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# Copyright(c) 1986 Association of Universities for Research in Astronomy Inc.
include <plset.h>
include "pllseg.h"
include <plio.h>
# PL_SECTNOTCONST -- Test whether the indicated mask image section is constant,
# i.e., all the pixels in the section have the same value. Return this value
# if the region is constant.
bool procedure pl_sectnotconst (pl_src, v1, v2, ndim, mval)
pointer pl_src #I mask descriptor
long v1[PL_MAXDIM] #I starting coordinates of section
long v2[PL_MAXDIM] #I ending coordinates of section
int ndim #I section dimension
int mval #O mask value, if constant region
pointer lp
int ll_src, lval, i
long v[PL_MAXDIM], vs[PL_MAXDIM], ve[PL_MAXDIM], vn[PL_MAXDIM]
bool pll_const()
int pl_reference(), plloop()
errchk plvalid, plsslv, pl_reference
begin
call plvalid (pl_src)
# Initialize the N-dimensional loop counters.
do i = 1, PL_MAXDIM
if (i <= ndim) {
if (v1[i] <= v2[i]) {
vs[i] = v1[i]
vn[i] = v2[i] - v1[i] + 1
} else {
vs[i] = v2[i]
vn[i] = v1[i] - v2[i] + 1
}
} else {
vs[i] = 1
vn[i] = 1
}
call plsslv (pl_src, vs, vn, v, ve)
mval = ERR
# Test each line segment in the section.
repeat {
# Determine if line segment is complex, or is all set to lval.
ll_src = pl_reference (pl_src, v)
if (ll_src == PL_EMPTYLINE)
lval = 0
else {
lp = Ref (pl_src, ll_src)
if (!pll_const (Mems[lp], vs[1], vn[1], lval))
return (true)
}
# Exit if the mask value changes, indicating a complex region.
if (mval == ERR)
mval = lval
else if (mval != lval)
return (true)
} until (plloop (v, vs, ve, PL_NAXES(pl_src)) == LOOP_DONE)
return (false)
end
# PLL_CONST -- Test whether a section of a line list is set to a constant
# value. If yes, return the value in mval.
bool procedure pll_const (ll_src, xs, npix, mval)
short ll_src[ARB] #I input line list
int xs #I first pixel to test
int npix #I length of region to be tested
int mval #O mask value, if constant valued segment
int nleft, x1, np, v_src, i
int d_src[LEN_PLLDES]
begin
# Advance to the indicated position in the source list.
x1 = 1
pll_init (ll_src, d_src)
do i = 1, ARB {
np = min (pll_nleft(d_src), xs - x1)
pll_getseg (ll_src, d_src, np, v_src)
x1 = x1 + np
if (x1 >= xs || np == 0)
break
}
# Test if the next npix pixels are all set to the same value.
# Note the line list is segmented and we have to read segments until
# we have examined NPIX pixels, or until the mask value changes.
mval = -1
for (nleft=npix; nleft > 0; nleft = nleft - np) {
np = min (pll_nleft(d_src), nleft)
pll_getseg (ll_src, d_src, np, v_src)
if (v_src != mval)
if (mval < 0)
mval = v_src
else
return (false)
}
return (true)
end
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