php处理图片实现

     <?php
 include("SimpleImage.php");//图片处理类在下面

 $url="http://f3.v.veimg.cn/meadincms/1/2013/0703/20130703100937552.jpg";
 $picfile = down($url);//下载图片（下载图片的路径可以处理完成后清空，这里未进行处理）
 $res = new SimpleImage();//图片处理实例
 $res = $res->load($picfile);
 $tmpfile = tempfile().'.jpg';//创建一个路径文件用来保存图片
 $width = '30';//设定图片的宽度
 $res->resizeToWidth($width);
 $res->save($tmpfile);//把处理后的图片保存（无.jpg后缀）
 //这里总共产生了3个文件，一个是图片下载的文件，一个是临时文件，最后一个是处理的图片文件。需要优化清理掉前两个文件。

 function down($url)
 {
         $http = array();
         $header = "http://f3.v.veimg.cn";
         if ($header) {
             $http['header'] = $header;
         }

         $http['timeout'] = 50;

         $ctx = stream_context_create(array(
             'http' => $http,
         ));
         $content = @file_get_contents($url, 0, $ctx);
         sleep(1);

         if (!$content) {
             return false;
         }

         $tmpfile = tempfile();

         file_put_contents($tmpfile, $content);

         return $tmpfile;
 }

 function tempfile()
 {
         $path = dirname(__FILE__);
         $path .= '/spider/' . date('Ymd') . '/'.date('His').'-' . (int)(time() / 300);

         if (!file_exists($path)) {
             mkdir($path, 0777, true);
         }

         do {
             $file = $path . '/' . dechex(mt_rand());
         }
         while (file_exists($file));

         touch($file);

         return $file;
 }

图片处理类：

<?php

/*
* 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);
		}

		if (!$this->image) {
			return false;
		}

		return $this;
	}

	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($width) {
		if ($this->getWidth() < $width) {
			$width = $this->getWidth();
		}
		$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;
	}

	function resize2($width,$height) {
		$new_image = imagecreatetruecolor($width, $height);
		if( $this->image_type == IMAGETYPE_GIF || $this->image_type == IMAGETYPE_PNG ) {
			$current_transparent = imagecolortransparent($this->image);
			if($current_transparent != -1) {
				$transparent_color = imagecolorsforindex($this->image, $current_transparent);
				$current_transparent = imagecolorallocate($new_image, $transparent_color['red'], $transparent_color['green'], $transparent_color['blue']);
				imagefill($new_image, 0, 0, $current_transparent);
				imagecolortransparent($new_image, $current_transparent);
			} elseif( $this->image_type == IMAGETYPE_PNG) {
				imagealphablending($new_image, false);
				$color = imagecolorallocatealpha($new_image, 0, 0, 0, 127);
				imagefill($new_image, 0, 0, $color);
				imagesavealpha($new_image, true);
			}
		}
		imagecopyresampled($new_image, $this->image, 0, 0, 0, 0, $width, $height, $this->getWidth(), $this->getHeight());
		$this->image = $new_image;
	}

}