功能：
环境 Linux + Nginx + Php 在不修改现有的源代码与图片路径位置的情况下，达到通过传参宽高来动态输出对应大小的图片并缓存。图片的处理要求是通过传参宽高的算出可用最大宽高，得到原图宽高。尽可能不毁图，不填白，不失真。
实例：
100*100：https://www.caojiefeng.com/content/uploadfile/201711/ba911509726344.png?param=100y100
200*200：https://www.caojiefeng.com/content/uploadfile/201711/ba911509726344.png?param=200y200
400*400：https://www.caojiefeng.com/content/uploadfile/201711/ba911509726344.png?param=400y400
600*400：https://www.caojiefeng.com/content/uploadfile/201711/ba911509726344.png?param=600y400
代码：
//nginx伪静态规则如下：
//只要是带参数的图片均处理，不带参数显示原图
if ($args !~ "^$"){
set $rule_0 1$rule_0;
}
if ($rule_0 = "1"){
rewrite ^/([\s\S]*?)\.png(.*)$ /image.php?type=png&url=$1&m=$args last;
}
if ($args !~ "^$"){
set $rule_1 1$rule_1;
}
if ($rule_1 = "1"){
rewrite ^/([\s\S]*?)\.jpg(.*)$ /image.php?type=jpg&url=$1&m=$args last;
}
location ~* \.(gif|jpg|jpeg|png|css|js|ico)$ {
expires 30d;
error_page 404 =200 /default.png;
}
//image.php代码
<?php
header("Cache-Control: max-age=2592000");
header("Pragma: cache");
$offset = 30*60*60*24; // cache 1 month
$ExpStr = "Expires: ".gmdate("D, d M Y H:i:s", time() + $offset)." GMT";
header($ExpStr);
define('EMLOG_ROOT', dirname(__FILE__));
$imgurl = $_GET['url'].'.'.$_GET['type'];
$imgurl1 = EMLOG_ROOT.$imgurl;
$param = explode("y",$_GET['param']);
$width = $param[0];
$height = $param[1];
if(file_exists($imgurl1) || $width =='' || $height ==''){
exit('PARAM ERROR');
}
imagecropper($imgurl,$width,$height);
function imagecropper($source_path, $target_width, $target_height){
$source_info = getimagesize($source_path);
$source_width = $source_info[0];
$source_height = $source_info[1];
$source_mime = $source_info['mime'];
$source_ratio = $source_height / $source_width;
$target_ratio = $target_height / $target_width;
// 源图过高
if ($source_ratio > $target_ratio){
$cropped_width = $source_width;
$cropped_height = $source_width * $target_ratio;
$source_x = 0;
$source_y = ($source_height - $cropped_height) / 2;
}
// 源图过宽
elseif ($source_ratio < $target_ratio)
{
$cropped_width = $source_height / $target_ratio;
$cropped_height = $source_height;
$source_x = ($source_width - $cropped_width) / 2;
$source_y = 0;
}// 源图适中
else{
$cropped_width = $source_width;
$cropped_height = $source_height;
$source_x = 0;
$source_y = 0;
}
switch ($source_mime){
case 'image/gif':
$source_image = imagecreatefromgif($source_path);
break;
case 'image/jpeg':
$source_image = imagecreatefromjpeg($source_path);
break;
case 'image/png':
$source_image = imagecreatefrompng($source_path);
break;
default:
return false;
break;
}
$target_image = imagecreatetruecolor($target_width, $target_height);
$cropped_image = imagecreatetruecolor($cropped_width, $cropped_height);
// 裁剪
imagecopy($cropped_image, $source_image, 0, 0, $source_x, $source_y, $cropped_width, $cropped_height);
// 缩放
imagecopyresampled($target_image, $cropped_image, 0, 0, 0, 0, $target_width, $target_height, $cropped_width, $cropped_height);
//保存图片到本地(两者选一)
//$randNumber = mt_rand(00000, 99999). mt_rand(000, 999);
//$fileName = substr(md5($randNumber), 8, 16) .".png";
//imagepng($target_image,'./'.$fileName);
//imagedestroy($target_image);
//直接在浏览器输出图片(两者选一)
header('Content-Type: image/jpeg');
imagepng($target_image);
imagedestroy($target_image);
imagejpeg($target_image);
imagedestroy($source_image);
imagedestroy($target_image);
imagedestroy($cropped_image);
}
?>
评论
4条评论null Lv.1
Chrome 67.0.3396.99 
Windows 回复
测试
辽宁省大连市 鹏博士长城宽带
null Lv.1
Chrome 69.0.3497.81 
Windows 回复
请问一下 这个评论系统是怎么做 刚好现在在做评论 有点模糊 网上教程有点不足
广东省深圳市龙岗区 联通
null Lv.1
Chrome 69.0.3497.81 
Windows 回复
撒大大
广东省深圳市龙岗区 联通
Yjsbv Lv.1
Chrome 67.0.3396.87 
Android 7.1.2 回复
测试下无刷新评论
广东省广州市 移动GSM/TD-SCDMA/LTE全省共用出口