Replace string element render types with RenderCommandType enum, decompose UI elements (Button, CheckBox, chrome) into drawing primitives via ToPrimitives(), emit per-element commands on flush, and move composite into IRenderSource.

Networking/TcpRpcServer.cs

@@ -87,6 +87,24 @@ public class TcpRpcServer(IPacketCrypto? crypto = null) : TcpRpcBase(crypto)
         return Task.WhenAll(sendTasks);
     }
 
+    /// <summary> Broadcasts raw binary payload to all connected clients. </summary>
+    public Task SendRawToAll(string type, byte[] payload)
+    {
+        List<Task> sendTasks = [];
+
+        foreach (TcpConnection conn in connections.Keys)
+        {
+            sendTasks.Add(SendRaw(conn, new TcpMessage
+            {
+                Type = type,
+                RequestId = Guid.NewGuid().ToString(),
+                Payload = payload
+            }));
+        }
+
+        return Task.WhenAll(sendTasks);
+    }
+
     protected override void OnConnectionClosed(TcpConnection conn)
     {
         _ = connections.TryRemove(conn, out _);

UI/GUI/Rendering/CanvasRenderSource.cs

@@ -1,6 +1,8 @@
 using Cosmos.Kernel.System.Graphics;
 using Cosmos.Kernel.System.Graphics.Fonts;
+using Cosmos.Kernel.System.Mouse;
 
+using RemSox.UI.GUI.UIEelements;
 using RemSox.Utils;
 
 using System.Drawing;
@@ -14,77 +16,97 @@ public sealed class CanvasRenderSource : IRenderSource
     private static readonly Dictionary<int, int> windowZIndices = [];
 
     // Sorted list keeps windows in Z-order without re-sorting.
-    // Key = (zIndex << 16 | windowId) so equal Z stays insertion-stable.
+    // Key = (zIndex << 32 | windowId) so equal Z stays insertion-stable.
     private static readonly SortedList<long, int> zOrderedWindows = [];
 
-    private static bool isContentDirty = true;   // pixel content changed
+    // Accumulated drawing primitives per window (in draw order).
-    private static bool isPositionDirty = true;   // only layout changed
+    private static readonly Dictionary<int, List<(int ElementId, RenderCommand Command)>> windowPrimitives = [];
+
+    private static readonly HashSet<int> dirtyWindows = [];
+    private static bool isPositionDirty = true;
     private static Point lastPointerPosition = new(-1, -1);
 
     private static readonly Lock renderLock = new();
 
-    private static readonly Dictionary<string, Action<Canvas, RenderCommand>> elementRenderers = new()
-    {
-        ["Circle"] = RenderCircle,
-        ["Rectangle"] = RenderRectangle,
-        ["Text"] = RenderText,
-        ["Line"] = RenderLine,
-        ["Button"] = RenderButton,
-        ["CheckBox"] = RenderCheckBox,
-    };
-
     public void Render(IEnumerable<RenderCommand> commands)
     {
         lock (renderLock)
         {
             foreach (RenderCommand command in commands)
             {
-                switch (command.ElementType)
+                switch (command.Type)
                 {
-                    case "WindowClose":
+                    case RenderCommandType.CreateWindow:
-                        RemoveWindow(command.WindowId);
+                        CreateOrUpdateWindow(command);
-                        continue;
+                        break;
 
-                    case "WindowMove":
+                    case RenderCommandType.DestroyWindow:
+                        RemoveWindow(command.WindowId);
+                        break;
+
+                    case RenderCommandType.MoveWindow:
                         if (windowCanvases.ContainsKey(command.WindowId))
                         {
                             windowPositions[command.WindowId] = command.Position;
                             isPositionDirty = true;
                         }
-                        continue;
+                        break;
 
-                    case "Window":
+                    case RenderCommandType.RemovePrimitives:
-                        ProcessWindowCommand(command);
+                        RemovePrimitives(command.WindowId, command.ElementId);
-                        isContentDirty = true;
+                        break;
-                        continue;
-                }
 
-                if (!windowCanvases.TryGetValue(command.WindowId, out Canvas? canvas))
+                    default:
-                {
+                        if (windowCanvases.ContainsKey(command.WindowId))
-                    continue;
+                        {
-                }
+                            UpsertPrimitive(command);
-
+                        }
-                if (elementRenderers.TryGetValue(command.ElementType, out Action<Canvas, RenderCommand>? renderer))
+                        break;
-                {
-                    renderer(canvas, command);
-                    isContentDirty = true;
                 }
             }
         }
     }
 
-    public static void CompositeAndDisplay(Canvas screenCanvas, Point pointerPosition)
+    public void Composite()
     {
+        Canvas screenCanvas = FullScreenCanvas.GetFullScreenCanvas();
+        Point pointerPosition = new(MouseManager.X, MouseManager.Y);
+
         lock (renderLock)
         {
             bool pointerMoved = pointerPosition != lastPointerPosition;
-            if (!isContentDirty && !isPositionDirty && !pointerMoved)
+            bool hasDirty = dirtyWindows.Count > 0;
+
+            if (!hasDirty && !isPositionDirty && !pointerMoved)
             {
                 return;
             }
 
-            screenCanvas.Clear(Color.Black);
+            // Redraw dirty windows from accumulated primitives
+            if (hasDirty)
+            {
+                foreach (int winId in dirtyWindows)
+                {
+                    if (!windowCanvases.TryGetValue(winId, out Canvas? canvas))
+                    {
+                        continue;
+                    }
 
+                    canvas.Clear(Color.Black);
+
+                    if (windowPrimitives.TryGetValue(winId, out var primitives))
+                    {
+                        foreach (var (_, cmd) in primitives)
+                        {
+                            DrawPrimitive(canvas, cmd);
+                        }
+                    }
+                }
+                dirtyWindows.Clear();
+            }
+
+            // Composite all windows to screen
+            screenCanvas.Clear(Color.Black);
             foreach (int windowId in zOrderedWindows.Values)
             {
                 if (windowPositions.TryGetValue(windowId, out Point pos) &&
@@ -98,17 +120,48 @@ public sealed class CanvasRenderSource : IRenderSource
             screenCanvas.Display();
 
             lastPointerPosition = pointerPosition;
-            isContentDirty = false;
             isPositionDirty = false;
         }
     }
 
