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Home php教程 php手冊 PHP圖片處理類 phpThumb參數用法介紹

PHP圖片處理類 phpThumb參數用法介紹

Jun 13, 2016 pm 12:01 PM
php introduce several parameter picture Basic deal with have usage use kind

phpThumb幾個基本參數
一些有用的參數列一下:
src:目標圖片的地址
w:輸出圖片的寬度
h:輸出圖片的高度(如果不指定他將按w參數等比縮放)
q:輸出如果是JPG格式的,可以規(guī)定它的輸出質量
bg:輸出時的背景(如果需要)
sw、sh、sx、sy:局部輸出,寬高、起始位置
f:輸出格式,可以為jpeg、png、gif、ico
sfn:輸出gif動畫中的某一幀
fltr[]:濾鏡,可以有很多效果,包括銳化、模糊、旋翻轉、水印、邊框、遮照、色彩調整等
更多效果可以參看官方例程:
http://phpthumb.sourceforge.net/demo/demo/phpThumb.demo.demo.php
使用 phpThumb 和 .htaccess 來緩存縮略圖
原理:用戶訪問 your.com/thumbs/images/image.50×50.jpg 這樣的網址,腳本生成 your.com/images/image.jpg 的縮略圖,并且保存到 your.com/thumbs/images/image.50×50.jpg,下次訪問就不用調 PHP 啦。
簡介
大約一年以前我碰到了 phpThumb 這個牛掰的腳本,它是個用來縮放圖片的開源項目。當然你可以用 GD2 或者 imagemagick(magickwand) 來干同樣的事情,但 phpThumb 是專門干這個的。它用起來相當簡單:
PHP圖片處理類 phpThumb參數用法介紹
如果訪問量很大的話就撐不住了,因為 apache 要為每個圖片的請求去調 PHP 來解析 phpThumb 的代碼。盡管 phpThumb 自己有緩存,它還是要調 PHP 來決定是否從緩存里讀。
我曾經看見有人用 mod_rewrite 把不存在的圖片重定向到一個可以生成縮略圖的腳本,以此來解決性能問題:
你需要:
Apache
mod_rewrite
PHP
這些東西通常虛擬主機都有,至于怎么安裝就不在本文的討論范圍之內了。
OK,快告訴我怎么弄吧!
上傳 phpThumb
從這里下載 phpThumb: http://phpthumb.sourceforge.net/ ,把它上傳到 yoursite.com/phpthumb
配置 Mod_Rewrite
新建 yoursite.com/thumbs/.htaccess :

RewriteEngine on
RewriteCond %{REQUEST_FILENAME} !-f
RewriteCond %{REQUEST_FILENAME} !-d
RewriteRule ^(.*)$ index.php?thumb=$1 [L,QSA]

新建縮略圖生成腳本:
新建 yoursite.com/thumbs/index.php

復制代碼 代碼如下:


$thumb = $_GET['thumb'];
if (!$thumb) {
exit;
}
//
$thumb_array = explode('.',$thumb);
$image = '../';
foreach($thumb_array as $k=>$thumb_part){
if ($k != count($thumb_array)-2) {
$image .= $thumb_part . '.';
}
}
$image = substr($image,0,-1);
list($width,$height) = explode('x',$thumb_array[count($thumb_array)-2]);
//
if (file_exists($image)) {
require('../phpthumb/phpthumb.class.php');
$phpThumb = new phpThumb();
$phpThumb->setSourceFilename($image);
$phpThumb->setParameter('w',$width);
$phpThumb->setParameter('h',$height);
//$phpThumb->setParameter('far','C'); // scale outside
//$phpThumb->setParameter('bg','FFFFFF'); // scale outside
if ($phpThumb->GenerateThumbnail()) {
mkdir(dirname($thumb),0777,true);
if ($phpThumb->RenderToFile($thumb)) {
header('Location: /thumbs/'.$thumb);
exit;
}
}
}


測試一下!
上傳一張圖片到 yoursite.com/images/myimage.jpg
打開你的瀏覽器,訪問 yoursite.com/thumbs/images/myimage.100×100.jpg
檢查 thumbs 目錄,應該有個縮略圖在那。下次訪問就不用調 PHP 啦。
官方網站 http://phpthumb.gxdlabs.com/
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