Code sharing for generating image thumbnails using PHP based on GD2 graphics library, _PHP tutorial

Sharing code for generating image thumbnails in PHP based on GD2 graphics library,

To use PHP to generate image thumbnails, make sure your PHP server has the GD2 graphics library installed. Use a class to generate image thumbnails

1. How to use

$resizeimage = new resizeimage("图片源文件地址", "200", "100", "0","缩略图地址");
//就只用上面的一句话,就能生成缩略图,其中,源文件和缩略图地址可以相同,200,100分别代表宽和高

2. Thumbnail code

//使用如下类就可以生成图片缩略图,
 
<&#63;php
class resizeimage
{
  //图片类型
  var $type;
  //实际宽度
  var $width;
  //实际高度
  var $height;
  //改变后的宽度
  var $resize_width;
  //改变后的高度
  var $resize_height;
  //是否裁图
  var $cut;
  //源图象
  var $srcimg;
  //目标图象地址
  var $dstimg;
  //临时创建的图象
  var $im;
 
  function resizeimage($img, $wid, $hei,$c,$dstpath)
  {
    $this->srcimg = $img;
    $this->resize_width = $wid;
    $this->resize_height = $hei;
    $this->cut = $c;
    //图片的类型
  
$this->type = strtolower(substr(strrchr($this->srcimg,"."),1));
 
    //初始化图象
    $this->initi_img();
    //目标图象地址
    $this -> dst_img($dstpath);
    //--
    $this->width = imagesx($this->im);
    $this->height = imagesy($this->im);
    //生成图象
    $this->newimg();
    ImageDestroy ($this->im);
  }
  function newimg()
  {
    //改变后的图象的比例
    $resize_ratio = ($this->resize_width)/($this->resize_height);
    //实际图象的比例
    $ratio = ($this->width)/($this->height);
    if(($this->cut)=="1")
    //裁图
    {
      if($ratio>=$resize_ratio)
      //高度优先
      {
        $newimg = imagecreatetruecolor($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)
      //宽度优先
      {
        $newimg = imagecreatetruecolor($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,$this->dstimg);
      }
    }
    else
    //不裁图
    {
      if($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;
  }
}
&#63;>

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