本文目录一览：
如何用PHP生成验证码
PHP生成验证码的原理：使用PHP的GD库，生成一张带验证码的图片，并将验证码保存在Session中。PHP生成验证码的大致流程有：
1、产生一张png的图片；
2、为图片设置背景色；
3、设置字体颜色和样式；
4、产生4位数的随机的验证码；
5、把产生的每个字符调整旋转角度和位置画到png图片上；
6、加入噪点和干扰线防止注册机器分析原图片来恶意破解验证码；
7、输出图片；
8、释放图片所占内存。
session_start();
getCode(4,60,20);
function getCode($num,$w,$h) {
$code = "";
for ($i = 0; $i $num; $i++) {
$code .= rand(0, 9);
}
//4位验证码也可以用rand(1000,9999)直接生成
//将生成的验证码写入session，备验证时用
$_SESSION["helloweba_num"] = $code;
//创建图片，定义颜色值
header("Content-type: image/PNG");
$im = imagecreate($w, $h);
$black = imagecolorallocate($im, 0, 0, 0);
$gray = imagecolorallocate($im, 200, 200, 200);
$bgcolor = imagecolorallocate($im, 255, 255, 255);
//填充背景
imagefill($im, 0, 0, $gray);
//画边框
imagerectangle($im, 0, 0, $w-1, $h-1, $black);
//随机绘制两条虚线，起干扰作用
$style = array ($black,$black,$black,$black,$black,
$gray,$gray,$gray,$gray,$gray
);
imagesetstyle($im, $style);
$y1 = rand(0, $h);
$y2 = rand(0, $h);
$y3 = rand(0, $h);
$y4 = rand(0, $h);
imageline($im, 0, $y1, $w, $y3, IMG_COLOR_STYLED);
imageline($im, 0, $y2, $w, $y4, IMG_COLOR_STYLED);
//在画布上随机生成大量黑点，起干扰作用;
for ($i = 0; $i 80; $i++) {
imagesetpixel($im, rand(0, $w), rand(0, $h), $black);
}
//将数字随机显示在画布上,字符的水平间距和位置都按一定波动范围随机生成
$strx = rand(3, 8);
for ($i = 0; $i $num; $i++) {
$strpos = rand(1, 6);
imagestring($im, 5, $strx, $strpos, substr($code, $i, 1), $black);
$strx += rand(8, 12);
}
imagepng($im);//输出图片
imagedestroy($im);//释放图片所占内存
}
php 怎么获取验证码的值
$_SESSION["vcode"] = $vcode;
验证码的值就在 $_SESSION["vcode"] 里面。
PHP制作验证码时候只显示一个白色框框
?php
ob_clean();
//header("Content-type:text/html");
header("Content-type:image/jpeg"); //以jpeg格式输出，注意上面不能输出任何字符，否则出错
$w = 100; //设置图片宽和高
$h = 50;
$fontsize=16;//设置字体大小
$str = Array(); //用来存储随机码
$string = "ABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789";//随机挑选其中4个字符，也可以选择更多，注意循环的时候加上，宽度适当调整
$vcode='';
for($i = 0;$i 4;$i++){
$str[$i] = $string[rand(0,strlen($string)-1)];
$vcode .= $str[$i];
}
//echo $vcode;
session_start(); //启用超全局变量session
//session_register("vcode");
$_SESSION["vcode"] = $vcode;
$im = imagecreatetruecolor($w,$h); //创建图片画布
$white = imagecolorallocate($im,255,255,255); //第一次调用设置背景色
$black = imagecolorallocate($im,0,0,0); //边框颜色
imagefilledrectangle($im,0,0,$w,$h,$white); //画一矩形填充
imagerectangle($im,0,0,$w-1,$h-1,$black); //画一矩形框
$fontsrc="consola.ttf" ;
//生成雪花背景
for($i = 1;$i 200;$i++){
$x = mt_rand(1,$w-9);
$y = mt_rand(1,$h-9);
$color = imagecolorallocate($im,mt_rand(200,255),mt_rand(200,255),mt_rand(200,255));
imagechar($im,1,$x,$y,"*",$color);
}
//将验证码写入图案
for($i = 0;$i count($str);$i++){
$x = 13 + $i * ($w - 15)/4;
$y = mt_rand(25,$h-15 );
$color = imagecolorallocate($im,mt_rand(0,225),mt_rand(0,150),mt_rand(0,225));
//imagechar($im,$fontsize,$x,$y,$str[$i],$color);
imagettftext($im,$fontsize,0,$x,$y,$color,$fontsrc,$str[$i]);
}
imagejpeg($im); //输出图片文件
imagedestroy($im); //销毁释放资源
?
