Trailing-Edge
-
PDP-10 Archives
-
decus_20tap5_198111
-
decus/20-0141/dagrid.for
There are 2 other files named dagrid.for in the archive. Click here to see a list.
SUBROUTINE DAGRID(JSTIFY,MAXWID,XLEFT,XRIGHT,MSHWID,
1 LTROFF)
C RENBR(/RATIONALIZE SCALE OF PRINTER PLOT)
C
C DONALD BARTH, HARVARD BUSINESS SCHOOL
C
C PROPORTIONS OF GRID SUPERIMPOSED UPON PLOT AREA BY
C DAPLAT ROUTINE MUST BE SPECIFIED BY CALLING PROGRAM.
C NUMBERS WHICH ARE PRINTED BESIDE AND BELOW PLOT
C MERELY REPRESENT DATA UNIT COORDINATES PLOTTED AT
C CENTERS OF COLUMNS AND LINES WHICH BEAR GRID LINES.
C RANGE OF DATA UNIT COORDINATES REPRESENTED BY THESE
C SCALES CAN BE DIFFICULT TO INTERPRET IF CALLING
C PROGRAM HOLDS GRID PROPORTIONS CONSTANT WHILE
C ATTEMPTING TO OBTAIN MAXIMUM RESOLUTION BY ADJUSTING
C MINIMUM AND MAXIMUM COORDINATES TO SPREAD CURVES
C ACROSS FULL WIDTH OR HEIGHT OF PLOT. DAPLAT CANNOT
C ITSELF CALCULATE GRID PROPORTIONS WHICH WOULD PRODUCE
C MINIMUM NUMBER OF NONZERO DIGITS IN EACH SCALE
C NUMBER. IF PREDETERMINED GRID SPACINGS AND OFFSETS
C ARE NOT NECESSARY, THEN ROUTINE DAGRID CAN BE CALLED
C ONCE FOR EACH SCALE BEFORE DATA IS PLOTTED TO SELECT
C GRID PROPORTIONS AND TO EXPAND COORDINATE RANGES
C SLIGHTLY TO GIVE NEATER SCALE NUMBERS.
C
C JSTIFY = -2, LEFT JUSTIFY LEFT GRID LINE
C = -1, LEFT JUSTIFY XLEFT
C = 0, CENTER RANGE
C = 1, RIGHT JUSTIFY XRIGHT
C = 2, RIGHT JUSTIFY RIGHT GRID LINE
C MAXWID = WIDTH (OR HEIGHT) OF PLOT STATED AS NUMBER
C OF COLUMNS (OR LINES).
C XLEFT = INPUT CONTAINING DATA UNIT COORDINATE TO BE
C REPRESENTED BY CENTER OF LEFT COLUMN (OR OF
C LOWER LINE) OF PLOT.
C = RETURNED CONTAINING DATA UNIT COORDINATE
C WHICH WOULD GIVE RATIONAL SCALE IF USED AS
C DATA UNIT COORDINATE REPRESENTED BY CENTER
C OF LEFT COLUMN (OR OF LOWER LINE) OF PLOT.
C XRIGHT = INPUT CONTAINING DATA UNIT COORDINATE TO BE
C REPRESENTED BY CENTER OF RIGHT COLUMN (OR OF
C UPPER LINE) OF PLOT.
C = RETURNED CONTAINING DATA UNIT COORDINATE
C WHICH WOULD GIVE RATIONAL SCALE IF USED AS
C DATA UNIT COORDINATE REPRESENTED BY CENTER
C OF RIGHT COLUMN (OR OF UPPER LINE) OF PLOT.
C MSHWID = RETURNED CONTAINING THE GRID DIVISION WIDTH
C STATED AS THE NUMBER OF COLUMNS (OR HEIGHT
C STATED AS NUMBER OF LINES). INPUT VALUE OF
C MSHWID IS IGNORED. A LINE SHOULD BE RULED
C EVERY MSHWID CHARACTERS ACROSS THE WIDTH (OR
C HEIGHT) OF THE PLOT. IF MSHWID IS RETURNED
C CONTAINING 10, THEN 9 COLUMNS (OR LINES)
C SHOULD APPEAR BETWEEN THE COLUMNS (OR LINES)
C BEARING GRID LINES.
C = 0, RETURNED IF THIS ROUTINE COULD NOT
C RATIONALIZE THE SCALE, AS FOR EXAMPLE IF
C XLEFT IS INPUT CONTAINING THE SAME VALUE AS
C XRIGHT, OR IF MAXWID IS INPUT TOO SMALL.
C LTROFF = RETURNED CONTAINING THE NUMBER OF COLUMNS
C (OR LINES) BY WHICH THE LEFT (OR LOWER) GRID
C LINE IS TO BE OFFSET FROM THE LEFT (OR
C LOWER) EDGE OF THE PLOT. INPUT VALUE OF
C LTROFF IS IGNORED. IF LTROFF IS RETURNED
C CONTAINING ZERO, THEN THE LEFT (OR LOWER)
C GRID LINE SHOULD APPEAR IN THE LEFT (OR
C LOWER) COLUMN OF THE PLOT. IF LTROFF IS
C RETURNED CONTAINING 5, THEN 5 COLUMNS (OR
C LINES) OF THE PLOT AREA SHOULD APPEAR TO THE
C LEFT OF (OR BELOW) THE LEFTMOST (OR LOWEST)
C GRID LINE.
