Fallback to default buffer size

Also fixes a bug when using Spectre.Console in GitHub Actions.

src/Spectre.Console/Capabilities.cs

@@ -38,6 +38,17 @@ namespace Spectre.Console
             LegacyConsole = legacyConsole;
         }
 
+        /// <summary>
+        /// Checks whether the current capabilities supports
+        /// the specified color system.
+        /// </summary>
+        /// <param name="colorSystem">The color system to check.</param>
+        /// <returns><c>true</c> if the color system is supported, otherwise <c>false</c>.</returns>
+        public bool Supports(ColorSystem colorSystem)
+        {
+            return (int)colorSystem <= (int)ColorSystem;
+        }
+
         /// <inheritdoc/>
         public override string ToString()
         {

src/Spectre.Console/Internal/AnsiConsoleRenderer.cs

@@ -21,7 +21,7 @@ namespace Spectre.Console.Internal
             {
                 if (_out.IsStandardOut())
                 {
-                    return System.Console.BufferWidth;
+                    return ConsoleHelper.GetSafeBufferWidth(Constants.DefaultBufferWidth);
                 }
 
                 return Constants.DefaultBufferWidth;
@@ -34,7 +34,7 @@ namespace Spectre.Console.Internal
             {
                 if (_out.IsStandardOut())
                 {
-                    return System.Console.BufferHeight;
+                    return ConsoleHelper.GetSafeBufferHeight(Constants.DefaultBufferHeight);
                 }
 
                 return Constants.DefaultBufferHeight;

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

@@ -3,7 +3,7 @@ using System.Diagnostics.CodeAnalysis;
 
 namespace Spectre.Console.Internal
 {
-    internal static class ConsoleExtensions
+    internal static class AnsiConsoleExtensions
     {
         public static IDisposable PushStyle(this IAnsiConsole console, Style style)
         {

src/Spectre.Console/Internal/FallbackConsoleRenderer.cs

@@ -24,7 +24,7 @@ namespace Spectre.Console.Internal
             {
                 if (_out.IsStandardOut())
                 {
-                    return System.Console.BufferWidth;
+                    return ConsoleHelper.GetSafeBufferWidth(Constants.DefaultBufferWidth);
                 }
 
                 return Constants.DefaultBufferWidth;
@@ -37,7 +37,7 @@ namespace Spectre.Console.Internal
             {
                 if (_out.IsStandardOut())
                 {
-                    return System.Console.BufferHeight;
+                    return ConsoleHelper.GetSafeBufferHeight(Constants.DefaultBufferHeight);
                 }
 
                 return Constants.DefaultBufferHeight;

src/Spectre.Console/Internal/Utilities/ConsoleHelper.cs

@@ -0,0 +1,44 @@
+using System.IO;
+using System.Runtime.InteropServices;
+
+namespace Spectre.Console.Internal
+{
+    internal static class ConsoleHelper
+    {
+        public static int GetSafeBufferWidth(int defaultValue = Constants.DefaultBufferWidth)
+        {
+            try
+            {
+                var width = System.Console.BufferWidth;
+                if (width == 0)
+                {
+                    width = defaultValue;
+                }
+
+                return width;
+            }
+            catch (IOException)
+            {
+                return defaultValue;
+            }
+        }
+
+        public static int GetSafeBufferHeight(int defaultValue = Constants.DefaultBufferWidth)
+        {
+            try
+            {
+                var height = System.Console.BufferHeight;
+                if (height == 0)
+                {
+                    height = defaultValue;
+                }
+
+                return height;
+            }
+            catch (IOException)
+            {
+                return defaultValue;
+            }
+        }
+    }
+}