A bit of testing with Lua.

BizHawk.Client.Common/BizHawk.Client.Common.csproj

@@ -142,6 +142,7 @@
     <Compile Include="lua\LuaFile.cs" />
     <Compile Include="lua\LuaFileList.cs" />
     <Compile Include="lua\LuaFunctionList.cs" />
+    <Compile Include="lua\LuaHelper.cs" />
     <Compile Include="lua\LuaLibraryBase.cs" />
     <Compile Include="lua\LuaMemoryBase.cs" />
     <Compile Include="lua\NamedLuaFunction.cs" />

BizHawk.Client.Common/lua/LuaHelper.cs

@@ -0,0 +1,30 @@
+using System;
+using System.Collections.Generic;
+using System.Linq;
+using System.Text;
+using LuaInterface;
+using System.Reflection;
+
+namespace BizHawk.Client.Common
+{
+	public static class LuaHelper
+	{
+		public static LuaTable ToLuaTable(Lua lua, object obj)
+		{
+			var table = lua.NewTable();
+
+			var type = obj.GetType();
+
+			var methods = type.GetMethods();
+			foreach (var method in methods)
+			{
+				if (method.IsPublic)
+				{
+					table[method.Name] = lua.RegisterFunction("", obj, method);
+				}
+			}
+
+			return table;
+		}
+	}
+}

BizHawk.Client.EmuHawk/BizHawk.Client.EmuHawk.csproj

@@ -771,6 +771,12 @@
     <Compile Include="tools\Lua\Libraries\EmuLuaLibrary.Input.cs" />
     <Compile Include="tools\Lua\Libraries\EmuLuaLibrary.Savestate.cs" />
     <Compile Include="tools\Lua\Libraries\EmuLuaLibrary.Tastudio.cs" />
+    <Compile Include="tools\Lua\LuaCanvas.cs">
+      <SubType>Form</SubType>
+    </Compile>
+    <Compile Include="tools\Lua\LuaCanvas.Designer.cs">
+      <DependentUpon>LuaCanvas.cs</DependentUpon>
+    </Compile>
     <Compile Include="tools\Lua\LuaCheckbox.cs">
       <SubType>Component</SubType>
     </Compile>
@@ -1330,6 +1336,9 @@
     <EmbeddedResource Include="tools\HexEditor\HexFind.resx">
       <DependentUpon>HexFind.cs</DependentUpon>
     </EmbeddedResource>
+    <EmbeddedResource Include="tools\Lua\LuaCanvas.resx">
+      <DependentUpon>LuaCanvas.cs</DependentUpon>
+    </EmbeddedResource>
     <EmbeddedResource Include="tools\Lua\LuaConsole.resx">
       <DependentUpon>LuaConsole.cs</DependentUpon>
     </EmbeddedResource>

BizHawk.Client.EmuHawk/tools/Lua/Libraries/EmuLuaLibrary.Gui.cs

@@ -596,5 +596,16 @@ namespace BizHawk.Client.EmuHawk
 
 			GlobalWin.OSD.AddGUIText(message, x, y, background ?? Color.Black, forecolor ?? Color.White, a);
 		}
+
+		[LuaMethodAttributes(
+			"createcanvas",
+			"Creates a canvas of the given size."
+		)]
+		public LuaTable Text(int width, int height)
+		{
+			var canvas = new LuaCanvas(width, height);
+			canvas.Show();
+			return LuaHelper.ToLuaTable(Lua, canvas);
+		}
 	}
 }

BizHawk.Client.EmuHawk/tools/Lua/LuaCanvas.Designer.cs

@@ -0,0 +1,66 @@
+namespace BizHawk.Client.EmuHawk
+{
+	partial class LuaCanvas
+	{
+		/// <summary>
+		/// Required designer variable.
+		/// </summary>
+		private System.ComponentModel.IContainer components = null;
+
+		/// <summary>
+		/// Clean up any resources being used.
+		/// </summary>
+		/// <param name="disposing">true if managed resources should be disposed; otherwise, false.</param>
+		protected override void Dispose(bool disposing)
+		{
+			if (disposing && (components != null))
+			{
+				components.Dispose();
+			}
+			base.Dispose(disposing);
+		}
+
+		#region Windows Form Designer generated code
+
+		/// <summary>
+		/// Required method for Designer support - do not modify
+		/// the contents of this method with the code editor.
+		/// </summary>
+		private void InitializeComponent()
+		{
+			this.pictureBox = new System.Windows.Forms.PictureBox();
+			((System.ComponentModel.ISupportInitialize)(this.pictureBox)).BeginInit();
+			this.SuspendLayout();
+			// 
+			// pictureBox
+			// 
+			this.pictureBox.Location = new System.Drawing.Point(0, 0);
+			this.pictureBox.Margin = new System.Windows.Forms.Padding(0);
+			this.pictureBox.Name = "pictureBox";
+			this.pictureBox.Size = new System.Drawing.Size(282, 260);
+			this.pictureBox.SizeMode = System.Windows.Forms.PictureBoxSizeMode.AutoSize;
+			this.pictureBox.TabIndex = 0;
+			this.pictureBox.TabStop = false;
+			// 
+			// LuaCanvas
+			// 
+			this.AutoScaleDimensions = new System.Drawing.SizeF(6F, 13F);
+			this.AutoScaleMode = System.Windows.Forms.AutoScaleMode.Font;
+			this.AutoSize = true;
+			this.AutoSizeMode = System.Windows.Forms.AutoSizeMode.GrowAndShrink;
+			this.ClientSize = new System.Drawing.Size(284, 261);
+			this.Controls.Add(this.pictureBox);
+			this.FormBorderStyle = System.Windows.Forms.FormBorderStyle.FixedSingle;
+			this.Name = "LuaCanvas";
+			this.Text = "LuaCanvas";
+			((System.ComponentModel.ISupportInitialize)(this.pictureBox)).EndInit();
+			this.ResumeLayout(false);
+			this.PerformLayout();
+
+		}
+
+		#endregion
+
+		private System.Windows.Forms.PictureBox pictureBox;
+	}
+}