-    // Helpers
+    // --- Accumulated state management ---
+
+    private static void CreateOrUpdateWindow(RenderCommand cmd)
+    {
+        int id = cmd.WindowId;
+        Size size = Get(cmd.Properties, "Size", new Size(160, 120));
+        int zIndex = Get(cmd.Properties, "ZIndex", 0);
+
+        if (!windowCanvases.TryGetValue(id, out Canvas? existing) ||
+            existing.Mode.Width != size.Width ||
+            existing.Mode.Height != size.Height)
+        {
+            windowCanvases[id] = new Canvas(size.Width, size.Height);
+        }
+
+        windowPositions[id] = cmd.Position;
+
+        if (windowZIndices.TryGetValue(id, out int oldZ))
+        {
+            _ = zOrderedWindows.Remove(ZKey(oldZ, id));
+        }
+        windowZIndices[id] = zIndex;
+        zOrderedWindows[ZKey(zIndex, id)] = id;
+
+        if (!windowPrimitives.ContainsKey(id))
+        {
+            windowPrimitives[id] = [];
+        }
+
+        _ = dirtyWindows.Add(id);
+        isPositionDirty = true;
+    }
 
     private static void RemoveWindow(int windowId)
     {
         _ = windowCanvases.Remove(windowId);
         _ = windowPositions.Remove(windowId);
+        _ = windowPrimitives.Remove(windowId);
 
         if (windowZIndices.TryGetValue(windowId, out int z))
         {
@@ -119,38 +172,69 @@ public sealed class CanvasRenderSource : IRenderSource
         isPositionDirty = true;
     }
 
-    private static void ProcessWindowCommand(RenderCommand command)
+    private static void UpsertPrimitive(RenderCommand cmd)
     {
-        int id = command.WindowId;
+        if (!windowPrimitives.TryGetValue(cmd.WindowId, out var list))
-
-        if (command.Properties.TryGetValue("ZIndex", out object? rawZ) && rawZ is int newZ)
         {
-            if (windowZIndices.TryGetValue(id, out int oldZ))
+            list = [];
-            {
+            windowPrimitives[cmd.WindowId] = list;
-                _ = zOrderedWindows.Remove(ZKey(oldZ, id));
-            }
-
-            windowZIndices[id] = newZ;
-            zOrderedWindows[ZKey(newZ, id)] = id;
-        }
-        else if (!windowZIndices.ContainsKey(id))
-        {
-            windowZIndices[id] = 0;
-            zOrderedWindows[ZKey(0, id)] = id;
         }
 
-        Size size = Get(command.Properties, "Size", new Size(160, 120));
+        int idx = list.FindIndex(p => p.ElementId == cmd.ElementId);
-
+        if (idx >= 0)
-        if (!windowCanvases.TryGetValue(id, out Canvas? current) ||
-            current.Mode.Width != size.Width ||
-            current.Mode.Height != size.Height)
         {
-            windowCanvases[id] = new Canvas(size.Width, size.Height);
+            list[idx] = (cmd.ElementId, cmd);
+        }
+        else
+        {
+            list.Add((cmd.ElementId, cmd));
         }
 
-        windowPositions[id] = command.Position;
+        _ = dirtyWindows.Add(cmd.WindowId);
-        isPositionDirty = true;
+    }
-        RenderWindow(windowCanvases[id], command);
+
+    private static void RemovePrimitives(int windowId, int baseElementId)
+    {
+        if (!windowPrimitives.TryGetValue(windowId, out var list))
+        {
+            return;
+        }
+
+        list.RemoveAll(p => p.ElementId >= 0
+            ? (p.ElementId >> UIElement.PrimitiveIdShift) == baseElementId
+            : p.ElementId == baseElementId);
+
+        _ = dirtyWindows.Add(windowId);
+    }
+
+    // --- Primitive drawing ---
+
+    private static void DrawPrimitive(Canvas canvas, RenderCommand cmd)
+    {
+        switch (cmd.Type)
+        {
+            case RenderCommandType.DrawFilledRect:
+                DrawFilledRect(canvas, cmd);
+                break;
+            case RenderCommandType.DrawRectBorder:
+                DrawRectBorder(canvas, cmd);
+                break;
+            case RenderCommandType.DrawFilledCircle:
+                DrawFilledCircle(canvas, cmd);
+                break;
+            case RenderCommandType.DrawCircle:
+                DrawCircle(canvas, cmd);
+                break;
+            case RenderCommandType.DrawPoint:
+                DrawPoint(canvas, cmd);
+                break;
+            case RenderCommandType.DrawText:
+                DrawText(canvas, cmd);
+                break;
+            case RenderCommandType.DrawLine:
+                DrawLine(canvas, cmd);
+                break;
+        }
     }
 
     // Builds a stable sort key from Z-index and window ID.
@@ -159,110 +243,61 @@ public sealed class CanvasRenderSource : IRenderSource
         return ((long)z << 32) | (uint)id;
     }
 
-    // Inline generic property getter — eliminates repeated TryGetValue + pattern-match boilerplate.
     private static T Get<T>(IReadOnlyDictionary<string, object?> props, string key, T fallback)
     {
         return props.TryGetValue(key, out object? raw) && raw is T value ? value : fallback;
     }
 
