Implemnted SetDesktopSize message and added an auto resizing feature …

…th the Avalonia VncView

samples/AvaloniaVncClient/Views/MainWindow.xaml

@@ -42,7 +42,7 @@
             </Grid>
         </Border>
 
-        <Border DockPanel.Dock="Right" BorderBrush="LightGray" BorderThickness="1,0,0,0">
+        <Border DockPanel.Dock="Right" BorderBrush="LightGray" BorderThickness="1,0,0,0" IsVisible="{Binding RfbConnection, Converter={x:Static ObjectConverters.IsNotNull}}">
             <Grid RowDefinitions="Auto,*,Auto,*" Margin="10">
                 <TextBlock Grid.Row="0" Margin="0,0,0,10" FontWeight="Bold" Text="Used Message Types:" />
                 <ListBox Grid.Row="1" Margin="0,0,0,10" Items="{Binding RfbConnection.UsedMessageTypes}" BorderThickness="0">
@@ -63,18 +63,19 @@
             </Grid>
         </Border>
 
-        <StackPanel Orientation="Vertical" Margin="10" Spacing="10">
-            <Grid ColumnDefinitions="3*,*">
-                <TextBox Grid.Column="0" Watermark="Host" UseFloatingWatermark="True" Text="{Binding Host}" Margin="0,0,10,0" />
-                <TextBox Grid.Column="1" Watermark="Port" UseFloatingWatermark="True" Text="{Binding Port}" />
+        <Border DockPanel.Dock="Top" BorderBrush="LightGray" BorderThickness="0,0,0,1">
+            <Grid RowDefinitions="Auto,Auto,Auto" ColumnDefinitions="3*,*" Margin="10">
+                <TextBox Grid.Row="0" Grid.Column="0" Watermark="Host" UseFloatingWatermark="True" Text="{Binding Host}" Margin="0,0,10,0" />
+                <TextBox Grid.Row="0" Grid.Column="1" Watermark="Port" UseFloatingWatermark="True" Text="{Binding Port}" />
+                <Button Grid.Row="1" Grid.Column="0" Grid.ColumnSpan="2" Name="ConnectButton" Command="{Binding ConnectCommand}" Margin="0,10,0,0" IsDefault="True" />
+                <TextBlock Grid.Row="2" Grid.Column="0" Grid.ColumnSpan="2" Foreground="Red" Text="{Binding ErrorMessage}"
+                           IsVisible="{Binding ErrorMessage, Converter={x:Static ObjectConverters.IsNotNull}}" Margin="0,10,0,0" />
             </Grid>
+        </Border>
 
-            <Button Name="ConnectButton" Command="{Binding ConnectCommand}" IsDefault="True" />
-            <TextBlock Foreground="Red" Text="{Binding ErrorMessage}"
-                       IsVisible="{Binding ErrorMessage, Converter={x:Static ObjectConverters.IsNotNull}}" />
-
-            <vnc:VncView Connection="{Binding RfbConnection, Mode=OneWay}" />
-        </StackPanel>
+        <ScrollViewer HorizontalScrollBarVisibility="Auto" VerticalScrollBarVisibility="Auto">
+            <vnc:VncView Connection="{Binding RfbConnection}" OptimalSize="{Binding $parent[ScrollViewer].Viewport}" />
+        </ScrollViewer>
     </DockPanel>
 
 </Window>

src/MarcusW.VncClient.Avalonia/MarcusW.VncClient.Avalonia.csproj

@@ -1,13 +1,13 @@
 <Project Sdk="Microsoft.NET.Sdk">
 
     <ItemGroup>
-        <PackageReference Include="Avalonia" Version="0.9.7"/>
-        <PackageReference Include="Microsoft.CodeAnalysis.FxCopAnalyzers" Version="3.0.0" PrivateAssets="all"/>
-        <PackageReference Include="Microsoft.Extensions.Logging" Version="3.1.3"/>
+        <PackageReference Include="Avalonia" Version="0.9.7" />
+        <PackageReference Include="Microsoft.CodeAnalysis.FxCopAnalyzers" Version="3.0.0" PrivateAssets="all" />
+        <PackageReference Include="Microsoft.Extensions.Logging" Version="3.1.3" />
     </ItemGroup>
 
