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|
C
C
C +-----------------------------------------------------------------+
C | |
C | Copyright (C) 1986 by UCAR |
C | University Corporation for Atmospheric Research |
C | All Rights Reserved |
C | |
C | NCARGRAPHICS Version 1.00 |
C | |
C +-----------------------------------------------------------------+
C
C
C ---------------------------------------------------------------------
C
SUBROUTINE AGQURV (XVEC,IIEX,YVEC,IIEY,NEXY,SVAL)
C
DIMENSION XVEC(1),YVEC(1)
C
C AGQURV plots the curve defined by the points ((X(I),Y(I)),I=1,NEXY),
C where
C
C X(I)=XVEC(1+(I-1)*IIEX) (unless IIEX=0, in which case X(I)=I), and
C Y(I)=YVEC(1+(I-1)*IIEY) (unless IIEY=0, in which case Y(I)=I).
C
C If, for some I, X(I)=SVAL or Y(I)=SVAL, curve line segments having
C (X(I),Y(I)) as an endpoint are omitted.
C
C The curve drawn is windowed. Portions of the curve which would fall
C outside the current curve window, as defined by the last SET call,
C are not drawn.
C
C Check first whether the number of curve points is properly specified.
C
IF (NEXY.LE.0) GO TO 901
C
C Initialization. Pretend that the last point was point number zero.
C Set the indices for the x and y vectors accordingly. Clear the line-
C drawn-to-last-point and last-point-outside-window flags.
C
INDP=0
INDX=1-IIEX
INDY=1-IIEY
LDLP=0
LPOW=0
C
C Initialization. Retrieve the current curve window, user window, and
C x/y linear/logarithmic flags.
C
CALL GETSET (XLCW,XRCW,YBCW,YTCW,XLUW,XRUW,YBUW,YTUW,LTYP)
C
C Initialization. Set linear/log flag and linear-window limits for
C x-axis values.
C
IF (LTYP.EQ.1.OR.LTYP.EQ.2) THEN
LLUX=0
XLLW=XLUW
XRLW=XRUW
ELSE
LLUX=1
XLLW=ALOG10(XLUW)
XRLW=ALOG10(XRUW)
END IF
C
C Initialization. Set linear/log flag and linear-window limits for
C y-axis values.
C
IF (LTYP.EQ.1.OR.LTYP.EQ.3) THEN
LLUY=0
YBLW=YBUW
YTLW=YTUW
ELSE
LLUY=1
YBLW=ALOG10(YBUW)
YTLW=ALOG10(YTUW)
END IF
C
C Initialization. Call SET, if necessary, to define a linear mapping.
C (This greatly simplifies the windowing code.)
C
IF (LTYP.NE.1)
+ CALL SET (XLCW,XRCW,YBCW,YTCW,XLLW,XRLW,YBLW,YTLW,1)
C
C Initialization. Compute mimimum and maximum values of x which are
C slightly outside the linear window. (Note: XLLW and XRLW will not
C be used after this.)
C
IF (XLLW.GT.XRLW) THEN
TEMP=XLLW
XLLW=XRLW
XRLW=TEMP
END IF
XEPS=.000001*(XRLW-XLLW)
XMIN=XLLW-XEPS
XMAX=XRLW+XEPS
C
C Initialization. Compute minimum and maximum values of y which are
C slightly outside the linear window. (Note: YBLW and YTLW will not
C be used after this.)
C
IF (YBLW.GT.YTLW) THEN
TEMP=YBLW
YBLW=YTLW
YTLW=TEMP
END IF
YEPS=.000001*(YTLW-YBLW)
YMIN=YBLW-YEPS
YMAX=YTLW+YEPS
C
C Beginning of loop through points. Update indices and determine the
C user-space coordinates of the next point.
C
101 IF (INDP.EQ.NEXY) GO TO 120
INDP=INDP+1
C
INDX=INDX+IIEX
XNXT=XVEC(INDX)
IF (IIEX.EQ.0) XNXT=FLOAT(INDP)
IF (LLUX.NE.0.AND.XNXT.LE.0.) XNXT=SVAL
C
INDY=INDY+IIEY
YNXT=YVEC(INDY)
IF (IIEY.EQ.0) YNXT=FLOAT(INDP)
IF (LLUY.NE.0.AND.YNXT.LE.0.) YNXT=SVAL
C
C Check whether (XNXT,YNXT) is a special-value point. Handle that case.
C
IF (XNXT.EQ.SVAL.OR.YNXT.EQ.SVAL) THEN
LPOW=0
IF (LDLP.EQ.0) GO TO 101
IF (LDLP.EQ.1) CALL VECTD (XLST,YLST)
CALL LASTD
LDLP=0
GO TO 101
END IF
C
C If user space is not linear/linear, modify XNXT and YNXT accordingly.
C
IF (LLUX.NE.0) XNXT=ALOG10(XNXT)
IF (LLUY.NE.0) YNXT=ALOG10(YNXT)
C
C Set the next-point-outside-window flag to a value between -4 and +4,
C inclusive. A non-zero value indicates that the next point is outside
C the window and indicates which of eight possible areas it falls in.
C
NPOW=IFIX(3.*(SIGN(.51,XNXT-XMIN)+SIGN(.51,XNXT-XMAX))+
+ (SIGN(.51,YNXT-YMIN)+SIGN(.51,YNXT-YMAX)))
C
C There are now various possible cases, depending on whether the line-
C drawn-to-last-point flag is set or not, whether the next point is in
C the window or not, and whether the last point was in the window, not
C in the window, or non-existent (point 0 or a special-value point).
