以html格式输入验证码

Question

我有一个html表单，而且我已经编写了必要的代码。

HTML在主代码：

<p id="formele" style="height:125px;"> 
<img src="captcha_code_file.php?rand=<?php echo rand(); ?>" style="width:200px;height:50px;"id='captchaimg' ><br> 
<label for='message'>Enter captcha here :</label><br> 
<input id="6_letters_code" style="background-color:lightblue; height : 25px;" name="6_letters_code" type="text" required /><br> 
</p> 

PHP在主代码：

if(empty($_SESSION['6_letters_code']) || 
     strcasecmp($_SESSION['6_letters_code'], $_POST['6_letters_code']) != 0) 
         { 
     //Note: the captcha code is compared case insensitively. 
     //if you want case sensitive match, update the check above to 
     $err=1; 
     echo "<p style='color:red;'>\nCaptcha code <em> DOES NOT MATCH</em>!! Press backspace and re-enter captcha</p>"; 
     echo "<p style='color:blue;'>Please re-enter password also(because password will be erased).<hr>"; 
     } 

而且我captcha_code_file.php代码（下载）：

<?php 
session_start(); 
//Settings: You can customize the captcha here 
$image_width = 200; 
$image_height = 50; 
$characters_on_image = 6; 
$font = './monofont.ttf'; 

//The characters that can be used in the CAPTCHA code. 
//avoid confusing characters (l 1 and i for example) 
$possible_letters = '23456789bcdfghjkmnpqrstvwxyz'; 
$random_dots = 0; 
$random_lines = 20; 
$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); 


/* setting the background, text and noise colours here */ 
$background_color = imagecolorallocate($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']); 


/* generating the dots randomly in background */ 
for($i=0; $i<$random_dots; $i++) { 
imagefilledellipse($image, mt_rand(0,$image_width), 
mt_rand(0,$image_height), 2, 3, $image_noise_color); 
} 


/* generating lines randomly in background of image */ 
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); 
} 


/* create a text box and add 6 letters code in it */ 
$textbox = imagettfbbox($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); 


/* Show captcha image in the page html page */ 
header('Content-Type: image/jpeg');// defining the image type to be shown in browser widow 
imagejpeg($image);//showing the image 
imagedestroy($image);//destroying the image instance 
$_SESSION['6_letters_code'] = $code; 

function hexrgb ($hexstr) 
{ 
$int = hexdec($hexstr); 

return array("red" => 0xFF & ($int >> 0x10), 
      "green" => 0xFF & ($int >> 0x8), 
      "blue" => 0xFF & $int); 
} 
?> 

的catcha图像不出现在我的网页上。我怎样才能解决这个问题？我很确定下载的代码没有问题。

Answer 1

我只是使用已经测试和工作的脚本，当在php中处理captcha时，您可以参考下面的链接，它将用于captcha的基本目的。

http://99webtools.com/blog/php-simple-captcha-script/

http://www.abeautifulsite.net/a-simple-php-captcha-script/

Answer 2

我测试的脚本和唯一的问题是字型（Monofont），我下载了被称为MONOFONT.TTF，而脚本使用monofont.ttf。我改变了文件名为小写，它的工作。

Answer 3

$font = './monofont.ttf';正在引发该问题。

而不是那个尝试$font = '/home/user/public_html/monofont.ttf';