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zentara wrote:
> On Mon, 03 Nov 2008 16:12:55 +0100, Josef Moellers
> <> wrote:
>
>
>> It seems that it has to do with the fact that I have a transparent
>> background ...
>
> Guess to remove layer:
> Try adding the flatten option.

I've tried to call $img->Flatten() and $img->Layers(method =>
'flatten'), none of which worked.

Josef
--
These are my personal views and not those of Fujitsu Siemens Computers!
Josef Möllers (Pinguinpfleger bei FSC)
If failure had no penalty success would not be a prize (T. Pratchett)
Company Details: http://www.fujitsu-siemens.com/imprint.html

On Tue, 04 Nov 2008 13:53:57 +0100, Josef Moellers
<> wrote:

>zentara wrote:
>> On Mon, 03 Nov 2008 16:12:55 +0100, Josef Moellers
>> <> wrote:
>>
>>
>>> It seems that it has to do with the fact that I have a transparent
>>> background ...
>>
>> Guess to remove layer:
>> Try adding the flatten option.
>
>I've tried to call $img->Flatten() and $img->Layers(method =>
>'flatten'), none of which worked.
>
>Josef

This worked for me:
tig.png is a green curve on a transparent alpha layer

tig.png PNG 32x32 32x32+0+0 8-bit DirectClass 5.4e+02b
#after script is run
tig-4c.png PNG 32x32 32x32+0+0 8-bit PseudoClass 4c 3e+02b

#!/usr/bin/perl
use warnings;
use strict;
use Image::Magick;
use MIME::Base64;

# tig.png is a green curve written on a transparent layer
# included here so we are on same page
my $blob = decode_base64(
'iVBORw0KGgoAAAANSUhEUgAAACAAAAAgCAYAAABzenr0AAAAB mJLR0QA/wD/AP+gvaeTAAAACXBI
WXMAAAsTAAALEwEAmpwYAAABwUlEQVRYw+2VvS8EURTFf8/4CKJQTKOgEIlEqFCIRnSUhE6iUOhV
Go3Kf0ChkiipNWqFQuErEtFJSEREfO7O0dyNid2Z3X3sbmHfy8 2bdzPv3TPnnnvHSaKWo4EajzqA
OoBGn0MOl+cT+l8pmANugEdb53wBuHIbkdGfAYKYOws0+qTBl4 GgyL5ehhUHcFVkX3ERfm9jraAq
IrQgLmbewX+TghcgsvKLAFVbA895xFQLgMOFQHstq2ACaMnD5T sklWyIEPGMiFDe3C7nrpyVy8AI
0JaQ81mHO3C4oJIp2E0R3TswBKxWJAWIW6M+W4D+LOLd7BaxWP q9xQP3I64teITIxAIvIc7t+dPW
N8QdIvwrAKex4PG5guhAjMd8T8bCh4m13wuAqX0H8ZCg+GlEA6 IV0YZYLvBOZKycIcaSADhJuebS
B0wCvcAUECbIZgC4AJqAZhNfaNWxA4wWOBMBl8AecAIc2n/lHsQ8Yh9xYvQlzW3EIKIZ0fKDsU7z
dyO2TANKYCWyFB0jZkgJmJsZxIZRHqRoBYQzG0AclXD3axqAF8 SaT3czED2ILsRmKoQCrjvEQtrX
egAKEMOI9R9lHH0BkYPO/OE8jeIAAAAASUVORK5CYII=');

my $img = Image::Magick->new(magick=>'png');
$img->BlobToImage( $blob );
$img->Write('tig.png');

$img->Quantize( colors => 4 );
$img->Set( type => 'Palette' );
$img->Write("tig-4c.png");
__END__

I'm using IM-6.4.3

Maybe your libpng is defective?

zentara