php网页生成验证码实现程序

2024-05-04 21:58:15

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首先在表单页面展现之前,生成一副图片,并添加上一些干扰像素或线段,防止OCR程序自动识别,再由PHP程序自动生成随机的待验证的一串数字和字母组合的字符,调用imagettftext()函数画到图片中,并把这串字符保存到Session级变量中.

完整实例:自动检测背景和字体,并随机选取背景图片中的一块范围,随机使用字体,显示验证字符串时随机显示字体大小,字符间距,字符颜色等,代码如下:

<?php

/**

* Class for Validate image

* @author  zcs

* @version 1.0-20090828

*/

session_start();

class validimg

{

//背景图片目录

var $backgroundpath = ‘validbg’;

//生成验证码宽度

var $width =’80′;

//生成验证码高度

var $height =’25′;

//背景

var $background;

//验证文本

var $text=’abcd’;

//字体目录

var $fontpath = ‘validbg’;

//字体

var $font=’simhei.ttf’;

//字体宽度

var $font_width = ’20′;

function validimg($text)

{

$this->text = $text;

//随机选取一个背景文件

$bgdir =  @dir($this->backgroundpath);

while(false !== ($image = $bgdir ->read()))

{

if($image != ‘.’ && $image != ‘..’ && $this->checktype($image) != false)

{

$backgroundarr[] = $image;

}

}

$bgdir->close();

//随机选取一个字体文件

$fonts =  @dir($this->fontpath);

while(false !== ($font = $fonts ->read()))

{

if($font != ‘.’ && $font != ‘..’ && $this->checktype($font,’FONT’) != false)

{

$fontsarr[] = $font;

}

}

$fonts->close();

$this->font = $fontsarr[array_rand($fontsarr,1)];

$this->background = $backgroundarr[array_rand($backgroundarr,1)];

$this->output();

}

//创建背景图像handdle

function createbackground()

{

switch ($this->checktype($this->background))

{

case ‘jpg’:

$bghanddle = @imagecreatefromjpeg( $this->backgroundpath.’/’.$this->background);

break;

case ‘gif’:

$bghanddle = @imagecreatefromgif( $this->backgroundpath.’/’.$this->background);

break;

case ‘png’:

$bghanddle = @imagecreatefrompng( $this->backgroundpath.’/’.$this->background);

break;

default:

}

return $bghanddle;

}

//检查文件类型

function checktype( $image,$type = ‘IMAGE’)

{

$ext = substr( $image, strrpos($image,’.')+1);

if($type == ‘IMAGE’)

{

if ($ext == ‘jpg’ || $ext ==’gif’ || $ext ==’png’)

return $ext;

else return false;

}else if($type == ‘FONT’)

{

if ($ext == ‘ttf’)

return $ext;

else return false;

}

}

//输出

function output()

{

header(“content-type:image/png;”);

//生成图像

$img = @imagecreatetruecolor( $this->width,$this->height);

$bghanddle = $this->createbackground();

//从背景图像随机位置载入一块作为背景

if($bghanddle)

{

$randx=rand(0,(imagesx($bghanddle) – $this->width));

$randy=rand(0,(imagesy($bghanddle) – $this->height));

}

imagecopy($img,$bghanddle,0,0,$randx,$randy,$this->width,$this->height);

//随机选择角度字体大小坐标输出文字

for($i=0;$i<strlen($this->text);$i++)

{

$angle = rand(-30,30);

$fontsize = rand(15,20);

$x = rand($this->font_width*$i,$this->font_width*$i+10);

$color = imagecolorallocate($img, rand(0,255), rand(0,255), rand(0,255));

imagettftext($img,$fontsize,$angle,$x,20,$color,$this->fontpath.’/’.$this->font,substr($this->text,$i,1));

}

imagepng($img);

//释放资源

imagedestroy($img);

imagedestroy($bghanddle);

}

}

new validimg($_SESSION['valid']);

?>

测试文件validtest.php,代码如下:

<?php

/**

* 验证码测试

* @author  zcs

*/

session_start();

$_SESSION['valid']= randstr();

echo $_SESSION['valid'];

//随机生成字符串

function randstr($num=4)

{

$chars = ‘ABDEFGHJKLMNPQRSTVWXYabdefghijkmnpqrstvwxy23456789′;

$randstr=”;

for($i=0;$i<$num;$i++)

{

$randstr.=substr($chars,rand(0,strlen($chars)),1);

}

return $randstr;

}

?>

<img src=”validimg.php” />

生成gif动态验证码,PHP生成GIF动画来实现动态图片验证码，以下是实现过程,ImageCode函数通过GIFEncoder类实现的GIF动画

/**

* ImageCode 生成GIF图片验证

* @param $string 字符串

* @param $width 宽度

* @param $height 高度

* */

function ImageCode($string = '', $width = 75, $height = 25)

