C	PROGRAM DYN2.FT
C	----------------
C
C
C
C	###SUBROUTINE DYN2(JX,JY,IOPR)
C
C	PETER LEMKIN
C	IMAGE PROCESSING UNIT, DCBD
C	NATIONAL CANCER INSTITUTE
C	NATIONAL INSTITUTES OF HEALTH
C	9000 ROCKVILLE PIKE
C	BETHESDA, MD. 20014
C
C	MAY 12, 1978
C	MAY 9, 1978
C	MAY 5, 1978
C	MAY 4, 1978
C	MAY 2, 1978
C	APRIL 27, 1978
C	APRIL 18, 1978
C
C	PURPOSE
C	-------
C	DYN2 FOLLOWS THE CURVE SPECIFIED BY (IX,IY) WHEN IT
C	IS INITIALIZED BY OPR #1. SUCCESSIVE CALLS RETURN
C	NEW CURVE POINTS UNTIL THE INITIAL POINT IS LOCATED
C	IN WHICH CASE (-1,0) IS RETURNED IN (IX,IY).
C
C
C	IOPR	FUNCTION
C	----	--------
C	1	START NEW BOUNDARY FOLLOWING STARTING AT
C		POINT (IX,IY) ==>(IXFIRST,IYFIRST).
C
C	2	GET NEXT (IX,IY) POINT ON BOUNDARY. NOTE THAT
C		THE BINARY NEIGHBORHOOD IS GIVEN I10:I18.
C		RETURN
C		(IX,IY) IF VALID NEXT POINT, CHAIN CODE DIRECTION ==>MQ
C		(-1,0) IF REACHED THE INITIAL (IXFIRST,IYFIRST),
C		(-2,0) IF ISOLATED PIXEL,
C		(-3,0) IF COMPONENT GOT LOST.
C
C	3	TEST IF CAUGHT IN A LOOP OF THE BOUNDARY BY LOOKING
C		BACKWARDS A LENGTH "LSUCLOOPLENGTH" POINTS IN THE STACK
C		FOR REPEATING SUBPATTERN WHICH OCCURS TWICE AND IS CAUGHT BY
C		THE 3RD OCCURRENCE OF THE FIRST POINT (JX,JY) OF
C		THE LOOP.  IF TRUE THEN RETURN (IVAL=1, IZ=PTR TO 2ND
C		OCCURRENCE OF (JX,JY) IN STACK) ELSE RETURN (IVAL=0).
C	OPDEFS
C	------
S	OPDEF	TADI	1400
S	OPDEF	DCAI	3400
C
C
S	OPDEF	DISP1	6435
S	OPDEF	DISP2	6436
C
C
S	OPDEF	MUY	7405
S	OPDEF	DVI	7407
C
S	OPDEF	MQA	7501
S	OPDEF	MQL	7421
S	OPDEF	BSW	7002
C
C
C	[0] DISPATCH
S	DUMMY JX
S	DUMMY JY
S	DUMMY IOPR
S	ENTRY DYN2
C
S	CPAGE 10
S JX,	BLOCK 2
S JY,	BLOCK 2
S IOPR,	BLOCK 2
C
S DYN2,	BLOCK 2
C
C	GET THE ARGS
S	TAD I DYN2
S	DCA JX
S	INC DYN2#
S	TAD I DYN2
S	DCA JX#
S	INC DYN2#
C
S	TAD I JX
S	DCA \JX
C
S	TAD I DYN2
S	DCA JY
S	INC DYN2#
S	TAD I DYN2
S	DCA JY#
S	INC DYN2#
C
S	TAD I JY
S	DCA \JY
C
S	TAD I DYN2
S	DCA IOPR
S	INC DYN2#
S	TAD I DYN2
S	DCA IOPR#
S	INC DYN2#
C
S	TAD I IOPR
S	DCA \IOPR
C
C
	J=0
	K=0
C
C
C	DISPATCH
	GOTO (1,2,3), IOPR
C
C	[0.1] RETURN
2047	CONTINUE
S	RETRN DYN2
C	[1] INIT THE FIRST (X,Y)<==(JX,JY)
1	IXFIRST=JX
	IYFIRST=JY
	LSTX=JX
	LSTY=JY
	ITHETA=45
C
	GOTO 2047
C
C
C
C	[2] FOLLOW THE OUTSIDE BORDER 1 POINT.
