my $pdf = PDF::API2->open($file);
my $f1 = $pdf->corefont('Times', -encode => 'latin1' );
my $ppage = $pdf->openpage(1);
my $gfx = $ppage->gfx;

$gfx->textlabel(15, 15, $f1, 12, "Wahoo!", -color => 'red');

$pdf->saveas("/tmp/foo.pdf");