GD库制作验证码

php代码：

<?php 
// 配置验证码
$code_ini = array(
		&#39;code_count&#39;	=> 4,	 // 验证码长度
		&#39;code_size&#39;		=> 20,	 // 验证码字体大小
		&#39;code_width&#39;	=> 100,	 // 验证码框宽度
		&#39;code_height&#39;	=> 30,	 // 验证码框高度
		&#39;code_num&#39;		=> true, // 开启数字
		&#39;code_upper&#39;	=> true, // 开启大写字母
		&#39;code_lower&#39;	=> true, // 开启小写字母 
		&#39;code_remove&#39;	=> &#39;1li0oO2zZ&#39; //排除易混淆字符
	);
// 将配置项转为对应变量
foreach ($code_ini as $key=>$value) {
	$$key = $value;
}
// 创建验证码画布
$code_img = imagecreatetruecolor($code_width, $code_height);
$black = imagecolorallocate($code_img, 0, 0, 0);
// 填充随机背景颜色
$bg = imagecolorallocate($code_img, rand(200, 255), rand(200, 255), rand(200, 255));
imagefill($code_img, 0, 0, $bg);

// 随机画100个干扰点
for ($i = 0; $i < 100; $i++) {
	$color = imagecolorallocate($code_img, rand(0, 200), rand(0, 200), rand(0, 200));
	imagesetpixel($code_img, rand(2, $code_width-2), rand(2, $code_height-2), $color);
}

// 随机画10个干扰线
for ($q = 0; $q < 10; $q++) {
	$color = imagecolorallocate($code_img, rand(0, 200), rand(0, 200), rand(0, 200));
	imageline($code_img, rand(2, $code_width-2), rand(2, $code_height-2), rand(2, $code_width-2), rand(2, $code_height-2), $color);
}


// 获取验证码
$code = get_code($code_count, $code_num, $code_upper, $code_lower, $code_remove);

for ($i=0; $i<$code_count; $i++) {
	$color = imagecolorallocate($code_img, rand(0, 200), rand(0, 200), rand(0,200));
	imagettftext($code_img, $code_size, rand(-30, 30), 5+20*$i, 24, $color, &#39;../fonts/msyh.ttf&#39;,$code[$i]);
}
imagerectangle($code_img, 0, 0, $code_width-1, $code_height-1, $black);
// 输出验证码
header(&#39;content-type:image/gif&#39;);
imagegif($code_img);

// 销毁资源
imagedestroy($code_img);

// 获得验证码
function get_code($code_count, $code_num, $code_upper, $code_lower, $code_remove) {
	$num = array();
	$upper = array();
	$lower = array();
	if ($code_num) {
		$num = range(0, 9);
	}
	if ($code_upper) {
		$upper = range(&#39;A&#39;, &#39;Z&#39;);
	}
	if ($code_lower) {
		$lower = range(&#39;a&#39;, &#39;z&#39;);
	}
	// 合并符合条件数组
	$arr = array_merge($num, $lower, $upper);
	// 排除易混淆字符
	$remove = str_split($code_remove);
	$arr1 = array_diff($arr, $remove);
	$mess = &#39;&#39;;
	for ($i=0; $i<$code_count; $i++) {
		$mess .= $arr1[array_rand($arr1)];
	}
	return $mess;
}