app2/try.php

<?php
        $stmt0 = $pdo->query("SELECT COUNT(*) AS count FROM article ");
        $row0 = $stmt0->fetch();
$rowcount = $row0[0];
$stmt1 = $pdo->query("SELECT category,COUNT(*) AS count FROM article GROUP BY category");
while ( $row1 = $stmt1->fetch(PDO::FETCH_ASSOC) ) {
  $width=5+$row1['count']/$rowcount*10;
  $height=3+$row1['count']/$rowcount*6;
  
  echo('<button type="button" style="height:'.$height.'em; width:'.$width.'em;">');
  echo($row1['category']);
  echo('</button>');

}
?>