Create shim over GuiApi so it can only be used via WithSurface

src/BizHawk.Client.Common/Api/ApiManager.cs

@@ -23,6 +23,7 @@ static ApiManager()
 
 		public static void AddApiType(Type type)
 		{
+			if (type == typeof(GuiApi)) return; // using `GuiApiShim` instead
 			var interfaceType = type.GetInterfaces().FirstOrDefault(t => typeof(IExternalApi).IsAssignableFrom(t) && t != typeof(IExternalApi));
 			if (interfaceType == null) return; // if we couldn't determine what it's implementing, then it's not an api impl. type
 			var ctor = type.GetConstructors().Single();

src/BizHawk.Client.Common/Api/Classes/GuiApi.cs

@@ -2,7 +2,6 @@
 using System.Diagnostics.CodeAnalysis;
 using System.Drawing;
 using System.Drawing.Drawing2D;
-using System.Drawing.Imaging;
 using System.Drawing.Text;
 using System.IO;
 using System.Linq;
@@ -28,8 +27,8 @@ private static Bitmap NullGraphicsBitmap
 
 		private readonly IDialogController _dialogController;
 
-		[RequiredService]
-		private IEmulator Emulator { get; set; }
+//		[RequiredService]
+		internal IEmulator Emulator { get; set; }
 
 		private readonly Action<string> LogCallback;
 
@@ -47,12 +46,9 @@ private static Bitmap NullGraphicsBitmap
 
 		private Color _defaultTextBackground = Color.FromArgb(128, 0, 0, 0);
 
-		private (int Left, int Top, int Right, int Bottom) _padding = (0, 0, 0, 0);
-
 		private FontFamily[]/*?*/ _pixelFonts = null;
 
-		private DisplaySurfaceID? _usingSurfaceID;
-		public bool HasGUISurface => true;
+		internal DisplaySurfaceID? SurfaceID { get; set; } = null;
 
 		public GuiApi(
 			IDialogController dialogController,
@@ -73,70 +69,23 @@ private IReadOnlyList<FontFamily> PixelFonts
 
 		private I2DRenderer Get2DRenderer(DisplaySurfaceID? surfaceID)
 		{
-			var nnID = surfaceID ?? _usingSurfaceID ?? throw new Exception();
+			if (surfaceID is not null && surfaceID != SurfaceID) throw new InvalidOperationException($"Mixed drawing surfaces! (Draw call targeting {surfaceID} within {nameof(WithSurface)}({SurfaceID}) scope)");
+			var nnID = surfaceID ?? SurfaceID ?? throw new Exception();
 			return _displayManager.GetApiHawk2DRenderer(nnID);
 		}
 
 		public void ToggleCompositingMode()
 			=> _compositingMode = (CompositingMode) (1 - (int) _compositingMode); // enum has two members, 0 and 1
 
-		public ImageAttributes GetAttributes() => null;
-
-		public void SetAttributes(ImageAttributes a)
-		{
-		}
-
 		public void WithSurface(DisplaySurfaceID surfaceID, Action<IGuiApi> drawingCallsFunc)
 		{
-			_usingSurfaceID = surfaceID;
-			try
-			{
-				drawingCallsFunc(this);
-			}
-			finally
-			{
-				_usingSurfaceID = null;
-			}
+			const string ERR_MSG_NESTED = $"Nested call to {nameof(IGuiApi)}.{nameof(WithSurface)} (or reference stored out of scope)!";
+			if (surfaceID != SurfaceID) throw new InvalidOperationException(ERR_MSG_NESTED);
+			// else it should be fine, but warn anyway
+			LogCallback(ERR_MSG_NESTED);
+			drawingCallsFunc(this);
 		}
 
-		public void WithSurface(DisplaySurfaceID surfaceID, Action drawingCallsFunc)
-		{
-			_usingSurfaceID = surfaceID;
-			try
-			{
-				drawingCallsFunc();
-			}
-			finally
-			{
-				_usingSurfaceID = null;
-			}
-		}
-
-		public void DrawNew(string name, bool clear)
-		{
-			switch (name)
-			{
-				case null:
-				case "emu":
-					LogCallback("the `DrawNew(\"emu\")` function has been deprecated");
-					return;
-				case "native":
-					throw new InvalidOperationException("the ability to draw in the margins with `DrawNew(\"native\")` has been removed");
-				default:
-					throw new InvalidOperationException("invalid surface name");
-			}
-		}
-
-		public void DrawFinish() => LogCallback("the `DrawFinish()` function has been deprecated");
-
-		public void SetPadding(int all) => _padding = (all, all, all, all);
-
-		public void SetPadding(int x, int y) => _padding = (x / 2, y / 2, x / 2 + x & 1, y / 2 + y & 1);
-
-		public void SetPadding(int l, int t, int r, int b) => _padding = (l, t, r, b);
-
-		public (int Left, int Top, int Right, int Bottom) GetPadding() => _padding;
-
 		public void AddMessage(string message, [LiteralExpected] int? duration = null)
 			=> _dialogController.AddOnScreenMessage(message, duration);
 