BizHawk.Client.EmuHawk/tools/Lua/LuaCanvas.cs

@@ -0,0 +1,88 @@
+using System;
+using System.Collections.Generic;
+using System.ComponentModel;
+using System.Data;
+using System.Drawing;
+using System.Linq;
+using System.Text;
+using System.Windows.Forms;
+
+namespace BizHawk.Client.EmuHawk
+{
+	public partial class LuaCanvas : Form
+	{
+		private Graphics graphics;
+
+		public LuaCanvas(int width, int height)
+		{
+			InitializeComponent();
+			pictureBox.Width = width;
+			pictureBox.Height = height;
+			pictureBox.Image = new Bitmap(width, height);
+			graphics = Graphics.FromImage(pictureBox.Image);
+		}
+
+		public void SetTitle(string title)
+		{
+			this.Text = title;
+		}
+
+		public void Clear(Color color)
+		{
+			graphics.Clear(color);
+		}
+
+		public void Refresh()
+		{
+			pictureBox.Refresh();
+		}
+
+		public void DrawRectangle(int x, int y, int width, int height, Color? outline = null, Color? fill = null)
+		{
+			if (fill.HasValue)
+			{
+				var brush = new SolidBrush(fill.Value);
+				graphics.FillRectangle(brush, x, y, width, height);
+			}
+
+			var pen = new Pen(outline.HasValue ? outline.Value : Color.Black);
+			graphics.DrawRectangle(pen, x, y, width, height);
+		}
+
+		public void DrawText(int x, int y, string message, Color? color = null, int? fontsize = null, string fontfamily = null, string fontstyle = null)
+		{
+			var family = FontFamily.GenericMonospace;
+			if (fontfamily != null)
+			{
+				family = new FontFamily(fontfamily);
+			}
+
+			var fstyle = FontStyle.Regular;
+			if (fontstyle != null)
+			{
+				switch (fontstyle.ToLower())
+				{
+					default:
+					case "regular":
+						break;
+					case "bold":
+						fstyle = FontStyle.Bold;
+						break;
+					case "italic":
+						fstyle = FontStyle.Italic;
+						break;
+					case "strikethrough":
+						fstyle = FontStyle.Strikeout;
+						break;
+					case "underline":
+						fstyle = FontStyle.Underline;
+						break;
+				}
+			}
+
+			var font = new Font(family, fontsize ?? 12, fstyle, GraphicsUnit.Pixel);
+			graphics.TextRenderingHint = System.Drawing.Text.TextRenderingHint.SingleBitPerPixelGridFit;
+			graphics.DrawString(message, font, new SolidBrush(color ?? Color.White), x, y);
+		}
+	}
+}

