Imager's default combining mode is "none" - which replaces the target pixel, you can supply a fill object (or get Imager to make one) that uses the "normal" mode to get the transparency effect you're after:

use strict;
use warnings;
use Imager;

my $img = Imager->new(xsize=>700, ysize => 500, channels => 4);

# setting Imager::Color->new($red, $green, $blue, $alpha);
my $blue = Imager::Color->new( 0, 0, 255, 255);
my $red = Imager::Color->new( 255, 0, 0, 63);

$img->box(color => $blue, xmin=>10, ymin=>30, xmax=>200, ymax=>300, 
      filled=> 1);
$img->box(fill => { solid => $red, combine => 'normal' }, 
      xmin=>50, ymin=>80, xmax=>250, ymax=>350);

$img->write(file => 'transbox.png')
  or die;

[download]

In reply to Re: Creating transparent images using Imager by tonyc
in thread Creating transparent images using Imager by hilitai

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