Fix Sixel rendering in Windows local sessions

Directory.Packages.props

@@ -21,5 +21,6 @@
     <PackageVersion Include="xunit.v3" Version="3.2.2" />
     <PackageVersion Include="xunit.runner.visualstudio" Version="3.1.4" />
     <PackageVersion Include="Microsoft.SourceLink.GitHub" Version="8.0.0" />
+    <PackageVersion Include="Microsoft.Windows.Console.ConPTY" Version="1.24.260710001" />
   </ItemGroup>
 </Project>

docs/advanced-vt-protocols.md

@@ -1,12 +1,11 @@
 # Advanced VT protocols
 
 > [!NOTE]
-> The public out-of-process Windows ConPTY may filter DCS payloads before they
-> reach a terminal client on some Windows builds, and APC sequences (kitty
-> graphics) can be affected the same way. The Core parser and renderer
-> support Sixel and kitty graphics when a connection transports those bytes
-> unchanged (for example, remote/Azure transports); local ConPTY support is
-> limited by the installed Windows pseudoconsole implementation.
+> Windows local sessions use the bundled Microsoft ConPTY runtime, including
+> `OpenConsole.exe`, rather than the OS copy that filters Sixel on some Windows
+> builds. With the built-in engine, Sixel producers such as `Get-XKCD -Show`
+> can render inline images. Other transports must likewise preserve graphics
+> payloads; the optional Ghostty engine does not expose image resources.
 
 `Devolutions.Terminal.Core` parses advanced string protocols without depending on Avalonia,
 Skia, Win32, or an image codec. It exposes decoded Sixel pixels and bounded
@@ -36,6 +35,9 @@ terminator split across input chunks. BEL does not terminate DCS. An `ESC`
 followed by anything other than `\` aborts the DCS and starts the new escape
 sequence.
 
+DECSDM defaults to reset (scrolling mode): Sixel images anchor at the cursor
+unless the application explicitly selects display mode with `CSI ? 80 h`.
+
 ## Limits
 
 Limits are public constants on `TerminalImageLimits` and `VtResourceLimits`.

docs/release.md

@@ -12,7 +12,17 @@ Commands are relative to the repository root.
 - WinApp CLI 0.6.0 for MSIX creation and validation
 - A trusted code-signing certificate for distributable MSIX artifacts
 
-Windows local sessions use ConPTY. Linux and macOS local sessions use the
+Windows local sessions use the pinned `Microsoft.Windows.Console.ConPTY` NuGet
+runtime. Ship `conpty.dll` and the architecture-specific `OpenConsole.exe`
+subdirectories together: without its host, ConPTY can fall back to the OS copy
+and silently lose Sixel output. `ConPtyHost.targets` supplies these files for
+RID-less builds, RID-specific publishes, and Control NuGet consumers, including
+the ARM64 host required by x64 processes running under emulation. Because
+`conpty.dll` lands under `runtimes\<rid>\native` for RID-less builds but at the
+output root once a RID is applied, the hosts are emitted in both layouts; a RID
+does not reliably flow to referenced projects, so the placement cannot depend on
+it.
+Linux and macOS local sessions use the
 bundled `forkpty` relay. The Avalonia shell, settings, renderer, and terminal
 engines are shared.
 
@@ -400,9 +410,9 @@ that `Control` needs, or a project that needs direct access to
 
 ## Platform constraints
 
-- Public out-of-process ConPTY can filter or alter DCS/APC payloads on some
-  Windows builds. Sixel works when the selected connection passes DCS bytes
-  through unchanged.
+- The OS-provided ConPTY can filter graphics payloads on some Windows builds.
+  Local sessions use the bundled runtime to preserve Sixel; remote connections
+  must also transport image sequences unchanged.
 - Avalonia 12 exposes the terminal as a readable UIA Document/Value provider,
   but does not provide a public bridge for native UIA TextPattern/TextPattern2
   or LiveSetting events. Managed ranges and visible notification text remain

