Bitmap bmp = new Bitmap(@"Background.bmp");
Room room = new Room(1);
Bitmap BackBuffer;
Graphics DrawingArea;

// in the form construction area
BackBuffer = new Bitmap(800, 600);
DrawingArea = Graphics.FromImage(BackBuffer);

void DrawMap(Bitmap bmp, Room r)
{
    for (int x = 0; x < 30; ++x)
    {
        for (int y = 0; y < 20; ++y)
        {

            Rectangle rect = new Rectangle(x * 30, y * 30, 30, 30);
            Pair p = r.getGround(posx + x, posy + y);
            DrawingArea.DrawImage(bmp, rect, (int)p.First * 30, (int)p.Second * 30, 30, 30, GraphicsUnit.Pixel);
        }
    }

    Graphics g = this.CreateGraphics();
    g.DrawImageUnscaled(BackBuffer, 0, 0);

}

		[DllImport("gdi32.dll")]		public static extern bool BitBlt(IntPtr hObject, int nXDest, int nYDest, int nWidth,			int nHeight, IntPtr hObjSource, int nXSrc, int nYSrc, TernaryRasterOperations dwRop);		public enum TernaryRasterOperations		{			SRCCOPY     = 0x00CC0020, /* dest = source*/			SRCPAINT    = 0x00EE0086, /* dest = source OR dest*/			SRCAND      = 0x008800C6, /* dest = source AND dest*/			SRCINVERT   = 0x00660046, /* dest = source XOR dest*/			SRCERASE    = 0x00440328, /* dest = source AND (NOT dest )*/			NOTSRCCOPY  = 0x00330008, /* dest = (NOT source)*/			NOTSRCERASE = 0x001100A6, /* dest = (NOT src) AND (NOT dest) */			MERGECOPY   = 0x00C000CA, /* dest = (source AND pattern)*/			MERGEPAINT  = 0x00BB0226, /* dest = (NOT source) OR dest*/			PATCOPY     = 0x00F00021, /* dest = pattern*/			PATPAINT    = 0x00FB0A09, /* dest = DPSnoo*/			PATINVERT   = 0x005A0049, /* dest = pattern XOR dest*/			DSTINVERT   = 0x00550009, /* dest = (NOT dest)*/			BLACKNESS   = 0x00000042, /* dest = BLACK*/			WHITENESS   = 0x00FF0062, /* dest = WHITE*/		};		[DllImport("gdi32.dll", ExactSpelling=true, 			 SetLastError=true)]		public static extern IntPtr CreateCompatibleDC(IntPtr hDC);		[DllImport("gdi32.dll", ExactSpelling=true, 			 SetLastError=true)]		public static extern bool DeleteDC(IntPtr hdc);		[DllImport("gdi32.dll", ExactSpelling=true)]		public static extern IntPtr SelectObject(IntPtr hDC, 			IntPtr hObject);		private void Blit(Image source, Image destination)		{			// Create a graphics object for the picture box			Graphics grphTarget = Graphics.FromImage(source);			// Get the picture box HDC			IntPtr grphTargetDc = grphTarget.GetHdc();			// Create a GDI device compatible DC from the DC of the GDI+ DC			IntPtr pSource = CreateCompatibleDC(grphTargetDc);			// Replaces the old DC with a DC to the bitmap of the picture in the picture box			SelectObject(pSource, ((Bitmap)destination).GetHbitmap());			// BitBlt  ** Add loops here **			BitBlt(grphTargetDc, 0, 0, 32, 32, pSource, 0, 0, TernaryRasterOperations.SRCCOPY);						// Delete the GDI DC			DeleteDC(pSource);			// Release the target DC			grphTarget.ReleaseHdc(grphTargetDc);			// Dispose of the target graphic object			grphTarget.Dispose();		}