     <ItemGroup>
-        <ProjectReference Include="..\MarcusW.VncClient\MarcusW.VncClient.csproj"/>
+        <ProjectReference Include="..\MarcusW.VncClient\MarcusW.VncClient.csproj" />
     </ItemGroup>
 
     <ItemGroup>
@@ -17,6 +17,9 @@
         <Compile Update="VncView.KeyInput.cs">
             <DependentUpon>VncView.cs</DependentUpon>
         </Compile>
+        <Compile Update="VncView.Sizing.cs">
+          <DependentUpon>VncView.cs</DependentUpon>
+        </Compile>
     </ItemGroup>
 
 </Project>

src/MarcusW.VncClient.Avalonia/VncView.Sizing.cs

@@ -0,0 +1,139 @@
+using System;
+using System.Collections.Immutable;
+using System.Linq;
+using System.Reactive.Disposables;
+using System.Reactive.Linq;
+using System.Reactive.Subjects;
+using Avalonia;
+using Avalonia.Controls;
+using MarcusW.VncClient.Protocol.Implementation.MessageTypes.Outgoing;
+
+namespace MarcusW.VncClient.Avalonia
+{
+    public partial class VncView
+    {
+        private enum SizeSource
+        {
+            None,
+            OwnBounds,
+            OptimalSizeProperty
+        }
+
+        private static readonly TimeSpan ThrottleTime = TimeSpan.FromSeconds(0.5);
+
+        /// <summary>
+        /// Defines the <see cref="AutoResizeRemote"/> property.
+        /// </summary>
+        public static readonly DirectProperty<VncView, bool> AutoResizeRemoteProperty =
+            AvaloniaProperty.RegisterDirect<VncView, bool>(nameof(AutoResizeRemote), o => o.AutoResizeRemote, (o, v) => o.AutoResizeRemote = v, true);
+
+        /// <summary>
+        /// Defines the <see cref="OptimalSize"/> property.
+        /// </summary>
+        public static readonly DirectProperty<VncView, global::Avalonia.Size?> OptimalSizeProperty =
+            AvaloniaProperty.RegisterDirect<VncView, global::Avalonia.Size?>(nameof(OptimalSize), o => o.OptimalSize, (o, v) => o.OptimalSize = v);
+
+        private bool _autoResizeRemote = true;
+        private global::Avalonia.Size? _optimalSize = null;
+
+        private SizeSource _sizeSource = SizeSource.None;
+        private IDisposable _sizeSubscription = Disposable.Empty;
+
+        /// <summary>
+        /// Gets or sets whether the remote view should be automatically resized to fit the current <see cref="VncView"/>'s size (or the <see cref="OptimalSize"/>).
+        /// </summary>
+        public bool AutoResizeRemote
+        {
+            get => _autoResizeRemote;
+            set
+            {
+                if (value)
+                    SetSizeSource(OptimalSize == null ? SizeSource.OwnBounds : SizeSource.OptimalSizeProperty);
+                else
+                    SetSizeSource(SizeSource.None);
+
+                SetAndRaise(AutoResizeRemoteProperty, ref _autoResizeRemote, value);
+            }
+        }
+
+        /// <summary>
+        /// Gets or sets the optimal size value that is used to resize the remote view to make it fit into this optimal size.
+        /// If set to <see langword="null"/>, the size of this <see cref="VncView"/> itself is used as the optimal size for the remote view.
