SUBROUTINE PLOT(X,Y,IP)
C
C	THIS ROUTINE IS THE HEART OF THE PLOTTING SYSTEM
C
C	THE CALL IS:
C
C	CALL PLOT(XP,YP,IPEN)
C
C	WHERE XP IS THE VIRTUAL X COORDANATE OF THE END POINT OF THE DESIRED
C	LINE,
C	WHERE YP IS THE VIRTUAL Y COORDANATE OF THE END POINT OF THE DESIRED
C	LINE,
C	AND IPEN IS THE PEN CONTROL PARAMETER.
C
C	IF THE ABSOLUTE VALUE OF IPEN IS 2, THE MOVE IS MADE WITH THE PEN DOWN,
C	IF THE ABSOLUTE VALUE OF IPEN IS 3, THE MOVE IS MADE WITH THE PEN UP.
C	IF THE ABSOLUTE VALUE OF IPEN IS ANYTHING ELSE, NO CHANGE IN THE PEN IS
C	MADE.
C	IF THE SIGN OF IPEN IS -, THE END POINT OF THE LINE DRAWN IS ASSIGNED TO
C	BE THE ORIGIN, (0,0).
C	IF THE SIGN OF IPEN IS +, THE ENDPOINT OF THE LINE WILL BE (XP,YP).
C
C	PLOT SHOULD BE CALLED ONCE TO INITIALIZE IT.
C	THE CALL 'CALL PLOT(0,0,3)' WOULD SUFFICE.
C
	COMMON/PLOTC/SCALE,IDEV,IPEN,XCUR,YCUR
C
C	SCALE IS THE SCALE EXPRESSED IN RASTER UNITS PER VIRTUAL UNIT.
C	IDEV IS A DEVICE SELECTION FLAG.
C	IPEN IS THE CURRENT IPEN PARAMETER
C	XCUR IS THE CURRENT VIRTUAL X COORDANATE IN RASTER UNITS.
C	YCUR IS THE CURRENT VIRYUAL Y COORDANATE IN RASTER UNITS.
C
	DATA XCUR,YCUR/0.,0./
	DATA IDEV,SCALE/1,200./
C
C	DEFAULT VALUES ARE SCALE=1, ANGLE=0, PEN AT (0,0).
C
	XT=IFIX(X*SCALE)
	YT=IFIX(Y*SCALE)
C
C	CALCULATIONS ARE DONE IN RASTER UNITS TO AVOID ROUND OFF ERROR
C
	CALL DELTAP(XT-XCUR,YT-YCUR,IABS(IP))
	IF(IP)23,25,25
25	XCUR=XT
	YCUR=YT
C
C	IPEN POSATIVE MEANS END POINT AS SPECIFIED PLUS/MINUS ONE RASTER UNIT
C
	RETURN
23	XCUR=0.
	YCUR=0.
C
C	IPEN NEGATIVE MEANS END POINT IS NEW ORIGIN
C
	RETURN
	END
	SUBROUTINE SYMBOL(X,Y,HGT,BCD,ANGD,N)
C
C	THIS IS THE SYMBOL DRAWING SUBROUTINE.
C
C	X AND Y SPECIFY THE POSITION AT WHICH THE SYMBOL IS TO BE DRAWN.
C	HGT IS THE HIGHT OF THE CHARACTERS IN VIRTUAL UNITS
C	BCD CONTAINS THE CHARACTERS (S) TO BE PLOTTED
C	ANGD IS THE ORIENTAION IN DEGREES RELATIVE TO THE X AXIS
C	N IS A CONTROL PARAMETER.
C
C	THE CHARACTER AND ITS SPACE FORMS A SQUARE OF WIDTH HGT.
C
C	IF N > 0, N CHARACTERS IN H FORMAT ARE PLOTTED.
C	IF N = 0, ONE CHARACTER IS PLOTTED WHOSE CODE IS BCD.
C
C	IF N >0, OR =0 , X AND Y ARE THE LOWER LEFT POINT OF THE CHARACTER.
