Memory leak with OrderedDither on user-defined threshold

[Samuel DEVULDER]

Hello!

While working with perlmagick under cygwin, I think I have found a memory leak when using OrderedDither on a user-defined threshold.

My version of (perl)Magick is:

Code: Select all

$ convert -version
Version: ImageMagick 6.7.6-3 2012-04-28 Q16 http://www.imagemagick.org
Copyright: Copyright (C) 1999-2012 ImageMagick Studio LLC
Features: OpenMP

Here is a sample self-contained perl program showing the memory leak. Notice it define a temporary HOME to prevent destroying the real ~/.magick/threshold.xml but you can bypass this part as long as you use a user-defined threshold matrix. With built-in matrices the memory usage remain stable. With user-defined matrix like the one defined by the program, the memory use will grow until all memory is exhausted:

Code: Select all

#!/bin/perl

# use a temporary ~/.magick/threshold.xml (can be disabled)
if(1) { 
my($home) = "/tmp";
$ENV{'HOME'} = $home;
mkdir($home);
mkdir("$home/.magick");
open(THR, ">$home/.magick/thresholds.xml");
print THR <<EOF;
	  <thresholds>
		 <threshold map="sd">
			<description>void and cluster 65 niveaux</description>
			<levels width="8" height="8" divisor="65">
			   35 57 19 55 7 51 4 21
			   29 6 41 27 37 17 59 45
			   61 15 53 12 62 25 33 9
			   23 39 31 49 2 47 13 43
			   3 52 8 22 36 58 20 56
			   38 18 60 46 30 5 42 28
			   63 26 34 11 64 16 54 10
			   14 48 1 44 24 40 32 50
			</levels>
		 </threshold>
	  </thresholds>
EOF
close(THR);}
	  
# real code starts here:
use Image::Magick;
$img = Image::Magick->new(size=>"256x256", depth=>16);
$img->Read("logo:");
while(1) {
	# this one causes memory leak
	$img->OrderedDither(threshold=>"sd,2");
	# this one doesn't:
	#$img->OrderedDither(threshold=>"o4x4,2");
}

This problem might show up with other version of perlmagick.

P.S.: The provided void-and-cluster dither matrix gives nice result

[magick]

We tried your script with recent versions of ImageMagick and cannot detect a leak. Consider upgrading your release of ImageMagick.

[Samuel DEVULDER]

Thanks for your reply.

Ok, I'll try to upgrade, though upgrading perl-magick under cygwin has previously been a real pain because the newly installed version refuses to work for some obscure internal reasons[*]. Hopefully this is an old story, and latest version will work like a charm
___
[*] perl-module not found in the installation but being present on isk, or some dll couldn't be loaded because it's load address clashes with another dll in spite of rebaseall'ed everything.

[Samuel DEVULDER]

Ok, I checked with

Code: Select all

$ convert -version
Version: ImageMagick 6.9.1-3 Q16 i686 2015-07-01 http://www.imagemagick.org
Copyright: Copyright (C) 1999-2015 ImageMagick Studio LLC
License: http://www.imagemagick.org/script/license.php
Features: DPC OpenMP
Delegates (built-in): autotrace bzlib cairo fftw fontconfig freetype fpx gslib jbig jng jpeg lcms lzma pangocairo png ps rsvg tiff webp x xml zlib

and the memory leak has gone.