@@ -490,16 +439,6 @@ public void DrawString(int x, int y, string message, Color? forecolor = null, Co
 			}
 		}
 
-		public void DrawText(int x, int y, string message, Color? forecolor = null, Color? backcolor = null, string fontfamily = null, DisplaySurfaceID? surfaceID = null)
-			=> PixelText(
-				x: x,
-				y: y,
-				message: message,
-				forecolor: forecolor,
-				backcolor: backcolor,
-				fontfamily: fontfamily,
-				surfaceID: surfaceID);
-
 		public void PixelText(
 			int x,
 			int y,

src/BizHawk.Client.Common/Api/Classes/GuiApiShim.cs

@@ -0,0 +1,241 @@
+using System.Diagnostics.CodeAnalysis;
+using System.Drawing;
+using System.Runtime.CompilerServices;
+
+using BizHawk.Emulation.Common;
+
+namespace BizHawk.Client.Common
+{
+	public sealed class GuiApiShim : IGuiApi
+	{
+		private static InvalidOperationException CantDrawOutsideBatch
+			=> new($"Can't make draw calls outside {nameof(WithSurface)}! Check you're calling this method on the instance passed to the lambda.");
+
+		private readonly GuiApi _realImpl;
+
+		[RequiredService]
+		private IEmulator Emulator
+		{
+			[MethodImpl(MethodImplOptions.AggressiveInlining)]
+			get => _realImpl.Emulator;
+			[MethodImpl(MethodImplOptions.AggressiveInlining)]
+			set => _realImpl.Emulator = value;
+		}
+
+		public GuiApiShim(
+			IDialogController dialogController,
+			DisplayManagerBase displayManager,
+			Action<string> logCallback)
+				=> _realImpl = new(dialogController, displayManager, logCallback);
+
+		[MethodImpl(MethodImplOptions.AggressiveInlining)]
+		public void AddMessage(string message, [LiteralExpected] int? duration = null)
+			=> _realImpl.AddMessage(message, duration: duration);
+
+		[MethodImpl(MethodImplOptions.AggressiveInlining)]
+		public void ClearGraphics(DisplaySurfaceID? surfaceID = null)
+			=> _realImpl.ClearGraphics(surfaceID);
+
+		[MethodImpl(MethodImplOptions.AggressiveInlining)]
+		public void ClearImageCache()
+			=> _realImpl.ClearImageCache();
+
+		[MethodImpl(MethodImplOptions.AggressiveInlining)]
+		public void ClearText()
+			=> _realImpl.ClearText();
+
+		[MethodImpl(MethodImplOptions.AggressiveInlining)]
+		public void Dispose()
+			=> _realImpl.Dispose();
+
+		public void DrawAxis(int x, int y, int size, Color? color = null, DisplaySurfaceID? surfaceID = null)
+			=> throw CantDrawOutsideBatch;
+
+		public void DrawBezier(
+			Point p1,
+			Point p2,
+			Point p3,
+			Point p4,
+			Color? color = null,
+			DisplaySurfaceID? surfaceID = null)
+				=> throw CantDrawOutsideBatch;
+
+		public void DrawBeziers(Point[] points, Color? color = null, DisplaySurfaceID? surfaceID = null)
+			=> throw CantDrawOutsideBatch;
+
+		public void DrawBox(
+			int x,
+			int y,
+			int x2,
+			int y2,
+			Color? line = null,
+			Color? background = null,
+			DisplaySurfaceID? surfaceID = null)
+				=> throw CantDrawOutsideBatch;
+
+		public void DrawEllipse(
+			int x,
+			int y,
+			int width,
+			int height,
+			Color? line = null,
+			Color? background = null,
+			DisplaySurfaceID? surfaceID = null)
+				=> throw CantDrawOutsideBatch;
+
+		public void DrawIcon(
+			string path,
+			int x,
+			int y,
+			int? width = null,
+			int? height = null,
+			DisplaySurfaceID? surfaceID = null)
+				=> throw CantDrawOutsideBatch;
+
+		public void DrawImage(
+			Image img,
+			int x,
+			int y,
+			int? width = null,
+			int? height = null,
+			bool cache = true,
+			DisplaySurfaceID? surfaceID = null)
+				=> throw CantDrawOutsideBatch;
+
+		public void DrawImage(
+			string path,
+			int x,
+			int y,
+			int? width = null,
+			int? height = null,
