Add ScreenInfo render command for desktop size synchronization

UI/GUI/Rendering/CanvasRenderSource.cs

@@ -26,6 +26,7 @@ public sealed class CanvasRenderSource : IRenderSource
     private static Point lastPointerPosition = new(-1, -1);
 
     private static Point cursorPosition;
+    private static int screenWidth, screenHeight;
 
     private static readonly Lock renderLock = new();
 
@@ -62,6 +63,12 @@ public sealed class CanvasRenderSource : IRenderSource
                         isPositionDirty = true;
                         break;
 
+                    case RenderCommandType.ScreenInfo:
+                        screenWidth = Get(command.Properties, "Width", 640);
+                        screenHeight = Get(command.Properties, "Height", 480);
+                        isPositionDirty = true;
+                        break;
+
                     default:
                         if (windowCanvases.ContainsKey(command.WindowId))
                         {

UI/GUI/Rendering/RenderCommand.cs

@@ -95,6 +95,11 @@ public class RenderCommand
                 WriteInt16(s, Position.X);
                 WriteInt16(s, Position.Y);
                 break;
+
+            case RenderCommandType.ScreenInfo:
+                WriteUInt16(s, GetProp("Width", 0));
+                WriteUInt16(s, GetProp("Height", 0));
+                break;
         }
     }
 
@@ -163,6 +168,11 @@ public class RenderCommand
             case RenderCommandType.SetCursor:
                 pos = new Point(ReadInt16(data, ref offset), ReadInt16(data, ref offset));
                 break;
+
+            case RenderCommandType.ScreenInfo:
+                props["Width"] = ReadUInt16(data, ref offset);
+                props["Height"] = ReadUInt16(data, ref offset);
+                break;
         }
 
         return new RenderCommand

UI/GUI/Rendering/RenderCommandType.cs

@@ -17,4 +17,6 @@ public enum RenderCommandType : byte
     RemovePrimitives = 0x20,
 
     SetCursor = 0x30,
+
+    ScreenInfo = 0xF0,
 }