php生成缩略图经典类

从国外网站找到的一款php生成缩略图代码，有需要的朋友可以参考一下。

代码如下

复制代码

/* * File: SimpleImage.php * Author: Simon Jarvis * Copyright: 2006 Simon Jarvis * Date: 08/11/06 * Link: http://www.white-hat-web-design.co.uk/articles/php-image-resizing.php * * This program is free software; you can redistribute it and/or * modify it under the terms of the GNU General Public License * as published by the Free Software Foundation; either version 2 * of the License, or (at your option) any later version. * * This program is distributed in the hope that it will be useful, * but WITHOUT ANY WARRANTY; without even the implied warranty of * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the * GNU General Public License for more details: * http://www.gnu.org/licenses/gpl.html * */   class SimpleImage {      var $image;    var $image_type;      function load($filename) {         $image_info = getimagesize($filename);       $this->image_type = $image_info[2];       if( $this->image_type == IMAGETYPE_JPEG ) {            $this->image = imagecreatefromjpeg($filename);       } elseif( $this->image_type == IMAGETYPE_GIF ) {            $this->image = imagecreatefromgif($filename);       } elseif( $this->image_type == IMAGETYPE_PNG ) {            $this->image = imagecreatefrompng($filename);       }    }    function save($filename, $image_type=IMAGETYPE_JPEG, $compression=75, $permissions=null) {         if( $image_type == IMAGETYPE_JPEG ) {          imagejpeg($this->image,$filename,$compression);       } elseif( $image_type == IMAGETYPE_GIF ) {            imagegif($this->image,$filename);       } elseif( $image_type == IMAGETYPE_PNG ) {            imagepng($this->image,$filename);       }       if( $permissions != null) {            chmod($filename,$permissions);       }    }    function output($image_type=IMAGETYPE_JPEG) {         if( $image_type == IMAGETYPE_JPEG ) {          imagejpeg($this->image);       } elseif( $image_type == IMAGETYPE_GIF ) {            imagegif($this->image);       } elseif( $image_type == IMAGETYPE_PNG ) {            imagepng($this->image);       }    }    function getWidth() {         return imagesx($this->image);    }    function getHeight() {         return imagesy($this->image);    }    function resizeToHeight($height) {         $ratio = $height / $this->getHeight();       $width = $this->getWidth() * $ratio;       $this->resize($width,$height);    }      function resizeToWidth($width) {       $ratio = $width / $this->getWidth();       $height = $this->getheight() * $ratio;       $this->resize($width,$height);    }      function scale($scale) {       $width = $this->getWidth() * $scale/100;       $height = $this->getheight() * $scale/100;       $this->resize($width,$height);    }      function resize($width,$height) {       $new_image = imagecreatetruecolor($width, $height);       imagecopyresampled($new_image, $this->image, 0, 0, 0, 0, $width, $height, $this->getWidth(), $this->getHeight());       $this->image = $new_image;    }        } ?>

Usage
Save the above file as SimpleImage.php and take a look at the following examples of how to use the script.

The first example below will load a file named picture.jpg resize it to 250 pixels wide and 400 pixels high and resave it as picture2.jpg

代码如下	复制代码
include('SimpleImage.php');    $image = new SimpleImage();    $image->load('picture.jpg');    $image->resize(250,400);    $image->save('picture2.jpg'); ?>

If you want to resize to a specifed width but keep the dimensions ratio the same then the script can work out the required height for you, just use the resizeToWidth function

代码如下	复制代码
include('SimpleImage.php');    $image = new SimpleImage();    $image->load('picture.jpg');    $image->resizeToWidth(250);    $image->save('picture2.jpg'); ?>