PHP imagick wrapper

ImagickFilter.php

<?php
class ImagickFilter {
    private $imagick;

    private function __construct($imagick)
	{
	    $this->imagick = clone $imagick;
		$this->imagick->profileImage('*', null);
	}
	
	public static function factoryByFile($path)
	{
	    $imagick = new Imagick($path);
	    $instance = new self($imagick);
		$imagick->destroy();

		return $instance;
	}
	
	public static function factoryByImagick($imagick)
	{
		return new self($imagick);
	}
	
	public function getImageSize()
	{
		$imagick = $this->imagick;
		
        $imagick->setFirstIterator();
        $page = $imagick->getImagePage();
        $size = $imagick->getImageGeometry();

        if ($page['width'] * $page['height'] > $size['width'] * $size['height']) {
            $size = $page;
        }

        return $size;	
	}
	
	/**
	 * 背景を決めて非透過処理を行う
	 *
	 * @param string $background [=#ffffff] #ffffffのようなImagickPixelが解釈可能な色を表す文字列
	 */
	public function nonTransparent($background = '#ffffff')
	{
        $size = $this->getImageSize();
        $base = $this->imagick->getImage();
        $base->newImage($size['width'], $size['height'], new \ImagickPixel($background));
        $base->compositeImage($this->imagick, \Imagick::COMPOSITE_DEFAULT, 0, 0, \Imagick::CHANNEL_ALL);
        $this->imagick->destroy();
        $this->imagick = $base;
	}
	
	public function toJpeg($quality = 100)
	{
	    $this->imagick->setImageFormat('JPEG');
        $this->imagick->setImageCompressionQuality($quality);
	}
	
	public function writeImageFile($filepath)
	{
	    return file_put_contents($filepath, $this->imagick->getImageBlob(), LOCK_EX);
	}
	
	public function getImagick()
	{
		return $this->imagick;
	}
}

//
if (debug_backtrace() === array()) {
    $filter = ImagickFilter::factoryByFile($tempfile);
    $filter->nonTransparent()
           ->cropImage($px, $py, $wx, $wy)
	   ->toJpeg()
	   ->writeImageFile('/tmp/test.jpg');
}