PHP 处理图片的类实现代码

<?php 
/** 
* author:yagas 
* email:yagas60@21cn.com 
*/ 
class Image 
{ 
/** 类保护变量 */ 
protected $th_width = 100; 
protected $th_height = 50; 
protected $quality = 85; //图片质量 
protected $transparent = 50; //水印透明度 
protected $background = "255,255,255"; //背景颜色 
/** 
* 生成缩略图文件 
* @param $src 原图文件 
* @param $dst 目标文件 
*/ 
public function thumb($src, $dst=null, $output=true) 
{ 
$thumb = array($this->th_width, $this->th_height); 
$this->scale($src, $thumb, $dst, $output); 
} 
/** 
* 对图片按百分比进行缩放处理 
* @param string $src 原图文件 
* @param string $dst 输入的目标文件 
* @param float/array $zoom 缩放比例，浮点类型时按百分比绽放，数组类型时按指定大小时行缩放 
* @param boolean $output 是否生成文件输出 
*/ 
public function scale($src, $dst=null, $zoom=1, $output=true) 
{ 
if(!file_exists($src)) die('File not exists.'); 
if(!$zoom) die('the zoom undefine.'); 
$src_im = $this->IM($src); 
$old_width = imagesx($src_im); 
if(is_float($zoom)) { 
//按百分比进行缩放 
$new_width = $old_width * $zoom; 
} 
elseif(is_array($zoom)) { 
//明确的缩放尺寸 
$new_width = $zoom[0]; 
} 
//是否定义的缩放的高度 
if(!isset($zoom[1])) { 
//等比例缩放 
$resize_im = $this->imageresize($src_im, $new_width); 
} 
else { 
//非等比例缩放 
$resize_im = $this->imageresize($src_im, $new_width, $zoom[1]); 
} 
if(!$output) { 
header("Content-type: image/jpeg"); 
imagejpeg($resize_im, null, $this->quality); 
} 
else { 
$new_file = empty($dst)? $src:$dst; 
imagejpeg($resize_im, $new_file, $this->quality); 
} 
imagedestroy($im); 
imagedestroy($nIm); 
} 
/** 
* 对图片进行裁切 
* @param $src 原始文件 
* @param $dst 目标文件 
* @param $output 是否生成目标文件 
*/ 
public function capture($src, $dst=null, $output=true) { 
if(!file_exists($src)) die('File not exists.'); 
$width = $this->th_width; 
$height = $this->th_height; 
$src_im = $this->IM($src); 
$old_width = imagesx($src_im); 
$old_height = imagesy($src_im); 
$capture = imagecreatetruecolor($width, $height); 
$rgb = explode(",", $this->background); 
$white = imagecolorallocate($capture, $rgb[0], $rgb[1], $rgb[2]); 
imagefill($capture, 0, 0, $white); 
//当图片大于缩略图时进行缩放 
if($old_width > $width && $old_height>$height) { 
$resize_im = $this->imageresize($src_im, $width); 
//图片比例不合规范时，重新计算比例进行裁切 
if(imagesy($resize_im) < $height) { 
$proportion = $old_height/$this->th_height; 
$resize_im = $this->imageresize($src_im, $old_width/$proportion); 
} 
$posx = 0; 
$posy = 0; 
} 
else { 
//图片小于缩略图时将图片居中显示 
$posx = ($width-$old_width)/2; 
$posy = ($height-$old_height)/2; 
$resize_im = $src_im; 
} 
imagecopy($capture, $resize_im, $posx, $posy, 0, 0, imagesx($resize_im), imagesy($resize_im)); 
if(!$output) { 
header("Content-type: image/jpeg"); 
imagejpeg($capture, null, $this->quality); 
} 
else { 
$new_file = empty($dst)? $src:$dst; 
imagejpeg($capture, $new_file, $this->quality); 
} 
imagedestroy($src_im); 
@imagedestroy($resize_im); 
imagedestroy($capture); 
} 
/** 
* 写入水印图片 
* @param $src 需要写入水印的图片 
* @param $mark 水印图片 
* @param $transparent 水印透明度 
*/ 
public function mark($src, $mark, $dst='', $output=true) 
{ 
$mark_info = getimagesize($mark); 
$src_info = getimagesize($src); 
list($mw,$mh) = $mark_info; 
list($sw,$sh) = $src_info; 
$px = $sw - $mw; 
$py = $sh - $mh; 
$im = $this->IM($src); 
$mim = $this->IM($mark); 
imagecopymerge($im, $mim, $px, $py, 0, 0, $mw, $mh, $this->transparent); 
if($output){ 
$new_file = empty($dst)? $src:$dst; 
imagejpeg($im, $new_file, $this->quality); 
} 
else 
{ 
header('Content-type: image/jpeg'); 
imagejpeg($im); 
} 
imagedestroy($im); 
imagedestroy($mim); 
} 
/** 
* 通过文件，获取不同的GD对象 
*/ 
protected function IM($file) 
{ 
if(!file_exists($file)) die('File not exists.'); 
$info = getimagesize($file); 
switch($info['mime']) 
{ 
case 'image/gif': 
$mim = imagecreatefromgif($file); 
break; 
case 'image/png': 
$mim = imagecreatefrompng($file); 
imagealphablending($mim, false); 
imagesavealpha($mim, true); 
break; 
case 'image/jpeg': 
$mim = imagecreatefromjpeg($file); 
break; 
default: 
die('File format errors.'); 
} 
return $mim; 
} 
/** 
* 对图片进行缩放的处理 
* @param resource $src_im 图像GD对象 
* @param integer $width 图片的宽度 
* @param integer $height 图片的高度，如果不设置高度，将对图片进行等比例缩放 
* @return resuorce $im 返回一个GD对象 
*/ 
protected function imageresize($src_im, $width, $height=null) { 
$old_width = imagesx($src_im); 
$old_height = imagesy($src_im); 
$proportion = $old_width/$old_height; 
$new_width = $width; 
$new_height = is_null($height)? round($new_width / $proportion):$height; 
//创建新的图象并填充默认的背景色 
$im = imagecreatetruecolor($new_width, $new_height); 
$rgb = explode(",", $this->background); 
$white = imagecolorallocate($im, $rgb[0], $rgb[1], $rgb[2]); 
imagefill($im, 0, 0, $white); 
//对图片进行缩放 
imagecopyresized($im, $src_im, 0, 0, 0, 0, $new_width, $new_height, $old_width, $old_height); 
return $im; 
} 
/** 
* 类变量赋值 
*/ 
public function __set($key, $value) 
{ 
$this->$key = $value; 
} 
/** 
* 获取类变量值 
*/ 
public function __get($key) 
{ 
return $this->$key; 
} 
} 
?>