用PHP实现图片验证码示例
1、产生随机字符串
2、创建一张简单的图片，设置背景色，文本色
3、再加一些干扰线，干扰素
4、输出图像
5、销毁图像资源
<?php
//PHP生成图片验证码
class VerifyImage{
private $verifyCode;
private $image;
//生成随机字串
private function createCode($type=1,$length=4){
if ($type == 1) {
$verifyCode = implode('', range(0, 9));
}elseif ($type == 2) {
$verifyCode = implode('', array_merge(range('a', 'z'),range('A', 'Z')));
}else{
$verifyCode = implode('', array_merge(range('a', 'z'),range(0, 9),range('A', 'Z')));
}
//判断生成字符是否符合要求
if (strlen($verifyCode)<$length) {
return false;
}
//打乱字符串
$verifyCode = str_shuffle($verifyCode);
return substr($verifyCode, 0,$length);
}
//生成图片,并加入干扰线，干扰素
public function createImage($type=1,$length=4,$width = 80,$height = 40){
$verifyCode = $this->createCode($type,$length);
$image = imagecreatetruecolor($width, $height);
//白色背景
$white = imagecolorallocate($image, 255, 255, 255);
//字体颜色
$fontStyle = imagecolorallocate($image, rand(0, 255),rand(0, 255), rand(0, 255));;
imagefill($image, 0, 0, $white);
imagestring($image, 5, 10, 10, $verifyCode, $fontStyle);
//加入干扰点
for($i = 0; $i < 80; $i++) {
$color = imagecolorallocate($image, rand(0, 255), rand(0, 255), rand(0, 255));
imagesetpixel($image, rand(0, $width), rand(0,$height), $color);
}
//干扰线
for($i = 0; $i < 5; $i++) {
$color = imagecolorallocate($image, rand(0, 255), rand(0, 255), rand(0, 255));
imageline($image, rand(0, $width), rand(0, $height), rand(0, $width), rand(0, $height), $color);
}
//输出图片
header("Content-type: image/png");
imagepng($image);
//释放资源
imagedestroy($image);
}
}
$im = new VerifyImage();;
$im->createImage(3);
?>