怎么用php生成图像，生成验证码
?php
//验证码类
class ValidateCode {
private $charset = 'abcdefghkmnprstuvwxyzABCDEFGHKMNPRSTUVWXYZ23456789';//随机因子
private $code;//验证码
private $codelen = 4;//验证码长度
private $width = 90;//宽度
private $height = 40;//高度
private $img;//图形资源句柄
private $font;//指定的字体
private $fontsize = 20;//指定字体大小
private $fontcolor;//指定字体颜色
//构造方法初始化
public function __construct() {
$this-font = dirname(__FILE__).'/font/elephant.ttf';//注意字体路径要写对，否则显示不了图片
}
//生成随机码
private function createCode() {
$_len = strlen($this-charset)-1;
for ($i=0;$i$this-codelen;$i++) {
$this-code .= $this-charset[mt_rand(0,$_len)];
}
}
//生成背景
private function createBg() {
$this-img = imagecreatetruecolor($this-width, $this-height);
$color = imagecolorallocate($this-img, mt_rand(157,255), mt_rand(157,255), mt_rand(157,255));
imagefilledrectangle($this-img,0,$this-height,$this-width,0,$color);
}
//生成文字
private function createFont() {
$_x = $this-width / $this-codelen;
for ($i=0;$i$this-codelen;$i++) {
$this-fontcolor = imagecolorallocate($this-img,mt_rand(0,156),mt_rand(0,156),mt_rand(0,156));
imagettftext($this-img,$this-fontsize,mt_rand(-30,30),$_x*$i+mt_rand(1,5),$this-height / 1.4,$this-fontcolor,$this-font,$this-code[$i]);
}
}
//生成线条、雪花
private function createLine() {
//线条
for ($i=0;$i6;$i++) {
$color = imagecolorallocate($this-img,mt_rand(0,156),mt_rand(0,156),mt_rand(0,156));
imageline($this-img,mt_rand(0,$this-width),mt_rand(0,$this-height),mt_rand(0,$this-width),mt_rand(0,$this-height),$color);
}
//雪花
for ($i=0;$i100;$i++) {
$color = imagecolorallocate($this-img,mt_rand(200,255),mt_rand(200,255),mt_rand(200,255));
imagestring($this-img,mt_rand(1,5),mt_rand(0,$this-width),mt_rand(0,$this-height),'*',$color);
}
}
//输出
private function outPut() {
header('Content-type:image/png');
imagepng($this-img);
imagedestroy($this-img);
}
//对外生成
public function doimg() {
$this-createBg();
$this-createCode();
$this-createLine();
$this-createFont();
$this-outPut();
}
//获取验证码
public function getCode() {
return strtolower($this-code);
}
}
求一个php验证码及如何使用的例子?
以前项目中的东西
在没有GB库的情况下也可以生成验证码
关键部分做出了注释
img src="image.php"
?php
//存为文件 image.php
error_reporting(E_ALL ^ E_NOTICE);
require_once('image.class.php');
$image_model = new Image();
//可以在此处更改属性达到验证码不同大小的图片
$image_model-outputBrowser();
?
