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;
}
}
?>