Add support for setting encoding

src/Spectre.Terminals/Drivers/Windows/WindowsTerminalReader.cs

@@ -8,14 +8,20 @@ namespace Spectre.Terminals.Windows
     internal sealed class WindowsTerminalReader : WindowsTerminalHandle, ITerminalReader
     {
         private readonly WindowsDriver _driver;
+        private Encoding _encoding;
+
+        public Encoding Encoding
+        {
+            get => _encoding;
+            set => SetEncoding(value);
+        }
 
-        public Encoding Encoding { get; }
         public bool IsRawMode => _driver.IsRawMode;
 
         public WindowsTerminalReader(WindowsDriver driver)
             : base(STD_HANDLE_TYPE.STD_INPUT_HANDLE)
         {
-            Encoding = EncodingHelper.GetEncodingFromCodePage((int)PInvoke.GetConsoleCP());
+            _encoding = EncodingHelper.GetEncodingFromCodePage((int)PInvoke.GetConsoleCP());
             _driver = driver;
         }
 
@@ -45,5 +51,13 @@ namespace Spectre.Terminals.Windows
 
             return (int)result;
         }
+
+        private void SetEncoding(Encoding encoding)
+        {
+            if (PInvoke.SetConsoleCP((uint)encoding.CodePage))
+            {
+                _encoding = encoding;
+            }
+        }
     }
 }

src/Spectre.Terminals/ITerminalReader.cs

@@ -11,7 +11,7 @@ namespace Spectre.Terminals
         /// <summary>
         /// Gets the encoding.
         /// </summary>
-        Encoding Encoding { get; }
+        Encoding Encoding { get; set; }
 
         /// <summary>
         /// Gets a value indicating whether or not the reader has been redirected.

src/Spectre.Terminals/TerminalInput.cs

@@ -9,7 +9,12 @@ namespace Spectre.Terminals
         private readonly object _lock;
         private ITerminalReader? _redirected;
 
-        public Encoding Encoding => GetEncoding();
+        public Encoding Encoding
+        {
+            get => GetEncoding();
+            set => SetEncoding(value);
+        }
+
         public bool IsRedirected => GetIsRedirected();
 
         public TerminalInput(ITerminalReader reader)
@@ -39,6 +44,19 @@ namespace Spectre.Terminals
             }
         }
 
+        private bool GetIsRedirected()
+        {
+            lock (_lock)
+            {
+                if (_redirected != null)
+                {
+                    return _redirected.IsRedirected;
+                }
+
+                return _reader.IsRedirected;
+            }
+        }
+
         private Encoding GetEncoding()
         {
             lock (_lock)
@@ -52,16 +70,23 @@ namespace Spectre.Terminals
             }
         }
 
-        private bool GetIsRedirected()
+        private void SetEncoding(Encoding encoding)
         {
+            if (encoding is null)
+            {
+                throw new ArgumentNullException(nameof(encoding));
+            }
+
             lock (_lock)
             {
                 if (_redirected != null)
                 {
-                    return _redirected.IsRedirected;
+                    _redirected.Encoding = encoding;
+                }
+                else
+                {
+                    _reader.Encoding = encoding;
                 }
-
-                return _reader.IsRedirected;
             }
         }
     }