/usr/bin/pamstretch-gen is in netpbm 2:10.0-15.3build1.
This file is owned by root:root, with mode 0o755.
The actual contents of the file can be viewed below.
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 | #!/bin/sh
#
# pamstretch-gen - a shell script which acts a little like a general
# form of pamstretch, by scaling up with pamstretch then scaling
# down with pnmscale.
#
# it also copes with N<1, but then it just uses pnmscale. :-)
#
# by Russell Marks, 1999.
# Contributed to the public domain.
if [ "$1" = "" ]; then
echo 'usage: pamstretch-gen N [pnmfile]'
exit 1
fi
tempfile=$(mktemp -t pnmig.XXXXXXXXXX) || exit 1 #219019
if ! cat $2 >$tempfile 2>/dev/null; then
echo 'pamstretch-gen: error reading file' 1>&2
exit 1
fi
# we use the width as indication of how much to scale; width and
# height are being scaled equally, so this should be ok.
width=`pnmfile $tempfile 2>/dev/null|cut -d " " -f 3`
if [ "$width" = "" ]; then
echo 'pamstretch-gen: not a PNM file' 1>&2
exit 1
fi
# should really use dc for maths, but awk is less painful :-)
target_width=`awk 'BEGIN{printf("%d",'0.5+"$width"*"$1"')}'`
# work out how far we have to scale it up with pnmstretch so that the
# new width is >= the target width.
int_scale=`awk '
BEGIN {
int_scale=1;int_width='"$width"'
while(int_width<'"$target_width"')
{
int_scale++
int_width+='"$width"'
}
print int_scale
}'`
if [ "$int_scale" -eq 1 ]; then
pnmscale "$1" $tempfile
else
pamstretch "$int_scale" $tempfile | pnmscale -xsi "$target_width"
fi
rm -f $tempfile;
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