<h2>Edit File: ppmfade</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
##############################################################################
#                                  ppmfade
##############################################################################
#
#  This program creates a fade (a sequence of frames) between two images.
#
#  By Bryan Henderson, Olympia WA; March 2000
#
#  Contributed to the public domain by its author.
#
#  Inspired by the program Pbmfade by Wesley C. Barris of AHPCRC,
#  Minnesota Supercomputer Center, Inc. January 7, 1994.  Pbmfade does
#  much the same thing, but handles non-Netpbm formats too, and is 
#  implemented in a more primitive language.
#
##############################################################################
use strict;
use File::Temp &quot;tempdir&quot;;

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 $termStatus = system(&#039;ppmmix&#039;, &#039;--version&#039;);
        exit($termStatus == 0 ? 0 : 1);
    }
}


my $SPREAD =  1;
my $SHIFT =   2;
my $RELIEF =  3;
my $OIL =     4;
my $EDGE =    5;
my $BENTLEY = 6;
my $BLOCK =   7;
my $MIX =     8;
#
#  Set some defaults.
#
my $nframes = 30;			# total number of files created (1 sec)
my $first_file = &quot;undefined&quot;;
my $last_file = &quot;undefined&quot;;
my $base_name = &quot;fade&quot;;		# default base name of output files
my $image = &quot;ppm&quot;;		# default output storage format
my $mode = $SPREAD;		# default fading mode

doVersionHack(\@ARGV);

my $n;  # argument number

for ($n = 0; $n &lt; @ARGV; $n++) {
    if (&quot;$ARGV[$n]&quot; eq &quot;-f&quot;) {
        $n++;
        $first_file = $ARGV[$n];
        if (-e $first_file) {
        } else {
            print &quot;I can&#039;t find first file &#039;$first_file&#039;\n&quot;;
            exit 1;
        }
    } elsif ($ARGV[$n] eq &quot;-l&quot;) {
        $n++;
        $last_file = $ARGV[$n];
        if (-e $last_file) {
        } else {
            print &quot;I can&#039;t find last file &#039;$last_file&#039;\n&quot;;
            exit 1;
        }
    } elsif ($ARGV[$n] eq &quot;-base&quot;) {
        $n++;
        $base_name = $ARGV[$n];
    } elsif ($ARGV[$n] eq &quot;-spread&quot;) {
        $mode = $SPREAD;
    } elsif ($ARGV[$n] eq &quot;-shift&quot;) {
        $mode = $SHIFT;
    } elsif ($ARGV[$n] eq &quot;-relief&quot;) {
        $mode = $RELIEF;
    } elsif ($ARGV[$n] eq &quot;-oil&quot;) {
        $mode = $OIL;
    } elsif (&quot;$ARGV[$n]&quot; eq &quot;-edge&quot;) {
        $mode = $EDGE;
    } elsif (&quot;$ARGV[$n]&quot; eq &quot;-bentley&quot;) {
        $mode = $BENTLEY;
    } elsif (&quot;$ARGV[$n]&quot; eq &quot;-block&quot;) {
        $mode = $BLOCK;
    } elsif (&quot;$ARGV[$n]&quot; eq &quot;-mix&quot;) {
        $mode = $MIX;
    } elsif ($ARGV[$n] eq &quot;-help&quot; || $ARGV[$n] eq &quot;--help&quot; || $ARGV[$n] eq &quot;-h&quot;) {
        print &quot;ppmfade: Use &#039;man ppmfade&#039; for help.\n&quot;;
        exit 1;
    } else {
        print &quot;Unknown argument: $ARGV[$n]\n&quot;;
        exit 1;
    } 
}
#
#  Define a couple linear ramps.
#
# We don&#039;t use element 0 of these arrays.
my @spline10 = (0, 0, 0.11, 0.22, 0.33, 0.44, 0.55, 0.66, 0.77, 0.88, 1.0);
my @spline20 = (0, 0, 0.05, 0.11, 0.16, 0.21, 0.26, 0.32, 0.37, 0.42, 0.47, 
                0.53, 0.58, 0.63, 0.69, 0.74, 0.79, 0.84, 0.89, 0.95, 1.0);
#
#  Just what are we supposed to do?
#
my ($height, $width);    # width and height of our frames
if ($first_file ne &quot;undefined&quot;) {
    if ((`pnmfile $first_file` =~ m{\b(\d+)\sby\s(\d+)} )) { 
        $width = $1; $height = $2;
    } else {
        print(&quot;Unrecognized results from pnmfile on $first_file.\n&quot;);
        exit 1;
    }
} elsif ($last_file ne &quot;undefined&quot;) {
    if ((`pnmfile $last_file` =~ m{\b(\d+)\sby\s(\d+)} )) { 
        $width = $1; $height = $2;
    } else {
        print(&quot;Unrecognized results from pnmfile on $first_file.\n&quot;);
        exit 1;
    }
} else {
    print(&quot;ppmfade:  You must specify -f or -l (or both)\n&quot;);
    exit 1;
}