C
C SCALE RANGE TO BE BETWEEN 1.0 AND 9.999...
IF(MAXWID.LE.0)GO TO 19
KNTJST=0
IF(JSTIFY.LE.0)GO TO 1
FORMER=XLEFT
XLEFT=XRIGHT
XRIGHT=FORMER
1 RANGE=XRIGHT-XLEFT
IF(RANGE.LT.0.0)RANGE=-RANGE
IF(RANGE.LE.0.0)GO TO 19
SHIFTD=RANGE
IPOWER=0
2 IF(SHIFTD.GE.10.0)GO TO 3
IF(SHIFTD.GE.1.0)GO TO 4
IF(IPOWER.LT.-99)GO TO 19
IF(IPOWER.GT.0)GO TO 4
IPOWER=IPOWER-1
SHIFTD=10.0*SHIFTD
GO TO 2
3 IF(IPOWER.GT.99)GO TO 19
IF(IPOWER.LT.0)GO TO 4
IPOWER=IPOWER+1
SHIFTD=SHIFTD/10.0
GO TO 2
C
C CALCULATE WIDTH OF EACH GRID DIVISION
4 STEP=0.25
IF(SHIFTD.GT.2.5)STEP=0.5
IF(SHIFTD.GT.5.0)STEP=1.0
STEP=STEP*(10.0**IPOWER)
MSHWID=FLOAT(MAXWID-1)*(STEP/RANGE)
IF(MSHWID.LE.0)GO TO 19
IF(JSTIFY.NE.0)GO TO 5
HLFWID=0.5*STEP*(FLOAT(MAXWID-1)/FLOAT(MSHWID))
IF(XLEFT.GT.XRIGHT)HLFWID=-HLFWID
CENTER=(XLEFT+XRIGHT)/2.0
XLEFT=CENTER-HLFWID
XRIGHT=CENTER+HLFWID
C
C GET INTEGRAL MULTIPLE OF STEP WHICH IS JUST GREATER
C THAN OR EQUAL TO ABSOLUTE VALUE OF LEFT EDGE OF PLOT
5 ORIGIN=STEP
KOUNT=0
COMPAR=XLEFT
IF(COMPAR.LT.0.0)COMPAR=-COMPAR
6 IF(ORIGIN.GE.COMPAR)GO TO 7
IF(KOUNT.GE.10)GO TO 19
KOUNT=KOUNT+1
ORIGIN=10.0*ORIGIN
GO TO 6
7 SEARCH=ORIGIN
8 LIMIT=10
9 FORMER=ORIGIN
ORIGIN=ORIGIN-SEARCH
IF(ORIGIN.LT.COMPAR)GO TO 10
LIMIT=LIMIT-1
IF(LIMIT.GT.0)GO TO 9
GO TO 11
10 ORIGIN=FORMER
11 IF(KOUNT.LE.0)GO TO 12
SEARCH=SEARCH/10.0
KOUNT=KOUNT-1
GO TO 8
C
C ADJUST ORIGIN FOR DIRECTION AND SIGN OF LEFT EDGE
12 IF(XLEFT.LE.XRIGHT)GO TO 14
STEP=-STEP
IF(XLEFT.LT.0.0)GO TO 13
ORIGIN=ORIGIN+STEP
GO TO 15
13 ORIGIN=-ORIGIN
GO TO 15
14 IF(XLEFT.GE.0.0)GO TO 15
ORIGIN=-ORIGIN+STEP
C
C CALCULATE GRID PROPORTIONS
15 LTROFF=0.5+(FLOAT(MSHWID)*((ORIGIN-XLEFT)/STEP))
IF(LTROFF.LT.MSHWID)GO TO 16
LTROFF=LTROFF-MSHWID
ORIGIN=ORIGIN-STEP
16 IF(LTROFF.LE.0)GO TO 17
IF(JSTIFY.LT.-1)GO TO 18
IF(JSTIFY.GT.1)GO TO 18
17 XLEFT=ORIGIN-(STEP*(FLOAT(LTROFF)/FLOAT(MSHWID)))
XRIGHT=ORIGIN+(STEP*(FLOAT(MAXWID-1-LTROFF)/
1FLOAT(MSHWID)))
IF(JSTIFY.LE.0)GO TO 20
FORMER=XLEFT
XLEFT=XRIGHT
XRIGHT=FORMER
LTROFF=MAXWID-LTROFF-1
LTROFF=LTROFF-(MSHWID*(LTROFF/MSHWID))
GO TO 20
C
C LOOP BACK IF NEED TO JUSTIFY GRID
18 XLEFT=ORIGIN-STEP
KNTJST=KNTJST+1
IF(KNTJST.LE.5)GO TO 1
C
C ERROR CONDITION
19 MSHWID=0
LTROFF=0
C
C RETURN TO CALLING PROGRAM
20 RETURN
C635919530735
END