{

    $authstr = $string ? $string : ((time() % 2 == 0) ? mt_rand(1000, 9999) : mt_rand(10000, 99999));



    $board_width = $width;

    $board_height = $height;

    // 生成一个32帧的GIF动画

    for($i = 0; $i < 32; $i++)

    {

        ob_start();

        $image = imagecreate($board_width, $board_height);

        imagecolorallocate($image, 0,0,0);

        // 设定文字颜色数组

        $colorList[] = ImageColorAllocate($image, 15,73,210);

        $colorList[] = ImageColorAllocate($image, 0,64,0);

        $colorList[] = ImageColorAllocate($image, 0,0,64);

        $colorList[] = ImageColorAllocate($image, 0,128,128);

        $colorList[] = ImageColorAllocate($image, 27,52,47);

        $colorList[] = ImageColorAllocate($image, 51,0,102);

        $colorList[] = ImageColorAllocate($image, 0,0,145);

        $colorList[] = ImageColorAllocate($image, 0,0,113);

        $colorList[] = ImageColorAllocate($image, 0,51,51);

        $colorList[] = ImageColorAllocate($image, 158,180,35);

        $colorList[] = ImageColorAllocate($image, 59,59,59);

        $colorList[] = ImageColorAllocate($image, 0,0,0);

        $colorList[] = ImageColorAllocate($image, 1,128,180);

        $colorList[] = ImageColorAllocate($image, 0,153,51);

        $colorList[] = ImageColorAllocate($image, 60,131,1);

        $colorList[] = ImageColorAllocate($image, 0,0,0);

        $fontcolor = ImageColorAllocate($image, 0,0,0);

        $gray = ImageColorAllocate($image, 245,245,245);



        $color = imagecolorallocate($image, 255,255,255);

        $color2 = imagecolorallocate($image, 255,0,0);



        imagefill($image, 0, 0, $gray);



        $space = 15;        // 字符间距

        if($i > 0)          // 屏蔽第一帧

        {

            for ($k = 0; $k < strlen($authstr); $k++)

            {

                $colorRandom = mt_rand(0,sizeof($colorList)-1);

                $float_top = rand(0,4);

                $float_left = rand(0,3);

                imagestring($image, 6, $space * $k, $top + $float_top, substr($authstr, $k, 1), $colorList[$colorRandom]);

            }

        }



        for ($k = 0; $k < 20; $k++)

        {

            $colorRandom = mt_rand(0,sizeof($colorList)-1);

            imagesetpixel($image, rand()%70 , rand()%15 , $colorList[$colorRandom]);



        }

        // 添加干扰线

        for($k = 0; $k < 3; $k++)

        {

            $colorRandom = mt_rand(0, sizeof($colorList)-1);

            // $todrawline = rand(0,1);

            $todrawline = 1;

            if($todrawline)

            {

                imageline($image, mt_rand(0, $board_width), mt_rand(0,$board_height), mt_rand(0,$board_width), mt_rand(0,$board_height), $colorList[$colorRandom]);

            }

            else

            {

                $w = mt_rand(0,$board_width);

                $h = mt_rand(0,$board_width);

                imagearc($image, $board_width - floor($w / 2) , floor($h / 2), $w, $h,  rand(90,180), rand(180,270), $colorList[$colorRandom]);

            }

        }

        imagegif($image);

        imagedestroy($image);

        $imagedata[] = ob_get_contents();

        ob_clean();

        ++$i;

    }



    $gif = new GIFEncoder($imagedata);

    Header ('Content-type:image/gif');

    echo $gif->GetAnimation();

}

<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">

<html xmlns="http://www.w3.org/1999/xhtml">

<head>

<meta http-equiv="Content-Type" content="text/html; charset=utf-8" />

<title>无标题文档</title>

<script language="javascript">

function refresh_code()

{

  form1.imgcode.src="verifycode.php?a="+Math.random();

}

</script>

</head>

<body>

<form id="form1" name="form1" method="post" action="checkcode.php">

  <label for="code">验证码：</label>

  <input type="text" name="code" id="textfield" />

  <img id="imgcode" src="VerifyCode.php" alt="验证码" />

  <a href="javascript：refresh_code()">看不清？换一个</a>

  <input type="submit" name="button" id="button" value="提交" />

</form>

</body>

</html>

checkcode.php文件如下:

<meta http-equiv="Content-Type" content="text/html; charset=utf-8" />

<?php

ini_set('display_errors', 'Off');

session_start();

  if((strtoupper($_POST["code"])) == strtoupper(($_SESSION["VerifyCode"]))){

print("验证码正确,");

  }else{

    print("验证码错误,");

  }

  echo "提交的验证码:".strtoupper($_POST["code"]).",正确的验证码：".strtoupper($_SESSION["VerifyCode"]);

?>