<h2>Edit File: ppmrainbow</h2><form method="post"><textarea name="content" rows="20" cols="80">#!/bin/sh

##############################################################################
# This is essentially a Perl program.  We exec the Perl interpreter specifying
# this same file as the Perl program and use the -x option to cause the Perl
# interpreter to skip down to the Perl code.  The reason we do this instead of
# just making /usr/bin/perl the script interpreter (instead of /bin/sh) is
# that the user may have multiple Perl interpreters and the one he wants to
# use is properly located in the PATH.  The user&#039;s choice of Perl interpreter
# may be crucial, such as when the user also has a PERL5LIB environment
# variable and it selects modules that work with only a certain main
# interpreter program.
#
# An alternative some people use is to have /usr/bin/env as the script
# interpreter.  We don&#039;t do that because we think the existence and
# compatibility of /bin/sh is more reliable.
#
# Note that we aren&#039;t concerned about efficiency because the user who needs
# high efficiency can use directly the programs that this program invokes.
#
##############################################################################

exec perl -w -x -S -- &quot;$0&quot; &quot;$@&quot;

#!/usr/bin/perl
use strict;
use Getopt::Long;
use File::Temp;

my ($FALSE, $TRUE) = (0,1);

(my $myname = $0) =~ s#\A.*/##;


sub doVersionHack($) {
    my ($argvR) = @_;

    my $arg1 = $argvR-&gt;[0];

    if (defined($arg1) &amp;&amp; (($arg1 eq &quot;--version&quot;) || ($arg1 eq &quot;-version&quot;))) {
        my $termStatus = system(&#039;pgmramp&#039;, &#039;--version&#039;);
        exit($termStatus == 0 ? 0 : 1);
    }
}


sub fatal($) {
    my ($msg) = @_;

    print(STDERR &quot;$msg\n&quot;);
    exit(1);
}


##############################################################################
#
#                                 MAINLINE
#
##############################################################################

doVersionHack(\@ARGV);

my ($Twid, $Thgt, $tmpdir, $repeat, $verbose);

# set defaults
$Twid = 600;
$Thgt = 8;
$tmpdir = $ENV{&quot;TMPDIR&quot;} || &quot;/tmp&quot;;
$repeat = $TRUE;
$verbose = $FALSE;

GetOptions(&quot;width=i&quot;   =&gt; \$Twid,
           &quot;height=i&quot;  =&gt; \$Thgt,
           &quot;tmpdir=s&quot;  =&gt; \$tmpdir,
           &quot;repeat!&quot;   =&gt; \$repeat,
           &quot;verbose!&quot;  =&gt; \$verbose);

if ($Twid &lt; 1 || $Thgt &lt; 1) {
    fatal(&quot;invalid width and/or height&quot;);
}
my $verboseCommand = $verbose ? &quot;set -x;&quot; : &quot;&quot;;

if (@ARGV &lt; 1) {
    fatal(&quot;You must specify at least one color as an argument&quot;);
} elsif (@ARGV &lt; 2 &amp;&amp; ! $repeat) {
    fatal(&quot;With the -norepeat option, you must specify at least two colors &quot; .
          &quot;as arguments.&quot;);
}

my @colorlist;

@colorlist = @ARGV;
if ($repeat) {
    push @colorlist, $ARGV[0];
}

my $ourtmp = File::Temp::tempdir(&quot;$tmpdir/ppmrainbowXXXX&quot;, UNLINK=&gt;1);

my $widthRemaining;
my $n;
my @outlist;

$n = 0;
$widthRemaining = $Twid;
@outlist = ();

while (@colorlist &gt;= 2) {
    my $outfile = sprintf(&quot;%s/file.%03u.ppm&quot;, $ourtmp, $n);
    push(@outlist, $outfile);

    my $w = int(($widthRemaining-1)/(@colorlist-1))+1;
    my $rc = system(&quot;$verboseCommand pgmramp -lr $w $Thgt | &quot; .
                    &quot;pgmtoppm \&quot;$colorlist[0]-$colorlist[1]\&quot; &gt;$outfile&quot;);
    if ($rc != 0) {
        fatal(&quot;pgmramp|pgmtoppm failed.&quot;);
    }
    $widthRemaining -= $w;
    $n++;
    shift @colorlist;
}

0 == system qq{$verboseCommand pnmcat -lr @outlist}
    or exit 1;

exit 0;

END {
    if (@outlist) {
        unlink(@outlist);
    }
    if (defined($ourtmp)) {
        rmdir($ourtmp);
    }
}
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