I do not know Moose in detail, so I cannot comment on the design. To not repeat yourself (DRY), though, you can use method names in variables: 
for my $att (qw/x y w h/) {
    my $predicate = "has_$att";
    $attr{$att} = $self->$att if $self->$predicate;
}

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In reply to Re: Moose attribute predicate alternative by choroba
in thread Moose attribute predicate alternative by antmico

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