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Author: paxtonproctor

Forms_Communication_to_USB_Device/DBGraphics.cs

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+using System;
+using System.Drawing;
+
+namespace GDIDB
+{
+	/// <summary>
+	/// Class to implement Double Buffering 
+	/// Author: NT Almond 
+	/// 24 July 2003
+    /// Used by the Graph class to update the display graphs.
+	/// </summary>
+	/// 
+	public class DBGraphics
+	{
+		private	Graphics	graphics;
+		private Bitmap		memoryBitmap;
+		private	int			width;
+		private	int			height;
+
+		/// <summary>
+		/// Default constructor
+		/// </summary>
+		public DBGraphics()
+		{
+			width	= 0;
+			height	= 0;
+		}
+
+		/// <summary>
+		/// Creates double buffer object
+		/// </summary>
+		/// <param name="g">Window forms Graphics Object</param>
+		/// <param name="width">width of paint area</param>
+		/// <param name="height">height of paint area</param>
+		/// <returns>true/false if double buffer is created</returns>
+		public bool CreateDoubleBuffer(Graphics g, int width, int height)
+		{
+
+			if (memoryBitmap != null)
+			{
+				memoryBitmap.Dispose();
+				memoryBitmap = null;
+			}
+
+			if (graphics != null)
+			{
+				graphics.Dispose();
+				graphics = null;
+			}
+
+			if (width == 0 || height == 0)
+				return false;
+
+
+			if ((width != this.width) || (height != this.height))
+			{
+				this.width = width;
+				this.height = height;
+
+				memoryBitmap	= new Bitmap(width, height);
+				graphics		= Graphics.FromImage(memoryBitmap);
+			}
+
+			return true;
+		}
+
+
+		/// <summary>
+		/// Renders the double buffer to the screen
+		/// </summary>
+		/// <param name="g">Window forms Graphics Object</param>
+		public void Render(Graphics g)
+		{
+			if (memoryBitmap != null)
+				g.DrawImage(memoryBitmap, new Rectangle(0,0, width, height),0,0, width, height, GraphicsUnit.Pixel);
+		}
+
+		/// <summary>
+		/// 
+		/// </summary>
+		/// <returns>true if double buffering can be achieved</returns>
+		public bool CanDoubleBuffer()
+		{
+			return graphics != null;
+		}
+
+		/// <summary>
+		/// Accessor for memory graphics object
+		/// </summary>
+		public Graphics g 
+		{
+			get 
+			{ 
+				return graphics; 
+			}
+		}		
+	}
+}