php图像验证代码

<?php教程
session_start();
header("content-type: image/png");
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$imgwidth = 110;
$imgheight = 24;
$authimg = imagecreate($imgwidth,$imgheight);
$bgcolor = imagecolorallocate($authimg,255,255,255);
$fontfile = "wrzc_net.ttf";
$white=imagecolorallocate($authimg,234,185,95);
imagearc($authimg, 150, 8, 20, 20, 75, 170, $white);
imagearc($authimg, 100, 7,50, 22, 75, 175, $white);
imageline($authimg,20,20,180,30,$white);
imageline($authimg,20,18,170,50,$white);
imageline($authimg,25,50,80,50,$white);
$noise_num = 100;
$line_num = 5;
imagecolorallocate($authimg,0xff,0xff,0xff);
$rectangle_color=imagecolorallocate($authimg,0xaa,0xaa,0xaa);
$noise_color=imagecolorallocate($authimg,0x33,0x33,0x33);
$font_color=imagecolorallocate($authimg,0x00,0x00,0x00);
$line_color=imagecolorallocate($authimg,0x00,0x00,0x00);
for($i=0;$i<$noise_num;$i++){
 imagesetpixel($authimg,mt_rand(0,$imgwidth),mt_rand(0,$imgheight),$noise_color);
}
for($i=0;$i<$line_num;$i++){
 imageline($authimg,mt_rand(0,$imgwidth),mt_rand(0,$imgheight),mt_rand(0,$imgwidth),mt_rand(0,$imgheight),$line_color);
}
$randnum=rand(0,strlen($str)-4);
if($randnum%2)$randnum+=1;
$str = substr($str,$randnum,8);
$_session['supdesverify'] = $str;
$str = iconv("gb2312","utf-8",$str);
imagettftext($authimg, 20, 0, 0, 21, $font_color, $fontfile, $str);
imagepng($authimg);
imagedestroy($authimg);
?>

超简单php教程 大图生成缩略图实现代码

<?php
/**
* 生成缩略图
*
* @param string $imagepath 图片路径
* @param string $thumb 生成缩略图名称
* @param integer $width 生成缩略图最大宽度
* @param integer $height 生成缩略图最大高度
*

*/
function resizeimage($imagepath, $thumb, $width = 200, $height = 200)
{
    list($imagewidth, $imageheight) = getimagesize($imagepath);
    $imagepath = imagecreatefromjpeg($imagepath);
    if ($width && ($imagewidth < $imageheight))
    {
        $width = ($height / $imageheight) * $imagewidth;
    }
    else
    {
        $height = ($width / $imagewidth) * $imageheight;
    }
    $image = imagecreatetruecolor($width, $height);
    imagecopyresampled($image, $imagepath, 0, 0, 0, 0, $width, $height, $imagewidth, $imageheight);
    imagepng($image, $thumb);
    imagedestroy($image);
}
resizeimage('test.jpg', 'test_thumb.jpg');
?>

gd库是php教程中一个处理图像的专用库，他可以方便快捷的处理大多数据处理，它提供了大量的图片处理函数，下面我们就利用gd库的函数来生成缩略图。
测试代码

<?php
include('resizeimage.php');
if(!empty($_post)){
echo($filename.".jpg?cache=".rand(0,999999));
}
?>
<form name="test" action="?submit=true" enctype="multipart/form-data" method="post" >
<input type="file" name="image" size="50" value="浏览"><p>
<input type="submit" value="上传图片">
</form>

resizeimage.php 文件

<?php
$filename="image.thumb";
// 生成图片的宽度
$resizewidth=400;
// 生成图片的高度
$resizeheight=400;

function resizeimage($im,$maxwidth,$maxheight,$name){
$width = imagesx($im);
$height = imagesy($im);
if(($maxwidth && $width > $maxwidth) || ($maxheight && $height > $maxheight)){
if($maxwidth && $width > $maxwidth){
$widthratio = $maxwidth/$width;
$resizewidth=true;
}
if($maxheight && $height > $maxheight){
$heightratio = $maxheight/$height;
$resizeheight=true;
}
if($resizewidth && $resizeheight){
if($widthratio < $heightratio){
$ratio = $widthratio;
}else{
$ratio = $heightratio;
}
}elseif($resizewidth){
$ratio = $widthratio;
}elseif($resizeheight){
$ratio = $heightratio;
}
$newwidth = $width * $ratio;
$newheight = $height * $ratio;
if(function_exists("imagecopyresampled")){
$newim = imagecreatetruecolor($newwidth, $newheight);
imagecopyresampled($newim, $im, 0, 0, 0, 0, $newwidth, $newheight, $width, $height);
}else{
$newim = imagecreate($newwidth, $newheight);
imagecopyresized($newim, $im, 0, 0, 0, 0, $newwidth, $newheight, $width, $height);
}
imagejpeg ($newim,$name . ".jpg");
imagedestroy ($newim);
}else{
imagejpeg ($im,$name . ".jpg");
}
}

