先确认你的PHP是不是支持GD库
<?php
/*-------------------------------------------------------------
| 名称: authimg class
| 用途: 根据图片数字字母验证
|图片生成:
|$ai = new authimg();
|$ai->render();
|判断结果是否正确:
|$ai = new authimg();
|$ai->is_true($str); // 返回0即相等
+-------------------------------------------------------------*/
class authimg
{
// public var
var $width = 72;
var $height = 20;
var $text_font = 5;
var $text_space = 10;
var $text_length = 5;
var $sess_name = "＿＿auth_xyz_123__";
var $num_only = false;
// private
var $_top = 1;
var $_move = 3;
var $_lines = 5;
function auth_image($params = array())
{
settype($params, "array");
foreach ($params as $key => $value)
{
if (isset($this->$key))
{
$this->$key = $value;
}
}
$this->_lines = intval($this->height / 10);
}
function set_sess_name($name = "")
{
if (!empty($name))
{
$this->sess_name = $name;
}
}
function set_text_length($length = 5)
{
$this->text_length = $length;
}
function set_img_size($width = 100, $height = 15)
{
$this->width = $width;
$this->height = $height;
}
function get_sess_value()
{
@session_start();
$sess_key = $this->sess_name;
$sess_value = NULL;
if (isset($_SESSION) && isset($_SESSION[$sess_key]))
{
$sess_value = $_SESSION[$sess_key];
unset($_SESSION[$sess_key]);
}
else
{
global $HTTP_SESSION_VARS;
if (isset($HTTP_SESSION_VARS[$sess_key]))
{
$sess_value = $HTTP_SESSION_VARS[$sess_key];
session_unregister($this->sess_name);
}
}
if (isset($GLOBALS[$sess_key]))
{
unset($GLOBALS[$sess_key]);
}
return $sess_value;
}
function is_true($str)
{
$sess_value = $this->get_sess_value();
return (strcasecmp($sess_value, $str));
}
function render()
{
$radix = "123456789";
if (!$this->num_only)
{
$radix .= "ABCDEFGHIJKLMNPQRSTUVWXYZ";
}
$radix_len = strlen($radix);
// 种下随机种子
mt_srand();
// 初始化图片
$image = ImageCreate($this->width, $this->height);
// 设定颜色
$r = mt_rand() % 255; //2 ? 255 : 0;
$g = mt_rand() % 255; //2 ? 255 : 0;
$b = mt_rand() % 255; //2 ? 255 : 0;
//$fgcolor = ImageColorAllocate($image, $r, $g, $b);
$fgcolor = ImageColorAllocate($image, 255, 255, 255);
//$bgcolor = ImageColorAllocate($image, 255 - $r, 255 - $g, 255 - $b);
$bgcolor = ImageColorAllocate($image, 0, 0, 0);
$silver = ImageColorAllocate($image, (255 - $r) * 2, (255 - $g) * 2, (255 - $b) * 2);
// 生成背景
ImageFill($image, 0, 0, $bgcolor);
// 画出横向干扰线
$line_space = ceil($this->height / ($this->_lines + 1));
$line_move = ceil($line_space * 2);
for ($i = 1; $i <= $this->_lines; $i++)
{
$y = $line_space * $i;
$y2 = $y + (($i - rand(0, 2 * $i)) % 2) * $line_move;
ImageLine($image, 0, $y, $this->width, $y2, $silver);
}
// 画出干扰点
$pixel_num = intval($this->height * $this->width / 20);
for($i = 0; $i < $pixel_num; $i++)
{
$x = mt_rand() % $this->width;
$y = mt_rand() % $this->height;
ImageSetPixel($image, $x, $y, $silver);
}
// 画出字符
$rand_str = "";
$step_len = intval($this->width / ($this->text_length + 1));
$left_len = $step_len - 6;
for ($i = 0; $i < $this->text_length; $i++)
{
$x = $left_len + ($step_len * $i);
$y = ($i % 2) * $this->_move + $this->_top;
$rand = mt_rand(0, $radix_len - 1);
$rand_str .= substr($radix, $rand, 1);
ImageString($image, $this->text_font, $x, $y, substr($radix, $rand, 1), $fgcolor);
}
// 设定 SESSION 值
@session_start();
if (isset($_SESSION))
{
$sess_key = $this->sess_name;
$_SESSION[$sess_key] = $rand_str;
}
else
{
session_register($this->sess_name, $rand_str);
}
// 输出图象
header("Content-type: image/png");
ImagePNG($image);
ImageDestroy($image);
}
}
?> ;
上面是类的代码,加了注释,很好看懂的应用也在说明里,
第一个页提供输入验证码的输入框,和验证码的图片
在第二个页面用类的is_true函数来验证
在上班,就不多说了
