ThinkPHP 3.2.3实现加减乘除图片验证码

<?php
namespace HomeCommon;
use ThinkVerify;
class VerifyProcess extends Verify {
private $_image = NULL;  // 验证码图片实例
private $_color = NULL;  // 验证码字体颜色
public function entryProcess($id = '') {
// 图片宽(px)
$this- imageW || $this- imageW = $this- length*$this- fontSize*1.5 +
$this- length*$this- fontSize/2;
// 图片高(px)
$this- imageH || $this- imageH = $this- fontSize * 2.5;
// 建立一幅 $this- imageW x $this- imageH 的图像
$this- _image = imagecreate($this- imageW, $this- imageH);
// 设置背景  
imagecolorallocate($this- _image, $this- bg[0], $this- bg[1], $this- bg[2]);
// 验证码字体随机颜色
$this- _color = imagecolorallocate($this- _image, mt_rand(1,150), 
mt_rand(1,150), mt_rand(1,150));
// 验证码使用随机字体
$ttfPath = $_SERVER['DOCUMENT_ROOT'].'/ThinkPHP/Library/Think/Verify/' . 
($this- useZh ? 'zhttfs' : 'ttfs') . '/';
if(empty($this- fontttf)){
$dir = dir($ttfPath);
$ttfs = array();  
while (false !== ($file = $dir- read())) {
if($file[0] != '.' && substr($file, -4) == '.ttf') {
$ttfs[] = $file;
}
}
$dir- close();
$this- fontttf = $ttfs[array_rand($ttfs)];
}
$this- fontttf = $ttfPath . $this- fontttf;
if($this- useImgBg) {
$this- _background();
}
if ($this- useNoise) {
// 绘杂点
$this- _writeNoise();
}
if ($this- useCurve) {
// 绘干扰线
$this- _writeCurve();
}
// 绘验证码
$codeNX = 0; // 验证码第N个字符的左边距
// 验证码为简单运算
$a = mt_rand(1,9);
$b = mt_rand(1,9);
$operate_array = array('+', '-', '*');
$key = mt_rand(0, count($operate_array) - 1);
if($operate_array[$key] == '+') { // 加法
$code = $a.'+'.$b.'=';
$result = intval($a + $b);
} elseif($operate_array[$key] == '-') { // 减法
$code = max($a,$b).'-'.min($a,$b).'=';
$result = intval(abs($a - $b));
} else { // 乘法
$code = $a.'*'.$b.'=';
$result = intval($a * $b);
}
$this- length = 4;
for ($i = 0; $i<$this- length; $i++) {
$codeNX += mt_rand($this- fontSize*1.2, $this- fontSize*1.6);
imagettftext($this- _image, $this- fontSize, mt_rand(-40, 40), 
$codeNX, $this- fontSize*1.6, $this- _color, $this- fontttf, $code[$i]);
}
// 保存验证码
$key  = $this- authcode($this- seKey);
$result  = $this- authcode($result);
$secode  = array();
$secode['verify_code'] = $result; // 把校验码保存到session
$secode['verify_time'] = NOW_TIME; // 验证码创建时间
session($key.$id, $secode);
header('Cache-Control: private, max-age=0, no-store, no-cache, must-revalidate');
header('Cache-Control: post-check=0, pre-check=0', false);  
header('Pragma: no-cache');
header("content-type: image/png");
// 输出图像
imagepng($this- _image);
imagedestroy($this- _image);
}
/**
* 画杂点
* 往图片上写不同颜色的字母或数字
*/
private function _writeNoise() {
$codeSet = '2345678abcdefhijkmnpqrstuvwxyz';
for($i = 0; $i < 10; $i++){
//杂点颜色
$noiseColor = imagecolorallocate($this- _image, mt_rand(150,225), 
mt_rand(150,225), mt_rand(150,225));
for($j = 0; $j < 5; $j++) {
// 绘杂点
imagestring($this- _image, 5, mt_rand(-10, $this- imageW), 
mt_rand(-10, $this- imageH), $codeSet[mt_rand(0, 29)], $noiseColor);
}
}
}
/**
* 画一条由两条连在一起构成的随机正弦函数曲线作干扰线(你可以改成更帅的曲线函数)
*  
*  高中的数学公式咋都忘了涅，写出来
*  正弦型函数解析式：y=Asin(ωx+φ)+b
*  各常数值对函数图像的影响：
*  A：决定峰值（即纵向拉伸压缩的倍数）
*  b：表示波形在Y轴的位置关系或纵向移动距离（上加下减）
*  φ：决定波形与X轴位置关系或横向移动距离（左加右减）
*  ω：决定周期（最小正周期T=2π/∣ω∣）
*
*/
private function _writeCurve() {
$px = $py = 0;
// 曲线前部分
$A = mt_rand(1, $this- imageH/2);     // 振幅
$b = mt_rand(-$this- imageH/4, $this- imageH/4); // Y轴方向偏移量
$f = mt_rand(-$this- imageH/4, $this- imageH/4); // X轴方向偏移量
$T = mt_rand($this- imageH, $this- imageW*2); // 周期
$w = (2* M_PI)/$T;
$px1 = 0; // 曲线横坐标起始位置
$px2 = mt_rand($this- imageW/2, $this- imageW * 0.8); // 曲线横坐标结束位置
for ($px=$px1; $px<=$px2; $px = $px + 1) {
if ($w!=0) {
$py = $A * sin($w*$px + $f)+ $b + $this- imageH/2; 
// y = Asin(ωx+φ) + b
$i = (int) ($this- fontSize/5);
while ($i   0) {
imagesetpixel($this- _image, $px + $i , $py + $i, $this- _color); 
// 这里(while)循环画像素点比imagettftext和imagestring用字体大小一次画出
（不用这while循环）性能要好很多   
$i--;
}
}
}
// 曲线后部分
$A = mt_rand(1, $this- imageH/2);     // 振幅 
$f = mt_rand(-$this- imageH/4, $this- imageH/4); // X轴方向偏移量
$T = mt_rand($this- imageH, $this- imageW*2); // 周期
$w = (2* M_PI)/$T;  
$b = $py - $A * sin($w*$px + $f) - $this- imageH/2;
$px1 = $px2;
$px2 = $this- imageW;
for ($px=$px1; $px<=$px2; $px=$px+ 1) {
if ($w!=0) {
$py = $A * sin($w*$px + $f)+ $b + $this- imageH/2; 
// y = Asin(ωx+φ) + b
$i = (int) ($this- fontSize/5);
while ($i   0) {  
imagesetpixel($this- _image, $px + $i, $py + $i, $this- _color); 
$i--;
}
}
}
}
/* 加密验证码 */
private function authcode($str){
$key = substr(md5($this- seKey), 5, 8);
$str = substr(md5($str), 8, 10);
return md5($key . $str);
} 
/**
* 绘制背景图片
* 注：如果验证码输出图片比较大，将占用比较多的系统资源
*/
private function _background() {
$path = dirname(__FILE__).'/Verify/bgs/';
$dir = dir($path);
$bgs = array();  
while (false !== ($file = $dir- read())) {
if($file[0] != '.' && substr($file, -4) == '.jpg') {
$bgs[] = $path . $file;
}
}
$dir- close();
$gb = $bgs[array_rand($bgs)];
list($width, $height) = @getimagesize($gb);
// Resample
$bgImage = @imagecreatefromjpeg($gb);
@imagecopyresampled($this- _image, $bgImage, 0, 0, 0, 0, $this- imageW, 
$this- imageH, $width, $height);
@imagedestroy($bgImage);
} 
}　　

