{
private $width,$height,$codenum;
public $checkcode; //产生的验证码
private $checkimage; //验证码图片
private $disturbColor = ''; //干扰像素
function __construct($width='80',$height='20',$codenum='4')
{
$this->width=$width;
$this->height=$height;
$this->codenum=$codenum;
}
function outImg()
{
//输出头
$this->outFileHeader();
//产生验证码
$this->createCode();
//产生图片
$this->createImage();
//设置干扰像素
$this->setDisturbColor();
//往图片上写验证码
$this->writeCheckCodeToImage();
imagepng($this->checkimage);
imagedestroy($this->checkimage);
}
private function outFileHeader()
{
header ("Content-type: image/png");
}
private function createCode()
{
$this->checkcode = strtoupper(substr(md5(rand()),$this->codenum));
}
private function createImage()
{
$this->checkimage = @imagecreate($this->width,$this->height);
$back = imagecolorallocate($this->checkimage,255,255);
$border = imagecolorallocate($this->checkimage,0);
imagefilledrectangle($this->checkimage,$this->width - 1,$this->height - 1,$back); // 白色底
imagerectangle($this->checkimage,$border); // 黑色边框
}
private function setDisturbColor()
{
for ($i=0;$i<=200;$i++)
{
$this->disturbColor = imagecolorallocate($this->checkimage,rand(0,255),255));
imagesetpixel($this->checkimage,rand(2,128),38),$this->disturbColor);
}
}
private function writeCheckCodeToImage()
{
for ($i=0;$i<=$this->codenum;$i++)
{
$bg_color = imagecolorallocate ($this->checkimage,255));
$x = floor($this->width/$this->codenum)*$i;
$y = rand(0,$this->height-15);
imagechar ($this->checkimage,rand(5,8),$x,$y,$this->checkcode[$i],$bg_color);
}
}
function __destruct()
{
unset($this->width,$this->height,$this->codenum);
}
}
?>