src/Devolutions.Terminal.Connection/ConPtyConnection.cs

@@ -158,7 +158,7 @@ public void Resize(int columns, int rows)
             if (pseudoConsole is not null && !pseudoConsole.IsInvalid && !pseudoConsole.IsClosed)
             {
                 var size = new Kernel32.Coord { X = (short)validatedColumns, Y = (short)validatedRows };
-                var hr = Kernel32.ResizePseudoConsole(pseudoConsole, size);
+                var hr = ConPty.ResizePseudoConsole(pseudoConsole, size);
                 if (hr != 0)
                 {
                     Marshal.ThrowExceptionForHR(hr);
@@ -225,7 +225,7 @@ private void StartCore(TerminalLaunchOptions options, CancellationToken cancella
                 X = (short)options.Columns,
                 Y = (short)options.Rows,
             };
-            var hr = Kernel32.CreatePseudoConsole(size, inputRead, outputWrite, 0, out var pseudoConsoleValue);
+            var hr = ConPty.CreatePseudoConsole(size, inputRead, outputWrite, 0, out var pseudoConsoleValue);
             if (hr != 0)
             {
                 Marshal.ThrowExceptionForHR(hr);

src/Devolutions.Terminal.Connection/ConPtyHost.targets

@@ -0,0 +1,34 @@
+<Project>
+  <PropertyGroup>
+    <ConPtyHostSourceRoot Condition="'$(ConPtyHostSourceRoot)' == ''">$(MSBuildThisFileDirectory)..\tools\conpty</ConPtyHostSourceRoot>
+  </PropertyGroup>
+  <!-- ConPTY resolves the host for the native OS architecture relative to conpty.dll,
+       and silently falls back to the OS conhost.exe (which strips DCS/sixel) when it is
+       missing. conpty.dll lands under runtimes\<rid>\native for RID-less builds and at the
+       output root for RID/self-contained publishes, so both layouts are populated: a RID
+       does not necessarily flow to this project when a referencing app is published.
+       ARM64 hosts are included for x64/x86 processes running under Windows emulation. -->
+  <Target Name="IncludeConPtyHosts" BeforeTargets="AssignTargetPaths">
+    <ItemGroup>
+      <_ConPtyArch Include="x86;x64;arm64" />
+      <_ConPtyRuntime Include="win-x86;win-x64;win-arm64" Condition="'$(RuntimeIdentifier)' == ''" />
+      <None Include="@(_ConPtyArch->'$(ConPtyHostSourceRoot)\%(Identity)\OpenConsole.exe')"
+            Link="%(_ConPtyArch.Identity)\OpenConsole.exe"
+            CopyToOutputDirectory="PreserveNewest" CopyToPublishDirectory="PreserveNewest" />
+      <None Include="@(_ConPtyRuntime->'$(ConPtyHostSourceRoot)\x86\OpenConsole.exe')"
+            Condition="'%(_ConPtyRuntime.Identity)' == 'win-x86'"
+            Link="runtimes\%(_ConPtyRuntime.Identity)\native\x86\OpenConsole.exe"
+            CopyToOutputDirectory="PreserveNewest" CopyToPublishDirectory="PreserveNewest" />
+      <None Include="@(_ConPtyRuntime->'$(ConPtyHostSourceRoot)\x64\OpenConsole.exe')"
+            Condition="'%(_ConPtyRuntime.Identity)' == 'win-x86' or '%(_ConPtyRuntime.Identity)' == 'win-x64'"
+            Link="runtimes\%(_ConPtyRuntime.Identity)\native\x64\OpenConsole.exe"
+            CopyToOutputDirectory="PreserveNewest" CopyToPublishDirectory="PreserveNewest" />
+      <None Include="@(_ConPtyRuntime->'$(ConPtyHostSourceRoot)\arm64\OpenConsole.exe')"
+            Link="runtimes\%(_ConPtyRuntime.Identity)\native\arm64\OpenConsole.exe"
+            CopyToOutputDirectory="PreserveNewest" CopyToPublishDirectory="PreserveNewest" />
+      <None Include="$(MSBuildThisFileDirectory)THIRD-PARTY-NOTICES-CONPTY.txt"
+            Link="THIRD-PARTY-NOTICES-CONPTY.txt"
+            CopyToOutputDirectory="PreserveNewest" CopyToPublishDirectory="PreserveNewest" />
+    </ItemGroup>
+  </Target>
+</Project>

src/Devolutions.Terminal.Connection/Devolutions.Terminal.Connection.csproj

@@ -7,6 +7,11 @@
     <IsPackable>false</IsPackable>
   </PropertyGroup>
   <ItemGroup>
+    <PackageReference Include="Microsoft.Windows.Console.ConPTY" GeneratePathProperty="true" ExcludeAssets="build" />
     <ProjectReference Include="..\Devolutions.Terminal.Core\Devolutions.Terminal.Core.csproj" />
   </ItemGroup>
+  <PropertyGroup>
+    <ConPtyHostSourceRoot>$(PkgMicrosoft_Windows_Console_ConPTY)\build\native\runtimes</ConPtyHostSourceRoot>
+  </PropertyGroup>
+  <Import Project="ConPtyHost.targets" />
 </Project>

