当我们要使用先在php.ini里增加一行引用：extension=php_gd2.dll
重启apache。做一个测试页 var_dump(gd_info());输出数据表明PHP GD库引用成功。
表单auth.html
<ol class="dp-xml"> <li class="alt"><span><strong><font color="#006699"><span class="tag"><span class="tag-name">html</span><span class="tag">></span></span></font></strong><span> </span></span></li> <li class=""> <span></span><strong><font color="#006699"><span class="tag"><span class="tag-name">head</span><span class="tag">></span></span></font></strong><span> </span> </li> <li class="alt"> <span></span><strong><font color="#006699"><span class="tag"><span class="tag-name">meta</span></span></font></strong><span> </span><span class="attribute"><font color="#ff0000">http-equiv</font></span><span>=</span><span class="attribute-value"><font color="#0000ff">'Content-Type'</font></span><span> </span><span class="attribute"><font color="#ff0000">content</font></span><span>=</span><span class="attribute-value"><font color="#0000ff">'text/html; charset=utf-8'</font></span><span class="tag"><strong><font color="#006699">></font></strong></span><span> </span> </li> <li class=""> <span></span><strong><font color="#006699"><span class="tag"><span class="tag-name">title</span><span class="tag">></span></span></font></strong><span>验证码</span><strong><font color="#006699"><span class="tag"></span><span class="tag-name">title</span><span class="tag">></span></font></strong><span> </span> </li> <li class="alt"> <span></span><strong><font color="#006699"><span class="tag"></span><span class="tag-name">head</span><span class="tag">></span></font></strong><span> </span> </li> <li class=""> <span></span><strong><font color="#006699"><span class="tag"><span class="tag-name">body</span><span class="tag">></span></span></font></strong><span> </span> </li> <li class="alt"> <span></span><strong><font color="#006699"><span class="tag"><span class="tag-name">h1</span><span class="tag">></span></span></font></strong><span>请输入验证码</span><strong><font color="#006699"><span class="tag"></span><span class="tag-name">h1</span><span class="tag">></span></font></strong><span> </span> </li> <li class=""> <span></span><strong><font color="#006699"><span class="tag"><span class="tag-name">form</span></span></font></strong><span> </span><span class="attribute"><font color="#ff0000">action</font></span><span>=</span><span class="attribute-value"><font color="#0000ff">"check_auth.php"</font></span><span> </span><span class="attribute"><font color="#ff0000">method</font></span><span>=</span><span class="attribute-value"><font color="#0000ff">"post"</font></span><span class="tag"><strong><font color="#006699">></font></strong></span><span> </span> </li> <li class="alt"> <span> </span><strong><font color="#006699"><span class="tag"><span class="tag-name">input</span></span></font></strong><span> </span><span class="attribute"><font color="#ff0000">name</font></span><span>=</span><span class="attribute-value"><font color="#0000ff">"auth"</font></span><span> </span><span class="attribute"><font color="#ff0000">type</font></span><span>=</span><span class="attribute-value"><font color="#0000ff">"text"</font></span><span class="tag"><strong><font color="#006699">></font></strong></span><span> </span> </li> <li class=""> <span> </span><strong><font color="#006699"><span class="tag"><span class="tag-name">img</span></span></font></strong><span> </span><span class="attribute"><font color="#ff0000">src</font></span><span>=</span><span class="attribute-value"><font color="#0000ff">"auth.php"</font></span><span> </span><span class="attribute"><font color="#ff0000">border</font></span><span>=</span><span class="attribute-value"><font color="#0000ff">"0"</font></span><span> </span><span class="tag"><strong><font color="#006699">/></font></strong></span><span> </span> </li> <li class="alt"> <span> </span><strong><font color="#006699"><span class="tag"><span class="tag-name">input</span></span></font></strong><span> </span><span class="attribute"><font color="#ff0000">type</font></span><span>=</span><span class="attribute-value"><font color="#0000ff">"submit"</font></span><span> </span><span class="attribute"><font color="#ff0000">value</font></span><span>=</span><span class="attribute-value"><font color="#0000ff">"提交"</font></span><span class="tag"><strong><font color="#006699">></font></strong></span><span> </span> </li> <li class=""> <span></span><strong><font color="#006699"><span class="tag"></span><span class="tag-name">form</span><span class="tag">></span></font></strong><span> </span> </li> <li class="alt"> <span></span><strong><font color="#006699"><span class="tag"></span><span class="tag-name">body</span><span class="tag">></span></font></strong><span> </span> </li> <li class=""> <span></span><strong><font color="#006699"><span class="tag"></span><span class="tag-name">html</span><span class="tag">></span></font></strong><span> </span> </li> </ol>
PHP GD库生成验证码 auth.php
<ol class="dp-xml">