C
C	IF N < 0, ONE CHARACTER WHOS CODE IS B IS PLOTTED CENTERED AROUND (X,Y
C	).
C
	COMMON/PLOTC/SCALE,IDEV,IPEN,XCUR,YCUR,SINA,COSA,SEG,ANG
	DATA ANG,SINA,COSA/0.,0.,1./
	CALL PLOT(X,Y,3)
C
C	FIRST GO TO THE SPECIFIED POINT
C
	IF(ANG-ANGD)10,20,10
C
C	IF THE REQUESTED ANGLE IS THE SAME AS THE CURRENT ONE,
C	AVOID CALCULATING THE SIN AND COSINE
C
10	ANG=ANGD
	SINA=SIND(ANG)
	COSA=COSD(ANG)
20	SEG=HGT/6.
C
C	CHARACTERS ARE ON A 6X6 GRID
C
	IF(N) 60,50,30
30	DO 40 J=1,N
C
C	THIS LOOP PLOTS THE N CHARACTERS IN BCD.
C
	CALL CGET(BCD,J,CHAR)
40	CALL CPLOT(CHAR)
	RETURN
50	CALL CPLOT(BCD)
C
C	THIS PLOTS ONE CHARACTER WHOS CODE IS BCD
C
	RETURN
60	CALL CPLOT(-BCD)
C
C	THIS PRODUCES A CENTERED CHARACTER.
C
	RETURN
	END
	SUBROUTINE CPLOT(CHAR)

C
C	THIS ROUTINE DRIVES THE CHARACTER GENERATOR.
C	THE ANGLE AND HIGHT HAVE ALREADY BE COMPUTED.
C
	COMMON/PLOTC/SCALE,IDEV,IPEN,XCUR,YCUR,SINA,COSA,SEG
	IF(CHAR)50,5,5
C
C	CHECK FOR CENTERED OR NORMAL CHARACTER
C
5	CALL WHERE(XLL,YLL)
C
C	SET THE LOWER LEFT OF THE CHARACTER AT CURRENT POSITION.
C
	CALL SELCQ(CHAR)
C
C	SET UP FOR REQUESTED CHARACTER.
C
10	CALL CQXY(X,Y,IPEN)
C
C	CALL FOR A VECTOR
C
	X=X*SEG
	Y=(Y-1.)*SEG
	XP=XLL+X*COSA-Y*SINA
	YP=YLL+X*SINA+Y*COSA
	IF(IPEN-7)25,20,20
C
C	CHECK FOR LAST VECTOR
C
25	CALL PLOT(XP,YP,IPEN)
C
C	PLOT RELATIVE TO XLL,YLL AND GO BACK FOR MORE
C
	GOTO 10
 20	IF(CHAR)30,40,40
C
C	CENTERED CHARACTERS GET FUDGED, SO CHECK FOR THAT
C
 40	CALL PLOT(XP,YP,IPEN)
	RETURN
 30	CALL PLOT(X0,Y0,IPEN)
C
C	PLOT TO CENTER OF CHARACTER
C
	RETURN
 50	CALL WHERE(X0,Y0)
C
C	FIND OUT WHERE CENTER OF CHARACTER SHOULD BE (IS)
C
	XLL=X0-2.*SEG
	YLL=Y0-3.*SEG
	CALL PLOT(XLL,YLL,3)
C
C	CALCULATE THE LOWER LEFT FROM GIVEN CENTER, THEN GO THERE.
C
	CALL SELCQ(-CHAR)
	GOTO 10
C
C	SELECT CENTERED CHARACTER, THEN PROCESS NORMALLY
C
	END
	SUBROUTINE ASSIGN(X,Y)
C
C	THIS ROUTINE ASSIGNS THE CURRENT PEN POSITION AS VIRTUAL (X,Y).