?php
/*
* \验证码生成类 存为文件image.class.php
* \如果不支持GD库，则采用像素画法
* \详见
*/
class Image
{
var $img_height = 20; //图片的长
var $img_width = 68; //图片的宽
var $img_cache = ''; //图像信息缓存
var $check_number = ''; //验证码
var $lenght = 4; //验证码位数
var $is_gd = false;
//'----------以下为不支持GD需要的变量
var $pixels = '';
var $digits = '';
var $lines = '';
var $data = '';
var $chunk = '';
var $crc_table = '';
function Image()
{
session_start();
session_register("check_number");
$this-session = $_SESSION;
$this-is_gd = function_exists('gd_info') ? true : false;
$this-getCheckNumber();
if( $this-is_gd ):
$this-getFromGD();
else:
$this-getFromCode();
endif;
}
//'----浏览器输出
function outputBrowser()
{
if( $this-is_gd )
{
Header("Content-type: image/png"); //告诉浏览器，下面的数据是图片，而不要按文字显示
Imagepng($this-img_cache); //生成png格式。。。嘿嘿效果蛮像回事的嘛。。。
ImageDestroy($this-img_cache);
}
else echo($this-img_cache);
}
//'----文件输出
function outputFile($filename=null)
{
if(!$filename)$filename=time().'.png';
$fp = fopen($filename, 'w+');
fwrite($fp, $this-img_cache);
fclose($fp);
}
//'----得到验证码
function getCheckNumber()
{
//srand(microtime() * 100000);//PHP420后，srand不是必须的
for($Tmpa=0;$Tmpa$this-lenght;$Tmpa++)
{
$this-check_number.= $this-is_gd ? dechex(rand(0,15)) : rand(0,3);
}
unset($Tmpa);
$this-session['check_number'] = strtoupper($this-check_number);
}
//'----用GD库生成
function getFromGD()
{
//$black = '';
$this-img_cache = imageCreate($this-img_width,$this-img_height); //生成图片
//图片底色，ImageColorAllocate第1次定义颜色PHP就认为是底色了
$black = ImageColorAllocate($this-img_cache, 255,255,255);
//下面该生成雪花背景了，其实就是在图片上生成一些符号
//先用100个做测试
/*
for ($i=1; $i=15; $i++)
{
imageString($this-img_cache,1,mt_rand(1,$this-img_height-10),mt_rand(1,$this-img_width-10),".",
imageColorAllocate($this-img_cache,mt_rand(100,255),mt_rand(0,250),mt_rand(0,200)));
//哈，看到了吧，其实也不是雪花，就是生成＊号而已。为了使它们看起来"杂乱无章、5颜6色"，就得在1个1个生成它们的时候，让它们的位置、颜色，甚至大小都用随机数，rand()或mt_rand都可以完成。
}
*/
//上面生成了背景，现在就该把已经生成的随机数放上来了。道理和上面差不多，随机数1个1个地放，同时让他们的位置、大小、颜色都用成随机数~~
//为了区别于背景，这里的颜色不超过200，上面的不小于200
imagettftext($this-img_cache, 20, 0, 10, 20, $black, "./html/VINERITC.TTF", "AC67");
for ($i=0;$istrlen($this-session['check_number']);$i++)
{
imagettftext($this-img_cache, 14, rand(0,30), $i*$this-img_width/4 + 3, 17, imageColorAllocate($this-img_cache,mt_rand(0,100),mt_rand(0,150),mt_rand(0,200)), "./html/VINERITC.TTF", $this-session['check_number'][$i]);
}
for($i=0;$i100;$i++)//加入干扰象素
{
imagesetpixel($this-img_cache, rand()%70 , rand()%30 , imageColorAllocate($this-img_cache,mt_rand(100,255),mt_rand(0,250),mt_rand(0,200)));
}
$black = ImageColorAllocate($this-img_cache, 0,0,0); //定义需要的黑色
//先成一黑色的矩形把图片包围
ImageRectangle($this-img_cache,0,0, $this-img_width-1,$this-img_height-1, $black);