print(&quot;Frames are &quot; . $width . &quot;W x &quot; . $height . &quot;H\n&quot;);

#
# We create a tmp-directory right here
#
my $tmpdir = tempdir(&quot;ppmfade.XXXXXX&quot;, CLEANUP =&gt; 1);


if ($first_file eq &quot;undefined&quot;) {
    print &quot;Fading from black to &quot;;
    system(&quot;ppmmake \\#000 $width $height &gt;$tmpdir/junk1$$.ppm&quot;);
} else {
    print &quot;Fading from $first_file to &quot;;
    system(&quot;cp&quot;, $first_file, &quot;$tmpdir/junk1$$.ppm&quot;);
}

if ($last_file eq &quot;undefined&quot;) {
    print &quot;black.\n&quot;;
    system(&quot;ppmmake \\#000 $width $height &gt;$tmpdir/junk2$$.ppm&quot;);
} else {
    print &quot;$last_file\n&quot;;
    system(&quot;cp&quot;, $last_file, &quot;$tmpdir/junk2$$.ppm&quot;);
}

#
#  Perform the fade.
#

# Here&#039;s what our temporary files are:
#   $tmpdir/junk1$$.ppm: The original (fade-from) image
#   $tmpdir/junk2$$.ppm: The target (fade-from) image
#   $tmpdir/junk3$$.ppm: The frame of the fade for the current iteration of the 
#                	 the for loop.
#   $tmpdir/junk1a$$.ppm: If the fade involves a ppmmix sequence from one intermediate
#                         image to another, this is the first frame of that 
#                         sequence.
#   $tmpdir/junk2a$$.ppm: This is the last frame of the above-mentioned ppmmix sequence