C	COPY J10[1:9]<==I10[1:9];
2	J10=I10
	J11=I11
	J12=I12
	J13=I13
	J14=I14
	J15=I15
	J16=I16
	J17=I17
	J18=I18
C
C
C	TEST FOR ILL-FORMED COMPONENT
C	IF J18=0
C		THEN GOTO [2.6.1];
S	TAD \J18
S	SNA CLA
S	JMP \261 /=0
C
C
C	[2.1] GET NEIGHBORHOOD
	IX=LSTX
	IY=LSTY
C
C
C	GET NEIGHBORHOOD OF BMj
	MEM=JBM
	IBYTE=JHGH
	CALL GETI1
C
C	NOTE: BMJ NGH IN I10:I18
C
C	[2.2] TEST IF ISOLATED PIXEL
C			THEN RETURN (-2,-2)==>(JX,JY)
	IF(J10+J11+J12+J13+J14+J15+J16+J17)910,902,910
902	JX=-2
	JY=0
S	TAD \JX
S	DCA I JX
S	TAD \JY
S	DCA I \JY
	GOTO 2047
C
C
C	[2.3] FIND THE MINIMUM COMPUTING WINDOW
910	NUMBERTIMESAROUND=0
C
C
C	[2.4] DISPATCH ACCORDING TO ANGLE IN DEGREES
S\900,	TAD \ITHETA
S	MQL
S	CPAGE 2
S	DVI
S	55 /45 DECIMAL
S	CLA
C
C	0:315==>1:9
S	MQA
S	IAC /+1
S	DCA \IVAL
C
C
	GOTO(1000,1045,1090,1135,1180,1225,1270,1315),IVAL
C
C
C
C
C	[2.5.1.45]
1045	IF(J11-1)1000,845,745
745	IF(I11-255)1000,845,1000
C	BEGIN "45 DEGREES"
845	IY=IY-1
	IX=IX+1
	JTHETA=1
	ITHETA=180
	GOTO 207
C	END "45"
C
C
C	[2.5.1.0]
1000	IF(J10-1)1315,800,700
700	IF(I10-255)1315,800,1315
C	BEGIN "00 DEGREES"
800	IX=IX+1
	JTHETA=0
	ITHETA=90
	GOTO 207
C	END "00"
C
C
C	[2.5.1.315]
1315	IF(J17-1)1270,831,731
731	IF(I17-255)1270,831,1270
C	BEGIN "315 DEGREES"
831	IY=IY+1
	IX=IX+1
	JTHETA=7
	ITHETA=90
	GOTO 207
C	END "315"
C
C
C	[2.5.1.270]
1270	IF(J16-1)1225,827,727
727	IF(J15-255)1225,827,1225
C	BEGIN "270 DEGREES"
827	IY=IY+1
	JTHETA=6
	ITHETA=0
	GOTO 207
C	END "270"
C
C
C	[2.5.1.225]
1225	IF(I15-1)1180,822,722
722	IF(I15-255)1180,822,1180
C	BEGIN "225 DEGREES"
822	IY=IY+1
	IX=IX-1
	JTHETA=5
	ITHETA=0
	GOTO 207
C	END "225"
C
C
C	[2.5.1.180]
1180	IF(J14-1)1135,818,718
718	IF(I14-255)1135,818,1135
C	BEGIN "180 DEGREES"
818	IX=IX-1
	JTHETA=4
	ITHETA=270
	GOTO 207
C	END "180"
C
C
C
C	[2.5.1.135]
1135	IF(J13-1)1090,813,713
713	IF(I13-255)1090,813,1090
C	BEGIN "135 DEGREES"
813	IY=IY-1
	IX=IX-1
	JTHETA=3
	ITHETA=270
	GOTO 207
C	END "135"
C
C
C
C	[2.5.1.90]
1090	IF(J12-1)209,890,790
790	IF(I12-255)209,890,209
C	BEGIN "90 DEGREES"
890	IY=IY-1
	JTHETA=2
	ITHETA=180
	GOTO 207
C	END "90"
C
C
C
C
C
C
C	[2.6] TEST IF WENT AROUND TWICE
C		THEN FAIL
C		ELSE GOTO [2.5.45]
209	NUMBEROFTIMESAROUND=NUMBEROFTIMESAROUND+1
S	TAD (-2
S	TAD \NUMBERTIMESAROUND
S	SPA CLA
S	JMP \1045 /NOT YET
C
C
C	[2.6.1] GOT LOST. RETURN FAILURE.
