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Text File  |  1991-04-13  |  957b  |  35 lines
  1.         SUBROUTINE SCALE(X,Y,VX,VY)
  2.     IMPLICIT NONE
  3.     REAL*4 X,Y,VX,VY,SMLLOG,XX,YY,ZZ
  4. C
  5. C       THIS SUBROUTINE CONVERTS THE POINT (X,Y) FROM WORLD COORDINATES
  6. C       TO THE POINT (VX,VY) IN VIRTUAL COORDINATES.
  7. C
  8.         INCLUDE DIGLIB$KOM:PLTCOM.PRM
  9.         INCLUDE DIGLIB$KOM:PLTSIZ.PRM
  10. C
  11. C       DEFINE "LOG10(0.0)" AS SMLLOG
  12. C
  13.         DATA SMLLOG /-100.0/
  14. C
  15.         XX = X
  16.         IF (.NOT. LOGX) GO TO 10
  17.                 IF (X .LE. 0.0) GO TO 5
  18.                         XX = ALOG10(X)
  19.                         GO TO 10
  20. 5                   CONTINUE
  21.                         XX = SMLLOG
  22. 10      CONTINUE
  23.         YY = Y
  24.         IF (.NOT. LOGY) GO TO 20
  25.                 IF (Y .LE. 0.0) GO TO 15
  26.                         YY = ALOG10(Y)
  27.                         GO TO 20
  28. 15                  CONTINUE
  29.                         YY = SMLLOG
  30. 20      CONTINUE
  31.         VX = XVSTRT + XVLEN*(XX-UX0)/UDX
  32.         VY = YVSTRT + YVLEN*(YY-UY0)/UDY
  33.         RETURN
  34.         END
  35.