if($_files['image']['size']){
if($_files['image']['type'] == "image/pjpeg"){
$im = imagecreatefromjpeg($_files['image']['tmp_name']);
}elseif($_files['image']['type'] == "image/x-png"){
$im = imagecreatefrompng($_files['image']['tmp_name']);
}elseif($_files['image']['type'] == "image/gif"){
$im = imagecreatefromgif($_files['image']['tmp_name']);
}
if($im){
if(file_exists("$filename.jpg")){
unlink("$filename.jpg");
}
resizeimage($im,$resizewidth,$resizeheight,$filename);
imagedestroy ($im);
}
}
?>

要做到替换所有图片或者是连接的alt title我们必须用到正则函数，下面看一个替换图片alt实例

*/

preg_replace('#alt="[^"]*"#i','alt="".$title.""',$str);

/*
mixed preg_replace ( mixed pattern, mixed replacement, mixed subject [, int limit])

在 subject 中搜索 pattern 模式的匹配项并替换为 replacement。如果指定了 limit，则仅替换 limit 个匹配，如果省略 limit 或者其值为 -1，则所有的匹配项都会被替换。

过滤所有html 标签
*/

$html_body ="<br />fdafdsa <div>内容</div>";
preg_replace("/(</?)(w+)([^>]*>)/e",
             "'1'.strtoupper('2').'3'",
             $html_body);

   
//更多详细内容请查看：php教程er/php-function/33530.htm">http://www.111cn.net/phper/php-function/33530.htm

<?php教程
$oimg = "test.jpg";//original image name
$classes = array('translation','autoheight','autowidth','stretch');//give classes for the new creating images' size which are defined in the specified ini file
$suffix = 'jpg';//the new image's suffix
$inifile = 'image.ini.php';

$size = getimagesize($oimg);
$x = $size[0]/$size[1];
$name = explode('.',$oimg);

if(!file_exists($inifile)) die('ini file does not exist!');
$cn = parse_ini_file($inifile,true);//parse the class style image size from ini file
foreach($classes as $class){
    foreach($cn as $k=>$v){
        if($k==$class){
            if($v['width'] && $v['height']){
                $thumbwidth = $v['width'];
                $thumbheight = $v['height'];
            }elseif($v['width']){
                $thumbwidth = $v['width'];
                $thumbheight = round($thumbwidth/$x);
            }elseif($v['height']){
                $thumbheight = $v['height'];
                $thumbwidth = round($thumbheight*$x);
            }else{
                $thumbwidth = $size[0];
                $thumbheight = $size[1];
            }
            break;
        }
    }
    if(!isset($thumbheight) && !isset($thumbwidth)) die('ini file settings error!');

    $nimg = $name[0].'_'.$class.'.'.$suffix;//new image file name
    $source = imagecreatefromjpeg($oimg);
    $thumb = imagecreatetruecolor($thumbwidth, $thumbheight);
    imagecopyresampled($thumb,$source,0,0,0,0,$thumbwidth,$thumbheight,$size[0],$size[1]);

    if($suffix=='jpg') $method = 'imagejpeg';
    else $method='image'.$suffix;
    $method($thumb, $nimg);
    imagedestroy($thumb);//release the image source
    imagedestroy($source);
}
?>

缩放图片的php代码，其中变量classes是一个数组，可以选择任意多个ini文件中指定的设置：

这是一个ini配置文件，上面的代码就要读取这个文件中的图片位置，可以多个。

<?php /*
;translate the image format using the original image size
[translation]
width=0
height=0

;stretch the image to the specified size
[stretch]
width=800
height=600

;zoom the image to the specified width with height auto size
[autoheight]
width=740
height=0

;zoom the image to the specified height with width auto size
[autowidth]
width=0
height=380
*/ ?>

注意：ini文件使用php解释时为注释文件，什么也没有输出，这是为了安全起见而故意为之。而;则是ini文件的注释。