-    private static void RenderWindow(Canvas canvas, RenderCommand command)
+    private static void DrawFilledRect(Canvas canvas, RenderCommand cmd)
     {
-        Size size = Get(command.Properties, "Size", new Size(160, 120));
+        Color color = Get(cmd.Properties, "Color", Color.White);
-        bool focused = Get(command.Properties, "IsFocused", false);
+        Size size = Get(cmd.Properties, "Size", new Size(10, 10));
-        string titleText = Get(command.Properties, "Title", string.Empty);
+        canvas.DrawFilledRectangle(color, cmd.Position.X, cmd.Position.Y, size.Width, size.Height);
-
-        Color border = focused ? Color.White : Color.DarkGray;
-        Color title = focused ? Color.FromArgb(0, 120, 215) : Color.FromArgb(80, 80, 80);
-
-        canvas.DrawFilledRectangle(Color.FromArgb(32, 32, 32), 0, 0, size.Width, size.Height);
-        canvas.DrawFilledRectangle(title, 0, 0, size.Width, 18);
-        canvas.DrawStringHeight(titleText, PCScreenFont.DefaultFont, Color.White, 4, 2, 18);
-        canvas.DrawRectangle(border, 0, 0, size.Width, size.Height - 1);
     }
 
-    private static void RenderCircle(Canvas canvas, RenderCommand command)
+    private static void DrawRectBorder(Canvas canvas, RenderCommand cmd)
     {
-        Color color = Get(command.Properties, "Color", Color.White);
+        Color color = Get(cmd.Properties, "Color", Color.White);
-        int radius = Get(command.Properties, "Radius", 10);
+        Size size = Get(cmd.Properties, "Size", new Size(10, 10));
-
+        canvas.DrawRectangle(color, cmd.Position.X, cmd.Position.Y, size.Width, size.Height);
-        canvas.DrawFilledCircle(color, command.Position.X + radius, command.Position.Y + radius, radius);
     }
 
-    private static void RenderRectangle(Canvas canvas, RenderCommand command)
+    private static void DrawFilledCircle(Canvas canvas, RenderCommand cmd)
     {
-        Color color = Get(command.Properties, "Color", Color.White);
+        Color color = Get(cmd.Properties, "Color", Color.White);
-        Size size = Get(command.Properties, "Size", new Size(10, 10));
+        int radius = Get(cmd.Properties, "Radius", 10);
-        bool isFilled = Get(command.Properties, "IsFilled", false);
+        canvas.DrawFilledCircle(color, cmd.Position.X + radius, cmd.Position.Y + radius, radius);
-
-        if (isFilled)
-        {
-            canvas.DrawFilledRectangle(color, command.Position.X, command.Position.Y, size.Width, size.Height);
-        }
-        else
-        {
-            canvas.DrawRectangle(color, command.Position.X, command.Position.Y, size.Width, size.Height);
-        }
     }
 
-    private static void RenderText(Canvas canvas, RenderCommand command)
+    private static void DrawCircle(Canvas canvas, RenderCommand cmd)
     {
-        Color color = Get(command.Properties, "Color", Color.White);
+        Color color = Get(cmd.Properties, "Color", Color.White);
-        string content = Get(command.Properties, "Content", string.Empty);
+        int radius = Get(cmd.Properties, "Radius", 10);
-        int fontSize = Get(command.Properties, "FontSize", 12);
+        canvas.DrawCircle(color, cmd.Position.X + radius, cmd.Position.Y + radius, radius);
+    }
+
+    private static void DrawPoint(Canvas canvas, RenderCommand cmd)
+    {
+        Color color = Get(cmd.Properties, "Color", Color.White);
+        canvas.DrawPoint(color, cmd.Position.X, cmd.Position.Y);
+    }
+
+    private static void DrawText(Canvas canvas, RenderCommand cmd)
+    {
+        Color color = Get(cmd.Properties, "Color", Color.White);
+        string content = Get(cmd.Properties, "Content", string.Empty);
+        int fontSize = Get(cmd.Properties, "FontSize", 12);
 
         if (!string.IsNullOrEmpty(content))
         {
-            canvas.DrawStringHeight(content, PCScreenFont.DefaultFont, color, command.Position.X, command.Position.Y, fontSize);
+            canvas.DrawStringHeight(content, PCScreenFont.DefaultFont, color, cmd.Position.X, cmd.Position.Y, fontSize);
         }
     }
 
-    private static void RenderLine(Canvas canvas, RenderCommand command)
+    private static void DrawLine(Canvas canvas, RenderCommand cmd)
     {
-        Color color = Get(command.Properties, "Color", Color.White);
+        Color color = Get(cmd.Properties, "Color", Color.White);
-        Point end = Get(command.Properties, "EndPosition", command.Position);
+        Point end = Get(cmd.Properties, "EndPosition", cmd.Position);
-
+        canvas.DrawLine(color, cmd.Position.X, cmd.Position.Y, end.X, end.Y);
-        canvas.DrawLine(color, command.Position.X, command.Position.Y, end.X, end.Y);
-    }
-
-    private static void RenderButton(Canvas canvas, RenderCommand command)
-    {
-        Color bg = Get(command.Properties, "BackgroundColor", Color.LightGray);
-        Color fg = Get(command.Properties, "TextColor", Color.Black);
-        Size size = Get(command.Properties, "Size", new Size(60, 20));
-        string text = Get(command.Properties, "Text", string.Empty);
-
-        canvas.DrawFilledRectangle(bg, command.Position.X, command.Position.Y, size.Width, size.Height);
-        canvas.DrawRectangle(Color.DarkGray, command.Position.X, command.Position.Y, size.Width, size.Height);
-
-        if (!string.IsNullOrEmpty(text))
-        {
-            int tx = command.Position.X + (size.Width / 2) - (text.Length * 4);
-            int ty = command.Position.Y + (size.Height / 2) - 8;
-            canvas.DrawStringHeight(text, PCScreenFont.DefaultFont, fg, tx, ty, size.Height - 8, size.Width);
-        }
-    }
-
-    private static void RenderCheckBox(Canvas canvas, RenderCommand command)
-    {
-        Color bg = Get(command.Properties, "BackgroundColor", Color.LightGray);
-        Color fg = Get(command.Properties, "TextColor", Color.White);
-        bool isChecked = Get(command.Properties, "IsChecked", false);
-        string text = Get(command.Properties, "Text", string.Empty);
-        Size size = Get(command.Properties, "Size", new Size(12, 12));
-
-        int boxSize = size.Height;
-
-        canvas.DrawFilledRectangle(bg, command.Position.X, command.Position.Y, boxSize, boxSize);
-        canvas.DrawRectangle(Color.DarkGray, command.Position.X, command.Position.Y, boxSize, boxSize);
-
-        if (isChecked)
-        {
-            canvas.DrawFilledRectangle(Color.Black, command.Position.X + 3, command.Position.Y + 3, boxSize - 6, boxSize - 6);
-        }
-
-        if (!string.IsNullOrEmpty(text))
-        {
-            canvas.DrawStringHeight(text, PCScreenFont.DefaultFont, fg, command.Position.X + boxSize + 5, command.Position.Y - 2, boxSize, size.Width);
-        }
     }
 }

