PHP生成图片验证码功能示例

本文实例讲述了php生成图片验证码功能。分享给大家供大家参考，具体如下：

只是简单的用随机函数实现了图片的生成，没有对验证的整个流程做介绍。

代码如下：

<?php
/**
 * created by jetbrains phpstorm.
 * user: lee
 * to change this template use file | settings | file templates.
 */
header("content-type:image/png");
$validatelength=4;
$strtodraw="";
$chars=[
  "0","1","2","3","4",
  "5","6","7","8","9",
  "a","b","c","d","e","f","g",
  "h","i","j","k","l","m","n",
  "o","p","q","r","s","t",
  "u","v","w","x","y","z",
  "a","b","c","d","e","f","g",
  "h","i","j","k","l","m","n",
  "o","p","q","r","s","t",
  "u","v","w","x","y","z"
];
$imgw=80;
$imgh=25;
$imgres=imagecreate($imgw,$imgh);
$imgcolor=imagecolorallocate($imgres,255,255,100);
$color=imagecolorallocate($imgres,0,0,0);
for($i=0;$i<$validatelength;$i++){
  $rand=rand(1,58);
  $strtodraw=$strtodraw." ".$chars[$rand];
}
imagestring($imgres,5,0,5,$strtodraw,$color);
for($i=0;$i<100;$i++){
  imagesetpixel($imgres,rand(0,$imgw),rand(0,$imgh),$color);
}
imagepng($imgres);
imagedestroy($imgres);

运行效果如下：

ps：这里再为大家推荐几款比较实用的图片处理工具供大家参考使用：

在线图片转换base64工具：

ico图标在线生成工具：

在线email邮箱图标制作工具：

在线图片格式转换(jpg/bmp/gif/png)工具：

更多关于php相关内容感兴趣的读者可查看本站专题：《php图形与图片操作技巧汇总》、《php基本语法入门教程》、《php运算与运算符用法总结》、《php面向对象程序设计入门教程》、《php网络编程技巧总结》、《php数组(array)操作技巧大全》、《php字符串(string)用法总结》、《php+mysql数据库操作入门教程》及《php常见数据库操作技巧汇总》

希望本文所述对大家php程序设计有所帮助。