261	JX=-3
	JY=0
S	TAD \JX
S	DCA I JX
S	TAD \JY
S	DCA I JY
	GOTO 2047
C
C
C	[2.6.2] FOUND VALID (IX,IY).
207	CONTINUE
C	RETURN JTHETA IN THE MQ
S	TAD \JTHETA
S	MQL
C***********DEBUG*****
S	TAD PISW
S	TAD (23 / "/T"
S	DCA 7
S	CPAGE 5
S	6211
S	TADI 7
S	DCA \INDEX
S	TAD \INDEX
S	SNA CLA
S	JMP \1999
	JTHETA=JTHETA*45
	WRITE(3,1998)JX,JY,J13,J12,I13,I12,I11,J14,J18,J10,I14,I18
     1,I10(1),J15,J16,J17,I15,I16,I17,JTHETA,IX,IY,ITHETA
JX,JY,J13,J12,I13,I12,I11,J14,J18,J10,I14,I18,I10(1),J15,J16,J17,I15,I16,I17
1998	FORMAT(' DYN2[',I3,',',I3,'] ',3(/,' ',3I1,'  ',3I4)
     1,/,' MOVED THETA=',I4,',[IX:IY]=[',I3,':',I3
     2,'], NEW THETA=',I4)
1999	CONTINUE
C*************************
C
C	SAVE LAST XY
	LSTX=IX
	LSTY=IY
C
C	PASS BACK (X,Y) AND TEST IF DONE
	JX=IX
	JY=IY
S	TAD \JX
S	DCA I JX
S	TAD \JY
S	DCA I JY
C
C
C	[2.6.3] IF (IX=IXFIRST AND IY=IYFIRST)
C		THEN GOTO [2.7]
C		ELSE RETURN;
S	TAD \IX
S	CIA
S	TAD \IXFIRST
S	SZA CLA
S	JMP \2047 /NO
C
S	TAD \IY
S	CIA
S	TAD \IYFIRST
S	SZA CLA
S	JMP \2047 /NO
C
C
C	[2.7] YES,  DONE WITH FSM CLOSE OUT THE SEGMENT
	JX=-1
	JY=0
S	TAD \JX
S	DCA I JX
S	TAD \JY
S	DCA I JY
	GOTO 2047
C	[3] TEST IF CAUGHT IN A LOOP OF THE BOUNDARY BY LOOKING
C	BACKWARDS A LENGTH "LSUCLOOPLENGTH" POINTS IN THE STACK FOR
C	REPEATING SUBPATTERN WHICH OCCURS TWICE AND IS CAUGHT BY
C	THE 3RD OCCURRENCE OF THE FIRST POINT (JX,JY) OF
C	THE LOOP.  IF TRUE THEN RETURN (IVAL=1, IZ=PTR TO 2ND
C	OCCURRENCE OF (JX,JY) IN STACK) ELSE RETURN (IVAL=0).
C
C	SAVE IX,IY
3	IXS=IX
	IYS=IY
C
C
C	[3.1] COMPUTE MIN INDEX ON SEARCH K.
C	K=MAX(1,(IPTOP-LSUCLOOPLENGTH))
S	TAD \LSUCLOOPLENGTH
S	CIA
S	TAD \IPTOP
S	SPA
S	CLA IAC /+1
S	SNA
S	IAC
S	DCA \K
C@C***DEBUG****
C@C	IF FBW4[11]=1
C@C		THEN LPT ELSE TTY:
C@S	6344
C@S	AND (0001
C@S	SZA CLA
C@S	TAD (2
C@S	IAC
C@S	DCA \LSNEW
C@	WRITE(LSNEW,1886)K,IPTOP
C@1886	FORMAT(' [3.1] K=',I5,' IPTOP=',I5)
C@C***************
C
C
C	[3.2] IF IPTOP < 2 THEN RETURN FALSE
	IVAL=0
S	TAD (-2
S	TAD \IPTOP
S	SPA CLA
S	JMP \399 /RETURN FALSE
C
C
C	[3.3] LOOK BACKWARD IN STACK A MAX OF LSUCLOOPLENGTH POINTS
C	FOR (IX,IY) PAIR MATCH (JX,JY)
	DO 330 LCNT=K,IPTOP
	INDEX=(IPTOP-LCNT)+K
S	JMS LOOKUP /(IX,IY)<==LOOKUP(INDEX)
C	IF [(IX=JX) AND (IY=JY)] EQV CITYBLOCK=0
C		THEN "HIT"
S	JMS CHECKXY /J=CITYBLOCK((IX,IY),(JX,JY))
C@C***DEBUG***
C@	WRITE(LSNEW,1885)LCNT,INDEX,J
C@1885	FORMAT(' [3.3] LCNT=',I5,', INDEX=',I5,', CHECKXY=',I5)
C@C*************
S	TAD \J
S	SNA CLA
S	JMP \340 /YES, HIT
330	CONTINUE
C	"FAILED"
	GOTO 399
C
C
C	[3.4] FOUND 1ST REPEAT POINT AT INDEX "J11".
