Sihal has asked for the wisdom of the Perl Monks concerning the following question:

Fellow monks:
I'm trying the following thing with Image::Magick. As you can see, it's all very simple, but it segfaults when trying to write the image in wbmp format..
Does anyone have any clues? 
#!/usr/bin/perl 
use Image::Magick ;

my @files = grep { /png/ } `ls` ;

foreach my $f (@files) {
        chomp $f ;
 
        my $loc = Image::Magick->new;
        $loc->Read($f);
        $loc->Set(monochrome => "True") ;
        $loc->Set(monochrome => "True",matte =>"True") ;
        my ($w, $h, $size, $format) = $loc->Ping("$f");
        $w = 1+int(($w-1)/8);
        $w *= 8;

        my $bg = Image::Magick->new;
        $bg->Set(debug =>"All") ;
        $bg->Set(size=>$w."x$h");
#       $bg->Set(type => "Grayscale") ; 
        $bg->Set(monochrome => "True") ;
        $bg->ReadImage('xc:white');
        $bg->Composite(image=>$loc, gravity=>"Center");
        undef $loc;
        $bg->Set(monochrome => "True",matte =>"True") ;
        $bg->Write("wbmp:foo.wbmp") ;
        
last;
}

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Re: PerlMagick segfault
by PodMaster (Abbot) on Apr 07, 2003 at 08:48 UTC
    Why aren't you doing any error checking? See ICON TO BMP (using Image::Magick) for hints ;)

    Also, just use my @files = glob '*.png'; instead of that grep/ls nonsense.

    MJD says you can't just make shit up and expect the computer to know what you mean, retardo!
    I run a Win32 PPM repository for perl 5.6x+5.8x. I take requests.
    ** The Third rule of perl club is a statement of fact: pod is sexy.

[reply]
[d/l]
      True, no error checking, this was just to provide an example of what i'm trying to do...
      Apparently there seems to be an issue with the png/wbmp conversion process. Can't find any info on how to solve it though
[reply]
Re: PerlMagick segfault
by Sihal (Pilgrim) on Apr 07, 2003 at 09:39 UTC
    Okay this is how I solved it, didn't manage to find the segfault reason though, just providing a quick way to do the job: 
    

        my $mime_data = shift ;

        my ($orig, $x);
        $orig = Image::Magick->new ;
        $orig->BlobToImage($mime_data) ;
        my ($w, $h, $size, $format) = $orig->Ping(blob => $mime_data);
        $w = 1+int(($w-1)/8);
        $w *= 8;

        # Creating bg for composite image
        my $bg = Image::Magick->new ;
        $bg->Set(size=>$w."x$h",monochrome =>"True",magick =>"png");
        $bg->ReadImage('xc:white');
        $bg->Composite(image=>$orig, gravity=>"Center");
        my $blob = $bg->ImageToBlob()
        undef ($orig,$bg) ;

        my $final = Image::Magick->new ;
        $final->BlobToImage($blob) ;  
        $final->Set(magick => "wbmp") ;
        $blob = $final->ImageToBlob() ;
        undef $final ;
        return $blob ;

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[d/l]

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