UI/GUI/Rendering/IRenderSource.cs

@@ -3,4 +3,5 @@ namespace RemSox.UI.GUI.Rendering;
 public interface IRenderSource
 {
     void Render(IEnumerable<RenderCommand> commands);
+    void Composite();
 }

UI/GUI/Rendering/NetworkRenderSource.cs

@@ -0,0 +1,21 @@
+using RemSox.Networking;
+
+namespace RemSox.UI.GUI.Rendering;
+
+public sealed class NetworkRenderSource(TcpRpcServer server) : IRenderSource
+{
+    private const string MessageType = "RenderCmd";
+
+    public void Render(IEnumerable<RenderCommand> commands)
+    {
+        foreach (RenderCommand cmd in commands)
+        {
+            byte[] data = cmd.ToBytes();
+            _ = server.SendRawToAll(MessageType, data);
+        }
+    }
+
+    public void Composite()
+    {
+    }
+}

UI/GUI/Rendering/RenderCommand.cs

@@ -1,4 +1,5 @@
 using System.Drawing;
+using System.Text;
 
 namespace RemSox.UI.GUI.Rendering;
 
@@ -6,7 +7,230 @@ public class RenderCommand
 {
     public required int WindowId { get; set; }
     public required int ElementId { get; set; }
-    public required string ElementType { get; set; }
+    public required RenderCommandType Type { get; set; }
-    public required Point Position { get; set; }
+    public Point Position { get; set; }
-    public required IReadOnlyDictionary<string, object?> Properties { get; set; }
+    public Dictionary<string, object?> Properties { get; set; } = [];
+
+    public byte[] ToBytes()
+    {
+        using MemoryStream ms = new();
+        Write(ms);
+        return ms.ToArray();
+    }
+
+    public void Write(Stream s)
+    {
+        s.WriteByte((byte)Type);
+        WriteVarint(s, WindowId);
+        WriteVarint(s, ElementId);
+
+        switch (Type)
+        {
+            case RenderCommandType.CreateWindow:
+                WriteInt16(s, Position.X);
+                WriteInt16(s, Position.Y);
+                Size size = GetProp("Size", new Size(160, 120));
+                WriteUInt16(s, size.Width);
+                WriteUInt16(s, size.Height);
+                WriteVarint(s, GetProp("ZIndex", 0));
+                break;
+
+            case RenderCommandType.DestroyWindow:
+                break;
+
+            case RenderCommandType.MoveWindow:
+                WriteInt16(s, Position.X);
+                WriteInt16(s, Position.Y);
+                break;
+
+            case RenderCommandType.DrawFilledRect:
+            case RenderCommandType.DrawRectBorder:
+                WriteInt16(s, Position.X);
+                WriteInt16(s, Position.Y);
+                Size rs = GetProp("Size", new Size(10, 10));
+                WriteUInt16(s, rs.Width);
+                WriteUInt16(s, rs.Height);
+                WriteColor(s, GetProp("Color", Color.White));
+                break;
+
+            case RenderCommandType.DrawFilledCircle:
+            case RenderCommandType.DrawCircle:
+                WriteInt16(s, Position.X);
+                WriteInt16(s, Position.Y);
+                WriteUInt16(s, GetProp("Radius", 10));
+                WriteColor(s, GetProp("Color", Color.White));
+                break;
+
+            case RenderCommandType.DrawPoint:
+                WriteInt16(s, Position.X);
+                WriteInt16(s, Position.Y);
+                WriteColor(s, GetProp("Color", Color.White));
+                break;
+
+            case RenderCommandType.DrawText:
+                WriteInt16(s, Position.X);
+                WriteInt16(s, Position.Y);
+                WriteColor(s, GetProp("Color", Color.White));
+                s.WriteByte((byte)GetProp("FontSize", 12));
+                string text = GetProp("Content", string.Empty);
+                byte[] utf8 = Encoding.UTF8.GetBytes(text);
+                WriteVarint(s, utf8.Length);
+                s.Write(utf8, 0, utf8.Length);
+                break;
+
+            case RenderCommandType.DrawLine:
+                WriteInt16(s, Position.X);
+                WriteInt16(s, Position.Y);
+                Point end = GetProp("EndPosition", Position);
+                WriteInt16(s, end.X);
+                WriteInt16(s, end.Y);
+                WriteColor(s, GetProp("Color", Color.White));
+                break;
+
+            case RenderCommandType.RemovePrimitives:
+                break;
+        }
+    }
+
+    public static RenderCommand FromBytes(byte[] data)
+    {
+        int offset = 0;
+        RenderCommandType type = (RenderCommandType)data[offset++];
+        int windowId = ReadVarint(data, ref offset);
+        int elementId = ReadVarint(data, ref offset);
+        Point pos = default;
