Wrong aspect ratio calculation?

Question

PHP

Script to bring all images to the same aspect ratio without stretching (overlaying on a white background)
But, for some reason, in fact, there is an error of several pixels in the aspect ratio. How to fix it?

<?php
 
$fnamefoto = $_GET['name'];
$img = new Imagick();
$img->readImage('/var/www/localhost/files/images/'.$fnamefoto);
$img->setImageFormat('jpeg');
$val = $img->getImageWidth() / $img->getImageHeight();
if ($val > 1.77272727273) {
    $height = intval($img->getImageHeight() + ($img->getImageHeight() * ($val - 1.77272727273)));
    $width = $img->getImageWidth();
} else {
    $width = intval($img->getImageWidth() + ($img->getImageWidth() * (1.77272727273 - $val)));
    $height = $img->getImageHeight();
}
$canvas = new Imagick();
$canvas->newImage($width, $height, 'white', 'jpg');
$geometry = $img->getImageGeometry();
$x = ($width - $geometry['width']) / 2;
$y = ($height - $geometry['height']) / 2;
$canvas->compositeImage($img, imagick::COMPOSITE_OVER, $x, $y);
$canvas->writeImage('/var/www/localhost/files/images/'.$fnamefoto);

Answer 1

Somehow you have too difficult to calculate everything.

$width = $img->getImageWidth();
$height = $img->getImageHeight();
if ($height*16 > $width*9) {
  $width = $height*16/9;
} else {
  $height = $width*9/16;
}

Answer 2

You do floating point calculations exactly, but then round up to an integer, and so on twice. Here is the difference.