<?php    session_start();    header("Content-type:image/png");    $img_width=100;    $img_height=20;    srand(microtime()*100000);    for($i=0;$i<4;$i++)    {         $new_number.=dechex(rand(0,15));    }    $_SESSION[check_auth]=$new_number;    $new_number=imageCreate($img_width,$img_height);//创建图象    ImageColorAllocate($new_number,255,255,255);  //设置背景色为白色    for($i=0;$i<strlen($_SESSION[check_auth]);$i++)    {        $font=mt_rand(3,5);        $x=mt_rand(1,8) + $img_width*$i/4;        $y=mt_rand(1,$img_height/4);        $color=imageColorAllocate($new_number,mt_rand(0,100),mt_rand(0,150),mt_rand(0,200));//设置字符颜色        imageString($new_number,$font,$x,$y,$_SESSION[check_auth][$i],$color);//输出字符    }    ImagePng($new_number);    ImageDestroy($new_number); ?>The GD library is a very powerful library for image manipulation in PHP. First add a line of reference in php.ini: extension=php_gd2.dllRestart apache. Make a test page var_dump(gd_info()); the output data shows that the GD library is referenced successfully. Form auth.html

php verification code class

php verification code generation class

A PHP verification code encapsulation class that implements powerful and practical functions. Friends in need can download and use it.

Code introduction: Free download of practical php verification code class

Share aphp verification code generation class code,output the image to the browser through this method,create the image background,Set interference elements, Draw text randomly into the image, Output the image. ##

IntroductionA class for php to generate image verification codes, is used to generate various verification codes, generate the character length, width, type, etc. of the verification code, friends in need Can be downloaded for reference.

Introducing a useful verification code php tool class, take out the characters from the set string , combine them into the verification code characters we want, generate the code and then draw it into the picture.

Share a PHP verification code class based on GD library, set the image height, width, number of characters, color font, image background, etc.

ASimple and easy-to-use PHP verification code class. Instructions: $image=new Captcha(); $image->config('width','height','number of characters','verification code session index'); $image->create();//This will output an image to the browser All parameters can be omitted

Give you a #supports numbers, letters, Chinese characters, mixed php verification code class,this type The object can dynamically obtain the verification code image, and the verification code characters are stored in SESSION['code']. supports 4 formats of mixed numbers, letters, and Chinese characters.

Needless to say the purpose of the verification code. After encapsulating it into a class, a constructor is added, which makes it easier to use. You can also continue to improve this verification code class, such as adding a destructor, how to save memory, etc.