+        Dictionary<string, object?> props = [];
+
+        switch (type)
+        {
+            case RenderCommandType.CreateWindow:
+                pos = new Point(ReadInt16(data, ref offset), ReadInt16(data, ref offset));
+                props["Size"] = new Size(ReadUInt16(data, ref offset), ReadUInt16(data, ref offset));
+                props["ZIndex"] = ReadVarint(data, ref offset);
+                break;
+
+            case RenderCommandType.DestroyWindow:
+                break;
+
+            case RenderCommandType.MoveWindow:
+                pos = new Point(ReadInt16(data, ref offset), ReadInt16(data, ref offset));
+                break;
+
+            case RenderCommandType.DrawFilledRect:
+            case RenderCommandType.DrawRectBorder:
+                pos = new Point(ReadInt16(data, ref offset), ReadInt16(data, ref offset));
+                props["Size"] = new Size(ReadUInt16(data, ref offset), ReadUInt16(data, ref offset));
+                props["Color"] = ReadColor(data, ref offset);
+                break;
+
+            case RenderCommandType.DrawFilledCircle:
+            case RenderCommandType.DrawCircle:
+                pos = new Point(ReadInt16(data, ref offset), ReadInt16(data, ref offset));
+                props["Radius"] = ReadUInt16(data, ref offset);
+                props["Color"] = ReadColor(data, ref offset);
+                break;
+
+            case RenderCommandType.DrawPoint:
+                pos = new Point(ReadInt16(data, ref offset), ReadInt16(data, ref offset));
+                props["Color"] = ReadColor(data, ref offset);
+                break;
+
+            case RenderCommandType.DrawText:
+                pos = new Point(ReadInt16(data, ref offset), ReadInt16(data, ref offset));
+                props["Color"] = ReadColor(data, ref offset);
+                props["FontSize"] = data[offset++];
+                int textLen = ReadVarint(data, ref offset);
+                props["Content"] = Encoding.UTF8.GetString(data, offset, textLen);
+                offset += textLen;
+                break;
+
+            case RenderCommandType.DrawLine:
+                pos = new Point(ReadInt16(data, ref offset), ReadInt16(data, ref offset));
+                props["EndPosition"] = new Point(ReadInt16(data, ref offset), ReadInt16(data, ref offset));
+                props["Color"] = ReadColor(data, ref offset);
+                break;
+
+            case RenderCommandType.RemovePrimitives:
+                break;
+        }
+
+        return new RenderCommand
+        {
+            Type = type,
+            WindowId = windowId,
+            ElementId = elementId,
+            Position = pos,
+            Properties = props,
+        };
+    }
+
+    // --- Serialization helpers ---
+
+    private T GetProp<T>(string key, T fallback) =>
+        Properties.TryGetValue(key, out object? raw) && raw is T val ? val : fallback;
+
+    private static void WriteVarint(Stream s, int value)
+    {
+        uint v = (uint)value;
+        while (v >= 0x80)
+        {
+            s.WriteByte((byte)(v | 0x80));
+            v >>= 7;
+        }
+        s.WriteByte((byte)v);
+    }
+
+    private static void WriteInt16(Stream s, int value)
+    {
+        s.WriteByte((byte)(value & 0xFF));
+        s.WriteByte((byte)((value >> 8) & 0xFF));
+    }
+
+    private static void WriteUInt16(Stream s, int value)
+    {
+        s.WriteByte((byte)(value & 0xFF));
+        s.WriteByte((byte)((value >> 8) & 0xFF));
+    }
+
+    private static void WriteColor(Stream s, Color c)
+    {
+        s.WriteByte(c.R);
+        s.WriteByte(c.G);
+        s.WriteByte(c.B);
+    }
+
+    private static int ReadVarint(byte[] data, ref int offset)
+    {
+        uint result = 0;
+        int shift = 0;
+        while (true)
+        {
+            byte b = data[offset++];
+            result |= (uint)(b & 0x7F) << shift;
+            if ((b & 0x80) == 0) return (int)result;
+            shift += 7;
+        }
+    }
+
+    private static int ReadInt16(byte[] data, ref int offset)
+    {
+        int lo = data[offset++];
+        int hi = data[offset++];
+        return (short)(lo | (hi << 8));
+    }
+
+    private static int ReadUInt16(byte[] data, ref int offset)
+    {
+        int lo = data[offset++];
+        int hi = data[offset++];
+        return lo | (hi << 8);
+    }
+
+    private static Color ReadColor(byte[] data, ref int offset)
+    {
+        byte r = data[offset++];
+        byte g = data[offset++];
+        byte b = data[offset++];
+        return Color.FromArgb(r, g, b);
+    }
 }

