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# Copyright(c) 1986 Association of Universities for Research in Astronomy Inc.
include <mach.h>
include <gset.h>
include <gio.h>
include "glabax.h"
define SZ_MANTISSA 3 # "10" or "-10"
define SZ_EXPONENT 4 # largest is "-999"
# GLB_LOGLAB -- Draw a tick label in log units at the given position.
# A log tick is a power of ten, e.g. 10^2, where the ^ signifies that
# the 2 is to be drawn one half character height higher than the 10.
procedure glb_loglab (gp, sx, sy, val, fmt, scaling)
pointer gp # graphics descriptor
real sx, sy # NDC coords of label
real val # value to be encoded (not the log of)
char fmt[ARB] # tick label gtext format (justification)
int scaling # type of scaling on axis
bool zero
char mantissa[SZ_MANTISSA]
char exponent[SZ_EXPONENT]
int len_mantissa, len_exponent, ip, hj, vj
real logval, char_height, char_width, left, xpos, ypos, txsize
bool fp_equalr()
real elogr(), gstatr(), ggetr()
int strlen(), strmatch(), itoc()
begin
# Compute the log value to be encoded.
if (scaling == LOG)
logval = log10 (val)
else {
logval = elogr (val)
zero = fp_equalr (logval, 0.0)
}
txsize = gstatr (gp, G_TXSIZE)
# Get char height and width in NDC coords.
char_height = ggetr (gp, "ch")
if (char_height < EPSILON)
char_height = DEF_CHARHEIGHT
char_height = char_height * txsize
char_width = ggetr (gp, "cw")
if (char_width < EPSILON)
char_width = DEF_CHARWIDTH
char_width = char_width * txsize
# Encode the mantissa and exponent strings.
if (zero) {
call strcpy ("0", mantissa, SZ_MANTISSA)
} else if (logval < 0 && scaling == ELOG) {
call strcpy ("-10", mantissa, SZ_MANTISSA)
logval = abs (logval)
} else
call strcpy ("10", mantissa, SZ_MANTISSA)
len_mantissa = strlen (mantissa)
if (zero)
len_exponent = 0
else
len_exponent = itoc (nint(logval), exponent, SZ_EXPONENT)
# Determine type of horizontal justification required.
ip = strmatch (fmt, "hj=")
if (ip <= 0)
hj = 'c'
else
hj = fmt[ip]
# Determine type of vertical justification required.
ip = strmatch (fmt, "vj=")
if (ip <= 0)
vj = 'c'
else
vj = fmt[ip]
# On devices with adjustable character sizes the most pleasing results
# are obtained if the digits "10" are nicely aligned on the vertical
# axis, regardless of the actual number of characters in the exponent
# string, minus signs etc (this type of alignment is more natural
# because the exponent is printed at half size). Hence if we are on
# a vertical axis (hj != c) fix the number of characters in the two
# strings so that the alignment comes out the same regardless of the
# actual number of chars in either field. The length of the exponent
# field is not completely fixed, rather we allow a little more space
# if the exponent is large. For small exponents len_exponent=1.
if (hj != 'c') {
len_mantissa = 2
len_exponent = (len_exponent + 1) / 2
}
# Compute XPOS, the NDC X coord of the point halfway between the
# last char of the mantissa and the first char of the exponent.
switch (hj) {
case 'l':
left = sx
case 'r':
left = sx - (len_mantissa + len_exponent) * char_width
default:
left = sx - ((len_mantissa + len_exponent) * char_width) / 2.0
}
xpos = left + len_mantissa * char_width
# Compute YPOS, the NDC Y coord of the center of a mantissa character
# and of the bottom of an exponent character. Using the same coordinate
# to address both positions makes the label come out the same regardless
# of the plot magnification, even on a device where the character size
# is fixed by the hardware.
switch (vj) {
case 'b':
ypos = sy + char_height / 2.0
case 't':
ypos = sy - char_height / 2.0
default:
ypos = sy
}
# Draw the mantissa.
call gtext (gp, xpos, ypos, mantissa, "hj=r,vj=c")
# Draw the exponent if there is one.
if (!zero) {
call gsetr (gp, G_TXSIZE, txsize / 2.0)
call gtext (gp, xpos, ypos, exponent, "hj=l;vj=b")
call gsetr (gp, G_TXSIZE, txsize)
}
end
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