+        /// </summary>
+        /// <remarks>
+        /// This property is useful when this <see cref="VncView"/> is contained in e.g. a <see cref="ScrollViewer"/>.
+        /// In this case the view would never shrink when this property isn't used.
+        /// </remarks>
+        public global::Avalonia.Size? OptimalSize
+        {
+            get => _optimalSize;
+            set
+            {
+                if (AutoResizeRemote)
+                    SetSizeSource(value == null ? SizeSource.OwnBounds : SizeSource.OptimalSizeProperty);
+                else
+                    SetSizeSource(SizeSource.None);
+
+                SetAndRaise(OptimalSizeProperty, ref _optimalSize, value);
+            }
+        }
+
+        private void InitSizing()
+        {
+            SetSizeSource(SizeSource.OwnBounds);
+        }
+
+        private void SetSizeSource(SizeSource newSizeSource)
+        {
+            if (newSizeSource == _sizeSource)
+                return;
+            _sizeSource = newSizeSource;
+
+            // Source has changed, dispose the previous subscription
+            _sizeSubscription.Dispose();
+
+            // Disable resizing?
+            if (_sizeSource == SizeSource.None)
+            {
+                _sizeSubscription = Disposable.Empty;
+                return;
+            }
+
+            // Setup a new subscription
+            IObservable<global::Avalonia.Size> observable = _sizeSource == SizeSource.OptimalSizeProperty
+                ? this.GetObservable(OptimalSizeProperty).Where(s => s.HasValue).Select(s => s!.Value)
+                : this.GetObservable(BoundsProperty).Select(bounds => bounds.Size);
+            _sizeSubscription = observable.Distinct().Throttle(ThrottleTime).Subscribe(HandleResize);
+        }
+
+        private void HandleResize(global::Avalonia.Size size)
+        {
+            RfbConnection? connection = Connection;
+            if (connection == null)
+                return;
+
+            if (!connection.DesktopIsResizable)
+                return;
+
+            connection.EnqueueMessage(new SetDesktopSizeMessage((currentSize, currentLayout) => {
+                var newSize = new Size((int)size.Width, (int)size.Height);
+                var newRectangle = new Rectangle(Position.Origin, newSize);
+
+                Screen newScreen;
+                if (!currentLayout.Any())
+                {
+                    // Create a new layout with one screen
+                    newScreen = new Screen(1, newRectangle, 0);
+                }
+                else
+                {
+                    // If there is more than one screen, only use one because multi-monitor is not supported
+                    Screen firstScreen = currentLayout.First();
+                    newScreen = new Screen(firstScreen.Id, newRectangle, firstScreen.Flags);
+                }
+
+                return (newSize, new[] { newScreen }.ToImmutableHashSet());
+            }));
+        }
+    }
+}

