Description: Initialize graphics mode and establish system variables
Mapped Command: SET GRAPHICS
FUNCTION __SetGraphics(mode)
   local screen, handle
   mode := if(mode == NIL, FALSE, mode)
   if mode                                       // is it on or off? (TRUE = on)
      sethires(0)                                // graphics mode
      for screen := 1 to MaxScreens              // establish a blank screen array
         _screens_[screen,1] := NullInteger      // upper left row
         _screens_[screen,2] := NullInteger      // upper left column
         _screens_[screen,3] := NullInteger      // lower right row
         _screens_[screen,4] := NullInteger      // lower right column
         _screens_[screen,5] := NullInteger      // dGE handle
         _screens_[screen,6] := NullString       // GL memvar
      next                                       // for n := 1 to MaxHandles
      for handle := 1 to MaxHandles              // establish a blank object array
         _handles_[handle,1] := NullInteger      // upper left row
         _handles_[handle,2] := NullInteger      // upper left column
         _handles_[handle,3] := NullInteger      // lower right row
         _handles_[handle,4] := NullInteger      // lower right column
         _handles_[handle,5] := NullString       // object text
         _handles_[handle,6] := NullInteger      // object type
         _handles_[handle,7] := ShadowOff        // shadow
         _handles_[handle,8] := NullString       // object name
         _handles_[handle,9] := InactiveObject   // status (inactive)
      next                                       // for n := 1 to MaxHandles
      _icnwidt_ := getfontinf(2)/PointsPerColumn // get the icon width
      _icnheig_ := getfontinf(3)/PointsPerLine   // get the icon height
   else
      settext()                                  // text mode
   endif                                         // if off                                        // if were leaving
RETURN(Void)