C	NOW TEST IF 2ND OCCURRENCE.
340	J11=INDEX
C@C****DEBUG****
C@	WRITE(LSNEW,1888)J11,IPTOP
C@1888	FORMAT(' [3.4] FOUND 1ST REPEAT AT ',I5,', IPTOP AT ',I5)
C@C****************
C	COMPUTE 2ND REPEAT PTR INTO STACK OF POTENTIAL
C	MATCH
	INDEX=J11-(IPTOP-J11)
C	IF INDEX < 1
C		THEN FAIL
S	CLA CMA
S	TAD \INDEX
S	SPA CLA
S	JMP \399 /FAIL
C
C	OK
S	JMS LOOKUP
C	IF [(IX=JX) AND (IY=JY)] EQV CITYBLOCK=0
C		THEN "HIT"
S	JMS CHECKXY /J=CITYBLOCK((IX,IY),(JX,JY))
S	TAD \J
S	SZA CLA
S	JMP \399 /FAILED!
C
C	SUCCESS! SAVE INDEX
	J12=INDEX
C
C
C	[3.5] FOUND 2ND REPEAT AT "J12"
C	IN EXTENDED ALGORITHM COULD MATCH SUB-STRINGS. BUT FOR NOW
C	IGNORE THEM.
C@C*******DEBUG****
C@	WRITE(LSNEW,1887)INDEX
C@1887	FORMAT(' [3.5] 2ND BACKWARD OCCURRANCE AT ',I5)
C@C*****************
C
C	==>LOOP IS TRUE. 
C	RETURN (IVAL=1, IZ=2ND STACK PTR).
	IVAL=1
	IZ=J11
C
C
C	[3.6] RESTORE IX,IY AND RETURN
399	IX=IXS
	IY=IYS
	GOTO 2047
C
C
C	***************************************************
C	*SUBROUTINE    L O O K U P
C	***************************************************
C	LOOKUP (IX,IY) FROM BM3H STACK(INDEX).
S	CPAGE 3
SRLOOKUP,	JMP I LOOKUP
S LOOKUP,	0
C
C
C	LOOKUP TWO BYTES
	MEM=3
	IBYTE=1
S	CLA CMA
S	TAD \INDEX
S	CLL RAL /*2
S	MQL
S	MQA
S	AND (377
S	DCA \IX
S	MQA
S	BSW; RTR
S	AND (0017
S	DCA \IY
	CALL FETCH2D
C	SAVE X
S	TAD \IZ
S	DCA \DDTGSTATUS
C
S	CLA CMA
S	TAD \INDEX
S	CLL RAL /*2
S	IAC
S	MQL
S	MQA
S	AND (377
S	DCA \IX
S	MQA
S	BSW; RTR
S	AND (0017
S	DCA \IY
	CALL FETCH2D
	IY=IZ
C	RESTORE X
S	TAD \DDTGSTATUS
S	DCA \IX
S	JMP RLOOKUP
C
C	***************************************************
C	*SUBROUTINE    C H E C K X Y
C	***************************************************
C	RETURN J = CITYBLOCK!DISTANCE = |IX-JX| + |IY-JY|;
S	CPAGE 3
SRCHECKXY,	JMP I CHECKXY
S CHECKXY,	0
C
C
S	CLA
S	TAD \IX
S	CIA
S	TAD \JX
S	SPA
S	CIA
S	DCA 7
S	TAD \IY
S	CIA
S	TAD \JY
S	SPA
S	CIA
S	TAD 7
S	DCA \J
S	JMP RCHECKXY
C	POINTERS
C	--------
C
S PISW,	\ISW
C
	END