src/MarcusW.VncClient.Avalonia/VncView.cs

@@ -34,7 +34,7 @@ static VncView()
         /// Gets or sets the connection that is shown in this VNC view.
         /// </summary>
         /// <remarks>
-        /// Interactions with this control will be forwarded to the selected <see cref="RfbConnection"/>.
+        /// Interactions with this <see cref="VncView"/> will be forwarded to the selected <see cref="RfbConnection"/>.
         /// In case this property is set to <see langword="null"/>, no connection will be attached to this view.
         /// </remarks>
         public RfbConnection? Connection
@@ -65,6 +65,11 @@ public RfbConnection? Connection
             }
         }
 
+        public VncView()
+        {
+            InitSizing();
+        }
+
         /// <inheritdoc />
         public virtual void RingBell()
         {

src/MarcusW.VncClient/Protocol/Implementation/DefaultImplementation.cs

@@ -146,7 +146,7 @@ public static IEnumerable<IMessageType> GetDefaultMessageTypes(RfbConnectionCont
             yield return new EnableContinuousUpdatesMessageType();
             yield return new PointerEventMessageType();
             yield return new KeyEventMessageType();
-            yield return new SetDesktopSizeMessageType();
+            yield return new SetDesktopSizeMessageType(context);
         }
 
         /// <summary>

src/MarcusW.VncClient/Protocol/Implementation/MessageTypes/Outgoing/SetDesktopSizeMessageType.cs

@@ -1,4 +1,9 @@
+using System;
+using System.Buffers.Binary;
+using System.Collections.Immutable;
+using System.Diagnostics;
 using System.Threading;
+using MarcusW.VncClient.Protocol.EncodingTypes;
 using MarcusW.VncClient.Protocol.MessageTypes;
 
 namespace MarcusW.VncClient.Protocol.Implementation.MessageTypes.Outgoing
@@ -8,6 +13,8 @@ namespace MarcusW.VncClient.Protocol.Implementation.MessageTypes.Outgoing
     /// </summary>
     public class SetDesktopSizeMessageType : IOutgoingMessageType
     {
+        private readonly ProtocolState _state;
+
         /// <inheritdoc />
         public byte Id => (byte)WellKnownOutgoingMessageType.SetDesktopSize;
 
@@ -17,18 +24,111 @@ public class SetDesktopSizeMessageType : IOutgoingMessageType
         /// <inheritdoc />
         public bool IsStandardMessageType => false;
 
+        /// <summary>
+        /// Initializes a new instance of the <see cref="SetDesktopSizeMessageType"/>.
+        /// </summary>
+        /// <param name="context">The connection context.</param>
+        public SetDesktopSizeMessageType(RfbConnectionContext context)
+        {
+            if (context == null)
+                throw new ArgumentNullException(nameof(context));
+            _state = context.GetState<ProtocolState>();
+        }
+
         /// <inheritdoc />
         public void WriteToTransport(IOutgoingMessage<IOutgoingMessageType> message, ITransport transport, CancellationToken cancellationToken = default)
         {
-            throw new System.NotImplementedException();
+            if (message == null)
+                throw new ArgumentNullException(nameof(message));
+            if (transport == null)
+                throw new ArgumentNullException(nameof(transport));
+            if (!(message is SetDesktopSizeMessage setDesktopSizeMessage))
+                throw new ArgumentException($"Message is no {nameof(SetDesktopSizeMessage)}.", nameof(message));
+
+            cancellationToken.ThrowIfCancellationRequested();
+
+            // Execute the mutation
+            (Size size, IImmutableSet<Screen> layout) = setDesktopSizeMessage.MutationFunc.Invoke(_state.RemoteFramebufferSize, _state.RemoteFramebufferLayout);
+
+            // Calculate message size
+            int messageSize = 2 + 2 * sizeof(ushort) + 2 + layout.Count * (sizeof(uint) + 4 * sizeof(ushort) + sizeof(uint));
+
+            // Allocate buffer
+            Span<byte> buffer = messageSize <= 1024 ? stackalloc byte[messageSize] : new byte[messageSize];
+
+            // Message header
+            buffer[0] = Id;
+            buffer[1] = 0; // Padding
+
+            // Size
+            BinaryPrimitives.WriteUInt16BigEndian(buffer[2..], (ushort)size.Width);
+            BinaryPrimitives.WriteUInt16BigEndian(buffer[4..], (ushort)size.Height);
+
+            // Number of screens
+            buffer[6] = (byte)layout.Count;
+            buffer[7] = 0; // Padding
+
+            // Screens
+            var bufferPosition = 8;
+            foreach (Screen screen in layout)
+            {
+                BinaryPrimitives.WriteUInt32BigEndian(buffer[bufferPosition..], screen.Id);
+                bufferPosition += sizeof(int);
+
+                BinaryPrimitives.WriteUInt16BigEndian(buffer[bufferPosition..], (ushort)screen.Rectangle.Position.X);
+                bufferPosition += sizeof(ushort);
+
+                BinaryPrimitives.WriteUInt16BigEndian(buffer[bufferPosition..], (ushort)screen.Rectangle.Position.Y);
+                bufferPosition += sizeof(ushort);
+
+                BinaryPrimitives.WriteUInt16BigEndian(buffer[bufferPosition..], (ushort)screen.Rectangle.Size.Width);
+                bufferPosition += sizeof(ushort);
+
+                BinaryPrimitives.WriteUInt16BigEndian(buffer[bufferPosition..], (ushort)screen.Rectangle.Size.Height);
+                bufferPosition += sizeof(ushort);
+
+                BinaryPrimitives.WriteUInt32BigEndian(buffer[bufferPosition..], screen.Flags);
+                bufferPosition += sizeof(int);
+            }
+
+            Debug.Assert(bufferPosition == messageSize, "bufferPosition == messageSize");
+
+            // Write buffer to stream
+            transport.Stream.Write(buffer);
         }
     }
 
