT/ANSI control code sequence for a <see cref="IRenderable"/>.
+        /// </summary>
+        /// <param name="console">The console.</param>
+        /// <param name="renderable">The renderable to the VT/ANSI control code sequence for.</param>
+        /// <returns>The VT/ANSI control code sequence.</returns>
+        public static string ToAnsi(this IAnsiConsole console, IRenderable renderable)
+        {
+            return AnsiBuilder.Build(console, renderable);
+        }
     }
 }

src/Spectre.Console/Internal/Backends/Ansi/AnsiBuilder.cs

@@ -1,23 +1,60 @@
 using System;
 using System.Linq;
+using System.Text;
+using Spectre.Console.Rendering;
 using static Spectre.Console.AnsiSequences;
 
 namespace Spectre.Console
 {
-    internal sealed class AnsiBuilder
+    internal static class AnsiBuilder
     {
-        private readonly Profile _profile;
+        private static readonly AnsiLinkHasher _linkHasher;
-        private readonly AnsiLinkHasher _linkHasher;
 
-        public AnsiBuilder(Profile profile)
+        static AnsiBuilder()
         {
-            _profile = profile ?? throw new ArgumentNullException(nameof(profile));
             _linkHasher = new AnsiLinkHasher();
         }
 
-        public string GetAnsi(string text, Style style)
+        public static string Build(IAnsiConsole console, IRenderable renderable)
         {
-            if (style is null)
+            var builder = new StringBuilder();
+            foreach (var segment in renderable.GetSegments(console))
+            {
+                if (segment.IsControlCode)
+                {
+                    builder.Append(segment.Text);
+                    continue;
+                }
+
+                var parts = segment.Text.NormalizeNewLines().Split(new[] { '\n' });
+                foreach (var (_, _, last, part) in parts.Enumerate())
+                {
+                    if (!string.IsNullOrEmpty(part))
+                    {
+                        builder.Append(Build(console.Profile, part, segment.Style));
+                    }
+
+                    if (!last)
+                    {
+                        builder.Append(Environment.NewLine);
+                    }
+                }
+            }
+
+            return builder.ToString();
+        }
+
+        private static string Build(Profile profile, string text, Style style)
+        {
+            if (profile is null)
+            {
+                throw new ArgumentNullException(nameof(profile));
+            }
+            else if (text is null)
+            {
+                throw new ArgumentNullException(nameof(text));
+            }
+            else if (style is null)
             {
                 throw new ArgumentNullException(nameof(style));
             }
@@ -29,7 +66,7 @@ namespace Spectre.Console
             {
                 codes = codes.Concat(
                     AnsiColorBuilder.GetAnsiCodes(
-                        _profile.Capabilities.ColorSystem,
+                        profile.Capabilities.ColorSystem,
                         style.Foreground,
                         true));
             }
@@ -39,7 +76,7 @@ namespace Spectre.Console
             {
                 codes = codes.Concat(
                     AnsiColorBuilder.GetAnsiCodes(
-                        _profile.Capabilities.ColorSystem,
+                        profile.Capabilities.ColorSystem,
                         style.Background,
                         false));
             }
@@ -54,7 +91,7 @@ namespace Spectre.Console
                 ? $"{SGR(result)}{text}{SGR(0)}"
                 : text;
 
-            if (style.Link != null && !_profile.Capabilities.Legacy)
+            if (style.Link != null && !profile.Capabilities.Legacy)
             {
                 var link = style.Link;
 

src/Spectre.Console/Internal/Backends/Ansi/AnsiConsoleBackend.cs

@@ -7,7 +7,6 @@ namespace Spectre.Console
 {
     internal sealed class AnsiConsoleBackend : IAnsiConsoleBackend
     {
-        private readonly AnsiBuilder _builder;
         private readonly IAnsiConsole _console;
 
         public IAnsiConsoleCursor Cursor { get; }
@@ -15,8 +14,6 @@ namespace Spectre.Console
         public AnsiConsoleBackend(IAnsiConsole console)
         {
             _console = console ?? throw new ArgumentNullException(nameof(console));
-            _builder = new AnsiBuilder(_console.Profile);
-
             Cursor = new AnsiConsoleCursor(this);
         }
 
@@ -33,33 +30,10 @@ namespace Spectre.Console
 
         public void Write(IRenderable renderable)
         {
-            var builder = new StringBuilder();
+            var result = AnsiBuilder.Build(_console, renderable);
-            foreach (var segment in renderable.GetSegments(_console))
+            if (result?.Length > 0)
             {
-                if (segment.IsControlCode)
+                _console.Profile.Out.Writer.Write(result);
-                {
-                    builder.Append(segment.Text);
-                    continue;
-                }
-
-                var parts = segment.Text.NormalizeNewLines().Split(new[] { '\n' });
-                foreach (var (_, _, last, part) in parts.Enumerate())
-                {
-                    if (!string.IsNullOrEmpty(part))
-                    {
-                        builder.Append(_builder.GetAnsi(part, segment.Style));
-                    }
-
-                    if (!last)
-                    {
-                        builder.Append(Environment.NewLine);
-                    }
-                }
-            }
-
-            if (builder.Length > 0)
-            {
-                _console.Profile.Out.Writer.Write(builder.ToString());
                 _console.Profile.Out.Writer.Flush();
             }
         }