my $i;    # Frame number
for ($i = 1; $i &lt;= $nframes; $i++) {
    print(&quot;Creating $i of $nframes...\n&quot;);
    if ($mode eq $SPREAD) {
        if ($i &lt;= 10) {
            my $n = $spline20[$i] * 100;
            system(&quot;ppmspread $n $tmpdir/junk1$$.ppm &gt;$tmpdir/junk3$$.ppm&quot;);
        } elsif ($i &lt;= 20) {
            my $n;
            $n = $spline20[$i] * 100;
            system(&quot;ppmspread $n $tmpdir/junk1$$.ppm &gt;$tmpdir/junk1a$$.ppm&quot;);
            $n = (1-$spline20[$i-10]) * 100;
            system(&quot;ppmspread $n $tmpdir/junk2$$.ppm &gt;$tmpdir/junk2a$$.ppm&quot;);
            $n = $spline10[$i-10];
            system(&quot;ppmmix $n $tmpdir/junk1a$$.ppm $tmpdir/junk2a$$.ppm &gt;$tmpdir/junk3$$.ppm&quot;);
        } else {
            my $n = (1-$spline20[$i-10])*100;
            system(&quot;ppmspread $n $tmpdir/junk2$$.ppm &gt;$tmpdir/junk3$$.ppm&quot;);
        }
    } elsif ($mode eq $SHIFT) {
        if ($i &lt;= 10) {
            my $n = $spline20[$i] * 100;
            system(&quot;ppmshift $n $tmpdir/junk1$$.ppm &gt;$tmpdir/junk3$$.ppm&quot;);
        } elsif ($i &lt;= 20) {
            my $n;
            $n = $spline20[$i] * 100;
            system(&quot;ppmshift $n $tmpdir/junk1$$.ppm &gt;$tmpdir/junk1a$$.ppm&quot;);
            $n = (1-$spline20[$i-10])*100;
            system(&quot;ppmshift $n $tmpdir/junk2$$.ppm &gt;$tmpdir/junk2a$$.ppm&quot;);
            $n = $spline10[$i-10];
            system(&quot;ppmmix $n $tmpdir/junk1a$$.ppm $tmpdir/junk2a$$.ppm &gt;$tmpdir/junk3$$.ppm&quot;);
        } else {
            my $n = (1-$spline20[$i-10]) * 100;
            system(&quot;ppmshift $n $tmpdir/junk2$$.ppm &gt;$tmpdir/junk3$$.ppm&quot;);
        }
    } elsif ($mode eq $RELIEF) {
        if ($i == 1) {
            system(&quot;ppmrelief $tmpdir/junk1$$.ppm &gt;$tmpdir/junk1r$$.ppm&quot;);
        }
        if ($i &lt;= 10) {
            my $n = $spline10[$i];
            system(&quot;ppmmix $n $tmpdir/junk1$$.ppm $tmpdir/junk1r$$.ppm &gt;$tmpdir/junk3$$.ppm&quot;);
        } elsif ($i &lt;= 20) {
            my $n = $spline10[$i-10];
            system(&quot;ppmmix $n $tmpdir/junk1r$$.ppm $tmpdir/junk2r$$.ppm &gt;$tmpdir/junk3$$.ppm&quot;);
        } else {
            my $n = $spline10[$i-20];
            system(&quot;ppmmix $n $tmpdir/junk2r$$.ppm $tmpdir/junk2$$.ppm &gt;$tmpdir/junk3$$.ppm&quot;);
        }
        if ($i == 10) {
            system(&quot;ppmrelief $tmpdir/junk2$$.ppm &gt;$tmpdir/junk2r$$.ppm&quot;);
        }
    } elsif ($mode eq $OIL) {
        if ($i == 1) {
            system(&quot;ppmtopgm $tmpdir/junk1$$.ppm | pgmoil &gt;$tmpdir/junko$$.ppm&quot;);
            system(&quot;rgb3toppm $tmpdir/junko$$.ppm $tmpdir/junko$$.ppm $tmpdir/junko$$.ppm &quot; .
                   &quot;&gt;$tmpdir/junk1o$$.ppm&quot;);
        }
        if ($i &lt;= 10) {
            my $n = $spline10[$i];
            system(&quot;ppmmix $n $tmpdir/junk1$$.ppm $tmpdir/junk1o$$.ppm &gt;$tmpdir/junk3$$.ppm&quot;);
        } elsif ($i &lt;= 20) {
            my $n = $spline10[$i-10];
            system(&quot;ppmmix $n $tmpdir/junk1o$$.ppm $tmpdir/junk2o$$.ppm &gt;$tmpdir/junk3$$.ppm&quot;);
        } else {
            my $n = $spline10[$i-20];
            system(&quot;ppmmix $n $tmpdir/junk2o$$.ppm $tmpdir/junk2$$.ppm &gt;$tmpdir/junk3$$.ppm&quot;);
        }
        if ($i == 10) {
            system(&quot;ppmtopgm $tmpdir/junk2$$.ppm | pgmoil &gt;$tmpdir/junko$$.ppm&quot;);
            system(&quot;rgb3toppm $tmpdir/junko$$.ppm $tmpdir/junko$$.ppm $tmpdir/junko$$.ppm &quot; .
                   &quot;&gt;$tmpdir/junk2o$$.ppm&quot;);
        }
    } elsif ($mode eq $EDGE) {
        if ($i == 1) {
            system(&quot;ppmtopgm $tmpdir/junk1$$.ppm | pgmedge &gt;$tmpdir/junko$$.ppm&quot;);