UI/GUI/Rendering/RenderCommandType.cs

@@ -0,0 +1,18 @@
+namespace RemSox.UI.GUI.Rendering;
+
+public enum RenderCommandType : byte
+{
+    CreateWindow = 0x01,
+    DestroyWindow = 0x02,
+    MoveWindow = 0x03,
+
+    DrawFilledRect = 0x10,
+    DrawRectBorder = 0x11,
+    DrawFilledCircle = 0x12,
+    DrawCircle = 0x13,
+    DrawText = 0x14,
+    DrawLine = 0x15,
+    DrawPoint = 0x16,
+
+    RemovePrimitives = 0x20,
+}

UI/GUI/UIEelements/Controls/Button.cs

@@ -1,3 +1,5 @@
+using RemSox.UI.GUI.Rendering;
+
 using System.Drawing;
 
 namespace RemSox.UI.GUI.UIEelements.Controls;
@@ -18,6 +20,58 @@ public class Button() : Control("Button")
         set => SetProperty(nameof(TextColor), ref field, value);
     } = Color.Black;
 
+    public override IEnumerable<RenderCommand> ToPrimitives(int windowId)
+    {
+        // Background fill
+        yield return new RenderCommand
+        {
+            WindowId = windowId,
+            ElementId = PrimitiveId(0),
+            Type = RenderCommandType.DrawFilledRect,
+            Position = Position,
+            Properties = new Dictionary<string, object?>
+            {
+                ["Color"] = BackgroundColor,
+                ["Size"] = Size,
+            }
+        };
+
+        // Border
+        yield return new RenderCommand
+        {
+            WindowId = windowId,
+            ElementId = PrimitiveId(1),
+            Type = RenderCommandType.DrawRectBorder,
+            Position = Position,
+            Properties = new Dictionary<string, object?>
+            {
+                ["Color"] = Color.DarkGray,
+                ["Size"] = Size,
+            }
+        };
+
+        // Text (centered)
+        if (!string.IsNullOrEmpty(Text))
+        {
+            int tx = Position.X + (Size.Width / 2) - (Text.Length * 4);
+            int ty = Position.Y + (Size.Height / 2) - 8;
+
+            yield return new RenderCommand
+            {
+                WindowId = windowId,
+                ElementId = PrimitiveId(2),
+                Type = RenderCommandType.DrawText,
+                Position = new Point(tx, ty),
+                Properties = new Dictionary<string, object?>
+                {
+                    ["Color"] = TextColor,
+                    ["Content"] = Text,
+                    ["FontSize"] = Size.Height - 8,
+                }
+            };
+        }
+    }
+
     public override void HandleMouseEvent(MouseEvent mouseEvent)
     {
         if (mouseEvent.Type == MouseEventType.ButtonDown && mouseEvent.Button == MouseButton.Left)

UI/GUI/UIEelements/Controls/CheckBox.cs

@@ -1,3 +1,5 @@
+using RemSox.UI.GUI.Rendering;
+
 using System.Drawing;
 
 namespace RemSox.UI.GUI.UIEelements.Controls;
@@ -28,6 +30,74 @@ public class CheckBox() : Control("CheckBox")
         set => SetProperty(nameof(TextColor), ref field, value);
     } = Color.White;
 
+    public override IEnumerable<RenderCommand> ToPrimitives(int windowId)
+    {
+        int boxSize = Size.Height;
+
+        // Checkbox box background
+        yield return new RenderCommand
+        {
+            WindowId = windowId,
+            ElementId = PrimitiveId(0),
+            Type = RenderCommandType.DrawFilledRect,
+            Position = Position,
+            Properties = new Dictionary<string, object?>
+            {
+                ["Color"] = BackgroundColor,
+                ["Size"] = new Size(boxSize, boxSize),
+            }
+        };
+
+        // Checkbox box border
+        yield return new RenderCommand
+        {
+            WindowId = windowId,
+            ElementId = PrimitiveId(1),
+            Type = RenderCommandType.DrawRectBorder,
+            Position = Position,
+            Properties = new Dictionary<string, object?>
+            {
+                ["Color"] = Color.DarkGray,
+                ["Size"] = new Size(boxSize, boxSize),
+            }
+        };
+
+        // Check mark (filled inner rect)
+        if (IsChecked)
+        {
+            yield return new RenderCommand
+            {
+                WindowId = windowId,
+                ElementId = PrimitiveId(2),
+                Type = RenderCommandType.DrawFilledRect,
+                Position = new Point(Position.X + 3, Position.Y + 3),
+                Properties = new Dictionary<string, object?>
+                {
+                    ["Color"] = Color.Black,
+                    ["Size"] = new Size(boxSize - 6, boxSize - 6),
+                }
+            };
+        }
+
+        // Label text
+        if (!string.IsNullOrEmpty(Text))
+        {
+            yield return new RenderCommand
+            {
+                WindowId = windowId,
+                ElementId = PrimitiveId(3),
+                Type = RenderCommandType.DrawText,
+                Position = new Point(Position.X + boxSize + 5, Position.Y - 2),
+                Properties = new Dictionary<string, object?>
+                {
+                    ["Color"] = TextColor,
+                    ["Content"] = Text,
+                    ["FontSize"] = boxSize,
+                }
+            };
+        }
+    }
+
     public override void HandleMouseEvent(MouseEvent mouseEvent)
     {
         if (mouseEvent.Type == MouseEventType.ButtonDown && mouseEvent.Button == MouseButton.Left)

UI/GUI/UIEelements/Shapes/Circle.cs

@@ -1,3 +1,7 @@
+using RemSox.UI.GUI.Rendering;
+
+using System.Drawing;
+
 namespace RemSox.UI.GUI.UIEelements.Shapes;
 
 public class Circle() : Shape("Circle")
@@ -7,4 +11,26 @@ public class Circle() : Shape("Circle")
         get;
         set => SetProperty(nameof(Radius), ref field, value);
     }
+
+    public bool IsFilled
+    {
+        get;
+        set => SetProperty(nameof(IsFilled), ref field, value);
+    } = true;
+
+    public override IEnumerable<RenderCommand> ToPrimitives(int windowId)
+    {
+        yield return new RenderCommand
+        {
+            WindowId = windowId,
+            ElementId = PrimitiveId(0),
+            Type = IsFilled ? RenderCommandType.DrawFilledCircle : RenderCommandType.DrawCircle,
+            Position = Position,
+            Properties = new Dictionary<string, object?>
+            {
+                ["Color"] = Color,
+                ["Radius"] = Radius,
+            }
+        };
+    }
 }

UI/GUI/UIEelements/Shapes/Line.cs

@@ -1,3 +1,5 @@
+using RemSox.UI.GUI.Rendering;
+
 using System.Drawing;
 
 namespace RemSox.UI.GUI.UIEelements.Shapes;
@@ -9,4 +11,20 @@ public class Line() : Shape("Line")
         get;
         set => SetProperty(nameof(EndPosition), ref field, value);
     }
+
+    public override IEnumerable<RenderCommand> ToPrimitives(int windowId)
+    {
+        yield return new RenderCommand
+        {
+            WindowId = windowId,
+            ElementId = PrimitiveId(0),
+            Type = RenderCommandType.DrawLine,
+            Position = Position,
+            Properties = new Dictionary<string, object?>
+            {
+                ["Color"] = Color,
+                ["EndPosition"] = EndPosition,
+            }
+        };
+    }
 }

UI/GUI/UIEelements/Shapes/Pixel.cs

@@ -0,0 +1,23 @@
+using RemSox.UI.GUI.Rendering;
+
+using System.Drawing;
+
+namespace RemSox.UI.GUI.UIEelements.Shapes;
+
+public class Pixel() : Shape("Pixel")
+{
+    public override IEnumerable<RenderCommand> ToPrimitives(int windowId)
+    {
+        yield return new RenderCommand
+        {
+            WindowId = windowId,
+            ElementId = PrimitiveId(0),
+            Type = RenderCommandType.DrawPoint,
+            Position = Position,
+            Properties = new Dictionary<string, object?>
+            {
+                ["Color"] = Color,
+            }
+        };
+    }
+}

