Make Rectangle a readonly struct.

OpenRA.Game/Primitives/Rectangle.cs

@@ -13,13 +13,12 @@
 
 namespace OpenRA.Primitives
 {
-	public struct Rectangle : IEquatable<Rectangle>
+	public readonly struct Rectangle : IEquatable<Rectangle>
 	{
-		// TODO: Make these readonly: this will require a lot of changes to the UI logic
-		public int X;
-		public int Y;
-		public int Width;
-		public int Height;
+		public readonly int X;
+		public readonly int Y;
+		public readonly int Width;
+		public readonly int Height;
 		public static readonly Rectangle Empty;
 
 		public static Rectangle FromLTRB(int left, int top, int right, int bottom)

OpenRA.Game/Widgets/Widget.cs

@@ -182,6 +182,28 @@ public class ChromeLogic : IDisposable
 		protected virtual void Dispose(bool disposing) { }
 	}
 
+	public struct WidgetBounds
+	{
+		public int X, Y, Width, Height;
+		public readonly int Left => X;
+		public readonly int Right => X + Width;
+		public readonly int Top => Y;
+		public readonly int Bottom => Y + Height;
+
+		public WidgetBounds(int x, int y, int width, int height)
+		{
+			X = x;
+			Y = y;
+			Width = width;
+			Height = height;
+		}
+
+		public readonly Rectangle ToRectangle()
+		{
+			return new Rectangle(X, Y, Width, Height);
+		}
+	}
+
 	public abstract class Widget
 	{
 		string defaultCursor = null;
@@ -201,7 +223,7 @@ public abstract class Widget
 		public bool IgnoreChildMouseOver;
 
 		// Calculated internally
-		public Rectangle Bounds;
+		public WidgetBounds Bounds;
 		public Widget Parent = null;
 		public Func<bool> IsVisible;
 
@@ -261,7 +283,7 @@ public virtual void Initialize(WidgetArgs args)
 
 			// Parse the YAML equations to find the widget bounds
 			var parentBounds = (Parent == null)
-				? new Rectangle(0, 0, Game.Renderer.Resolution.Width, Game.Renderer.Resolution.Height)
+				? new WidgetBounds(0, 0, Game.Renderer.Resolution.Width, Game.Renderer.Resolution.Height)
 				: Parent.Bounds;
 
 			var substitutions = args.TryGetValue("substitutions", out var subs) ?
@@ -276,15 +298,15 @@ public virtual void Initialize(WidgetArgs args)
 			substitutions.Add("PARENT_BOTTOM", parentBounds.Height);
 
 			var readOnlySubstitutions = new ReadOnlyDictionary<string, int>(substitutions);
-			var width = Width != null ? Width.Evaluate(readOnlySubstitutions) : 0;
-			var height = Height != null ? Height.Evaluate(readOnlySubstitutions) : 0;
+			var width = Width?.Evaluate(readOnlySubstitutions) ?? 0;
+			var height = Height?.Evaluate(readOnlySubstitutions) ?? 0;
 
 			substitutions.Add("WIDTH", width);
 			substitutions.Add("HEIGHT", height);
 
-			var x = X != null ? X.Evaluate(readOnlySubstitutions) : 0;
-			var y = Y != null ? Y.Evaluate(readOnlySubstitutions) : 0;
-			Bounds = new Rectangle(x, y, width, height);
+			var x = X?.Evaluate(readOnlySubstitutions) ?? 0;
+			var y = Y?.Evaluate(readOnlySubstitutions) ?? 0;
+			Bounds = new WidgetBounds(x, y, width, height);
 		}
 
 		public void PostInit(WidgetArgs args)

OpenRA.Mods.Common/Widgets/BackgroundWidget.cs

@@ -9,7 +9,6 @@
  */
 #endregion
 
-using OpenRA.Primitives;
 using OpenRA.Widgets;
 
 namespace OpenRA.Mods.Common.Widgets
@@ -50,11 +49,11 @@ public override bool HandleMouseInput(MouseInput mi)
 					break;
 				case MouseInputEvent.Down:
 					moving = true;
-					Bounds = new Rectangle(Bounds.X + vec.X, Bounds.Y + vec.Y, Bounds.Width, Bounds.Height);
+					Bounds = new WidgetBounds(Bounds.X + vec.X, Bounds.Y + vec.Y, Bounds.Width, Bounds.Height);
 					break;
 				case MouseInputEvent.Move:
 					if (moving)
-						Bounds = new Rectangle(Bounds.X + vec.X, Bounds.Y + vec.Y, Bounds.Width, Bounds.Height);
+						Bounds = new WidgetBounds(Bounds.X + vec.X, Bounds.Y + vec.Y, Bounds.Width, Bounds.Height);
 					break;
 			}
 

OpenRA.Mods.Common/Widgets/DropDownButtonWidget.cs

@@ -13,7 +13,6 @@
 using System.Collections.Generic;
 using System.Linq;
 using OpenRA.Graphics;
-using OpenRA.Primitives;
 using OpenRA.Widgets;
 
 namespace OpenRA.Mods.Common.Widgets
@@ -107,7 +106,7 @@ public void AttachPanel(Widget p, Action onCancel)
 			// Mask to prevent any clicks from being sent to other widgets
 			fullscreenMask = new MaskWidget
 			{
-				Bounds = new Rectangle(0, 0, Game.Renderer.Resolution.Width, Game.Renderer.Resolution.Height)
+				Bounds = new WidgetBounds(0, 0, Game.Renderer.Resolution.Width, Game.Renderer.Resolution.Height)
 			};
 
 			fullscreenMask.OnMouseDown += mi => { Game.Sound.PlayNotification(ModRules, null, "Sounds", ClickSound, null); RemovePanel(); };
@@ -129,7 +128,7 @@ public void AttachPanel(Widget p, Action onCancel)
 			if (panelY + oldBounds.Height > Game.Renderer.Resolution.Height)
 				panelY -= Bounds.Height + oldBounds.Height;
 
