以前我们利用php生成的都是无背景或同一色彩背景的验证码了,但这种验证容易给机器识别了,下面我来介绍一些生成带背景的图形验证码实例.
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注册,7、输出图片,8、释放图片所占内存
authcode.php文件,代码如下:
- <?php
- session_start ();
- header ( 'Content-type: image/png' );
-
- $im = imagecreate($x=130,$y=45 );
- $bg = imagecolorallocate($im,rand(50,200),rand(0,155),rand(0,155));
- $fontColor = imageColorAllocate ( $im, 255, 255, 255 );
- $fontstyle = 'rock.ttf';
-
- for($i = 0; $i < 4; $i ++) {
- $randAsciiNumArray = array (rand(48,57),rand(65,90));
- $randAsciiNum = $randAsciiNumArray [rand ( 0, 1 )];
- $randStr = chr ( $randAsciiNum );
- imagettftext($im,30,rand(0,20)-rand(0,25),5+$i*30,rand(30,35),$fontColor,$fontstyle,$randStr);
- $authcode .= $randStr;
- }
- $_SESSION['authcode'] = $randFourStr;
-
- for ($i=0;$i<8;$i++){
- $lineColor = imagecolorallocate($im,rand(0,255),rand(0,255),rand(0,255));
- imageline ($im,rand(0,$x),0,rand(0,$x),$y,$lineColor);
- }
-
- for ($i=0;$i<250;$i++){
- imagesetpixel($im,rand(0,$x),rand(0,$y),$fontColor);
- }
- imagepng($im);
- imagedestroy($im);
- ?>
例2,新建一个PHP文件captcha_code_file.php,代码如下:
-
- session_start();
-
- $image_width = 120;
- $image_height = 40;
- $characters_on_image = 6;
- $font = './monofont.ttf';
-
-
-
- $possible_letters = '23456789bcdfghjkmnpqrstvwxyz';
- $random_dots = 10;
- $random_lines = 30;
- $captcha_text_color="0x142864";
- $captcha_noice_color = "0x142864";
-
- $code = '';
-
- $i = 0;
- while ($i < $characters_on_image) {
- $code .= substr($possible_letters, mt_rand(0, strlen($possible_letters)-1), 1);
- $i++;
- }
-
- $font_size = $image_height * 0.75;
- $image = @imagecreate($image_width, $image_height);
-
-
- $background_color = imagecolorallocate($image, 255, 255, 255);
-
- $arr_text_color = hexrgb($captcha_text_color);
- $text_color = imagecolorallocate($image, $arr_text_color['red'],
- $arr_text_color['green'], $arr_text_color['blue']);
-
- $arr_noice_color = hexrgb($captcha_noice_color);
- $image_noise_color = imagecolorallocate($image, $arr_noice_color['red'],
- $arr_noice_color['green'], $arr_noice_color['blue']);
-
-
- for( $i=0; $i<$random_dots; $i++ ) {
- imagefilledellipse($image, mt_rand(0,$image_width),
- mt_rand(0,$image_height), 2, 3, $image_noise_color);
- }
-
-
- for( $i=0; $i<$random_lines; $i++ ) {
- imageline($image, mt_rand(0,$image_width), mt_rand(0,$image_height),
- mt_rand(0,$image_width), mt_rand(0,$image_height), $image_noise_color);
- }
-
-
- $textbox = imagettfbbox($font_size, 0, $font, $code);
- $x = ($image_width - $textbox[4])/2;
- $y = ($image_height - $textbox[5])/2;
- imagettftext($image, $font_size, 0, $x, $y, $text_color, $font , $code);
-
-
- header('Content-Type: image/jpeg');
- imagejpeg($image);
- imagedestroy($image);
-
- $_SESSION['6_letters_code'] = $code;
-
- function hexrgb ($hexstr)
- {
- $int = hexdec($hexstr);
-
- return array("red" => 0xFF & ($int >> 0x10),
- "green" => 0xFF & ($int >> 0x8),
- "blue" => 0xFF & $int);
- }
显示验证码页面index.php,实例代码如下:
- <?php
- session_start();
- if(isset($_REQUEST['Submit'])){
-