}
//End Function getGD
#-----------------------------------------------------------------------------------------------------------------------
function set_4pixel($r, $g, $b, $x, $y)
{
$ofs = 3 * ($this-img_width * $y + $x);
$this-pixels[$ofs] = chr($r);
$this-pixels[$ofs + 1] = chr($g);
$this-pixels[$ofs + 2] = chr($b);
$this-pixels[$ofs + 3] = chr($r);
$this-pixels[$ofs + 4] = chr($g);
$this-pixels[$ofs + 5] = chr($b);
$ofs += 3 * $this-img_width;
$this-pixels[$ofs] = chr($r);
$this-pixels[$ofs + 1] = chr($g);
$this-pixels[$ofs + 2] = chr($b);
$this-pixels[$ofs + 3] = chr($r);
$this-pixels[$ofs + 4] = chr($g);
$this-pixels[$ofs + 5] = chr($b);
}
//生成数字图象的函数
function draw2digits($x, $y, $number)
{
//$this-draw_digit($x, $y, intval($number / 10) );
$this-draw_digit($x + 11, $y, $number % 10);
}
function draw_digit($x, $y, $digit)
{
$digit = $this-digits[$digit];
$m = 8;
for($b = 1, $i = 0; $i 7; $i++, $b *= 2)
{
if(($b $digit) == $b)
{
$j = $i * 4;
$x0 = $this-lines[$j] * $m + $x;
$y0 = $this-lines[$j + 1] * $m + $y;
$x1 = $this-lines[$j + 2] * $m + $x;
$y1 = $this-lines[$j + 3] * $m + $y;
if($x0 == $x1)
{
$ofs = 3 * ($this-img_width * $y0 + $x0);
for($h = $y0; $h = $y1; $h++, $ofs += 3 * $this-img_width)
{
$this-pixels[$ofs] = chr(0);
$this-pixels[$ofs + 1] = chr(0);
$this-pixels[$ofs + 2] = chr(0);
}
}
else
{
$ofs = 3 * ($this-img_width * $y0 + $x0);
for($w = $x0; $w = $x1; $w++)
{
$this-pixels[$ofs++] = chr(0);
$this-pixels[$ofs++] = chr(0);
$this-pixels[$ofs++] = chr(0);
}
}
}//End if
}//End for
}
//将文字加入到图象中
function add_chunk($type)
{
// chunk :为层
// length: 4 字节: 用来计算 chunk
// chunk type: 4 字节
// chunk data: length bytes
// CRC: 4 字节: 循环冗余码校验
// copy data and create CRC checksum
$len = strlen($this-data);
$this-chunk = pack("c*", ($len 24) 255,
($len 16) 255,
($len 8) 255,
$len 255);
$this-chunk .= $type;
$this-chunk .= $this-data;
//calculate a CRC checksum with the bytes chunk[4..len-1]
$z = 16777215;
$z |= 255 24;
$c = $z;
for ($n = 4; $n strlen($this-chunk); $n++) {
$c8 = ($c 8) 0xffffff;
$c = $this-crc_table[($c ^ ord($this-chunk[$n])) 0xff] ^ $c8;
}
$crc = $c ^ $z;
$this-chunk .= chr(($crc 24) 255);
$this-chunk .= chr(($crc 16) 255);
$this-chunk .= chr(($crc 8) 255);
$this-chunk .= chr($crc 255);
//将结果加到$img_cache中
$this-img_cache .= $this-chunk;
}
//主程序
function getFromCode()
{
//填充
for($h = 0; $h $this-img_height; $h++)
{
for($w = 0; $w $this-img_width; $w++)
{
$r = 100 / $this-img_width * $w + 155;
$g = 100 / $this-img_height * $h + 155;
$b = 255 - (100 / ($this-img_width + $this-img_height) * ($w + $h));
$this-pixels .= chr($r);
$this-pixels .= chr($g);
$this-pixels .= chr($b);
}
}
