图像在PHP中不旋转

Question

我为我的个人网站编写了一些代码来旋转图像，但是当图像旋转时，图像不能正常旋转。

/**<
 * Rotate an image (left or right)
 *
 * @param string $sImage Full path to the image
 * @param string $sCmd Command to perform. Must be "left" or "right" (without quotes)
 * @return mixed FALSE on failure, NULL on success
 */
public function rotate($sImage, $sCmd)
    {
        if (!$this->_load($sImage))
        {
            return false;
        }           

        switch ($this->_aInfo[2])
        {
            case 1:
                $hFrm = @imageCreateFromGif($this->sPath);
                break;
            case 3:
                $hFrm = @imageCreateFromPng($this->sPath);
                break;
            default:
                $hFrm = @imageCreateFromJpeg($this->sPath);               
                break;
        }       

        @unlink($this->sPath);

        if (function_exists('imagerotate'))
        {
            if ($sCmd == 'left')
            {
                $im2 = imagerotate($hFrm, 90,0);
            }
            else
            {
                $im2 = imagerotate($hFrm, 270,0);
            }
        }
        else
        {
            $wid = imagesx($hFrm);
            $hei = imagesy($hFrm);
            $im2 = imagecreatetruecolor($hei,$wid);

            switch($this->sType)
            {       
                case 'jpeg':
                case 'jpg':
                case 'jpe':
                    imagealphablending($im2, true);
                    break;          
                case 'png':
                    //imagealphablending($im2, false);
                    //imagesavealpha($im2, true);
            break;
            }            

            for($i = 0;$i < $wid; $i++)
            {
                for($j = 0;$j < $hei; $j++)
                {
                    $ref = imagecolorat($hFrm,$i,$j);
                    if ($sCmd == 'right')
                    {
                        imagesetpixel($im2,($hei - 1) - $j,$i,$ref);
                    }
                    else 
                    {
                        imagesetpixel($im2,$j, $wid - $i,$ref);
                    }
                }
            }
        }

        switch ($this->sType)
        {
            case 'gif':
                @imagegif($im2, $this->sPath);
            break;
            case 'png':
                imagealphablending($im2, false);
                imagesavealpha($im2, true);
                @imagepng($im2, $this->sPath);                              
            break;
            default:
                @imagejpeg($im2, $this->sPath);
                break;
        }       

        imagedestroy($hFrm); 
        imagedestroy($im2);

        if (Libs::getParam('core.allow_cdn'))
        {
            Libs::getLib('cdn')->put($this->sPath);
        }       
    }