GEEKING

Roblox.Test/TestCases/CaptureScreen.cs

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+using System;
+using System.Drawing;
+
+
+namespace Roblox.Test
+{
+	/// <summary>
+	/// This class shall keep all the functionality for capturing 
+	/// the desktop.
+	/// </summary>
+	public class CaptureScreen
+	{
+		#region Public Class Functions
+		public static Bitmap GetDesktopImage()
+		{
+			//In size variable we shall keep the size of the screen.
+			SIZE size;
+			
+			//Variable to keep the handle to bitmap.
+			IntPtr hBitmap;
+
+			//Here we get the handle to the desktop device context.
+			IntPtr 	hDC = PlatformInvokeUSER32.GetDC(PlatformInvokeUSER32.GetDesktopWindow()); 
+
+			//Here we make a compatible device context in memory for screen device context.
+			IntPtr hMemDC = PlatformInvokeGDI32.CreateCompatibleDC(hDC);
+			
+			//We pass SM_CXSCREEN constant to GetSystemMetrics to get the X coordinates of screen.
+			size.cx = PlatformInvokeUSER32.GetSystemMetrics(PlatformInvokeUSER32.SM_CXSCREEN);
+
+			//We pass SM_CYSCREEN constant to GetSystemMetrics to get the Y coordinates of screen.
+			size.cy = PlatformInvokeUSER32.GetSystemMetrics(PlatformInvokeUSER32.SM_CYSCREEN);
+			
+			//We create a compatible bitmap of screen size using screen device context.
+			hBitmap = PlatformInvokeGDI32.CreateCompatibleBitmap(hDC, size.cx, size.cy);
+
+			//As hBitmap is IntPtr we can not check it against null. For this purspose IntPtr.Zero is used.
+			if (hBitmap!=IntPtr.Zero)
+			{
+				//Here we select the compatible bitmap in memeory device context and keeps the refrence to Old bitmap.
+				IntPtr hOld = (IntPtr) PlatformInvokeGDI32.SelectObject(hMemDC, hBitmap);
+				//We copy the Bitmap to the memory device context.
+				PlatformInvokeGDI32.BitBlt(hMemDC, 0, 0,size.cx,size.cy, hDC, 0, 0, PlatformInvokeGDI32.SRCCOPY);
+				//We select the old bitmap back to the memory device context.
+				PlatformInvokeGDI32.SelectObject(hMemDC, hOld);
+				//We delete the memory device context.
+				PlatformInvokeGDI32.DeleteDC(hMemDC);
+				//We release the screen device context.
+				PlatformInvokeUSER32.ReleaseDC(PlatformInvokeUSER32.GetDesktopWindow(), hDC);
+				//Image is created by Image bitmap handle and stored in local variable.
+				Bitmap bmp = System.Drawing.Image.FromHbitmap(hBitmap); 
+				//Release the memory for compatible bitmap.
+				PlatformInvokeGDI32.DeleteObject(hBitmap);
+				//This statement runs the garbage collector manually.
+				GC.Collect();
+				//Return the bitmap 
+				return bmp;
+			}
+		
+			//If hBitmap is null retunrn null.
+			return null;
+		}
+		#endregion
+	}
+}