Hi, I wrote a little script using GD to "slice and dice" an image and make it a clickable html image map. It all works good, except for some pallette problems, which can be seen here. I've tried using png instead of jpg, and got the same results. A little web searching says to use gif's as your original file format, to get better palettes, but GD dosn't support gif. The problem is that the "truecolor=1" setting gives a faithful copy, but with some bad tiles. Where "truecolor=0" gives uniform results, but somewhat dergaded. Any ideas to solve this? 
#!/usr/bin/perl
use warnings;
use strict;
use GD;

my @tiles = ();
my $file = shift or die "need filename\n";
my $tempname = $file;
$tempname =~ s/^(.+)(\.\w+)$/$1/;
print "$tempname\n";

#set tile size 
my $x = 100;
my $y = 100;

#truecolor with 1 instead of 0, looks better 
#but some tile pallettes might get screwed up 
#safer with 0 
my $image = GD::Image->newFromJpeg($file,0);
my ($width,$height) = $image->getBounds();
print "width->$width   height->$height\n";

#$image->trueColorToPalette(); #dosn't help much 
                               #you can experiment 

my $rows = int($height/$y +1) - 1; #make it 0 based 
my $cols = int($width/$x + 1) - 1;
print "rows->$rows  cols->$cols\n";

foreach my $row(0..$rows){
    foreach my $col(0..$cols){
      my $imageout =  new GD::Image($x,$y);
      #$image->copy($sourceImage,$dstX,$dstY, 
       #                          $srcX,$srcY,$width,$height) 
      $imageout->copy($image,0,0,($col*$y),($row*$x),$x,$y);
      my $tilename = $tempname .'-'.$row.'-'.$col.'.jpg';
      push(@tiles,$tilename);
      open(OUT, '>', $tilename) or warn $!;
      print OUT  $imageout->jpeg;
      close OUT;
    }
}

######################################################################
+ 
#make an html page with tiles reassembled and clickable 

open(HT,">$tempname-jpg.html") or warn $!;

print HT "<html><body><h1>$tempname.jpg</h1>";
print HT "<table border=0 cellspacing=0 cellpadding=0>";

#putting border=0 in the IMG<> makes it seamless 
#I have border=1 for demonstration 
foreach my $row(0..$rows){
  print HT "<tr>";
         foreach my $col(0..$cols){
         print HT "<td><a href= $tempname-$row-$col.html> 
                   <IMG SRC=$tempname-$row-$col.jpg border=1 HEIGHT=$y
+ WIDTH=$x  
                   alt=$tempname-$row-$col.jpg></a></td>"
     }
  print HT "</tr>";
}
print HT "</table></body></html>";

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In reply to pallette problems with GD slicing images by zentara

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