Generate thumbnail image class in php_PHP tutorial

class resizeimage
{
//Image type
var $type;
//Actual width
var $width;
//Actual height
var $height;
//Changed width
var $resize_width;
//Height after change
var $resize_height;
//Whether to crop the image
var $cut;
//Source image
var $srcimg;
//Target image address
var $dstimg;
//Temporarily created image
var $im;
Function resizeimage($img, $wid, $hei,$c,$dstpath)
{ 
           $this->srcimg = $img;                                           $this->resize_width = $wid;                                              $this->resize_height = $hei;                                                  $this->cut = $c;                                 //Type of image

$this->type = strtolower(substr(strrchr($this->srcimg,"."),1));
//Initialize image
           $this->initi_img();                              //Target image address
          $this -> dst_img($dstpath);
           //--                                                                $this->width = imagesx($this->im); 
           $this->height = imagesy($this->im); 
//Generate image
$this->newimg();
ImageDestroy ($this->im);
}  
Function newimg()
{ 
//The proportion of the changed image
         $resize_ratio = ($this->resize_width)/($this->resize_height);
//Proportion of actual image
         $ratio = ($this->width)/($this->height);
If(($this->cut)=="1")
// Creed                                                                                    If($ratio>=$resize_ratio)
//High priority
                                                                     $newimg = imagecreatetruecolor($this->resize_width,$this->resize_height);
imagecopyresampled($newimg, $this->im, 0, 0, 0, 0, $this->resize_width,$this->resize_height, (($this->height)*$resize_ratio), $this ->height);
ImageJpeg ($newimg,$this->dstimg);
                                                                                                                                If($ratio<$resize_ratio)
//Width first
                                                                     $newimg = imagecreatetruecolor($this->resize_width,$this->resize_height);
imagecopyresampled($newimg, $this->im, 0, 0, 0, 0, $this->resize_width, $this->resize_height, $this->width, (($this->width) /$resize_ratio));
ImageJpeg ($newimg,$this->dstimg);
                                                                                                                                                                                                                                                      else
//No cropping
                                                                                   If($ratio>=$resize_ratio)
                                                                                          $newimg = imagecreatetruecolor($this->resize_width,($this->resize_width)/$ratio);
imagecopyresampled($newimg, $this->im, 0, 0, 0, 0, $this->resize_width, ($this->resize_width)/$ratio, $this->width, $this-> ;height);
ImageJpeg ($newimg,$this->dstimg);
                                                                                                                                If($ratio<$resize_ratio)
                                                                                    $newimg = imagecreatetruecolor(($this->resize_height)*$ratio,$this->resize_height); 
                imagecopyresampled($newimg, $this->im, 0, 0, 0, 0, ($this->resize_height)*$ratio, $this->resize_height, $this->width, $this->height); 
                ImageJpeg ($newimg,$this->dstimg); 
            } 
        } 
    } 
    //初始化图象 
    function initi_img() 
    { 
        if($this->type=="jpg") 
        { 
            $this->im = imagecreatefromjpeg($this->srcimg); 
        } 
        if($this->type=="gif") 
        { 
            $this->im = imagecreatefromgif($this->srcimg); 
        } 
        if($this->type=="png") 
        { 
            $this->im = imagecreatefrompng($this->srcimg); 
        } 
    } 
    //图象目标地址 
    function dst_img($dstpath) 
    { 
        $full_length  = strlen($this->srcimg); 
        $type_length  = strlen($this->type); 
        $name_length  = $full_length-$type_length; 

        $name         = substr($this->srcimg,0,$name_length-1); 
        $this->dstimg = $dstpath; 