src/Devolutions.Terminal.Connection/Native/ConPty.cs

@@ -0,0 +1,18 @@
+using System.Runtime.InteropServices;
+using System.Runtime.Versioning;
+using Microsoft.Win32.SafeHandles;
+
+namespace Devolutions.Terminal.Connection.Native;
+
+[SupportedOSPlatform("windows")]
+internal static partial class ConPty
+{
+    [LibraryImport("conpty.dll", EntryPoint = "ConptyCreatePseudoConsole")]
+    internal static partial int CreatePseudoConsole(Kernel32.Coord size, SafeFileHandle hInput, SafeFileHandle hOutput, uint dwFlags, out nint phPC);
+
+    [LibraryImport("conpty.dll", EntryPoint = "ConptyResizePseudoConsole")]
+    internal static partial int ResizePseudoConsole(SafePseudoConsoleHandle hPC, Kernel32.Coord size);
+
+    [LibraryImport("conpty.dll", EntryPoint = "ConptyClosePseudoConsole")]
+    internal static partial void ClosePseudoConsole(nint hPC);
+}

src/Devolutions.Terminal.Connection/Native/Kernel32.cs

@@ -68,15 +68,6 @@ internal struct ProcessInformation
         public int dwThreadId;
     }
 
-    [LibraryImport("kernel32.dll", SetLastError = true)]
-    internal static partial int CreatePseudoConsole(Coord size, SafeFileHandle hInput, SafeFileHandle hOutput, uint dwFlags, out nint phPC);
-
-    [LibraryImport("kernel32.dll", SetLastError = true)]
-    internal static partial int ResizePseudoConsole(SafePseudoConsoleHandle hPC, Coord size);
-
-    [LibraryImport("kernel32.dll", SetLastError = true)]
-    internal static partial void ClosePseudoConsole(nint hPC);
-
     [LibraryImport("kernel32.dll", SetLastError = true)]
     [return: MarshalAs(UnmanagedType.Bool)]
     internal static partial bool CreatePipe(out SafeFileHandle hReadPipe, out SafeFileHandle hWritePipe, nint lpPipeAttributes, uint nSize);

src/Devolutions.Terminal.Connection/Native/SafeHandles.cs

@@ -21,7 +21,7 @@ internal SafePseudoConsoleHandle(nint handle)
 
     protected override bool ReleaseHandle()
     {
-        Kernel32.ClosePseudoConsole(handle);
+        ConPty.ClosePseudoConsole(handle);
         return true;
     }
 }

src/Devolutions.Terminal.Connection/THIRD-PARTY-NOTICES-CONPTY.txt

@@ -0,0 +1,24 @@
+Microsoft Windows Console ConPTY
+https://github.com/microsoft/terminal
+
+Copyright (c) Microsoft Corporation. All rights reserved.
+
+MIT License
+
+Permission is hereby granted, free of charge, to any person obtaining a copy
+of this software and associated documentation files (the "Software"), to deal
+in the Software without restriction, including without limitation the rights
+to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+copies of the Software, and to permit persons to whom the Software is
+furnished to do so, subject to the following conditions:
+
+The above copyright notice and this permission notice shall be included in all
+copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED *AS IS*, WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+SOFTWARE.

src/Devolutions.Terminal.Control/Devolutions.Terminal.Control.csproj

@@ -36,6 +36,7 @@
     <PackageReference Include="SkiaSharp.HarfBuzz" />
     <PackageReference Include="SkiaSharp.NativeAssets.Linux" />
     <PackageReference Include="HarfBuzzSharp.NativeAssets.Linux" />
+    <PackageReference Include="Microsoft.Windows.Console.ConPTY" GeneratePathProperty="true" ExcludeAssets="build" />
   </ItemGroup>
   <ItemGroup>
     <!--
@@ -62,6 +63,14 @@
                       Link="Assets\Fonts\NotoColorEmoji.ttf" />
   </ItemGroup>
   <Import Project="..\..\native\noto-emoji\NotoEmoji.targets" />
+  <ItemGroup>
+    <None Include="..\Devolutions.Terminal.Connection\ConPtyHost.targets"
+          Pack="true" PackagePath="buildTransitive\Devolutions.Terminal.Control.targets" />
+    <None Include="..\Devolutions.Terminal.Connection\THIRD-PARTY-NOTICES-CONPTY.txt"
+          Pack="true" PackagePath="buildTransitive" />
+    <None Include="$(PkgMicrosoft_Windows_Console_ConPTY)\build\native\runtimes\**\OpenConsole.exe"
+          Pack="true" PackagePath="tools\conpty" />
+  </ItemGroup>
 
