制作或使用什么样的库，以便通过调整Symfony 3.0配置来调整图像的大小

你好，我的渐近 3.0 项目我想创建一个库，当构建时从 config.yml 读取这些参数：

• max_width
• max_height

该库将读取它们，并将执行图像大小调整为 config.yml 或任何其他读取配置方式提供的这些尺寸。

为了更清楚，我有这个实体：

<?php
namespace AppBundle'Entity;
use Doctrine'ORM'Mapping as ORM;
use Symfony'Component'Validator'Constraints as Assert;
use Symfony'Component'HttpFoundation'File'UploadedFile;
use Symfony'Component'Filesystem'Filesystem;
/**
* @ORM'Entity
* @ORM'Table(name="images")
* @ORM'Entity(repositoryClass="AppBundle'Entity'ImagesRepository")
* @ORM'HasLifecycleCallbacks
*/
class Images
{
    /**
     * @ORM'Column(type="string", length=60)
     * @ORM'Id
     * @ORM'GeneratedValue(strategy="CUSTOM")
     * @ORM'CustomIdGenerator(class="AppBundle'Doctrine'AutoIdGenerate")
     */
    private $id;
    /**
    * Filename of the Image
    * @ORM'Column(type="string", length=100)
    */
    private $name;
    /**
    * Filename of the Thumbnail
    * @ORM'Column(type="string", length=100)
    */
    private $name_small;
    /**
    * ImageGroup og the Image
    * @ORM'ManyToOne(targetEntity="AppBundle'Entity'ImageGroups", inversedBy="images")
    */
    private $group;

    /**
     * @Assert'File(maxSize="20000000")
     */
    private $file;
    private $upload_dir='images';
    private $temp;
    /**
     * Get file.
     *
     * @return UploadedFile
     */
    public function getFile()
    {
        return $this->file;
    }
    /**
     * Sets file.
     *
     * @param UploadedFile $file
     */
    public function setFile(UploadedFile $file,$upload_dir)
    {
        $this->file = $file;
        // check if we have an old image path
        if (isset($this->name))
        {
            // store the old name to delete after the update
            $this->temp = $this->name;
            $this->name = null;
        }
        else
        {
            $this->name = sha1(uniqid(mt_rand(), true)).'.'.$file->guessExtension();
        }
        $this->name_small="small_".$this->name;
        $this->upload_dir=$upload_dir;
        return $this;
    }
    /**
     * @ORM'PrePersist()
     * @ORM'PreUpdate()
     */
    public function preUpload()
    {
        if (null !== $this->getFile())
        {
            // do whatever you want to generate a unique name
            $filename = sha1(uniqid(mt_rand(), true));
            $this->name = $filename.'.'.$this->getFile()->guessExtension();
            $this->name_small='small_'.$this->name;
        }
    }
    /**
    *Getting the directory that will upload the file
    */
    public function getUploadRootDir()
    {
      $dir= __DIR__.'/../../../web/'.$this->upload_dir;
      return $dir;
    }

    /**
     * @ORM'PostPersist()
     * @ORM'PostUpdate()
     */
    public function upload()
    {
        if (null === $this->getFile())
        {
            return;
        }
        // if there is an error when moving the file, an exception will
        // be automatically thrown by move(). This will properly prevent
        // the entity from being persisted to the database on error
        //-- Make the Thumbnail Here --
        $dir=$this->getUploadRootDir();
        $fs = new Filesystem();
        if(!$fs->exists($dir))
        {
          $fs->mkdir($dir,0777,true);
        }
        $file=$this->getFile();
        $file->move($dir, $this->name);
        // check if we have an old image
        if (isset($this->temp))
        {
            // delete the old image
            unlink($this->getUploadRootDir().'/'.$this->temp);
            // clear the temp image path
            $this->temp = null;
        }
        $this->file = null;
    }
    /**
     * @ORM'PostRemove()
     */
    public function removeUpload()
    {
        $file = $this->getUploadRootDir();
        error_reporting(E_ERROR | E_PARSE); //If the file does not exist just ingore the warning
        if (file_exists($file.'/'.$this->name)===true)
        {
            unlink($file.'/'.$this->name);
        }
        if(file_exists($file.'/'.$this->name_small)===true);
        {
          unlink($file.'/'.$this->name_small);
        }
        error_reporting(E_ERROR | E_WARNING | E_PARSE | E_NOTICE);//But we want warnings back
    }

    /**
     * Get id
     *
     * @return string
     */
    public function getId()
    {
        return $this->id;
    }

    /**
     * Get name
     *
     * @return string
     */
    public function getName()
    {
        return $this->name;
    }
    /**
     * Get nameSmall
     *
     * @return string
     */
    public function getNameSmall()
    {
        return $this->name_small;
    }
    /**
     * Set group
     *
     * @param 'AppBundle'Entity'ImageGroups $group
     *
     * @return Images
     */
    public function setGroup('AppBundle'Entity'ImageGroups $group = null)
    {
        $this->group = $group;
        return $this;
    }
    /**
     * Get group
     *
     * @return 'AppBundle'Entity'ImageGroups
     */
    public function getGroup()
    {
        return $this->group;
    }
    /**
     * Set name
     *
     * @param string $name
     *
     * @return Images
     */
    public function setName($name)
    {
        $this->name = $name;
        return $this;
    }
    /**
     * Set nameSmall
     *
     * @param string $nameSmall
     *
     * @return Images
     */
    public function setNameSmall($nameSmall)
    {
        $this->name_small = $nameSmall;
        return $this;
    }
}

如您所见，上面的实体具有 Doctrine 触发器。内部函数上传我想调用：

new ImageProcessor($image_path,$extention)->to_thumb($filename) 

这将从config.yml读取max_width和max_height，并将执行图像大小调整。图像处理器将是进行任何类型的图像处理（如裁剪，调整大小等）的库。

问题不在于如何调整图像大小，而在于如何使这个库可重新订阅并通过 config.yml 轻松配置。我找不到一个好的教程或手册来做到这一点。