Got a screenshot? The reason I ask is because I get results (1, 2) which look great. Maybe your font is corrupt? Try upgrading your copy of Image::Magick.

update: It's just your code run through perltidy with the "Tahoma Bold" font.

#!/usr/bin/perl

use strict;
use warnings;

use Image::Magick;

my $label = Image::Magick->new(
    size => "600x600",
);

$label->Read("xc:white");
$label->Draw(
    primitive => 'line',
    points    => "300,100 300,500",
    stroke    => '#600',
);

$label->Draw(
    primitive => 'line',
    points    => "100,300 500,300",
    stroke    => '#600',
);

$label->Draw(
    primitive => 'rectangle',
    points    => "100,100 500,500",
    fill      => 'none',
    stroke    => '#600',
);

my $x = $label->Annotate(
    text      => "North West",
    'x'       => 150,
    'y'       => 150,
    pointsize => 40,
    font      => $ENV{WINDIR}.'\Fonts\Tahomabd.ttf',
);

die "$x" if "$x";

$label->Write("annot2.png");
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