$CPU 8086          ' make compatible with XT systems
$LIB ALL OFF       ' turn off all PowerBASIC libraries
$ERROR ALL OFF     ' turn off all PowerBASIC error checking
$OPTIMIZE SIZE     ' optimize for smaller code
 $COMPILE UNIT      ' compile to a UNIT (.PBU)
'$COMPILE EXE       ' compile to a UNIT (.PBU)

DEFINT A-Z         ' Required for all numeric functions, forces PB to not
                   ' include floating point in UNIT (makes it smaller)
'/*------------------------------------------------------------------*/
DECLARE FUNCTION GETSCREEN() AS STRING
DECLARE SUB PUTSCREEN(BYVAL X AS STRING)
DECLARE SUB MDELAY(COUNT AS WORD)
DECLARE FUNCTION GETVIDEOSEGMENT() AS INTEGER
'/*------------------------------------------------------------------*/
$CODE SEG "MLIB5"
'/*------------------------------------------------------------------*/
' DSCREENJ(SCREEN$)
'     Display Screen format J.
'     Display Screen by moving new in as a spiral outside in.
'     SCREEN$ = Mem (binary) screen to display.
'     Returns old screen.
'     EXAMPLE:  OLD$ = DSCREENJ(SCREEN$)
'/*------------------------------------------------------------------*/
FUNCTION DSCREENJ(TEMP$) PUBLIC AS STRING
  R$ = GETSCREEN
'/*-21---------------------------------------------------------------*/
    Speed% = 10
    Attr% = 0
SRow% = 1 : ERow% = 25 : SCol% = 1 : ECol% = 80 : PokeBackScreen% = 0

IF LEN(TEMP$) THEN
  PokeBackScreen% = 1
  DEF SEG=GETVIDEOSEGMENT
ELSE
  IF Attr% THEN
    FGround% = 15 AND Attr%
    BGround% = 255 AND (Attr% - LowByte%) \ 16
    COLOR FGround%,BGround%
  ELSE
    COLOR 0,0
  END IF
END IF

FOR a% = 1 TO 12
  FOR i% = SCol% TO ECol%
    LOCATE SRow%,i%,0
    IF PokeBackScreen% THEN
      Address% = ((SRow% - 1) * 160) + (i% * 2) - 2
      POKE$ Address%,GetByte$(TEMP$,Address%,2)
    ELSE
      PRINT " ";
    END IF
  CALL MDELAY(1)
    FOR j% = 1 TO Speed%
      FOR k% = 1 TO Speed% : NEXT k%
    NEXT j%
  NEXT i%
  INCR SRow% : DECR ECol%
  FOR i% = SRow% TO ERow%
    LOCATE i%,ECol%,0
    IF PokeBackScreen% THEN
      Address% = ((i% - 1) * 160) + (ECol% * 2) - 2
      POKE$ Address%,GetByte$(TEMP$,Address%,4)
    ELSE
      PRINT "  ";
    END IF
    FOR j% = 1 TO Speed%
      FOR k% = 1 TO Speed% : NEXT k%
    NEXT j%
  NEXT i%
  DECR ECol%
  FOR i% = ECol% TO SCol% STEP -1
    LOCATE ERow%,i%,0
    IF PokeBackScreen% THEN
      Address% = ((ERow% - 1) * 160) + (i% * 2) - 2
      POKE$ Address%,GetByte$(TEMP$,Address%,2)
    ELSE
      PRINT " ";
    END IF
    FOR j% = 1 TO Speed%
      FOR k% = 1 TO Speed% : NEXT k%
    NEXT j%
  NEXT i%
  DECR ERow%
  FOR i% = ERow% TO SRow% STEP -1
    LOCATE i%,SCol%,0
    IF PokeBackScreen% THEN
      Address% = ((i% - 1) * 160) + (SCol% * 2) - 2
      POKE$ Address%,GetByte$(TEMP$,Address%,4)
    ELSE
      PRINT "  ";
    END IF
    FOR j% = 1 TO Speed%
      FOR k% = 1 TO Speed% : NEXT k%
    NEXT j%
  NEXT i%
  INCR SCol%,2
NEXT a%

'This is the final centre part ----------------------------------------------

FOR i% = SCol% TO ECol%
  LOCATE SRow%,i%,0
    IF PokeBackScreen% THEN
      Address% = ((SRow% - 1) * 160) + (i% * 2) - 2
      POKE$ Address%,GetByte$(TEMP$,Address%,2)
    ELSE
      PRINT " ";
    END IF
    FOR j% = 1 TO Speed%
      FOR k% = 1 TO Speed% : NEXT k%
    NEXT j%
NEXT i%
DEF SEG
'============================================================================
  FUNCTION = R$
END FUNCTION
'/*------------------------------------------------------------------*/
FUNCTION GetByte$(BaseScreen$,Address%,NumBytes%)

GetByte$ = MID$(BaseScreen$,Address% + 1,NumBytes%)

'============================================================================
END FUNCTION
'/*------------------------------------------------------------------*/
'   $INCLUDE "C:\CODE\MLIB\MLIB.INC"
'   TD$ = GETMEM("c:\code\mapper\APOGEE.MEM")
'   T2$ = GETMEM("c:\code\mapper\VMESAM.MEM")
'     PUTSCREEN T2$
'     Y$ = GETKEY
'     T$ = DSCREENJ(TD$)
'     Y$ = GETKEY
'/*------------------------------------------------------------------*/