simplify renderer api

BizHawk.Client.EmuHawk/CustomControls/ControlRenderer/GDIRenderer.cs

@@ -43,8 +43,6 @@ namespace BizHawk.Client.EmuHawk.CustomControls
 				DeleteObject(fc.Value.HFont);
 			}
 
-			EndOffScreenBitmap();
-
 			System.Diagnostics.Debug.Assert(_hdc == IntPtr.Zero, "Disposed a GDIRenderer while it held an HDC");
 			System.Diagnostics.Debug.Assert(_g == null, "Disposed a GDIRenderer while it held a Graphics");
 		}
@@ -71,12 +69,14 @@ namespace BizHawk.Client.EmuHawk.CustomControls
 			DeleteObject(hBmp);
 		}
 
-		public IDisposable LockGraphics(Graphics g)
+		public IDisposable LockGraphics(Graphics g, int width, int height)
 		{
 			_g = g;
 			_hdc = g.GetHdc();
 			SetBkMode(_hdc, BkModes.TRANSPARENT);
-			return new GdiGraphicsLock(this);
+			var l = new GdiGraphicsLock(this);
+			StartOffScreenBitmap(width, height);
+			return l;
 		}
 		
 		public Size MeasureString(string str, Font font)
@@ -183,7 +183,7 @@ namespace BizHawk.Client.EmuHawk.CustomControls
 		private int _bitW;
 		private int _bitH;
 
-		public void StartOffScreenBitmap(int width, int height)
+		private void StartOffScreenBitmap(int width, int height)
 		{
 			_bitW = width;
 			_bitH = height;
@@ -194,7 +194,7 @@ namespace BizHawk.Client.EmuHawk.CustomControls
 			SetBkMode(_bitHdc, BkModes.TRANSPARENT);
 		}
 
-		public void EndOffScreenBitmap()
+		private void EndOffScreenBitmap()
 		{
 			_bitW = 0;
 			_bitH = 0;
@@ -206,7 +206,7 @@ namespace BizHawk.Client.EmuHawk.CustomControls
 			_bitMap = IntPtr.Zero;
 		}
 
-		public void CopyToScreen()
+		private  void CopyToScreen()
 		{
 			BitBlt(_hdc, 0, 0, _bitW, _bitH, _bitHdc, 0, 0, 0x00CC0020);
 		}
@@ -448,6 +448,8 @@ namespace BizHawk.Client.EmuHawk.CustomControls
 
 			public void Dispose()
 			{
+				_gdi.CopyToScreen();
+				_gdi.EndOffScreenBitmap();
 				_gdi._g.ReleaseHdc(_gdi._hdc);
 				_gdi._hdc = IntPtr.Zero;
 				_gdi._g = null;

BizHawk.Client.EmuHawk/CustomControls/ControlRenderer/IControlRenderer.cs

@@ -8,11 +8,7 @@ namespace BizHawk.Client.EmuHawk.CustomControls
 		/// <summary>
 		/// Required to use before calling drawing methods
 		/// </summary>
-		IDisposable LockGraphics(Graphics g);
-
-		void StartOffScreenBitmap(int width, int height);
-		void EndOffScreenBitmap();
-		void CopyToScreen();
+		IDisposable LockGraphics(Graphics g, int width, int height);
 
 		/// <summary>
 		/// Measure the width and height of string <paramref name="str"/> when drawn on device context HDC

BizHawk.Client.EmuHawk/CustomControls/InputRoll.Drawing.cs

@@ -10,10 +10,8 @@ namespace BizHawk.Client.EmuHawk
 	{
 		protected override void OnPaint(PaintEventArgs e)
 		{
-			using (_renderer.LockGraphics(e.Graphics))
+			using (_renderer.LockGraphics(e.Graphics, Width, Height))
 			{
-				_renderer.StartOffScreenBitmap(Width, Height);
-
 				// White Background
 				_renderer.SetBrush(Color.White);
 				_renderer.SetSolidPen(Color.White);
@@ -38,9 +36,6 @@ namespace BizHawk.Client.EmuHawk
 
 				DrawColumnDrag(e);
 				DrawCellDrag(e);
-
-				_renderer.CopyToScreen();
-				_renderer.EndOffScreenBitmap();
 			}
 		}
 

BizHawk.Client.EmuHawk/CustomControls/InputRoll.cs

@@ -75,7 +75,7 @@ namespace BizHawk.Client.EmuHawk
 			_renderer = new GdiRenderer();
 
 			using (var g = CreateGraphics())
-			using (_renderer.LockGraphics(g))
+			using (_renderer.LockGraphics(g, Width, Height))
 			{
 				_charSize = _renderer.MeasureString("A", commonFont); // TODO make this a property so changing it updates other values.
 			}