Function: plotcopy
Section: graphic
C-Name: plotcopy
Prototype: vLLGGD0,L,
Help: plotcopy(sourcew,destw,dx,dy,{flag=0}): copy the contents of
 rectwindow sourcew to rectwindow destw with offset (dx,dy). If flag's bit 1
 is set, dx and dy express fractions of the size of the current output
 device, otherwise dx and dy are in pixels. dx and dy are relative positions
 of northwest corners if other bits of flag vanish, otherwise of: 2:
 southwest, 4: southeast, 6: northeast corners.
Doc: copy the contents of rectwindow \var{sourcew} to rectwindow \var{destw}
 with offset (dx,dy). If $\fl$'s bit 1 is set, dx and dy express fractions of
 the size of the current output device, otherwise dx and dy are in pixels. dx
 and dy are relative positions of northwest corners if other bits of $\fl$
 vanish, otherwise of: 2: southwest, 4: southeast, 6: northeast corners.