//echo $this->dstimg; 
    } 
} 

$resizeimage = new resizeimage("11.jpg", "200", "150", "1","17.jpg"); 
?>

/**
* Generate thumbnail
* @author yangzhiguo0903@163.com
* @param string The absolute complete address of the source image {with file name and suffix}
* @param string The absolute complete address of the target image {with file name and suffix}
* @param int Thumbnail width {0: At this time, the target height cannot be 0, and the target width is the source image width * (target height/source image height)}
* @param int Thumbnail height {0: At this time, the target width cannot be 0, and the target height is the source image height * (target width/source image width)}
* @param int Whether to crop {width and height must be non-0}
* @param int/float Scale {0: No scaling, 0 * @return boolean
​*/
function img2thumb($src_img, $dst_img, $width = 75, $height = 75, $cut = 0, $proportion = 0)
{
    if(!is_file($src_img))
    {
        return false;
    }
    $ot = fileext($dst_img);
    $otfunc = 'image' . ($ot == 'jpg' ? 'jpeg' : $ot);
    $srcinfo = getimagesize($src_img);
    $src_w = $srcinfo[0];
    $src_h = $srcinfo[1];
    $type  = strtolower(substr(image_type_to_extension($srcinfo[2]), 1));
    $createfun = 'imagecreatefrom' . ($type == 'jpg' ? 'jpeg' : $type);

    $dst_h = $height;
    $dst_w = $width;
    $x = $y = 0;

    /**
* * The thumbnail should not exceed the size of the source image (provided there is only one width or height)
​​*/
    if(($width> $src_w && $height> $src_h) || ($height> $src_h && $width == 0) || ($width> $src_w && $height == 0))
    {
        $proportion = 1;
    }
    if($width> $src_w)
    {
        $dst_w = $width = $src_w;
    }
    if($height> $src_h)
    {
        $dst_h = $height = $src_h;
    }

    if(!$width && !$height && !$proportion)
    {
        return false;
    }
    if(!$proportion)
    {
        if($cut == 0)
        {
            if($dst_w && $dst_h)
            {
                if($dst_w/$src_w> $dst_h/$src_h)
                {
                    $dst_w = $src_w * ($dst_h / $src_h);
                    $x = 0 - ($dst_w - $width) / 2;
                }
                else
                {
                    $dst_h = $src_h * ($dst_w / $src_w);
                    $y = 0 - ($dst_h - $height) / 2;
                }
            }
            else if($dst_w xor $dst_h)
            {
                if($dst_w && !$dst_h)  //有宽无高
                {
                    $propor = $dst_w / $src_w;
                    $height = $dst_h  = $src_h * $propor;
                }
                else if(!$dst_w && $dst_h)  //有高无宽
                {
                    $propor = $dst_h / $src_h;
                    $width  = $dst_w = $src_w * $propor;
                }
            }
        }
        else
        {
            if(!$dst_h)  //裁剪时无高
            {
                $height = $dst_h = $dst_w;
            }
            if(!$dst_w)  //裁剪时无宽
            {
                $width = $dst_w = $dst_h;
            }
            $propor = min(max($dst_w / $src_w, $dst_h / $src_h), 1);
            $dst_w = (int)round($src_w * $propor);
            $dst_h = (int)round($src_h * $propor);
            $x = ($width - $dst_w) / 2;
            $y = ($height - $dst_h) / 2;
        }
    }
    else
    {
        $proportion = min($proportion, 1);
        $height = $dst_h = $src_h * $proportion;
        $width  = $dst_w = $src_w * $proportion;
    }

    $src = $createfun($src_img);
    $dst = imagecreatetruecolor($width ? $width : $dst_w, $height ? $height : $dst_h);
    $white = imagecolorallocate($dst, 255, 255, 255);
    imagefill($dst, 0, 0, $white);

    if(function_exists('imagecopyresampled'))
    {
        imagecopyresampled($dst, $src, $x, $y, 0, 0, $dst_w, $dst_h, $src_w, $src_h);
    }
    else
    {
        imagecopyresized($dst, $src, $x, $y, 0, 0, $dst_w, $dst_h, $src_w, $src_h);
    }
    $otfunc($dst, $dst_img);
    imagedestroy($dst);
    imagedestroy($src);
    return true;
}