PHP image crop resize

resize_crop.php

//if the image if taller than wide, resize W to desired length then crop the top and bottom to fit
if($image_w < $image_h) {
  $tmp_h=$image_h*($new_h/$image_w);
  $tmp_big = imagecreatetruecolor($new_w, $tmp_h);
  $tmp = imagecreatetruecolor($new_w, $new_h);
  $diff = ($tmp_h - $new_h)/2;

  imagecopyresampled($tmp_big,$image,0,0,0,$diff,$new_w,$tmp_h,$image_w,$image_h); 
  imagecopyresampled($tmp,$tmp_big,0,0,0,$diff,$new_w,$new_h,$new_w,$new_h); 
                        
  imagedestroy($tmp_big);

//if the image if wider than tall, resize H to desired length then crop the left and right to fit
} elseif($image_w > $image_h) {
  $tmp_w=$image_w*($new_w/$image_h);
  $tmp_big = imagecreatetruecolor($tmp_w, $new_h);
  $tmp = imagecreatetruecolor($new_w, $new_h);
  $diff = ($tmp_w - $new_w)/2;

  imagecopyresampled($tmp_big,$image,0,0,0,0,$tmp_w,$new_h,$image_w,$image_h); 
  imagecopyresampled($tmp,$tmp_big,0,0,$diff,0,$new_w,$new_h,$new_w,$new_h); 
                        
  imagedestroy($tmp_big);
}