php 生产验证码

<?php
/**
* 生成验证码
* @author chenzhouyu
* 类用法
* $checkcode = new checkcode();
* $checkcode->doimage();
* //取得验证
* $_SESSION['code']=$checkcode->get_code();
*/
class checkcode {
//验证码的宽度
public $width=130;

//验证码的高
public $height=50;

//设置字体的地址
private $font;

//设置字体色
public $font_color;

//设置随机生成因子
public $charset = 'abcdefghkmnprstuvwyzABCDEFGHKLMNPRSTUVWYZ23456789';

//设置背景色
public $background = '#EDF7FF';

//生成验证码字符数
public $code_len = 5;

//字体大小
public $font_size = 20;

//验证码
private $code;

//图片内存
private $img;

//文字X轴开始的地方
private $x_start;

function __construct() {
$rand = rand(0,1);
if($rand==0) {
$this->font = PC_PATH.'libs'.DIRECTORY_SEPARATOR.'data'.DIRECTORY_SEPARATOR.'font'.DIRECTORY_SEPARATOR.'elephant.ttf';
} else {
$this->font = PC_PATH.'libs'.DIRECTORY_SEPARATOR.'data'.DIRECTORY_SEPARATOR.'font'.DIRECTORY_SEPARATOR.'Vineta.ttf';
}
}

/**
* 生成随机验证码。
*/
protected function creat_code() {
$code = '';
$charset_len = strlen($this->charset)-1;
for ($i=0; $i<$this->code_len; $i++) {
$code .= $this->charset[rand(1, $charset_len)];
}
$this->code = $code;
return $code;
}

/**
* 获取验证码
*/
public function get_code() {
return strtolower($this->code);
}

/**
* 生成图片
*/
public function doimage() {
$code = $this->creat_code();
$this->img = imagecreatetruecolor($this->width, $this->height);
if (!$this->font_color) {
$this->font_color = imagecolorallocate($this->img, rand(0,156), rand(0,156), rand(0,156));
} else {
$this->font_color = imagecolorallocate($this->img, hexdec(substr($this->font_color, 1,2)), hexdec(substr($this->font_color, 3,2)), hexdec(substr($this->font_color, 5,2)));
}
//设置背景色
$background = imagecolorallocate($this->img,hexdec(substr($this->background, 1,2)),hexdec(substr($this->background, 3,2)),hexdec(substr($this->background, 5,2)));
//画一个柜形，设置背景颜色。
imagefilledrectangle($this->img,0, $this->height, $this->width, 0, $background);
$this->creat_font();
$this->creat_line();
$this->output();
}

/**
* 生成文字
*/
private function creat_font() {
$x = $this->width/$this->code_len;
for ($i=0; $i<$this->code_len; $i++) {
imagettftext($this->img, $this->font_size, rand(-30,30), $x*$i+rand(0,5), $this->height/1.4, $this->font_color, $this->font, $this->code[$i]);
if($i==0)$this->x_start=$x*$i+5;
}
}

/**
* 画线
*/
private function creat_line() {
imagesetthickness($this->img, 3);
$xpos   = ($this->font_size * 2) + rand(-5, 5);
$width  = $this->width / 2.66 + rand(3, 10);
$height = $this->font_size * 2.14;

if ( rand(0,100) % 2 == 0 ) {
$start = rand(0,66);
$ypos  = $this->height / 2 - rand(10, 30);
$xpos += rand(5, 15);
} else {
$start = rand(180, 246);
$ypos  = $this->height / 2 + rand(10, 30);
}

$end = $start + rand(75, 110);

imagearc($this->img, $xpos, $ypos, $width, $height, $start, $end, $this->font_color);

if ( rand(1,75) % 2 == 0 ) {
$start = rand(45, 111);
$ypos  = $this->height / 2 - rand(10, 30);
$xpos += rand(5, 15);
} else {
$start = rand(200, 250);
$ypos  = $this->height / 2 + rand(10, 30);
}

$end = $start + rand(75, 100);

imagearc($this->img, $this->width * .75, $ypos, $width, $height, $start, $end, $this->font_color);
}

/**
* 输出图片
*/
private function output() {
header("content-type:image/png\r\n");
imagepng($this->img);
imagedestroy($this->img);
}
}