SUBROUTINE SHADE(IX,IY,ISIZE)
C
C	SUBROUTINE TO PRODUCE SHADED PICTURE (SIMILAR TO VERSATEC TONE)
C
C	IX,IY	= ARRAY OF COORDINATES FORMING A CLOSED POLYGON
C	ISIZE	= NUMBER OF POINTS
C
	INTEGER IY(ISIZE),IX(ISIZE),IA(50),IC(50)
	MIN	= 1023			!SET UP TO FIND MIN,MAX
	MAX	= 0
	DO 10 J	= 1,ISIZE		!SEARCH THRU ALL POINTS
	ITEMP	= IX(J)
	IF(ITEMP .LT. MIN) MIN	= ITEMP
	IF(ITEMP .GT. MAX) MAX	= ITEMP
10	CONTINUE
	IF(MIN .LT. 0) MIN	= 0	!LOWEST X VALUE IS 0
	IF(MAX .GT. 1023)MAX	= 1023	!LARGEST IS 1023
	DO 100 IXP	= MIN,MAX,2	!SHADE OVER ALL VALUES
	ISZ	= 0			!WILL BE # OF SEGMENTS
	ITEMP	= 0
	DO 80 J	= 1,ISIZE		!LOOK FOR HORIZ. BOUNDARIES
	K	= J + 1			!J,K DEFINE PT. # AT ENDS OF LINES
	IF(K .GT. ISIZE) K	= 1	!FIRST,LAST POINT JOIN
	IF(IXP .GE. IX(J) .AND. IXP .LT. IX(K)) GO TO 40
	IF(IXP .LT. IX(J) .AND. IXP .GE. IX(K)) GO TO 40
	GO TO 80			!NO HORIZANTAL SEGMENT FOUND, DONE
40	TEMP	= IX(K) - IX(J)
	IF(TEMP .EQ. 0.) GO TO 50
	TEMP	= (IY(K) - IY(J))/TEMP
50	TEMP	= IY(J) + (IXP - IX(J)) * TEMP
	IF(TEMP .LT. 0.)TEMP	= 0.	!MINIMUM Y VALUE IS 0
	IF(TEMP .GT. 779.)TEMP	= 779.	!MAXIMUM IS 779.
	ISZ	= ISZ + 1		!NUMBER OF BOUNDARIES FOUND
	IA(ISZ)	= TEMP			!Y BOUNDARIES
	IF(ISZ .EQ. 50) GO TO 81	!DONE
80	CONTINUE
81	DO 85	I	= 1,ISZ		!PUT Y VALUES INTO ASCENDING ORDER
	IC(I)	= IXP
	DO 85	J	= I,ISZ
	IF(IA(J) .GE. IA(I)) GO TO 85	!IF LOWER INDEX VALUE NOT SMALLER
	K	= IA(J)			!SWAP THEM
	IA(J)	= IA(I)
	IA(I)	= K
85	CONTINUE
	DO 90 I	= 1,ISZ,2		!PLOT ALL SEGMENTS
90	IA(I)	= -IA(I)		!2 POINT SEGMENTS
	CALL VECT(IC,IA,-2)		!PLOT THE SEGMENTS
100	CONTINUE
	RETURN

	ENTRY	BOXIT(IX1,IY1,IX2,IY2)
C
C	SUBROUTINE TO MAKE A RECTANGULAR OUTLINE
C
	IXP	= IX1
	ITEST	= 1
	DO 200 II	= IX1,IX2,20
	MAX	= IX2 - II + 2
	IF(MAX .GT. 20) MAX	= 20
	DO 190 I	= 1,MAX,2
	IA(I)	= IXP
	IA(I+1)	= IXP
	IC(I)	= IY1
	IC(I+1)	= IY2
	IF(ITEST .GT. 0)GO TO 180
	IC(I)	= IY2
	IC(I+1)	= IY1
180	ITEST	= -ITEST
190	IXP	= IXP + 2
	CALL VECT(IA,IC,-MAX)
200	CONTINUE
	RETURN
	END