PHP verification code class based on GD library and supports Chinese and English fonts, backgrounds, interference points, lines, distortions, etc.

<?php
/*
* Captcha Class base on PHP GD Lib
* @author Design
* @version 1.0
* @copyright js8.in 2010
* @demo
* include(&#39;captchaClass.php&#39;);
* $captchaDemo=new Captcha();
* $captchaDemo->createImage();
*/
class Captcha
{
//@定义验证码图片高度
private $height;
//@定义验证码图片宽度
private $width;
//@定义验证码字符个数
private $textNum;
//@定义验证码字符内容
private $textContent;
//@定义字符颜色
private $fontColor;
//@定义随机出的文字颜色
private $randFontColor;
//@定义字体大小
private $fontSize;
//@定义字体
private $fontFamily;
//@定义背景颜色
private $bgColor;
//@定义随机出的背景颜色
private $randBgColor;
//@定义字符语言
private $textLang;
//@定义干扰点数量
private $noisePoint;
//@定义干扰线数量
private $noiseLine;
//@定义是否扭曲
private $distortion;
//@定义扭曲图片源
private $distortionImage;
//@定义是否有边框
private $showBorder;
//@定义验证码图片源
private $image;

//@Constructor 构造函数
public function Captcha()
{
$this->textNum = 4;
$this->fontSize = 16;
$this->fontFamily = &#39;c:\windows\fontsSIMYOU.ttf&#39;; //设置中文字体，可以改成linux的目录
$this->textLang = &#39;en&#39;;
$this->noisePoint = 30;
$this->noiseLine = 3;
$this->distortion = false;
$this->showBorder = false;
}


//@设置图片宽度
public function setWidth($w)
{
$this->width = $w;
}

//@设置图片高度
public function setHeight($h)
{
$this->height = $h;
}

//@设置字符个数
public function setTextNumber($textN)
{
$this->textNum = $textN;
}

//@设置字符颜色
public function setFontColor($fc)
{
$this->fontColor = sscanf($fc, &#39;#%2x%2x%2x&#39;);
}

//@设置字号
public function setFontSize($n)
{
$this->fontSize = $n;
}

//@设置字体
public function setFontFamily($ffUrl)
{
$this->fontFamily = $ffUrl;
}

//@设置字符语言
public function setTextLang($lang)
{
$this->textLang = $lang;
}

//@设置图片背景
public function setBgColor($bc)
{
$this->bgColor = sscanf($bc, &#39;#%2x%2x%2x&#39;);
}

//@设置干扰点数量
public function setNoisePoint($n)
{
$this->noisePoint = $n;
}

//@设置干扰线数量
public function setNoiseLine($n)
{
$this->noiseLine = $n;
}

//@设置是否扭曲
public function setDistortion($b)
{
$this->distortion = $b;
}

//@设置是否显示边框
public function setShowBorder($border)
{
$this->showBorder = $border;
}

//@初始化验证码图片
public function initImage()
{
if (empty($this->width)) {
$this->width = floor($this->fontSize * 1.3) * $this->textNum + 10;
}
if (empty($this->height)) {
$this->height = $this->fontSize * 2;
}
$this->image = imagecreatetruecolor($this->width, $this->height);
if (empty($this->bgColor)) {
$this->randBgColor = imagecolorallocate($this->image, mt_rand(100, 255), mt_rand(100, 255), mt_rand(100, 255));
} else {
$this->randBgColor = imagecolorallocate($this->image, $this->bgColor[0], $this->bgColor[1], $this->bgColor[2]);
}
imagefill($this->image, 0, 0, $this->randBgColor);
}

//@产生随机字符
public function randText($type)
{
$string = &#39;&#39;;
switch ($type) {
case &#39;en&#39;:
$str = &#39;ABCDEFGHJKLMNPQRSTUVWXY3456789&#39;;
for ($i = 0; $i < $this->textNum; $i++) {
$string = $string . &#39;,&#39; . $str[mt_rand(0, 29)];
}
break;
case &#39;cn&#39;:
for ($i = 0; $i < $this->textNum; $i++) {
$string = $string . &#39;,&#39; . chr(rand(0xB0, 0xCC)) . chr(rand(0xA1, 0xBB));
}
$string = iconv(&#39;GB2312&#39;, &#39;UTF-8&#39;, $string); //转换编码到utf8
break;
}
return substr($string, 1);
}

