Zeichnen einer Bitmap im Hintergrund eines Fensters

[HELPVISTAWIN7]

Wie? Die Bitmap liegt in Form eines char Buffers vor. Wie zeichne ich sie?

HBITMAP bmp;
    switch(msg)
    {
    case WM_DESTROY:
        {
            PostQuitMessage(0);
        }break;

    case WM_PAINT:
        {
            PAINTSTRUCT ps;
			HDC MemDC;
            HDC hdc = BeginPaint(hWnd, &ps);
			bmp = (HBITMAP)BUF; // BUF = Bitmap

			// Create a memory device compatible with the above DC variable
			MemDC = CreateCompatibleDC(hdc);
			// Select the new bitmap
			SelectObject(MemDC, bmp);

			// Copy the bits from the memory DC into the current dc
			BitBlt(hdc, 0, 0, 450, 400, MemDC, 0, 0, SRCCOPY);
			// Restore the old bitmap
			DeleteDC(MemDC);
			DeleteObject(bmp);
            EndPaint(hWnd, &ps);
        }return 0;
    }
    return DefWindowProc(hWnd,msg,wParam,lParam);
}

[Rom]

viele Wege führen nach Rom:

LRESULT WINAPI WndProc(HWND hWnd,UINT uMsg,WPARAM wParam,LPARAM lParam)
{
	RECT rect;
	static int x=0;

	switch (uMsg)
	{
	case WM_CLOSE:
	{
		PostQuitMessage(0);
	}break;	
	case WM_CREATE:
	{
		SetTimer(hWnd,0,20,0);
	}	break;
	case WM_TIMER:
	{
		GetClientRect(hWnd,&rect);
		if(x>(rect.right-20))
			x=0;
		else
			x++;

		InvalidateRect(hWnd,0,0);
	}	break;
	case WM_PAINT:
	{
		PAINTSTRUCT ps;
		HDC hMemDC;
		HBITMAP hBmp;		

		GetClientRect(hWnd,&rect);
		BeginPaint(hWnd,&ps);

		hMemDC=CreateCompatibleDC(ps.hdc);
		hBmp=(HBITMAP)SelectObject(hMemDC,CreateCompatibleBitmap(ps.hdc,rect.right,rect.bottom));
		FillRect(hMemDC,&rect,(HBRUSH)GetStockObject(WHITE_BRUSH));

		Rectangle(hMemDC,x,10,x+20,10+20);

		BitBlt(ps.hdc,0,0,rect.right,rect.bottom,hMemDC,0,0,SRCCOPY);
		DeleteObject(SelectObject(hMemDC,hBmp));
		DeleteDC(hMemDC);
		EndPaint(hWnd,&ps);

	}	break;
	default:
		return DefWindowProc(hWnd,uMsg,wParam,lParam);
	}
	return 0;
}

[Martin Richter]

Dann würde ich jetzt noch WM_ERASEBKGND behandeln und TRUE zurückgeben. Das verhindert unnötiges Flackern.