Image resizing without deformation

Question

I'm trying to create a thumbnail with gd library, but my thumbnail is always distorted. What I want is to cut the image starting from the center respecting a new resolution and losing the old proportion.

What I've tried:

$im = ImageCreateFromJPEG($target_file);
$n_width = 500; // Fix the width of the thumb nail images
$n_height = 500; // Fix the height of the thumb nail imaage
$width = ImageSx($im); // Original picture width is stored
$height = ImageSy($im); // Original picture height is stored
$newimage = imagecreatetruecolor($n_width, $n_height);
imagecopyresampled($newimage, $im, 0, 0, 0, 0, $n_width, $n_height, $width, $height);
$thumb_target = $target_dir . $filename_without_ext . '-thumb.' . $params['file_ext'];
ImageJpeg($newimage, $thumb_target);
chmod("$thumb_target", 0777);

Tried to change imagecreatetruecolor to imagecrop but still not with the behavior that I want.

Please let me know if I was not clear enough.

Answer 1

Solved it using ImageManipulator library. Found the solution in this answer.

My final code:

$im = new ImageManipulator($target_file);
$centreX = round($im->getWidth() / 2);
$centreY = round($im->getHeight() / 2);

$x1 = $centreX - 500;
$y1 = $centreY - 500;

$x2 = $centreX + 500;
$y2 = $centreY + 500;

$im->crop($x1, $y1, $x2, $y2);
$im->save($target_dir . $filename_without_ext . '-thumb.' . $params['file_ext']);