As best I understand it, the Imager set of modules should support image transparency. However, I can't get the results I would expect from the following snippet:

use Imager;

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

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

$img->box(color => $blue, xmin=>10, ymin=>30, xmax=>200, ymax=>300, fi
+lled=> 1);
$img->box(color => $red, xmin=>50, ymin=>80, xmax=>250, ymax=>350, fil
+led=> 1);

my $outfile = "foo.png";

$img->write(file=>$outfile) or die $img->errstr;

[download]

I'd expect the resulting image to contain a blue rectangle partly covered by a semitransparent red rectangle, such that the area covered by both shapes shows as purple.

Instead, I get the blue rectangle partly offset from and completely obscured by a pale red rectangle, with nothing like what I'd call transparency.

Am I using Imager::Color incorrectly? How should transparency work?

In reply to Creating transparent images using Imager by hilitai

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