#!/usr/local/bin/perl
# Name: mybin/xv2small		Author: Joe Smith <js-cgi@inwap.com> 27-Sep-97
# Purpose: Given the name of a .xvpics directory, it looks at the thumbnail
#   images there (created by xv-3.10), and creates a .small directory
#   with the thumbnails converted to 80x60 GIFs.  The names of the images
#   are sent to STDOUT in the form of an HTML table.  If no *.gif files are
#   in .xvpics, the thumbnails will be created in the current directory.
# Uses: "index.txt" to provide additional information about the pictures.
# Format of index.txt: <filename><whitespace><text>
#	filename1	description of first file
#	filename2	description of second file ...
#
$source_to_xv = "ftp.cis.upenn.edu/pub/xv/ and http://www.trilon.com/xv/";

$usage = "Usage: $0 .xvpics >index.html\n";

$small = "small";		# Directory hold the small gifs
$index_txt = "index.txt";	# Name of file with one-line descriptions
# An alternative name for index.txt can be specified as first argument.
$index_txt = shift(@ARGV) if -f $ARGV[0];

if (! @ARGV) {			# If no command line arguments
  if (-d ".xvpics") {
    push(@ARGV,".xvpics");	# Use default directory
  } else {
    print "Unable to locate the .xvpics in the current directory.\n";
    print "The 'xv' program can be found at $source_to_xv\n"
	unless -f "/usr/local/bin/xv";
    die $usage;
  }
}
die $usage unless -d $ARGV[0];	# Must have one or more .xvpics directories
foreach (@ARGV) {
  &xvpics($_);		# Do thumbnails
}
exit;

sub xvpics {
  local($xvpics) = @_;
  unless (($parent,$basename) = $xvpics =~ m%(.*/)(.*)%) {
          ($parent,$basename) = ("",$xvpics);
  }
  &make_small;		# Pass $parent, $basename, $xvpics to subroutine
  &make_table;		# Output %tabledata
}

sub make_small {
  @files = ();
  opendir(DIR,$xvpics) || return(warn("Cannot open directory $xvpics: $!\n"));
  foreach $_ (grep(!/^\./,readdir(DIR))) {
    push(@files,$_) if -s "$parent$_" > 4096;	# Skip thumbnails of thumbnails
  }; closedir(DIR);

  $gif_files = grep(/\.gif$/,@files);	# False if only *.jpg
  if ($gif_files) {
    $destdir = "$parent$small" ;
    mkdir($destdir,0775) unless -d $destdir;
  } else {
    $destdir = $parent;	# Put GIFs in current directory
  }
  %tabledata = ();
  foreach $file (@files) {
    $xv = "$xvpics/$file";
    @statxv = stat($xv);
    open(IN,$xv) || warn("Could not read $xv: $!\n");
    $_ = <IN>;		# "P7 332" for thumbnail with 3 red 3 green 2 blue bits
    $_ = <IN>;		# "#XVVERSION:Version 3.10a  Rev: 12/29/94"
    chop($_ = <IN>);	# "#IMGINFO:754x510 JPEG file  (61922 bytes)"
    close(IN);
    next unless s/#IMGINFO://;	# Skip files with "#BUILTIN:UNKNOWN"
    $imginfo = $_;
    $mtime = $statxv[9];
    if ($gif_files) {
      $sm = $file =~ /\.gif$/ ? "$destdir/$file" : "$destdir/$file.gif";
    } else {
      ($sm = "$destdir$file") =~ s/\....$/.gif/;	# Use *.gif for *.jpg
    }
    @statsm = stat($sm);	# Failure is to be expected
    if ($statsm[9] < $mtime || $statsm[7] == 0) { # If gif is old or empty
      $| = 1; print STDERR ">$sm\t\t";
      system("xvpictoppm <$xv | ppmtogif >$sm"); # Make small .gif
      utime($mtime,$mtime,$sm) || warn("Could not set mtime on $sm: $!\n");
    }
    # Determine how big the thumbnail is.  Usually 80 x 60 pixels.
    open(IN,$sm); read(IN,$string,15); close(IN);
    # 4749 4638 3761 5000 3600 A5 = GIF87a 0050 x 0036 (5 bits)
    ($magic,$width,$height,$bits) = unpack("a6 v v c",$string);
    warn("Unknown file type: $magic $width $height $bits\n")
	unless $magic =~ /GIF8\da/;
    $_  = "<tr><td rowspan=2 align=center><A HREF=\"$parent$file\"><IMG SRC=\"$sm\"";
    $_ .= " width=$width height=$height" if $width && $height;
    $_ .= " border=0></A></td>\n    <td><A HREF=\"$parent$file\">";
    $_ .= "<b>$parent$file</b></A> - $imginfo</td></tr>\n";
    $tabledata{$file} = $_;
  }
}

sub make_table {
  $file = $parent . $index_txt;		# List of names and descriptions
  if (open(IN,$file)) {
    @description = (<IN>);		# Images will be listed in this order
    close(IN);
  } else {
    warn "$file not found\n";
    @description = ();
  }
  ($file,$descr) = split(" ",$description[0],2); # First line of index.txt
  if ($file eq ".") {			# Look for ". Title"
    chop($descr);
    shift(@description);
  } else {
    $descr = "Pictures in " . $parent ? "'$parent'" : "this directory";
  }
  print "<TITLE>$descr</TITLE><H1>$descr</H1>\n";

  $_ = (keys %tabledata);		# Number of pictures
  $_ = scalar(@description) if scalar(@description) > $_;
  $pics_per_table = $_ > 20 ? 10 : $_;	# Make multiple tables if too many

  # First, do all the pictures with descriptions, putting them in the
  # same order that they are mentioned in index.txt

  $count = 0;
  foreach (@description) {		# Do images with descriptions first
    s/\015//;				# Chop off CR from MS-DOS
    ($file,$descr) = split(" ",$_,2);
    print("$descr\n"),next if $file eq ".";
    if ($file eq "" || /</) {		# Blank line or <H2>text</H2>
      print "</table>\n<p>\n" if $count > 0;
      $count = 0; $pics_per_table = 20;
      print $_;				# Output embedded HTML or blank line
      next;
    }
    next unless -f "$parent$file";	# Skip deleted pics
    chop($descr);
    print "<table border>\n" if $count == 0;
    if ($tabledata{$file}) {
      print "$tabledata{$file}<tr><td>$descr</td></tr>\n";
      delete $tabledata{$file};
    } else {				# Text files listed in "index.txt"
      next if $file =~ /\.gif$/;	# Skip listed thumbnails
      print "<tr><td rowspan=2 align=center><A HREF=\"$parent$file\">TEXT</A>";
      print "</td>\n    <td><A HREF=\"$parent$file\">";
      print "<b>$parent$file</b></A> - (", -s "$parent$file", " bytes)</td></tr>\n";
      print "<tr><td>$descr</td></tr>\n";
    }
    if (++$count == $pics_per_table) {
      print "</table>\n<p>\n";
      $count = 0;
    }
  }
  foreach $file (sort keys %tabledata) {  # Do images without descriptions
    chop($descr = `ls -l $parent$file`);
    print "<table border>\n" if $count == 0;
    print "$tabledata{$file}<tr><td>$descr</td></tr>\n";
    if (++$count == $pics_per_table) {
      print "</table>\n<p>\n";
      $count = 0;
    }
  }
  print "</table>\n<p>\n" if $count;
}