UI/GUI/UIEelements/Shapes/Rectangle.cs

@@ -1,3 +1,5 @@
+using RemSox.UI.GUI.Rendering;
+
 using System.Drawing;
 
 namespace RemSox.UI.GUI.UIEelements.Shapes;
@@ -15,4 +17,20 @@ public class Rectangle() : Shape("Rectangle")
         get;
         set => SetProperty(nameof(IsFilled), ref field, value);
     } = true;
+
+    public override IEnumerable<RenderCommand> ToPrimitives(int windowId)
+    {
+        yield return new RenderCommand
+        {
+            WindowId = windowId,
+            ElementId = PrimitiveId(0),
+            Type = IsFilled ? RenderCommandType.DrawFilledRect : RenderCommandType.DrawRectBorder,
+            Position = Position,
+            Properties = new Dictionary<string, object?>
+            {
+                ["Color"] = Color,
+                ["Size"] = Size,
+            }
+        };
+    }
 }

UI/GUI/UIEelements/Shapes/Text.cs

@@ -1,3 +1,5 @@
+using RemSox.UI.GUI.Rendering;
+
 using System.Drawing;
 
 namespace RemSox.UI.GUI.UIEelements.Shapes;
@@ -21,4 +23,21 @@ public class Text() : UIElement("Text")
         get;
         set => SetProperty(nameof(FontSize), ref field, value);
     } = 12;
+
+    public override IEnumerable<RenderCommand> ToPrimitives(int windowId)
+    {
+        yield return new RenderCommand
+        {
+            WindowId = windowId,
+            ElementId = PrimitiveId(0),
+            Type = RenderCommandType.DrawText,
+            Position = Position,
+            Properties = new Dictionary<string, object?>
+            {
+                ["Color"] = Color,
+                ["Content"] = Content,
+                ["FontSize"] = FontSize,
+            }
+        };
+    }
 }

UI/GUI/UIEelements/UIEelement.cs

@@ -1,3 +1,4 @@
+using RemSox.UI.GUI.Rendering;
 using RemSox.Utils;
 
 using System.Drawing;
@@ -6,6 +7,8 @@ namespace RemSox.UI.GUI.UIEelements;
 
 public abstract class UIElement(string type) : ChangedPropertiesTracker
 {
+    public const int PrimitiveIdShift = 6;
+
     public int Id { get; init; }
 
     public string Type { get; set; } = type;
@@ -15,4 +18,10 @@ public abstract class UIElement(string type) : ChangedPropertiesTracker
         get;
         set => SetProperty(nameof(Position), ref field, value);
     }
+
+    /// <summary> Expands this UI element into drawing primitives. </summary>
+    public abstract IEnumerable<RenderCommand> ToPrimitives(int windowId);
+
+    /// <summary> Builds a stable primitive ID from element ID and sub-index. </summary>
+    protected int PrimitiveId(int subIndex) => (Id << PrimitiveIdShift) | subIndex;
 }

UI/GUI/Windows/Window.cs

@@ -143,9 +143,19 @@ public sealed class Window(string title, int processId, int id, IRenderSource re
             }
         }
 
-        if (removed && AutoFlush)
+        if (removed)
         {
-            Flush();
+            renderSource.Render([new RenderCommand
+            {
+                WindowId = Id,
+                ElementId = elementId,
+                Type = RenderCommandType.RemovePrimitives,
+            }]);
+
+            if (AutoFlush)
+            {
+                Flush();
+            }
         }
     }
 
@@ -158,8 +168,13 @@ public sealed class Window(string title, int processId, int id, IRenderSource re
         Flush();
     }
 
+    private const int ChromeClientBg = -1;
+    private const int ChromeTitleBg = -2;
+    private const int ChromeTitleText = -3;
+    private const int ChromeBorder = -4;
+
     /// <summary>
-    /// Sends current window and element state to the renderer.
+    /// Sends current window and element state to the renderer (delta-only).
     /// </summary>
     public void Flush()
     {
@@ -168,69 +183,83 @@ public sealed class Window(string title, int processId, int id, IRenderSource re
             return;
         }
 
-        bool anyChildChanged;
         List<UIElement> elementsCopy;
-
         lock (uiElementsLock)
         {
-            anyChildChanged = uiElements.Values.Any(e => e.AnyPropertyChanged);
+            elementsCopy = [.. uiElements.Values];
-            elementsCopy = uiElements.Values.ToList();
         }
 
-        bool windowStateChanged = isFirstRender || Size != lastRenderedSize || IsFocused != lastRenderedIsFocused || Title != lastRenderedTitle;
+        bool sizeChanged = Size != lastRenderedSize;
         bool positionChanged = Position != lastRenderedPosition;
         bool zIndexChanged = ZIndex != lastRenderedZIndex;
-
+        bool titleChanged = Title != lastRenderedTitle;
-        bool fullRedraw = windowStateChanged || anyChildChanged;
+        bool focusChanged = IsFocused != lastRenderedIsFocused;
+        bool chromeChanged = isFirstRender || sizeChanged || titleChanged || focusChanged;
 
         List<RenderCommand> commands = [];
 
-        if (fullRedraw)
+        // --- Structural commands ---
+        if (isFirstRender || sizeChanged || zIndexChanged)
         {
             commands.Add(new RenderCommand
             {
                 WindowId = Id,
                 ElementId = Id,
-                ElementType = "Window",
+                Type = RenderCommandType.CreateWindow,
                 Position = Position,
                 Properties = new Dictionary<string, object?>
                 {
-                    [nameof(Title)] = Title,
+                    ["Size"] = Size,
-                    [nameof(Size)] = Size,
+                    ["ZIndex"] = ZIndex,
-                    [nameof(IsFocused)] = IsFocused,
-                    [nameof(IsResizable)] = IsResizable,
-                    [nameof(IsDraggable)] = IsDraggable,
-                    [nameof(ZIndex)] = ZIndex
                 }
             });
+        }
+        else if (positionChanged)
+        {
+            commands.Add(new RenderCommand
+            {
+                WindowId = Id,
+                ElementId = Id,
+                Type = RenderCommandType.MoveWindow,
+                Position = Position,
+            });
+        }
 
