Window, 0, XSize=256, YSize=256
TV, BytScl(scan, Top=199)
!Err = 0
Window, 1, XSize=256, YSize=256, /Pixmap
TV, BytScl(scan, Top=199)
WSet, 0
WShow, 0 
TVLct, 255, 255, 0, 200
Cursor, x1, y1, /Device, /Down
XYOuts, x1, y1, /Device, 'HELLO', CharSize=3, Align=0.5, Color=200
WHILE (!Err NE 4) DO BEGIN
  Cursor, x2, y2, /Device, /NoWait
  Device, Copy=[0, 0, 256, 256, 0, 0, 1]
  XYOuts, x2, y2, /Device, 'HELLO', CharSize=3, Align=0.5, Color=200
ENDWHILE
WDelete, 1
END