C
IF (LDLP.EQ.0) GO TO 102
IF (NPOW.NE.0) GO TO 103
C
C Line drawn to last point, next point inside, last point inside.
C
CALL VECTD (XNXT,YNXT)
LDLP=LDLP+1
GO TO 119
C
102 IF (NPOW.NE.0) GO TO 109
IF (LPOW.NE.0) GO TO 105
C
C No line drawn to last point, next point inside, no last point.
C
CALL FRSTD (XNXT,YNXT)
LDLP=1
GO TO 119
C
C Line drawn to last point, next point outside, last point inside.
C
103 XPIW=XLST
YPIW=YLST
XPOW=XNXT
YPOW=YNXT
ASSIGN 104 TO JUMP
GO TO 107
104 CALL VECTD (XPEW,YPEW)
CALL LASTD
LDLP=0
GO TO 119
C
C No line drawn to last point, next point inside, last point outside.
C
105 XPIW=XNXT
YPIW=YNXT
XPOW=XLST
YPOW=YLST
ASSIGN 106 TO JUMP
GO TO 107
106 CALL FRSTD (XPEW,YPEW)
CALL VECTD (XNXT,YNXT)
LDLP=2
GO TO 119
C
C The following local procedure, given a point (XPIW,YPIW) inside the
C window and a point (XPOW,YPOW) outside the window, finds the point of
C intersection (XPEW,YPEW) of a line joining them with the window edge.
C
107 XPEW=XPIW
YPEW=YPIW
XDIF=XPOW-XPIW
YDIF=YPOW-YPIW
C
IF (ABS(XDIF).GT.XEPS) THEN
XPEW=XMIN
IF (XDIF.GE.0.) XPEW=XMAX
YPEW=YPIW+(XPEW-XPIW)*YDIF/XDIF
IF (YPEW.GE.YMIN.AND.YPEW.LE.YMAX) GO TO 108
END IF
C
IF (ABS(YDIF).GT.YEPS) THEN
YPEW=YMIN
IF (YDIF.GE.0.) YPEW=YMAX
XPEW=XPIW+(YPEW-YPIW)*XDIF/YDIF
END IF
C
108 GO TO JUMP , (104,106)
C
C No line drawn to last point, next point outside. Jump if no last
C point.
C
109 IF (LPOW.EQ.0) GO TO 119
C
C No line drawn to last point, next point outside, last point outside.
C Check whether a portion of the line joining them lies in the window.
C
MPOW=9*LPOW+NPOW+41
C
GO TO (119,119,119,119,119,110,119,110,110,
+ 119,119,119,111,119,110,111,110,110,
+ 119,119,119,111,119,119,111,111,119,
+ 119,113,113,119,119,110,119,110,110,
+ 119,119,119,119,119,119,119,119,119,
+ 112,112,119,112,119,119,111,111,119,
+ 119,113,113,119,119,113,119,119,119,
+ 112,112,113,112,119,113,119,119,119,
+ 112,112,119,112,119,119,119,119,119) , MPOW
C
110 XPE1=XMIN
YPT1=YMIN
XPE2=XMAX
YPT2=YMAX
GO TO 114
C
111 XPE1=XMIN
YPT1=YMAX
XPE2=XMAX
YPT2=YMIN
GO TO 114
C
112 XPE1=XMAX
YPT1=YMAX
XPE2=XMIN
YPT2=YMIN
GO TO 114
C
113 XPE1=XMAX
YPT1=YMIN
XPE2=XMIN
YPT2=YMAX
C
114 XDIF=XNXT-XLST
YDIF=YNXT-YLST
C
IF (ABS(XDIF).LE.XEPS) GO TO 116
YPE1=YLST+(XPE1-XLST)*YDIF/XDIF
YPE2=YLST+(XPE2-XLST)*YDIF/XDIF
C
IF (ABS(YDIF).LE.YEPS) GO TO 118
IF (YPE1.GE.YMIN.AND.YPE1.LE.YMAX) GO TO 115
YPE1=YPT1
XPE1=XLST+(YPE1-YLST)*XDIF/YDIF
IF (XPE1.LT.XMIN.OR.XPE1.GT.XMAX) GO TO 119
C
115 IF (YPE2.GE.YMIN.AND.YPE2.LE.YMAX) GO TO 118
GO TO 117
C
116 YPE1=YPT1
XPE1=XLST+(YPE1-YLST)*XDIF/YDIF
IF (XPE1.LT.XMIN.OR.XPE1.GT.XMAX) GO TO 119
C
117 YPE2=YPT2
XPE2=XLST+(YPE2-YLST)*XDIF/YDIF
IF (XPE2.LT.XMIN.OR.XPE2.GT.XMAX) GO TO 119
C
118 CALL FRSTD (XPE1,YPE1)
CALL VECTD (XPE2,YPE2)
CALL LASTD
C
C Processing of next point is done. It becomes the last point and we
C go back for a new next point.
C
119 LPOW=NPOW
XLST=XNXT
YLST=YNXT
GO TO 101
C
C Last point was final point. Finish up.
C
120 IF (LDLP.NE.0) THEN
IF (LDLP.EQ.1) CALL VECTD (XLST,YLST)
CALL LASTD
END IF
C
C Restore logarithmic mapping, if appropriate.
C
IF (LTYP.NE.1)
+ CALL SET (XLCW,XRCW,YBCW,YTCW,XLUW,XRUW,YBUW,YTUW,LTYP)
C
C Return to caller.
C
RETURN
C
C Error exit.
C
901 CALL SETER ('AGQURV - NUMBER OF POINTS IS LESS THAN OR EQUAL TO ZE
+RO',7,2)
C
END
|
