CI框架中，扩展验证码类。

使用CI框架的朋友，应该都知道CI框架的的验证码辅助函数，不太好用。它需要写入到数据库中，然后再进行比对。

大家在实际项目中，好像不会这样去使用，因为会对数据库造成一定的压力。

所以，我们还是利用session来临时存储验证码，比较的稳妥。

下面附上验证码类的代码。这个类是放在libraries这个库文件夹下。

<?php

/**
* 验证码类
*/

class Code{
//资源
private $img;
//画布宽度
public $width = 150;
//画布高度
public $height = 45;
//背景颜色
public $bgColor = "#ffffff";
//验证码
public $code;
//验证码的随机种子
public $codeStr = "123456789abcdefghijklmnpqrstuvwsyz";
//验证码长度
public $codeLen = 4;
//验证码字体
public $font = "";//具体环境具体需要更改路径
//验证码字体大小
public $fontSize = 22;
//验证码字体颜色
public $fontColor = "";

/**
* 构造函数
*/
public function __construct($arr = array()) {

$width = '';
$height = '';
$codeLen = '';
$fontSize = '';
$bgColor = '';
$fontColor = '';

if(!empty($arr)){
extract($arr);
}
$this->font = BASEPATH . "fonts/font.ttf";
if (!is_file($this->font)) {
error("验证码字体文件不存在");
}
$this->width = empty($width) ? $this->width : $width;
$this->height = empty($height) ? $this->height : $height;
$this->bgColor = empty($bgColor) ? $this->bgColor : $bgColor;
$this->codeLen = empty($codeLen) ? $this->codeLen : $codeLen;
$this->fontSize = empty($fontSize) ? $this->fontSize : $fontSize;
$this->fontColor = empty($fontColor) ? $this->fontColor : $fontColor;
$this->create();//生成验证码
}

/**
* 生成验证码
*/
private function createCode() {
$code = '';
for ($i = 0; $i < $this->codeLen; $i++) {
$code .= $this->codeStr [mt_rand(0, strlen($this->codeStr) - 1)];
}
$this->code = strtoupper($code);
if(!isset($_SESSION)){
session_start();
}
$_SESSION ['code'] = $this->code;
}

/**
* 返回验证码
*/
public function getCode() {
return $this->code;
}

/**
* 建画布
*/
public function create() {
if (!$this->checkGD())
return false;
$w = $this->width;
$h = $this->height;
$bgColor = $this->bgColor;
$img = imagecreatetruecolor($w, $h);
$bgColor = imagecolorallocate($img, hexdec(substr($bgColor, 1, 2)), hexdec(substr($bgColor, 3, 2)), hexdec(substr($bgColor, 5, 2)));
imagefill($img, 0, 0, $bgColor);
$this->img = $img;
$this->createLine();
$this->createFont();
$this->createPix();
$this->createRec();
}
/**
*  画线
*/
private function createLine(){
$w = $this->width;
$h = $this->height;
$line_height = $h/10;
$line_color = "#D0D0D0";
$color = imagecolorallocate($this->img, hexdec(substr($line_color, 1, 2)), hexdec(substr($line_color, 3, 2)), hexdec(substr($line_color, 5, 2)));
for($i=0;$i<10;$i++){
$step =$line_height*$i+2;
imageline($this->img, 0, $step, $w,$step, $color);
}
$line_width = $w/10;
for($i=0;$i<10;$i++){
$step =$line_width*$i+2;
imageline($this->img, $step-2, 0, $step+2,$h, $color);
}
}
/**
* 画矩形边框
*/
private function createRec() {
imagerectangle($this->img, 0, 0, $this->width - 1, $this->height - 1, $this->fontColor);
}

/**
* 写入验证码文字
*/
private function createFont() {
$this->createCode();
$color = $this->fontColor;
if (!empty($color)) {
$fontColor = imagecolorallocate($this->img, hexdec(substr($color, 1, 2)), hexdec(substr($color, 3, 2)), hexdec(substr($color, 5, 2)));
}
$x = ($this->width - 10) / $this->codeLen;
for ($i = 0; $i < $this->codeLen; $i++) {
if (empty($color)) {
$fontColor = imagecolorallocate($this->img, mt_rand(50, 155), mt_rand(50, 155), mt_rand(50, 155));
}
imagettftext($this->img, $this->fontSize, mt_rand(- 30, 30), $x * $i + mt_rand(6, 10), mt_rand($this->height / 1.3, $this->height - 5), $fontColor, $this->font, $this->code [$i]);
}
$this->fontColor = $fontColor;
}

/**
* 画线
*/
private function createPix() {
$pix_color = $this->fontColor;
for ($i = 0; $i < 50; $i++) {
imagesetpixel($this->img, mt_rand(0, $this->width), mt_rand(0, $this->height), $pix_color);
}

for ($i = 0; $i < 2; $i++) {
imageline($this->img, mt_rand(0, $this->width), mt_rand(0, $this->height), mt_rand(0, $this->width), mt_rand(0, $this->height), $pix_color);
}
//画圆弧
for ($i = 0; $i < 1; $i++) {
// 设置画线宽度
// imagesetthickness($this->img, mt_rand(1, 3));
imagearc($this->img, mt_rand(0, $this->width), mt_rand(0, $this->height), mt_rand(0, $this->width), mt_rand(0, $this->height)
, mt_rand(0, 160), mt_rand(0, 200), $pix_color);
}
imagesetthickness($this->img, 1);
}

/**
* 显示验证码
*/
public function show() {
header("Content-type:image/png");
imagepng($this->img);
imagedestroy($this->img);
exit;
}

/**
* 验证GD库是不否打开imagepng函数是否可用
*/
private function checkGD() {
return extension_loaded('gd') && function_exists("imagepng");
}
}

　　然后再控制器中调用就可以了。



最后，提醒大家记得开启在自动加载文件中session哦。