php中使用GD库做验证码

2024-05-04 23:44:48

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本文给大家分享的是使用php的GD库来实现验证码功能的方法和全部代码，有需要的小伙伴可以参考下

<?php

require_once 'string.func.php';

//通过GD库做验证码

/**

*添加验证文字

* @param int $type

* @param int $length

*/

function buildRandomString($type=1,$length=4){

  $row='';

  if($type==1){

    $row=join('',range(0, 9));

  }else if($type==2){

    $row=join('', array_merge(range('a','z'),range('A', 'Z')));

  }else if($type==3){

    $row=join('', array_merge(range('a','z'),range('A', 'Z'),range(0, 9)));

  };

  $row=str_shuffle($row);



  $row=substr($row,0,$length);

  return $row;

}

/**

* 生成缩略图

* @param int $type //包含数字或者英文

* @param int $length 多少个字符

* @param int $pixel 干扰小点的密度

* @param int $dst_h 干扰线的密度

* @param string //验证码在$_SESSION中的名字

*/

function verifyImage($type=1,$length=4,$pixel=0,$line=0,$sess_name = "verify"){

  //session_start();

  //创建画布

  $width = 100;

  $height = 40;

  $image = imagecreatetruecolor ( $width, $height );

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

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

  //用填充矩形填充画布

  imagefilledrectangle ( $image, 1, 1, $width - 2, $height - 2, $white );

  $chars = buildRandomString ( $type, $length );

  $_SESSION [$sess_name] = $chars;

  //$fontfiles = array ("MSYH.TTF", "MSYHBD.TTF", "SIMLI.TTF", "SIMSUN.TTC", "SIMYOU.TTF", "STZHONGS.TTF" );

  $fontfiles = array ("SIMKAI.TTF" );

  //由于字体文件比较大，就只保留一个字体，如果有需要的同学可以自己添加字体，字体在你的电脑中的fonts文件夹里有，直接运行输入fonts就能看到相应字体

  for($i = 0; $i < $length; $i ++) {

    $size = mt_rand ( 14, 18 );

    $angle = mt_rand ( - 15, 15 );

    $x = 5 + $i * $size;

    $y = mt_rand ( 20, 26 );

    $fontfile = "../fonts/" . $fontfiles [mt_rand ( 0, count ( $fontfiles ) - 1 )];

    $color = imagecolorallocate ( $image, mt_rand ( 50, 90 ), mt_rand ( 80, 200 ), mt_rand ( 90, 180 ) );

    $text = substr ( $chars, $i, 1 );

    imagettftext ( $image, $size, $angle, $x, $y, $color, $fontfile, $text );

  }

  if ($pixel) {

    for($i = 0; $i < 50; $i ++) {

      imagesetpixel ( $image, mt_rand ( 0, $width - 1 ), mt_rand ( 0, $height - 1 ), $black );

    }

  }

  if ($line) {

    for($i = 1; $i < $line; $i ++) {

      $color = imagecolorallocate ( $image, mt_rand ( 50, 90 ), mt_rand ( 80, 200 ), mt_rand ( 90, 180 ) );

      imageline ( $image, mt_rand ( 0, $width - 1 ), mt_rand ( 0, $height - 1 ), mt_rand ( 0, $width - 1 ), mt_rand ( 0, $height - 1 ), $color );

    }

  }

  header ( "content-type:image/gif" );

  imagegif ( $image );

  imagedestroy ( $image );

}