$this-digits = array(95, 5, 118, 117, 45, 121, 123, 69, 127, 125);
$this-lines = array(1, 1, 1, 2, 0, 1, 0, 2, 1, 0, 1, 1, 0, 0, 0, 1, 0, 2, 1, 2, 0, 1, 1, 1, 0, 0, 1, 0);
for($i=0; $i$this-lenght; $i++)
{
$this-draw2digits($i*13, 2, $this-check_number[$i]);
}
//$this-set_4pixel(0, 0, 0, 26, 7);
//$this-set_4pixel(0, 0, 0, 26, 13);
//$this-set_4pixel(0, 0, 0, 52, 7);
//$this-set_4pixel(0, 0, 0, 52, 13);
//创建循环冗余码校验表
$z = -306674912;// = 0xedb88320
for ($n = 0; $n 256; $n++)
{
$c = $n;
for ($k = 0; $k 8; $k++)
{
$c2 = ($c 1) 0x7fffffff;
if($c 1) $c = $z ^ ($c2);
else $c = $c2;
}
$this-crc_table[$n] = $c;
}
// PNG file signature
$this-img_cache = pack("c*", 137,80,78,71,13,10,26,10);
// IHDR chunk data:
// width: 4 bytes
// height: 4 bytes
// bit depth: 1 byte (8 bits per RGB value)
// color type: 1 byte (2 = RGB)
// compression method: 1 byte (0 = deflate/inflate)
// filter method: 1 byte (0 = adaptive filtering)
// interlace method: 1 byte (0 = no interlace)
$this-data = pack("c*", ($this-img_width24) 255,
($this-img_width 16) 255,
($this-img_width 8) 255,
$this-img_width 255,
($this-img_height 24) 255,
($this-img_height 16) 255,
($this-img_height 8) 255,
$this-img_height 255, 8, 2, 0, 0, 0);
$this-add_chunk("IHDR");
//以下不敢乱翻译，请自行参考
// scanline:
// filter byte: 0 = none
// RGB bytes for the line
// the scanline is compressed with "zlib", method 8 (RFC-1950):
// compression method/flags code: 1 byte ($78 = method 8, 32k window)
// additional flags/check bits: 1 byte ($01: FCHECK = 1, FDICT = 0, FLEVEL = 0)
// compressed data blocks: n bytes
// one block (RFC-1951):
// bit 0: BFINAL: 1 for the last block
// bit 1 and 2: BTYPE: 0 for no compression
// next 2 bytes: LEN (LSB first)
// next 2 bytes: one's complement of LEN
// LEN bytes uncompressed data
// check value: 4 bytes (Adler-32 checksum of the uncompressed data)
$len = ($this-img_width * 3 + 1) * $this-img_height;
$this-data = pack("c*", 0x78, 0x01, 1, $len 255, ($len8) 255, 255 - ($len 255), 255 - (($len 8) 255) );
$start = strlen($this-data);
$i2 = 0;
for($h = 0; $h $this-img_height; $h++)
{
$this-data .= chr(0);
for($w = 0; $w $this-img_width * 3; $w++)
{
$this-data .= $this-pixels[$i2++];
}
}
//calculate a Adler32 checksum with the bytes data[start..len-1]
$s1 = 1;
$s2 = 0;
for ($n = $start; $n strlen($this-data); $n++)
{
$s1 = ($s1 + ord($this-data[$n])) % 65521;
$s2 = ($s2 + $s1) % 65521;
}
$adler = ($s2 16) | $s1;
$this-data .= chr(($adler 24) 255);
$this-data .= chr(($adler 16) 255);
$this-data .= chr(($adler 8) 255);
$this-data .= chr($adler 255);
$this-add_chunk("IDAT");
//IEND: marks the end of the PNG-file
$this-data = "";
$this-add_chunk("IEND");
//列印图象
//echo($this-img_cache);
}
}//End Class
?
