	PROGRAM TEST6
	DIMENSION X(512),Y(512),IBUF(30)
	DO 10 I=1,512
	X(I)=ALOG10(FLOAT(I))
	R=(6.2832)*FLOAT(I)/200.
	Y(I)=SIN(R)
10	CONTINUE
	CALL VTCLR
	CALL GRAPHS(IBUF,227+4,X,Y,512,-1.0,0)
C
	CALL VTHTXT(8,23,1,' CHANGING SHADE LINE POSITION ')
	CALL BOUNDS(1,Y,YMAX,YMIN,512,0,0,0)
	DO 30 J=1,3
	DO 20 I=1,100
	FI=I
	SHADE=((FI/100.)*(YMAX-YMIN))+YMIN
	CALL GRSHAD(IBUF,SHADE,0)
20	CONTINUE
	DO 30 I=1,100
	FI=100.-I
	SHADE=((FI/100.)*(YMAX-YMIN))+YMIN
	CALL GRSHAD(IBUF,SHADE,0)
30	CONTINUE
	call vtclr
	CALL EXIT
	END