C
	COMMON/PLOTC/SCALE,IDEV,IPEN,XCUR,YCUR,SINA,COSA,SEG
	XCUR=IFIX(X*SCALE)
	YCUR=IFIX(Y*SCALE)
C
C	XCUR AND YCUR ARE STORED IN RASTER TS
C
	RETURN
	END
	SUBROUTINE WHERE(X,Y)
C
C	THIS ROUTINE RETURNS THE VIRTUAL COORDANADTES OF THE CURRENT
C	PEN POSITION
C
	COMMON/PLOTC/SCALE,IDEV,IPEN,XCUR,YCUR,SINA,COSA,SEG
	X=XCUR/SCALE
	Y=YCUR/SCALE
C
C	XCUR AND YCUR ARE IN RASTER UNITS
C
	RETURN
	END
	SUBROUTINE FACTOR(FACT)
C
C	THIS ROUTINE ESTABLISHES A NEW SCALE FACTOR
C	FACT=1 IS 1 UNIT = 1 INCH
C
	COMMON/PLOTC/SCALE,IDEV,IPEN,XCUR,YCUR,SINA,COSA,SEG,ANG
	SCALE=FACT*200.
C
C	MY PLOTTER HAS 200 STEPS PER INCH
C
	RETURN
	END
	SUBROUTINE NUMBER (XP, YP, HGT, FPN, THETA, ND)
C
C	THIS ROUTINE CONVERTS A NUMBER INTO PLOTTED FORM
C
C	XP AND YP ARE THE COORDANATES WHERE THE PLOTTED NUMBER SHOULD BEGIN
C	HGT IS THE HIGHT IF THE CHARACTERS.
C	FPN IS THE NUMBER (FLOATING OR FIXED IN PDP) TO BE CONVERTED
C	THETA IS THE ANGLE THE CHARACTERS MAKE WITH THE X AXIS
C
C	IF ND>0, IT SPECIFIES THE NUMBER OF DIGITS TO THE RIGHT OF THE DECIMAL
C	POINT THAT ARE TO BE CONVERTED AND PLOTTED, AFTER PROPER ROUNDING.
C	FOR EXAMBLE, ASSUME AN INTERNAL VALUE OF -0.1234567X10^3. IF
C	ND WERE 2, THE PLOTTED NUMBER WOULD BE '-123.46' .
C
C	IF ND=0, ONLY THE INTEGER PORTION AND A DECIMAL POINT
C	ARE PLOTTED, AFTER ROUNDING.
C
C	IF ND=-1, ONLY THE NUMBERS INTEGER PORTION IS PLOTTED, AFTER
C	ROUNDING. (THE NUMBER ABOVE WOULD BE PLOTTED AS '-123' W/O DECIMAL POINT
C
C	IF ND<-1, ABS(ND)-1 DIGITS ARE TRUNCATED FROM THE INTEGER PORTION,
C	AFTER ROUNDING..
C
	COMMON/PLOTC/SCALE,IDEV,IPEN,XCUR,YCUR,SINA,COSA,SEG,ANG
	DATA MAXN/9/
	DATA SINA,COSA,ANG/0.,1.,0./
C	MOVE TO REQURSTED LOCATION
	CALL PLOT(XP,YP,3)
C	IF THE ANGLE IS THE SAME, SAVE THE SIN-COSIN WORK
	IF(THETA-ANG) 5, 6, 5
5	ANG=THETA	SINA=SIND(ANG)
	COSA=COSD(ANG)
