PHP校验码生成--备忘

yuandan

<?php
session_start();//保存生成值,以与用户输入比较
//-------------------------------------------------------------------------
$img_w       = 80;// 设置图片宽
$img_h       = 20;// 设置图片高
$pixel_num   = 200;//点越多干扰越大
$is_set_line = true;// 启用干扰线
$pixel_mode  = 2;// 干扰点模式,1,同色;2，杂色
//-------------------------------------------------------------------------
// 随机数产生器
function make_seed()
{
list($usec, $sec) = explode(' ', microtime());
return (float) $sec + ((float) $usec * 100000);
}
mt_srand(make_seed());//4.2.0以下版本适用
$authnum = mt_rand(100, 99999);
// 加入session
$_SESSION['verifycode']=$authnum;
//echo $authnum;
//生成验证码图片
Header("Content-type: image/PNG");
$im = imagecreatetruecolor($img_w, $img_h);
$bg_color = ImageColorAllocate($im, mt_rand(250,255),mt_rand(250,255),mt_rand(250,255));
// 绘制背景
imagefill($im,0,0,$bg_color);
$total_width = 0;
$word_info = array();
// 循环，获取文字信息
$word_length = strlen($authnum);
for($ii=0; $ii<$word_length; $ii++)
{
$word_space = mt_rand(1,5);
$font = rand(3,5);
mt_rand(1,9)%2 == 0?$top = 1:$top = 3;
$word_info[$ii]['char']   = substr($authnum,$ii,1);
$word_info[$ii]['font']   = $font;
$word_info[$ii]['offset'] = $top;
if($ii == 0)
{
$word_info[$ii]['width'] = 0;
}
$word_info[$ii]['width']  = imageFontWidth($font)+$word_space;
$word_info[$ii]['height'] = imageFontHeight($font);
$word_info[$ii]['color']  = imageColorAllocate($im, mt_rand(0,50),mt_rand(0,150),mt_rand(0,200));
// 文字总宽度
$total_width += $word_info[$ii]['width'];
// 取第一个字体的高度
if($ii == 0)
{
$total_height = imagefontHeight($font);
}
}
// 计算偏移
$offset_x = floor(($img_w - $total_width)/2);
$offset_y = floor(($img_h - $total_height)/2);
// 填充验证码
$wid = 0;
$i = 0;
foreach($word_info as $key=>$val)
{
if($i>0)
{
$wid += $val['width'];
}
imagestring($im, $val['font'], $offset_x + $wid, $val['offset'] + $offset_y, $val['char'], $val['color']);
$i++;
}
switch($pixel_mode)
{
case 1:
$pixel_color  = ImageColorAllocate($im,
mt_rand(50,255),
mt_rand(50,255),
mt_rand(50,255));
// 干扰象素
for($i=0;$i<$pixel_num;$i++)
{
imagesetpixel($im, mt_rand()%$img_w , mt_rand()%$img_h , $pixel_color);
}
break;
case '2':
// 干扰象素
for ($i=0;$i<=128;$i++)
{
$pixel_color = imagecolorallocate ($im, rand(0,255), rand(0,255), rand(0,255));
imagesetpixel($im,mt_rand(2,128),mt_rand(2,38),$pixel_color);
}
break;
default:
$pixel_color  = ImageColorAllocate($im,
mt_rand(50,255),
mt_rand(50,255),
mt_rand(50,255));
// 干扰象素
for($i=0;$i<$pixel_num;$i++)
{
imagesetpixel($im, mt_rand()%$img_w , mt_rand()%$img_h , $pixel_color);
}
break;
}
ImagePNG($im);
?>