   <!--
     Bundle the build outputs of the internal, non-packable project
@@ -81,4 +90,3 @@
     </ItemGroup>
   </Target>
 </Project>
-

src/Devolutions.Terminal.Core/TerminalEngine.cs

@@ -72,7 +72,7 @@ public sealed class TerminalEngine : ITerminalEngine, IVtDispatch
     private int _modifyOtherKeys;
     private bool _win32InputMode;
     private bool _allowKittyKeyboard = true;
-    private bool _sixelDisplayMode = true;
+    private bool _sixelDisplayMode;
     private double _cellWidth = 10;
     private double _cellHeight = 20;
     private int _cursorStyle;
@@ -252,7 +252,7 @@ public void Reset()
         _alternateScroll = false;
         _inBandResize = false;
         _titleStack.Clear();
-        _sixelDisplayMode = true;
+        _sixelDisplayMode = false;
         _vt52Graphics = false;
         _rectangularAttributeExtent = false;
         _drcsDesignator = null;
@@ -3039,7 +3039,7 @@ private void SoftReset()
         _synchronizedOutputDepth = 0;
         _alternateScroll = false;
         _inBandResize = false;
-        _sixelDisplayMode = true;
+        _sixelDisplayMode = false;
         _vt52Graphics = false;
         _rectangularAttributeExtent = false;
         _sgr = CellAttributes.Default;

src/Devolutions.Terminal.Package/Scripts/Write-MsiComponents.ps1

@@ -27,7 +27,7 @@ function Get-ParentPath {
         return ''
     }
 
-    $normalized = $Path.Replace('\\', '/')
+    $normalized = $Path.Replace('\', '/')
     $index = $normalized.LastIndexOf('/')
     if ($index -lt 0) {
         return ''
@@ -54,13 +54,13 @@ function Get-RelativePath {
             return '.'
         }
 
-        return $relative.Replace('\\', '/')
+        return $relative.Replace('\', '/')
     }
 
     $baseUri = [Uri]::new(($baseFull + [IO.Path]::DirectorySeparatorChar))
     $targetUri = [Uri]::new($targetFull)
     $relative = [Uri]::UnescapeDataString($baseUri.MakeRelativeUri($targetUri).ToString())
-    return $relative.Replace('\\', '/')
+    return $relative.Replace('\', '/')
 }
 
 foreach ($file in $files) {
@@ -120,7 +120,7 @@ foreach ($file in $files) {
         $directoryId = 'INSTALLLOCATION'
     }
     else {
-        $directoryId = $directoryIds[$relativeDirectory.Replace('\\', '/')]
+        $directoryId = $directoryIds[$relativeDirectory.Replace('\', '/')]
     }
 
     $componentId = 'cmp_' + (($relativePath -replace '[^A-Za-z0-9_]', '_').Trim('_'))

src/Devolutions.Terminal.Render/SkiaTerminalRenderer.cs

@@ -583,8 +583,9 @@ private SKRect ImageDestination(
         var naturalHeight = (float)bitmap.Height;
         if (image.Sixel is not null)
         {
-            var sixelWidth = naturalWidth * (float)(image.CellGeometry.CellWidth / 10);
-            var sixelHeight = naturalHeight * (float)(image.CellGeometry.CellHeight / 20);
+            // The engine retains physical cell pixels; the canvas uses DIPs.
+            var sixelWidth = naturalWidth * (float)(image.CellGeometry.CellWidth / 10) * PhysicalPixel;
+            var sixelHeight = naturalHeight * (float)(image.CellGeometry.CellHeight / 20) * PhysicalPixel;
             return SKRect.Create(
                 left,
                 top,

tests/Devolutions.Terminal.Connection.Tests/AzureCloudShellTests.cs

@@ -303,7 +303,7 @@ public async Task CloseAbortsWhenCloseOutputDoesNotComplete()
         await using var connection = fixture.Connection;
         await connection.StartAsync(string.Empty, null, 80, 24);
 
-        await connection.CloseAsync().WaitAsync(TimeSpan.FromSeconds(2));
+        await connection.CloseAsync().WaitAsync(TimeSpan.FromSeconds(10));
 