+    /// <summary>
+    /// A message for updating the remote framebuffer size and layout.
+    /// </summary>
     public class SetDesktopSizeMessage : IOutgoingMessage<SetDesktopSizeMessageType>
     {
-        // TODO
+        /// <summary>
+        /// Represents the method that mutates a remote framebuffer size and layout.
+        /// </summary>
+        /// <param name="size">The current size.</param>
+        /// <param name="layout">The current layout.</param>
+        public delegate (Size size, IImmutableSet<Screen> layout) MutationFuncDelegate(Size size, IImmutableSet<Screen> layout);
+
+        /// <summary>
+        /// Gets the function that mutates the current remote framebuffer size and layout.
+        /// It will be called by the sender thread right before the message gets sent.
+        /// </summary>
+        public MutationFuncDelegate MutationFunc { get; }
+
+        /// <summary>
+        /// Initializes a new instance of the <see cref="SetDesktopSizeMessage"/>.
+        /// </summary>
+        /// <param name="mutationFunc">
+        /// The function that mutates the current remote framebuffer size and layout.
+        /// It will be called by the sender thread right before the message gets sent.
+        /// </param>
+        public SetDesktopSizeMessage(MutationFuncDelegate mutationFunc)
+        {
+            MutationFunc = mutationFunc ?? throw new ArgumentNullException(nameof(mutationFunc));
+        }
 
         /// <inheritdoc />
-        public string? GetParametersOverview() => "TODO TODO TODO TODO TODO TODO";
+        public string? GetParametersOverview() => $"MutationFunc: {MutationFunc}";
     }
 }

src/MarcusW.VncClient/Protocol/Implementation/ProtocolState.cs

@@ -162,7 +162,11 @@ public bool ServerSupportsContinuousUpdates
         public bool ServerSupportsExtendedDesktopSize
         {
             get => _serverSupportsExtendedDesktopSizeValue.Value;
-            set => _serverSupportsExtendedDesktopSizeValue.Value = value;
+            set
+            {
+                _serverSupportsExtendedDesktopSizeValue.Value = value;
+                _context.ConnectionDetails.SetDesktopIsResizable(value);
+            }
         }
 
         /// <summary>

src/MarcusW.VncClient/Protocol/RfbConnectionContext.cs

@@ -154,6 +154,12 @@ internal ConnectionDetailsAccessor(RfbConnection connection)
             /// <param name="desktopName">The new desktop name.</param>
             public void SetDesktopName(string? desktopName) => _connection.DesktopName = desktopName;
 
+            /// <summary>
+            /// Sets the value of the <seealso cref="RfbConnection.DesktopIsResizable"/> property on the <see cref="RfbConnection"/> object.
+            /// </summary>
+            /// <param name="desktopIsResizable">The new state.</param>
+            public void SetDesktopIsResizable(bool desktopIsResizable) => _connection.DesktopIsResizable = desktopIsResizable;
+
             /// <summary>
             /// Sets the value of the <seealso cref="RfbConnection.ContinuousUpdatesEnabled"/> property on the <see cref="RfbConnection"/> object.
             /// </summary>