Inaccurate results from ImageMagick function queryFontMetrics - imagemagick

Question

Imagick::queryFontMetrics does not seem to be working. When I use the metrics provided by queryFontMetrics to size the image, some fonts are still being cut off. Any ideas?
Here's my code:
if (!file_exists($cache['dirname'].'/'.$cache['basename'])) {
try {
$draw = new ImagickDraw();
$draw->setFont($font_path['dirname'].'/'.$font_path['basename']);
$draw->setFontSize($size);
$draw->setGravity(Imagick::GRAVITY_CENTER);
$draw->setFillColor($color);
$canvas = new Imagick();
$metrics = $canvas->queryFontMetrics($draw, $text);
$canvas->newImage($metrics['textWidth'], $metrics['textHeight'], "transparent", "png");
$canvas->annotateImage($draw, 0, 0, 0, $text);
$canvas->setImageFormat('PNG');
mkdir($cache['dirname'], 0777, true);
$canvas->writeImage($cache['dirname'].'/'.$cache['basename']);
header("Content-Type: image/png");
echo $canvas;
$canvas->clear();
$canvas->destroy();
$draw->clear();
$draw->destroy();
} catch(Exception $e) {
// Output an error message
echo 'Error: ', $e->getMessage(), "";
}
} else {
// Output the image
$canvas = new Imagick($cache['dirname'].'/'.$cache['basename']);
header("Content-Type: image/png");
echo $canvas;
}

Answer 1

Okay, it looks like I'll be answering this one myself. After quite a bit of research, I've discovered that it's basically impossible to get correct metrics from the font itself. This is because each font designer could potentially define the metrics differently. The best way to proceed is to simply make the image much larger than necessary (to ensure that no clipping occurs) and then use the trim command: http://www.php.net/manual/en/imagick.trimimage.php.