            system(&quot;rgb3toppm $tmpdir/junko$$.ppm $tmpdir/junko$$.ppm $tmpdir/junko$$.ppm &quot; .
                   &quot;&gt;$tmpdir/junk1o$$.ppm&quot;);
        }
        if ($i &lt;= 10) {
            my $n = $spline10[$i];
            system(&quot;ppmmix $n $tmpdir/junk1$$.ppm $tmpdir/junk1o$$.ppm &gt;$tmpdir/junk3$$.ppm&quot;);
        } elsif ($i &lt;= 20) {
            my $n = $spline10[$i-10];
            system(&quot;ppmmix $n $tmpdir/junk1o$$.ppm $tmpdir/junk2o$$.ppm &gt;$tmpdir/junk3$$.ppm&quot;);
        } else {
            my $n = $spline10[$i-20];
            system(&quot;ppmmix $n $tmpdir/junk2o$$.ppm $tmpdir/junk2$$.ppm &gt;$tmpdir/junk3$$.ppm&quot;);
        }
        if ($i == 10) {
            system(&quot;ppmtopgm $tmpdir/junk2$$.ppm | pgmedge &gt;$tmpdir/junko$$.ppm&quot;);
            system(&quot;rgb3toppm $tmpdir/junko$$.ppm $tmpdir/junko$$.ppm $tmpdir/junko$$.ppm &quot; .
                   &quot;&gt;$tmpdir/junk2o$$.ppm&quot;);
        } 
    } elsif ($mode eq $BENTLEY) {
        if ($i == 1) {
            system(&quot;ppmtopgm $tmpdir/junk1$$.ppm | pgmbentley &gt;$tmpdir/junko$$.ppm&quot;);
            system(&quot;rgb3toppm $tmpdir/junko$$.ppm $tmpdir/junko$$.ppm $tmpdir/junko$$.ppm &quot; .
                   &quot;&gt;$tmpdir/junk1o$$.ppm&quot;);
        }
        if ($i &lt;= 10) {
            my $n = $spline10[$i];
            system(&quot;ppmmix $n $tmpdir/junk1$$.ppm $tmpdir/junk1o$$.ppm &gt;$tmpdir/junk3$$.ppm&quot;);
        } elsif ($i &lt;= 20) {
            my $n = $spline10[$i-10];
            system(&quot;ppmmix $n $tmpdir/junk1o$$.ppm $tmpdir/junk2o$$.ppm &gt;$tmpdir/junk3$$.ppm&quot;);
        } else {
            my $n = $spline10[$i-20];
            system(&quot;ppmmix $n $tmpdir/junk2o$$.ppm $tmpdir/junk2$$.ppm &gt;$tmpdir/junk3$$.ppm&quot;);
        }
        if ($i == 10) {
            system(&quot;ppmtopgm $tmpdir/junk2$$.ppm | pgmbentley &gt;$tmpdir/junko$$.ppm&quot;);
            system(&quot;rgb3toppm $tmpdir/junko$$.ppm $tmpdir/junko$$.ppm $tmpdir/junko$$.ppm &quot; .
                   &quot;&gt;$tmpdir/junk2o$$.ppm&quot;);
        }
    } elsif ($mode eq $BLOCK) {
        if ($i &lt;= 10) {
            my $n = 1 - 1.9*$spline20[$i];
            system(&quot;pamscale $n $tmpdir/junk1$$.ppm | &quot; .
                   &quot;pamscale -width $width -height $height &gt;$tmpdir/junk3$$.ppm&quot;);
        } elsif ($i &lt;= 20) {
            my $n = $spline10[$i-10];
            system(&quot;ppmmix $n $tmpdir/junk1a$$.ppm $tmpdir/junk2a$$.ppm &gt;$tmpdir/junk3$$.ppm&quot;);
        } else {
            my $n = 1 - 1.9*$spline20[31-$i];
            system(&quot;pamscale $n $tmpdir/junk2$$.ppm | &quot; .
                   &quot;pamscale -width $width -height $height &gt;$tmpdir/junk3$$.ppm&quot;);
        }
        if ($i == 10) {
            system(&quot;cp&quot;, &quot;$tmpdir/junk3$$.ppm&quot;, &quot;$tmpdir/junk1a$$.ppm&quot;);
            system(&quot;pamscale $n $tmpdir/junk2$$.ppm | &quot; .
                   &quot;pamscale -width $width -height $height &gt;$tmpdir/junk2a$$.ppm&quot;);
        }    
    } elsif ($mode eq $MIX) {
        my $fade_factor = sqrt(1/($nframes-$i+1));
        system(&quot;ppmmix $fade_factor $tmpdir/junk1$$.ppm $tmpdir/junk2$$.ppm &gt;$tmpdir/junk3$$.ppm&quot;);
    } else {
        print(&quot;Internal error: impossible mode value &#039;$mode&#039;\n&quot;);
    }

    my $outfile = sprintf(&quot;%s.%04d.ppm&quot;, $base_name, $i);
    system(&quot;cp&quot;, &quot;$tmpdir/junk3$$.ppm&quot;, $outfile);
}

#
#  Clean up shop.
#
system(&quot;rm $tmpdir/junk*$$.ppm&quot;);

exit(0);
</textarea><br><input type="hidden" name="edit_file" value="ppmfade"><input type="submit" value="Save"></form>