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# Copyright(c) 1986 Association of Universities for Research in Astronomy Inc.
include <mach.h>
include "glabax.h"
# GLB_ENCODE -- Encode a floating point number as a character string for a
# tick label. We have to be careful how we do this, since on the one hand
# we want the most concise label possible (e.g., 500 not 500.00) but on the
# other we must provide enough precision to discriminate between ticks that
# are close together (e.g., 500.02 and 500.04). The extra information is
# given by the "ndigits" argument, which was calculated knowing the range
# and step at setup time.
procedure glb_encode (x, out, maxch, format, step)
real x # number to be encoded
char out[ARB] # output string
int maxch # max chars out
char format[ARB] # sprintf format
real step # tick spacing
int ip, op
real nicex
define trim_ 91
begin
# Test for the zero tick, to avoid tick labels that look like the
# machine epsilon.
if (abs (x / step) < TOL)
nicex = 0
else
nicex = x
# Encode number.
call sprintf (out, maxch, format)
call pargr (nicex)
# Lop off any insignificant trailing zeros or periods. Watch out for
# trailing zeros in exponential format, e.g., "1.0E10".
for (ip=1; out[ip] != EOS; ip=ip+1)
if (out[ip] == 'E' || out[ip] == 'D')
goto trim_
for (ip=ip-1; ip > 1 && out[ip] == '0'; ip=ip-1)
;
if (ip > 1 && out[ip] == '.')
ip = ip - 1
if (ip >= 1)
out[ip+1] = EOS
# Lop off any insignificant leading zeros, but be sure to leave at
# least one digit.
trim_
for (op=1; out[op] == '-' || out[op] == '+'; op=op+1)
;
for (ip=op; out[ip] == '0' && out[ip+1] != EOS; ip=ip+1)
;
while (out[ip] != EOS) {
out[op] = out[ip]
op = op + 1
ip = ip + 1
}
out[op] = EOS
end
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