CodeIgniter中的多个大小调整

$config['image_library'] = 'gd2';
$config['source_image'] = 'path/to/image/file';
$config['create_thumb'] = TRUE;
$config['maintain_ratio'] = TRUE;
$config['width'] = 75;
$config['height'] = 50;

$this->load->library('image_lib', $config);

$this->image_lib->resize();

$source_image = imagecreatefromjpeg('path/to/image/file');
$thumb_width = 75;
$thumb_height = 50;

$thumb_image = imagecreatetruecolor($thumb_width, $thumb_height);

imagecopyresized($thumb_image, $source_image, 0, 0, 0, 0, $thumb_width, $thumb_height, imagesx($source_image), imagesy($source_image));

imagejpeg($thumb_image, 'path/to/thumbnail/file');

$image = new Imagick('path/to/image/file');
$thumb_width = 75;
$thumb_height = 50;

$image->resizeImage($thumb_width, $thumb_height, Imagick::FILTER_LANCZOS, 1);

$image->writeImage('path/to/thumbnail/file');