+        // --- Chrome primitives (title bar, border, background) ---
+        if (chromeChanged)
+        {
+            ChromePrimitives(commands);
+        }
+
+        // --- Child element primitives (delta) ---
+        if (isFirstRender)
+        {
             foreach (UIElement element in elementsCopy)
             {
+                commands.AddRange(element.ToPrimitives(Id));
+                element.ClearChangedProperties();
+            }
+        }
+        else
+        {
+            foreach (UIElement element in elementsCopy)
+            {
+                if (!element.AnyPropertyChanged)
+                {
+                    continue;
+                }
+
+                // Remove old primitives for this element, then emit new ones
                 commands.Add(new RenderCommand
                 {
                     WindowId = Id,
                     ElementId = element.Id,
-                    ElementType = element.Type,
+                    Type = RenderCommandType.RemovePrimitives,
-                    Position = element.Position,
-                    Properties = element.AllProperties
                 });
+                commands.AddRange(element.ToPrimitives(Id));
                 element.ClearChangedProperties();
             }
         }
-        else if (positionChanged || zIndexChanged)
-        {
-            commands.Add(new RenderCommand
-            {
-                WindowId = Id,
-                ElementId = Id,
-                ElementType = "WindowMove",
-                Position = Position,
-                Properties = new Dictionary<string, object?>
-                {
-                    [nameof(ZIndex)] = ZIndex
-                }
-            });
-        }
 
         if (commands.Count > 0)
         {
@@ -244,6 +273,72 @@ public sealed class Window(string title, int processId, int id, IRenderSource re
         }
     }
 
+    private void ChromePrimitives(List<RenderCommand> commands)
+    {
+        Color border = IsFocused ? Color.White : Color.DarkGray;
+        Color title = IsFocused ? Color.FromArgb(0, 120, 215) : Color.FromArgb(80, 80, 80);
+
+        // Client area background
+        commands.Add(new RenderCommand
+        {
+            WindowId = Id,
+            ElementId = ChromeClientBg,
+            Type = RenderCommandType.DrawFilledRect,
+            Position = Point.Empty,
+            Properties = new Dictionary<string, object?>
+            {
+                ["Color"] = Color.FromArgb(32, 32, 32),
+                ["Size"] = Size,
+            }
+        });
+
+        // Title bar background
+        commands.Add(new RenderCommand
+        {
+            WindowId = Id,
+            ElementId = ChromeTitleBg,
+            Type = RenderCommandType.DrawFilledRect,
+            Position = Point.Empty,
+            Properties = new Dictionary<string, object?>
+            {
+                ["Color"] = title,
+                ["Size"] = new Size(Size.Width, 18),
+            }
+        });
+
+        // Title bar text
+        if (!string.IsNullOrEmpty(Title))
+        {
+            commands.Add(new RenderCommand
+            {
+                WindowId = Id,
+                ElementId = ChromeTitleText,
+                Type = RenderCommandType.DrawText,
+                Position = new Point(4, 2),
+                Properties = new Dictionary<string, object?>
+                {
+                    ["Color"] = Color.White,
+                    ["Content"] = Title,
+                    ["FontSize"] = 18,
+                }
+            });
+        }
+
+        // Window border
+        commands.Add(new RenderCommand
+        {
+            WindowId = Id,
+            ElementId = ChromeBorder,
+            Type = RenderCommandType.DrawRectBorder,
+            Position = Point.Empty,
+            Properties = new Dictionary<string, object?>
+            {
+                ["Color"] = border,
+                ["Size"] = Size,
+            }
+        });
+    }
+
     /// <summary> Dispatches a key event to the window's registered event handlers. </summary>
     public void HandleKeyEvent(Sys.Keyboard.KeyEvent keyEvent)
     {

UI/GUI/Windows/WindowManager.cs

@@ -71,7 +71,7 @@ public static class WindowManager
         wasRightButtonDown = rightButtonDown;
         wasMiddleButtonDown = middleButtonDown;
 
-        CanvasRenderSource.CompositeAndDisplay(canvas, pointerPosition);
+        renderSource.Composite();
 
         lastPointerPosition = pointerPosition;
     }
@@ -244,7 +244,7 @@ public static class WindowManager
             activeInteractWindow = null;
         }
 
-        renderSource.Render([new RenderCommand { WindowId = window.Id, ElementId = window.Id, ElementType = "WindowClose", Position = window.Position, Properties = new Dictionary<string, object?>() }]);
+        renderSource.Render([new RenderCommand { WindowId = window.Id, ElementId = window.Id, Type = RenderCommandType.DestroyWindow, Position = window.Position }]);
     }
 
     /// <summary>
@@ -300,7 +300,7 @@ public static class WindowManager
             List<RenderCommand> closeCommands = [];
             foreach (Window window in windowsToClose)
             {
-                closeCommands.Add(new RenderCommand { WindowId = window.Id, ElementId = window.Id, ElementType = "WindowClose", Position = window.Position, Properties = new Dictionary<string, object?>() });
+                closeCommands.Add(new RenderCommand { WindowId = window.Id, ElementId = window.Id, Type = RenderCommandType.DestroyWindow, Position = window.Position });
             }
             renderSource.Render(closeCommands);
         }
@@ -448,5 +448,19 @@ public static class WindowManager
                 source.Render(commands);
             }
         }
+
+        public void Composite()
+        {
+            List<IRenderSource> sourcesCopy;
+            lock (sourcesLock)
+            {
+                sourcesCopy = sources.ToList();
+            }
+
+            foreach (IRenderSource source in sourcesCopy)
+            {
+                source.Composite();
+            }
+        }
     }
 }