<?php
namespace HomeController;
use ThinkController;
use HomeCommonVerifyProcess;
class TestVerifyController extends Controller {
// 界面
public function index() {
$this- display('User/verify');
}
// 验证
public function check_verify() {
$verify = new VerifyProcess();
if(!$verify- check($_POST['verify'])) {
$this- error('验证码错误');
}
}
// 显示验证码
public function verify() {
$verify = new VerifyProcess();
$verify- entryProcess();
} 
}

<!DOCTYPE html 
<html lang="en" 
<head 
<meta charset="UTF-8" 
<title Document</title 
<script src="http://lib.sinaapp.com/js/jquery/1.9.1/jquery-1.9.1.min.js" </script 
</head 
<body 
<form action="{:U('Home/TestVerify/check_verify','','')}" method="post" 
<table 
<tr 
<td 验证码：</td 
<td <input type="text" name="verify" </td 
<td 
<img id="verify" src="{:U('Home/TestVerify/verify','','')}" 
style="cursor: pointer;" alt="" 
<a id="refresh" href="javascript:void(0)" rel="external nofollow"  更换验证码</a 
</td 
</tr 
<tr 
<td colspan="2" 
<input type="submit" value="提交" 
</td 
</tr 
</table 
</form 
</body 
<script 
$(function(){
$src = $("#verify").attr('src');
$("#refresh").click(function(){
change_verify();
}); 
$("#verify").click(function(){
change_verify();
});
function change_verify() {
$('#verify').attr('src', $src + '?' + Math.random());
}
});
</script 
</html