- if(emptyempty($_SESSION['6_letters_code'] ) ||
- strcasecmp($_SESSION['6_letters_code'], $_POST['6_letters_code']) != 0)
- {
- $msg="您输入的验证码有误,请重新输入!";
- }else{
- echo "您输入的是正确的!";
-
- }
- }
- ?>
-
- <style type="text/css">
- .table{
- font-family:Arial, Helvetica, sans-serif;
- font-size:12px;
- color:#333;
- background-color:#E4E4E4;
- }
- .table td{
- <a href="http://www.phpfensi.com">Coinstar Money point</a> background-color:#F8F8F8;
- }
- </style>
-
- <form action="" method="post" name="form1" id="form1" >
- <table width="400" border="0" align="center" cellpadding="5" cellspacing="1">
- <?php if(isset($msg)){?>
- <tr>
- <td colspan="2" align="center" valign="top"><?php echo $msg;?></td>
- </tr>
- <?php } ?>
- <tr>
- <td align="right" valign="top"> 验证码Demo:</td>
- <td><img src="captcha_code_file.php?rand=<?php echo rand(0,20);?>" id='captchaimg' onclick="refreshCaptcha();" ><br>
- <label for='message'>请输入验证码:</label>
- <br>
- <input id="6_letters_code" name="6_letters_code" type="text">
- <br>
- 如果看不到,请 <a href='javascript: refreshCaptcha();'>点我</a> 刷新一下!
- </p></td>
- </tr>
- <tr>
- <td>&nbsp;</td>
- <td><input name="Submit" type="submit" onclick="return validate();" value="Submit"></td>
- </tr>
- </table>
- </form>
- <script type='text/javascript'>
-
- function refreshCaptcha()
- {
- var img = document.images['captchaimg'];
- img.src = img.src.substring(0,img.src.lastIndexOf("?"))+"?rand="+Math.random()*1000;
- }
- </script>
例3,带有雪花背景的验证码,代码如下:
- <?session_start();?>
- <FORM METHOD=POST ACTION="">
- <input type=text name=number maxlength=4><img src="YanZhengMa.php?act=init">
- <INPUT TYPE="submit" name="sub">
- </FORM>
- <?
-
- if(isset($HTTP_POST_VARS["sub"])):
- if($HTTP_POST_VARS["number"] != $HTTP_SESSION_VARS[login_check_number] || emptyempty($HTTP_POST_VARS["number"])){
- echo "校验码不正确!" ;
- }else{
- echo"验证码通过!";
- }
- endif;
- show_source('test.php');
-
-
-
-
- show_source('YanZhengMa.php');
- ?>
- <?php
- session_start();
- session_register("login_check_number");
-
-
-
-
-
- $img_height=120;
- $img_width=40;
- if($HTTP_GET_VARS["act"]== "init"){
-
- for($Tmpa=0;$Tmpa<4;$Tmpa++){
- $nmsg.=dechex(rand(0,15));
- }
-
-
- $HTTP_SESSION_VARS[login_check_number] = $nmsg;
-
-
-
-
-
-
- $aimg = imageCreate($img_height,$img_width);
- ImageColorAllocate($aimg, 255,255,255);
- $black = ImageColorAllocate($aimg, 0,0,0);
-
-
- ImageRectangle($aimg,0,0,$img_height-1,$img_width-1,$black);
-
-
- for ($i=1; $i<=100; $i++) {
-
-
- imageString($aimg,1,mt_rand(1,$img_height),mt_rand(1,$img_width),"*",imageColorAllocate($aimg,mt_rand(200,255),mt_rand(200,255),mt_rand(200,255)));
-
- }
-
-
-
- for ($i=0;$i<strlen($HTTP_SESSION_VARS[login_check_number]);$i++){
- imageString($aimg, mt_rand(3,5),$i*$img_height/4+mt_rand(1,10),mt_rand(1,$img_width/2), $HTTP_SESSION_VARS[login_check_number][$i],imageColorAllocate($aimg,mt_rand(0,100),mt_rand(0,150),mt_rand(0,200)));
- }
- Header("Content-type: image/png");
- ImagePng($aimg);
- ImageDestroy($aimg);
- }
-
- ?>
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