+			bool cache = true,
+			DisplaySurfaceID? surfaceID = null)
+				=> throw CantDrawOutsideBatch;
+
+		public void DrawImageRegion(
+			Image img,
+			int source_x,
+			int source_y,
+			int source_width,
+			int source_height,
+			int dest_x,
+			int dest_y,
+			int? dest_width = null,
+			int? dest_height = null,
+			DisplaySurfaceID? surfaceID = null)
+				=> throw CantDrawOutsideBatch;
+
+		public void DrawImageRegion(
+			string path,
+			int source_x,
+			int source_y,
+			int source_width,
+			int source_height,
+			int dest_x,
+			int dest_y,
+			int? dest_width = null,
+			int? dest_height = null,
+			DisplaySurfaceID? surfaceID = null)
+				=> throw CantDrawOutsideBatch;
+
+		public void DrawLine(int x1, int y1, int x2, int y2, Color? color = null, DisplaySurfaceID? surfaceID = null)
+			=> throw CantDrawOutsideBatch;
+
+		public void DrawPie(
+			int x,
+			int y,
+			int width,
+			int height,
+			int startangle,
+			int sweepangle,
+			Color? line = null,
+			Color? background = null,
+			DisplaySurfaceID? surfaceID = null)
+				=> throw CantDrawOutsideBatch;
+
+		public void DrawPixel(int x, int y, Color? color = null, DisplaySurfaceID? surfaceID = null)
+			=> throw CantDrawOutsideBatch;
+
+		public void DrawPolygon(
+			Point[] points,
+			Color? line = null,
+			Color? background = null,
+			DisplaySurfaceID? surfaceID = null)
+				=> throw CantDrawOutsideBatch;
+
+		public void DrawRectangle(
+			int x,
+			int y,
+			int width,
+			int height,
+			Color? line = null,
+			Color? background = null,
+			DisplaySurfaceID? surfaceID = null)
+				=> throw CantDrawOutsideBatch;
+
+		public void DrawString(
+			int x,
+			int y,
+			string message,
+			Color? forecolor = null,
+			Color? backcolor = null,
+			int? fontsize = null,
+			string fontfamily = null,
+			string fontstyle = null,
+			string horizalign = null,
+			string vertalign = null,
+			DisplaySurfaceID? surfaceID = null)
+				=> throw CantDrawOutsideBatch;
+
+		[MethodImpl(MethodImplOptions.AggressiveInlining)]
+		public Color GetDefaultTextBackground()
+			=> _realImpl.GetDefaultTextBackground();
+
+		public void PixelText(
+			int x,
+			int y,
+			string message,
+			Color? forecolor = null,
+			Color? backcolor = null,
+			string fontfamily = null,
+			DisplaySurfaceID? surfaceID = null)
+				=> throw CantDrawOutsideBatch;
+
+		[MethodImpl(MethodImplOptions.AggressiveInlining)]
+		public void SetDefaultBackgroundColor(Color color)
+			=> _realImpl.SetDefaultBackgroundColor(color);
+
+		[MethodImpl(MethodImplOptions.AggressiveInlining)]
+		public void SetDefaultForegroundColor(Color color)
+			=> _realImpl.SetDefaultForegroundColor(color);
+
+		[MethodImpl(MethodImplOptions.AggressiveInlining)]
+		public void SetDefaultPixelFont(string fontfamily)
+			=> _realImpl.SetDefaultPixelFont(fontfamily);
+
+		[MethodImpl(MethodImplOptions.AggressiveInlining)]
+		public void SetDefaultTextBackground(Color color)
+			=> _realImpl.SetDefaultTextBackground(color);
+
+		[MethodImpl(MethodImplOptions.AggressiveInlining)]
+		public void Text(int x, int y, string message, Color? forecolor = null, string anchor = null)
+			=> _realImpl.Text(x: x, y: y, message: message, forecolor, anchor: anchor);
+
+		[MethodImpl(MethodImplOptions.AggressiveInlining)]
+		public void ToggleCompositingMode()
+			=> _realImpl.ToggleCompositingMode();
+
+		public void WithSurface(DisplaySurfaceID surfaceID, Action<IGuiApi> drawingCallsFunc)
+		{
+			_realImpl.SurfaceID = surfaceID;
+			try
+			{
+				drawingCallsFunc(_realImpl);
+			}
+			finally
+			{
+				_realImpl.SurfaceID = null;
+			}
+		}
+	}
+}