PROGRAM PGEX12
C-----------------------------------------------------------------------
C Test routine for PGPLOT: draw arrows with PGARRO.
C-----------------------------------------------------------------------
      INTEGER NV, I, K, PGOPEN
      REAL A, D, X, Y, XT, YT
C
C Number of arrows.
C
      NV =16
C
C Call PGOPEN to initiate PGPLOT and open the output device; PGOPEN
C will prompt the user to supply the device name and type. Always
C check the return code from PGOPEN.
C
      IF (PGOPEN('?') .LE. 0) STOP
C
C Select a square viewport.
C
      CALL PGBBUF
      CALL PGSAVE
      CALL PGSCH(0.7)
      CALL PGSCI(2)
      CALL PGENV(-1.05,1.05,-1.05,1.05,1,-1)
      CALL PGLAB(' ', ' ', 'PGPLOT Example 12: PGARRO')
      CALL PGSCI(1)
C
C Draw the arrows
C
      K = 1
      D = 360.0/57.29577951/NV
      A = -D
      DO 20 I=1,NV
          A = A+D
          X = COS(A)
          Y = SIN(A)
          XT = 0.2*COS(A-D)
          YT = 0.2*SIN(A-D)
          CALL PGSAH(K, 80.0-3.0*I, 0.5*REAL(I)/REAL(NV))
          CALL PGSCH(0.25*I)
          CALL PGARRO(XT, YT, X, Y)
          K = K+1
          IF (K.GT.2) K=1
   20 CONTINUE
C
      CALL PGUNSA
      CALL PGEBUF
C
C Finally, call PGCLOS to terminate things properly.
C
      CALL PGCLOS
C
      END