6	SEG=HGT/6.
	FPV = FPN
	N = ND
C	SET N VALUE TO + OR - MAXN, IF OUT OF RANGE
	IF (N - MAXN) 11, 11, 10
	10 N = MAXN
	11 IF (N + MAXN) 12, 20, 20
	12 N = -MAXN
C	INSERT MINUS SIGN IN FRONT OF NUMBER, IF NEGATIVE
	20 IF (FPV) 21, 30, 30
	21 CALL CPLOT(45)
C	WHEN SYMBOL IS CALLED WITH SAMEV FOR X AND Y, THE CHARACTER STRING
C	CONTINUES FROM THE LAST CHARACTER PLOTTED BY SYMBOL
C	MN LOCATES EXPONENT VALUE FOR PROPER ROUNDING OF NUMBER
	30 MN = -N
C	IF SCALING IS DONE, MN MUST BE ADJUSTED
	IF (N) 31, 32, 32
	31 MN = MN - 1
C	ROUND INPUT NUMBER AND SET TO POSITIVE VALUE
	32 FPV = ABS(FPV) + (0.5 * 10. ** MN)
C	DETERMINE CHARACTERISTIC OF FPV AND INCREMENT IT BY 1
	I = ALOG10(FPV) + 1.0
	ILP = I
C	IF SCALING IS DONE, ILP MUST BE REDUCED ACCORDING TO SCALING
	IF (N + 1)	40, 41, 41
	40 ILP = ILP + N + 1
C	IF NUMBER IS LESS THAN 1 PLOT A ZERO BEFORE DECIMAL (IF ANY)
	41 IF (ILP)	50, 50, 51
	50 CALL CPLOT(48)
	GO TO 61
C	ILP IS NUMBER OF DIGITS TO LEFT OF DECIMAL POINT
	51 DO 60 J = 1, ILP
C	LOCATE SINGLE LEFTMOST DIGIT OF NUMBER
	K = FPV * 10. ** (J - I)
	CALL CPLOT(K+48)
C	SUBTRACT VALUE OF PREVIOUS DIGIT FROM NUMBER TO LOCATE NEXT DIGIT
	60	FPV = FPV - (FLOAT(K) * 10. ** (I - J))
C	NO DECIMAL POINT IS PLOTTED IF N IS NEGATIVE, EXIT FROM ROUTINE
	61 IF (N) 99, 70, 70
	70 CALL CPLOT(46)
C	PLOT DIGITS TO RIGHT OF DECIMAL IF N GT 0, OTHERWISE EXIT
	IF (N)	99, 99, 80
	80 DO 90 J = 1, N
C	SCALE FRACTIONAL REMAINDER TO GIVE INTEGER DIGIT
	K = FPV * 10.
	CALL CPLOT(K+48)
C	SUBTRACT INTEGER VALUE TO LOCATE NEXT DIGIT
	90	FPV = FPV * 10. - FLOAT(K)
	99 RETURN
	END
	SUBROUTINE AXIS(XPAGE,YPAGE,IBCD,NCHAR,AXLEN,ANGLE,FIRSTV,DELTAV)
C.....	XPAGE,YPAGE	COORDINATES OF STARTING POINT OF AXIS, IN INCHES
C.....	IBCD	AXIS TITLE.
C.....	NCHAR	NUMBER OF CHARACTERS IN TITLE. + FOR C.C-W SIDE.
C.....	AXLEN	FLOATING POINT AXIS LENGTH IN INCHES.
C.....	ANGLE	ANGLE OF AXIS FROM THE X-DIRECTION, IN DEGREES.
C.....	FIRSTV	SCALE VALUE AT THE FIRST TIC MARK.