BizHawk.Client.EmuHawk/tools/Lua/LuaCanvas.resx

@@ -0,0 +1,120 @@
+<?xml version="1.0" encoding="utf-8"?>
+<root>
+  <!-- 
+    Microsoft ResX Schema 
+    
+    Version 2.0
+    
+    The primary goals of this format is to allow a simple XML format 
+    that is mostly human readable. The generation and parsing of the 
+    various data types are done through the TypeConverter classes 
+    associated with the data types.
+    
+    Example:
+    
+    ... ado.net/XML headers & schema ...
+    <resheader name="resmimetype">text/microsoft-resx</resheader>
+    <resheader name="version">2.0</resheader>
+    <resheader name="reader">System.Resources.ResXResourceReader, System.Windows.Forms, ...</resheader>
+    <resheader name="writer">System.Resources.ResXResourceWriter, System.Windows.Forms, ...</resheader>
+    <data name="Name1"><value>this is my long string</value><comment>this is a comment</comment></data>
+    <data name="Color1" type="System.Drawing.Color, System.Drawing">Blue</data>
+    <data name="Bitmap1" mimetype="application/x-microsoft.net.object.binary.base64">
+        <value>[base64 mime encoded serialized .NET Framework object]</value>
+    </data>
+    <data name="Icon1" type="System.Drawing.Icon, System.Drawing" mimetype="application/x-microsoft.net.object.bytearray.base64">
+        <value>[base64 mime encoded string representing a byte array form of the .NET Framework object]</value>
+        <comment>This is a comment</comment>
+    </data>
+                
+    There are any number of "resheader" rows that contain simple 
+    name/value pairs.
+    
+    Each data row contains a name, and value. The row also contains a 
+    type or mimetype. Type corresponds to a .NET class that support 
+    text/value conversion through the TypeConverter architecture. 
+    Classes that don't support this are serialized and stored with the 
+    mimetype set.
+    
+    The mimetype is used for serialized objects, and tells the 
+    ResXResourceReader how to depersist the object. This is currently not 
+    extensible. For a given mimetype the value must be set accordingly:
+    
+    Note - application/x-microsoft.net.object.binary.base64 is the format 
+    that the ResXResourceWriter will generate, however the reader can 
+    read any of the formats listed below.
+    
+    mimetype: application/x-microsoft.net.object.binary.base64
+    value   : The object must be serialized with 
+            : System.Runtime.Serialization.Formatters.Binary.BinaryFormatter
+            : and then encoded with base64 encoding.
+    
+    mimetype: application/x-microsoft.net.object.soap.base64
+    value   : The object must be serialized with 
+            : System.Runtime.Serialization.Formatters.Soap.SoapFormatter
+            : and then encoded with base64 encoding.
+
+    mimetype: application/x-microsoft.net.object.bytearray.base64
+    value   : The object must be serialized into a byte array 
+            : using a System.ComponentModel.TypeConverter
+            : and then encoded with base64 encoding.
+    -->
+  <xsd:schema id="root" xmlns="" xmlns:xsd="http://www.w3.org/2001/XMLSchema" xmlns:msdata="urn:schemas-microsoft-com:xml-msdata">
+    <xsd:import namespace="http://www.w3.org/XML/1998/namespace" />
+    <xsd:element name="root" msdata:IsDataSet="true">
+      <xsd:complexType>
+        <xsd:choice maxOccurs="unbounded">
+          <xsd:element name="metadata">
+            <xsd:complexType>
+              <xsd:sequence>
+                <xsd:element name="value" type="xsd:string" minOccurs="0" />
+              </xsd:sequence>
+              <xsd:attribute name="name" use="required" type="xsd:string" />
+              <xsd:attribute name="type" type="xsd:string" />
+              <xsd:attribute name="mimetype" type="xsd:string" />
+              <xsd:attribute ref="xml:space" />
+            </xsd:complexType>
+          </xsd:element>
+          <xsd:element name="assembly">
+            <xsd:complexType>
+              <xsd:attribute name="alias" type="xsd:string" />
+              <xsd:attribute name="name" type="xsd:string" />
+            </xsd:complexType>
+          </xsd:element>
+          <xsd:element name="data">
+            <xsd:complexType>
+              <xsd:sequence>
+                <xsd:element name="value" type="xsd:string" minOccurs="0" msdata:Ordinal="1" />
+                <xsd:element name="comment" type="xsd:string" minOccurs="0" msdata:Ordinal="2" />
+              </xsd:sequence>
+              <xsd:attribute name="name" type="xsd:string" use="required" msdata:Ordinal="1" />
+              <xsd:attribute name="type" type="xsd:string" msdata:Ordinal="3" />
+              <xsd:attribute name="mimetype" type="xsd:string" msdata:Ordinal="4" />
+              <xsd:attribute ref="xml:space" />
+            </xsd:complexType>
+          </xsd:element>
+          <xsd:element name="resheader">
+            <xsd:complexType>
+              <xsd:sequence>
+                <xsd:element name="value" type="xsd:string" minOccurs="0" msdata:Ordinal="1" />
+              </xsd:sequence>
+              <xsd:attribute name="name" type="xsd:string" use="required" />
+            </xsd:complexType>
+          </xsd:element>
+        </xsd:choice>
+      </xsd:complexType>
+    </xsd:element>
+  </xsd:schema>
+  <resheader name="resmimetype">
+    <value>text/microsoft-resx</value>
+  </resheader>
+  <resheader name="version">
+    <value>2.0</value>
+  </resheader>
+  <resheader name="reader">
+    <value>System.Resources.ResXResourceReader, System.Windows.Forms, Version=4.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089</value>
+  </resheader>
+  <resheader name="writer">
+    <value>System.Resources.ResXResourceWriter, System.Windows.Forms, Version=4.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089</value>
+  </resheader>
+</root>

output/Lua/test.lua

@@ -0,0 +1,5 @@
+local canvas = gui.createcanvas(200, 200);
+canvas.Clear(0xFF000000);
+canvas.DrawRectangle(50, 50, 100, 100, 0xFFFF0000, 0xFF0000FF);
+canvas.DrawText(0, 0, "Hello, world!");
+canvas.Refresh();