//@输出文字到验证码
public function createText()
{
$textArray = explode(&#39;,&#39;, $this->randText($this->textLang));
$this->textContent = join(&#39;&#39;, $textArray);
if (empty($this->fontColor)) {
$this->randFontColor = imagecolorallocate($this->image, mt_rand(0, 100), mt_rand(0, 100), mt_rand(0, 100));
} else {
$this->randFontColor = imagecolorallocate($this->image, $this->fontColor[0], $this->fontColor[1], $this->fontColor[2]);
}
for ($i = 0; $i < $this->textNum; $i++) {
$angle = mt_rand(-1, 1) * mt_rand(1, 20);
imagettftext($this->image, $this->fontSize, $angle, 5 + $i * floor($this->fontSize * 1.3), floor($this->height * 0.75), $this->randFontColor, $this->fontFamily, $textArray[$i]);
}
}

//@生成干扰点
public function createNoisePoint()
{
for ($i = 0; $i < $this->noisePoint; $i++) {
$pointColor = imagecolorallocate($this->image, mt_rand(0, 255), mt_rand(0, 255), mt_rand(0, 255));
imagesetpixel($this->image, mt_rand(0, $this->width), mt_rand(0, $this->height), $pointColor);
}

}

//@产生干扰线
public function createNoiseLine()
{
for ($i = 0; $i < $this->noiseLine; $i++) {
$lineColor = imagecolorallocate($this->image, mt_rand(0, 255), mt_rand(0, 255), 20);
imageline($this->image, 0, mt_rand(0, $this->width), $this->width, mt_rand(0, $this->height), $lineColor);
}
}

//@扭曲文字
public function distortionText()
{
$this->distortionImage = imagecreatetruecolor($this->width, $this->height);
imagefill($this->distortionImage, 0, 0, $this->randBgColor);
for ($x = 0; $x < $this->width; $x++) {
for ($y = 0; $y < $this->height; $y++) {
$rgbColor = imagecolorat($this->image, $x, $y);
imagesetpixel($this->distortionImage, (int) ($x + sin($y / $this->height * 2 * M_PI - M_PI * 0.5) * 3), $y, $rgbColor);
}
}
$this->image = $this->distortionImage;
}

//@生成验证码图片
public function createImage()
{
$this->initImage(); //创建基本图片
$this->createText(); //输出验证码字符
if ($this->distortion) {
$this->distortionText();
} //扭曲文字
$this->createNoisePoint(); //产生干扰点
$this->createNoiseLine(); //产生干扰线
if ($this->showBorder) {
imagerectangle($this->image, 0, 0, $this->width - 1, $this->height - 1, $this->randFontColor);
} //添加边框
imagepng($this->image);
imagedestroy($this->image);
if ($this->distortion) {
imagedestroy($this->$distortionImage);
}
return $this->textContent;
}

}
?>

<?php
//session_start();
header("Content-type:image/png");
include(&#39;captcha5_class.php&#39;);
$captcha5 = new Captcha();

//@设置验证码宽度
//$captcha5->setWidth(200);

//@设置验证码高度
//$captcha5->setHeight(50);

//@设置字符个数
$captcha5->setTextNumber(5);

//@设置字符颜色
//$captcha5->setFontColor(&#39;#ff9900&#39;);

//@设置字号大小
//$captcha5->setFontSize(25);

//@设置字体
$captcha5->setFontFamily(&#39;c:\windows\fonts\STXINGKA.TTF&#39;);

//@设置语言
$captcha5->setTextLang(&#39;cn&#39;);

//@设置背景颜色
//$captcha5->setBgColor(&#39;#000000&#39;);

//@设置干扰点数量
//$captcha5->setNoisePoint(600);

//@设置干扰线数量
//$captcha5->setNoiseLine(10);

//@设置是否扭曲
//$captcha5->setDistortion(true);

//@设置是否显示边框
$captcha5->setShowBorder(true);

//输出验证码
$code = $captcha5->createImage();
//$_SESSION[&#39;captchaCode&#39;][&#39;content&#39;]=$code;
//$_SESSION[&#39;captchaCode&#39;][&#39;time&#39;]=microtime();
?>