SUBROUTINE  VISRS (Z1,ZE,Z2,NX,MX,NY,MY,TH,PL)

C     [ROTATED SEQUENCE]
C     ZE(J,I) ARRAY OF FUNCTION VALUES
C     (Z1,Z2) SPAN OF Z VALUES
C     NX,NY   RANGES OF J AND I
C     MX,MY   MAXIMA ATTAINABLE BY J AND I
C     TH      ANGLE OF ROTATION (DEGREES, CLOCKWISE).
C     L       DIRECTION OF VIEW (1=WEST, -1=EAST)
C     M       DIRECTION OF VIEW (1=SOUTH, -1=NORTH)
C     PL      PEN MOVEMENT SUBROUTINE
C     THE HORIZONTAL SCALE IS NOT ALWAYS CONSTANT, BUT IS ADJUSTED
C     SO THAT THE DRAWING WILL OCCUPY THE FULL BREADTH OF THE PAGE.
C     [19-DEC-74]

      EXTERNAL    PL
      DIMENSION   ZE(1),U(501),V(501)
      DATA        M,MK,VF/1,501,0.333/

      IX(J,I)=(I-1)*MX+J
      SC(Z)=ZS*(Z-Z1)

      IF (TH.LT.0.0) L=-1
      IF (TH.GE.0.0) L= 1
      N=L*M
      MM=1
      SI=SIND(TH)
      CO=COSD(TH)
      EL=FLOAT(L)
      EM=FLOAT(M)
      ZS=(1.0-VF)/(Z2-Z1)
      SF=1.0/(ABS(CO)+ABS(SI))
      U0=0.25*(EL+1.0)*(1.0-SF*(CO-SI))
      V0=0.15*(EL-1.0)*SF*SI
      DUI=-(SF*SI)/FLOAT(MY-1)
      DUJ= (SF*CO)/FLOAT(MX-1)
      DVI= (VF*SF*CO)/FLOAT(MY-1)
      DVJ= (VF*SF*SI)/FLOAT(MX-1)

      I0=(NY+1-M*(NY-3))/2
      J0=(NX+1-L*(NX-1))/2
      K0=((MK+1)*(1-N))/2
   10 K=K0
      I=MAX0(MIN0(I0,NY+1),0)
      J=J0
      EU=U0+DUI*FLOAT(I-1)+DUJ*FLOAT(J-1)
      VE=V0+DVI*FLOAT(I-1)+DVJ*FLOAT(J-1)
   20 IF ((I.LT.1).OR.(I.GT.NY)) GO TO 22
      K=MAX0(MIN0(K+N,MK),1)
      U(K)=EU
      V(K)=VE+SC(ZE(IX(J,I)))
   22 I=I-M
      EU=EU-EM*DUI
      VE=VE-EM*DVI
      IF ((I.LT.1).OR.(I.GT.NY)) GO TO 30
      K=MAX0(MIN0(K+N,MK),1)
      U(K)=EU
      V(K)=VE+SC(ZE(IX(J,I)))
      J=J+L
      EU=EU+EL*DUJ
      VE=VE+EL*DVJ
      IF ((J.GE.1).AND.(J.LE.NX)) GO TO 20
   30 IF (L.GT.0) CALL VISHO (U,V,K,MM,PL)
      IF (L.LT.0) CALL VISHO (U(K),V(K),MK-K+1,MM,PL)
      MM=-MM
      I0=I0+M
      IF ((I0.GE.0).AND.(I0.LE.NY+1)) GO TO 10
      J0=J0+L
      IF ((J0.GE.1).AND.(J0.LE.NX))   GO TO 10
      RETURN

      END