C.....	DELTAV	CHANGE IN SCALE BETWEEN TIC MARKS ONE INCH APART
	DIMENSION IBCD(2)
	KN=NCHAR
	A=1.0
	IF (KN) 1,2,2
	1	A=-A
	KN=-KN
	2	EX=0.0
	ADX= ABS	(DELTAV)
	IF (ADX) 3,7,3
	3	IF (ADX- 99.0) 6,4,4
	4	ADX=ADX/10.0
	EX=EX+1.0
	GO TO 3
	5	ADX=ADX*10.0
	EX=EX-1.0
	6	IF (ADX-0.01) 5,7,7
	7	XVAL=FIRSTV*10.0**(-EX)
	ADX= DELTAV*10.0**(-EX)
	STH=ANGLE*0.0174533
	CTH=COS(STH	STH=SIN(STH)
	DXB=-0.1
	DYB=0.15*A-0.05
	XN=XPAGE+DXB*CTH-DYB*STH
	YN=YPAGE+DYB*CTH+DXB*STH
	NTIC=AXLEN+1.0
	NT=NTIC/2
	DO	20	I=1,NTIC
	CALL NUMBER(XN,YN,0.105,XVAL,ANGLE,2)
	XVAL=XVAL+ADX
	XN=XN+CTH
	YN=YN+STH
	IF (NT) 20,11,20
 11	Z=KN
	IF (EX)	12,13,12
 12	Z=Z+7.0
 13	DXB=-.07*Z+AXLEN*0.5
	DYB=0.325*A-0.075
	XT=XPAGE+DXB*CTH-DYB*STH
	YT=YPAGE+DYB*CTH+DXB*STH
	CALL SYMBOL(XT,YT,0.14,IBCD(1),ANGLE,KN)
	IF (EX)	14,20,14
 14	Z=KN+2
	XT=XT+Z*CTH*0.14
	YT=YT+Z*STH*0.14
	CALL SYMBOL(XT,YT,0.14,3H*10,ANGLE,3)
	XT=XT+(3.0*CTH-0.8*STH)*0.14
	YT=YT+(3.0*STH+0.8*CTH)*0.14
	CALL NUMBER(XT,YT,0.07,EX,ANGLE,-1)
 20	NT=NT-1
	CALL PLOT(XPAGE+AXLEN*CTH,YPAGE+AXLEN*STH,3)
	DXB=-0.07*A*STH
	DYB=+0.07*A*CTH
	A=NTIC-1
	XN=XPAGE+A*CTH
	YN=YPAGE+A*STH
	DO	30	I=1,NTIC
	CALL PLOT(XN,YN,2)
	CALL PLOT(XN+DXB,YN+DYB,2)
	CALL PLOT(XN,YN,2)
	XN=XN-CTH
	YN=YN-STH
 30	CONTINUE
	RETURN
	END
C
C	THIS ROUTINE PRODUCES A SYMBOL TABLE, WHICH SHOWS THE CHARACTERS
C	AVAILABLE IN THE SYMBOL ROUTINE.
C
C	MAXCHR IS THE INTEGER EQUIVALENT OF THE LAST CHARACTER.
	MAXCHR=63
	CALL PLOT(0,0,3)
	CALL PLOT (0.0,11.0,2)
	CALL PLOT (8.5,11.0,2)
	CALL PLOT (8.5,0.0,2)
	CALL PLOT (0.0,0.0,2)
	CALL SYMBOL(0.75,10.4,.14,49HCHARACTERS AVAILABLE IN SYMBOL ROUTIN
	1E ( PDP 8E ),0.,49)
	CALL PLOT(8.25,10.,3)
	CALL PLOT(0.25,10.,2)
	CALL PLOT(0.25,0.25,2)
	CALL PLOT(8.25,0.25,2)
	CALL PLOT(8.25,10.0,2)
	X=0.5
	K=0
	DO 200 I=1,5
	Y=9.4
	DO 100 J=1,13
	CALL NUMBER(X,Y+0.1,.14,FLOAT (K),0.0,-1)
	4	CALL SYMBOL(X+0.45,Y,0.35,K,0.0,0)
 10	IO1=K/8
	IO2=K-IO1*8
	CALL NUMBER(X+0.90,Y+0.1,0.14,FLOAT (IO1),0.0,-1)
	CALL NUMBER(X+1.04,Y+0.1,0.14,FLOAT (IO2),0.0,-1)
	GO TO 20
	15	CALL SYMBOL(X+1.0,Y+0.1,.14,1H-,0.0,1)
	20	K=K+1
	Y=Y-.7307
	IF(K-MAXCHR) 100,100,300
	100	CONTINUE
	CALL PLOT(X+1.35,0.25,3)
	CALL PLOT(X+1.35,10.,2)
	200	X=X+1.6
300	CALL WAIT
	END
`x