Procedure ScreenOrigin(X,Y:Word)

    Updates VX and VY       : Yes
    Updates Cursor Position : Yes

    This moves the screen origin.  That  is, where the top left corner of
    the screen is on the  virtual  page.    This  uses  X and Y in pixels
    and can thus be used for smooth  scrolling.   The  top left corner is
    (0,0).

    VGA Example (9x16 pixels)

    ScreenOrigin(18,16)

    moves the viewable area to  text  position  (3,2).   To  view the top
    left corner (text position (1,1)), one would use

    ScreenOrigin(0,0).


                ###########################################
                ##(1,1)                                  ##
                ##                                       ##
                ##   ##########                          ##
                ##   #(3,2)   #                          ##
                ##   #        #                          ##
                ##   #        #  ####################### ##
                ##   ##########  #(82,15)              # ##
                ##               #                     # ##
                ##               ####################### ##
                ##                                       ##
                ##                                       ##
                ##                                       ##
                ##                               (160,50)##
                ###########################################


    Above, the complete virtual  screen  is  (1,1) to (160,50), indicated
    by #####.  This is created with

    SetVirtualScreen(160,50).

    The area of this virtual screen  that  appears  on the user's monitor
    is indicated by  #####.   The  lower  right  corner  of  this area is
    determined by the text mode  and  the  amount  of  text that mode can
    display at one time.  Most users use text mode 3, 80x25.

    Finally, the area that  is  written  to  by the program is the window
    area, indicated by #####.  This is setup with

    Window(82,15,150,40).

    The window area may be any size.  By  using the above window, one can
    use

    GotoXY(1,1)

    and this will move the cursor to position (82,15).