<li class="alt"><span><strong><font color="#006699"><span class="tag"></span><span class="tag-name">php</span></font></strong><span> </span></span></li>
<li class=""><span> session_start(); </span></li>
<li class="alt"><span> header("Content-type:image/png"); </span></li>
<li class=""><span> </span></li>
<li class="alt">
<span> $</span><span class="attribute"><font color="#ff0000">img_width</font></span><span>=</span><span class="attribute-value"><font color="#0000ff">100</font></span><span>; </span>
</li>
<li class="">
<span> $</span><span class="attribute"><font color="#ff0000">img_height</font></span><span>=</span><span class="attribute-value"><font color="#0000ff">20</font></span><span>; </span>
</li>
<li class="alt"><span> </span></li>
<li class=""><span> srand(microtime()*100000); </span></li>
<li class="alt">
<span> for($</span><span class="attribute"><font color="#ff0000">i</font></span><span>=</span><span class="attribute-value"><font color="#0000ff">0</font></span><span>;$i</span><strong><font color="#006699"><span class="tag"><span class="tag-name">4</span></span></font></strong><span>;$i++) </span>
</li>
<li class=""><span> { </span></li>
<li class="alt">
<span> $</span><span class="attribute"><font color="#ff0000">new_number.</font></span><span>=</span><span class="attribute-value"><font color="#0000ff">dechex</font></span><span>(rand(0,15)); </span>
</li>
<li class=""><span> } </span></li>
<li class="alt"><span> </span></li>
<li class=""><span> $_SESSION[check_auth]=$new_number; </span></li>
<li class="alt">
<span> $</span><span class="attribute"><font color="#ff0000">new_number</font></span><span>=</span><span class="attribute-value"><font color="#0000ff">imageCreate</font></span><span>($img_width,$img_height);//创建图象 </span>
</li>
<li class=""><span> ImageColorAllocate($new_number,255,255,255); //设置背景色为白色 </span></li>
<li class="alt"><span> </span></li>
<li class="">
<span> for($</span><span class="attribute"><font color="#ff0000">i</font></span><span>=</span><span class="attribute-value"><font color="#0000ff">0</font></span><span>;$i</span><strong><font color="#006699"><span class="tag"><span class="tag-name">strlen</span></span></font></strong><span>($_SESSION[check_auth]);$i++) </span>
</li>
<li class="alt"><span> { </span></li>
<li class="">
<span> $</span><span class="attribute"><font color="#ff0000">font</font></span><span>=</span><span class="attribute-value"><font color="#0000ff">mt_rand</font></span><span>(3,5); </span>
</li>
<li class="alt">
<span> $</span><span class="attribute"><font color="#ff0000">x</font></span><span>=</span><span class="attribute-value"><font color="#0000ff">mt_rand</font></span><span>(1,8) + $img_width*$i/4; </span>
</li>
<li class="">
<span> $</span><span class="attribute"><font color="#ff0000">y</font></span><span>=</span><span class="attribute-value"><font color="#0000ff">mt_rand</font></span><span>(1,$img_height/4); </span>
</li>
<li class="alt">
<span> $</span><span class="attribute"><font color="#ff0000">color</font></span><span>=</span><span class="attribute-value"><font color="#0000ff">imageColorAllocate</font></span><span>($new_number,mt_rand(0,100),mt_rand(0,150),mt_rand(0,200));//设置字符颜色 </span>
</li>
<li class=""><span> imageString($new_number,$font,$x,$y,$_SESSION[check_auth][$i],$color);//输出字符 </span></li>
<li class="alt"><span> } </span></li>
<li class=""><span> </span></li>
<li class="alt"><span> ImagePng($new_number); </span></li>
<li class=""><span> ImageDestroy($new_number); </span></li>
<li class="alt">
<span></span><span class="tag"><strong><font color="#006699">?></font></strong></span><span> </span>
</li>
</ol>
PHP GD库提交页面 check_auth.php
<ol class="dp-xml">
<li class="alt"><span><strong><font color="#006699"><span class="tag"></span><span class="tag-name">php</span></font></strong><span> </span></span></li>
<li class=""><span> session_start(); </span></li>
<li class="alt">
<span> $</span><span class="attribute"><font color="#ff0000">auth</font></span><span>=$_POST['auth']; </span>
</li>
<li class=""><span> </span></li>
<li class="alt"><span> if(empty($auth)) </span></li>
<li class=""><span> { </span></li>
<li class="alt"><span> echo '错误：验证码不能为空'; </span></li>
<li class=""><span> die; </span></li>
<li class="alt"><span> } </span></li>
<li class=""><span> </span></li>
<li class="alt">
<span> if($</span><span class="attribute"><font color="#ff0000">auth</font></span><span>==$_SESSION['check_auth']) </span>
</li>
<li class=""><span> { </span></li>
<li class="alt"><span> echo '正确'; </span></li>
<li class=""><span> } </span></li>
<li class="alt"><span> else </span></li>
<li class=""><span> { </span></li>
<li class="alt"><span> echo '错误：验证码输入错误'; </span></li>
<li class=""><span> } </span></li>
<li class="alt">
<span></span><span class="tag"><strong><font color="#006699">?></font></strong></span><span> </span>
</li>
</ol>
以上就是本文所介绍的PHP GD库生成验证码的相关知识，希望对大家有所帮助。
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