         Assert.Equal(TerminalConnectionState.Closed, connection.State);
         Assert.Contains(diagnostics, value => value.Code == "WebSocketCloseTimedOut");

tests/Devolutions.Terminal.Connection.Tests/ConnectionContractTests.cs

@@ -5,6 +5,7 @@
 using System.Text;
 using System.Text.RegularExpressions;
 using Devolutions.Terminal.Connection;
+using Devolutions.Terminal.Core;
 using Microsoft.Win32;
 using Xunit;
 
@@ -109,6 +110,48 @@ public async Task CapturesUnicodeOutputAndExitCode()
         Assert.Equal(TerminalExitReason.ProcessExited, connection.LastExitInfo?.Reason);
     }
 
+    [Fact(Skip = "ConPTY is Windows-only.", SkipUnless = nameof(IsWindows))]
+    public async Task SixelSurvivesConPtyAndDecodesToImage()
+    {
+        await using var connection = new ConPtyConnection();
+        var engine = new TerminalEngine(80, 24);
+        var output = new List<byte>();
+        var exited = new TaskCompletionSource<int>(TaskCreationOptions.RunContinuationsAsynchronously);
+        connection.OutputReceived += (_, bytes) =>
+        {
+            lock (output)
+            {
+                output.AddRange(bytes.ToArray());
+                engine.Feed(bytes.Span);
+            }
+        };
+        engine.ResponseReady += (_, bytes) => connection.Write(bytes);
+        connection.Exited += (_, code) => exited.TrySetResult(code);
+        connection.Faulted += (_, error) => exited.TrySetException(error);
+        const string sixel = "\u001bPq\"1;1;60;6#0;2;100;0;0#0!60~\u001b\\";
+        var payload = Convert.ToBase64String(Encoding.UTF8.GetBytes("BEFORE" + sixel + "AFTER"));
+        var script = $"[Console]::Write([Text.Encoding]::UTF8.GetString([Convert]::FromBase64String('{payload}')))";
+        var command = "powershell.exe -NoLogo -NoProfile -EncodedCommand " +
+            Convert.ToBase64String(Encoding.Unicode.GetBytes(script));
+
+        await connection.StartAsync(command, null, 80, 24, TestContext.Current.CancellationToken);
+
+        Assert.Equal(0, await exited.Task.WaitAsync(TimeSpan.FromSeconds(10)));
+        await WaitForOutputAsync(output, "AFTER");
+        lock (output)
+        {
+            var text = Encoding.UTF8.GetString([.. output]);
+            Assert.Contains("BEFORE", text);
+            Assert.Contains(sixel, text);
+            var image = Assert.Single(engine.Images);
+            Assert.Equal(TerminalImageProtocol.Sixel, image.Protocol);
+            Assert.NotNull(image.Sixel);
+            Assert.Equal(60, image.Sixel.Width);
+            Assert.Equal(6, image.Sixel.Height);
+            Assert.All(image.Sixel.ToRgba32(), pixel => Assert.Equal(0xFFFF0000u, pixel));
+        }
+    }
+
     [Fact(Skip = "ConPTY is Windows-only.", SkipUnless = nameof(IsWindows))]
     public async Task ResizesRunningPseudoConsole()
     {
@@ -455,13 +498,14 @@ public async Task InteractivePowerShellLoadsPsReadLine()
         };
         connection.Exited += (_, code) => exited.TrySetResult(code);
 
-        await connection.StartAsync($"\"{powershell}\" -NoLogo", null, 80, 24);
+        await connection.StartAsync($"\"{powershell}\" -NoLogo -NoProfile", null, 80, 24);
+        await WaitForOutputAsync(output, "PS ", TimeSpan.FromSeconds(20));
         connection.Write(
-            "if (Get-Module PSReadLine) { 'PSREADLINE_OK' } else { 'PSREADLINE_MISSING' }\r");
+            "if (Get-Module PSReadLine) { 'PSREAD' + 'LINE_OK' } else { 'PSREADLINE_MISSING' }\r");
+        await WaitForOutputAsync(output, "PSREADLINE_OK", TimeSpan.FromSeconds(20));
         connection.Write("exit\r");
 
-        Assert.Equal(0, await exited.Task.WaitAsync(TimeSpan.FromSeconds(10)));
-        await WaitForOutputAsync(output, "PSREADLINE_OK");
+        Assert.Equal(0, await exited.Task.WaitAsync(TimeSpan.FromSeconds(20)));
         lock (output)
         {
             Assert.DoesNotContain(