-			panel.Bounds = new Rectangle(
+			panel.Bounds = new WidgetBounds(
 				panelX,
 				panelY,
 				oldBounds.Width,

OpenRA.Mods.Common/Widgets/Logic/Settings/DisplaySettingsLogic.cs

@@ -16,7 +16,6 @@
 using System.Linq;
 using OpenRA.Graphics;
 using OpenRA.Mods.Common.Traits;
-using OpenRA.Primitives;
 using OpenRA.Widgets;
 
 namespace OpenRA.Mods.Common.Widgets.Logic
@@ -501,7 +500,7 @@ static void RecalculateWidgetLayout(Widget w, bool insideScrollPanel = false)
 				return;
 
 			var parentBounds = w.Parent == null
-				? new Rectangle(0, 0, Game.Renderer.Resolution.Width, Game.Renderer.Resolution.Height)
+				? new WidgetBounds(0, 0, Game.Renderer.Resolution.Width, Game.Renderer.Resolution.Height)
 				: w.Parent.Bounds;
 
 			var substitutions = new Dictionary<string, int>
@@ -515,18 +514,18 @@ static void RecalculateWidgetLayout(Widget w, bool insideScrollPanel = false)
 			};
 
 			var readOnlySubstitutions = new ReadOnlyDictionary<string, int>(substitutions);
-			var width = w.Width != null ? w.Width.Evaluate(readOnlySubstitutions) : 0;
-			var height = w.Height != null ? w.Height.Evaluate(readOnlySubstitutions) : 0;
+			var width = w.Width?.Evaluate(readOnlySubstitutions) ?? 0;
+			var height = w.Height?.Evaluate(readOnlySubstitutions) ?? 0;
 
 			substitutions.Add("WIDTH", width);
 			substitutions.Add("HEIGHT", height);
 
 			if (insideScrollPanel)
-				w.Bounds = new Rectangle(w.Bounds.X, w.Bounds.Y, width, w.Bounds.Height);
+				w.Bounds = new WidgetBounds(w.Bounds.X, w.Bounds.Y, width, w.Bounds.Height);
 			else
-				w.Bounds = new Rectangle(
-					w.X != null ? w.X.Evaluate(readOnlySubstitutions) : 0,
-					w.Y != null ? w.Y.Evaluate(readOnlySubstitutions) : 0,
+				w.Bounds = new WidgetBounds(
+					w.X?.Evaluate(readOnlySubstitutions) ?? 0,
+					w.Y?.Evaluate(readOnlySubstitutions) ?? 0,
 					width,
 					height);
 

OpenRA.Mods.Common/Widgets/ScrollPanelWidget.cs

@@ -225,11 +225,10 @@ public override void DrawOuter()
 
 			// ChildOrigin enumerates the widget tree, so only evaluate it once
 			var co = ChildOrigin;
-			drawBounds.X -= co.X;
-			drawBounds.Y -= co.Y;
+			drawBounds = new Rectangle(drawBounds.X - co.X, drawBounds.Y - co.Y, drawBounds.Width, drawBounds.Height);
 
 			foreach (var child in Children)
-				if (child.Bounds.IntersectsWith(drawBounds))
+				if (child.Bounds.ToRectangle().IntersectsWith(drawBounds))
 					child.DrawOuter();
 
 			Game.Renderer.DisableScissor();

OpenRA.Mods.Common/Widgets/SupportPowerTimerWidget.cs

@@ -78,7 +78,7 @@ public override void Draw()
 			foreach (var t in texts)
 			{
 				var textSize = font.Measure(t.Text);
-				var location = new float2(Bounds.Location) + new float2(0, y);
+				var location = new float2(Bounds.X, Bounds.Y + y);
 
 				if (Align == TextAlign.Center)
 					location += new int2((Bounds.Width - textSize.X) / 2, 0);

OpenRA.Mods.Common/Widgets/TextNotificationsDisplayWidget.cs

@@ -51,9 +51,8 @@ public override void Initialize(WidgetArgs args)
 			var wholeLines = (int)Math.Floor((double)((Bounds.Height - BottomSpacing) / lineHeight));
 			var visibleChildrenHeight = wholeLines * lineHeight;
 
-			overflowDrawBounds = new Rectangle(RenderOrigin.X, RenderOrigin.Y, Bounds.Width, Bounds.Height);
-			overflowDrawBounds.Y += Bounds.Height - visibleChildrenHeight;
-			overflowDrawBounds.Height = visibleChildrenHeight;
+			var y = RenderOrigin.Y + Bounds.Height - visibleChildrenHeight;
+			overflowDrawBounds = new Rectangle(RenderOrigin.X, y, Bounds.Width, visibleChildrenHeight);
 		}
 
 		public override void DrawOuter()
@@ -66,9 +65,10 @@ public override void DrawOuter()
 			if (mostRecentMessageOverflows && HideOverflow)
 				Game.Renderer.EnableScissor(overflowDrawBounds);
 
+			var bounds = Bounds.ToRectangle();
 			for (var i = Children.Count - 1; i >= 0; i--)
 			{
-				if (Bounds.Contains(Children[i].Bounds) || !HideOverflow || mostRecentMessageOverflows)
+				if (!HideOverflow || mostRecentMessageOverflows || bounds.Contains(Children[i].Bounds.ToRectangle()))
 					Children[i].DrawOuter();
 
 				if (mostRecentMessageOverflows)