PHP绘图函数生成图片验证码

PHP绘图函数生成图片验证码

// Set some important CAPTCHA constants
  define('CAPTCHA_NUMCHARS', 6);  // number of characters in pass-phrase
  define('CAPTCHA_WIDTH', 100);   // width of image
  define('CAPTCHA_HEIGHT', 25);   // height of image// Generate the random pass-phrase$pass_phrase = "";
  for ($i = 0; $i $i++) {
    $pass_phrase .= chr(rand(97, 122));
  }

  // Store the encrypted pass-phrase in a session variable$_SESSION['pass_phrase'] = SHA($pass_phrase);

  // Create the image$img = imagecreatetruecolor(CAPTCHA_WIDTH, CAPTCHA_HEIGHT);

  // Set a white background with black text and gray graphics$bg_color = imagecolorallocate($img, 255, 255, 255);     // white$text_color = imagecolorallocate($img, 0, 0, 0);         // black$graphic_color = imagecolorallocate($img, 64, 64, 64);   // dark gray// Fill the background
  imagefilledrectangle($img, 0, 0, CAPTCHA_WIDTH, CAPTCHA_HEIGHT, $bg_color);
  // Draw some random linesfor ($i = 0; $i 5; $i++) {
    imageline($img, 0, rand() % CAPTCHA_HEIGHT, CAPTCHA_WIDTH, rand() % CAPTCHA_HEIGHT, $graphic_color);
  }

  // Sprinkle in some random dotsfor ($i = 0; $i 50; $i++) {
    imagesetpixel($img, rand() % CAPTCHA_WIDTH, rand() % CAPTCHA_HEIGHT, $graphic_color);
  }
  // Draw the pass-phrase string
  imagettftext($img, 18, 0, 5, CAPTCHA_HEIGHT - 5, $text_color, 'Courier New Bold.ttf', $pass_phrase);

  // Output the image as a PNG using a header
  header("Content-type: image/png");
  imagepng($img);

  // Clean up
  imagedestroy($img);
?>

在页面中使用这个生成验证码的脚本

  session_start();
?>htmlxmlns="http://www.w3.org/1999/xhtml"xml:lang="en"lang="en">head>metahttp-equiv="Content-Type"content="text/html; charset=utf-8" />title>Guitar Wars - Add Your High Scoretitle>linkrel="stylesheet"type="text/css"href="style.css" />head>body>h2>Guitar Wars - Add Your High Scoreh2>require_once('appvars.php');
  require_once('connectvars.php');

  if (isset($_POST['submit'])) {
    // Connect to the database$dbc = mysqli_connect(DB_HOST, DB_USER, DB_PASSWORD, DB_NAME);

    // Grab the score data from the POST$name = mysqli_real_escape_string($dbc, trim($_POST['name']));
    $score = mysqli_real_escape_string($dbc, trim($_POST['score']));
    $screenshot = mysqli_real_escape_string($dbc, trim($_FILES['screenshot']['name']));
    $screenshot_type = $_FILES['screenshot']['type'];
    $screenshot_size = $_FILES['screenshot']['size']; 

    // Check the CAPTCHA pass-phrase for verification$user_pass_phrase = SHA($_POST['verify']);
    if ($_SESSION['pass_phrase'] == $user_pass_phrase) {
      if (!empty($name) && is_numeric($score) && !empty($screenshot)) {
        if ((($screenshot_type == 'image/gif') || ($screenshot_type == 'image/jpeg') || ($screenshot_type == 'image/pjpeg') || ($screenshot_type == 'image/png'))
          && ($screenshot_size > 0) && ($screenshot_size if ($_FILES['screenshot']['error'] == 0) {
            // Move the file to the target upload folder$target = GW_UPLOADPATH . $screenshot;
            if (move_uploaded_file($_FILES['screenshot']['tmp_name'], $target)) {
              // Write the data to the database$query = "INSERT INTO guitarwars (date, name, score, screenshot) VALUES (NOW(), '$name', '$score', '$screenshot')";
              mysqli_query($dbc, $query);

              // Confirm success with the userecho'
Thanks for adding your new high score! It will be reviewed and added to the high score list as soon as possible.
';
              echo'
Name: ' . $name . '
';
              echo'Score: ' . $score . '
';
              echo'';
              echo'
<< Back to high scores
';

              // Clear the score data to clear the form$name = "";
              $score = "";
              $screenshot = "";

              mysqli_close($dbc);
            }
            else {
              echo'
Sorry, there was a problem uploading your screen shot image.
';
            }
          }
        }
        else {
          echo'
The screen shot must be a GIF, JPEG, or PNG image file no greater than ' . (GW_MAXFILESIZE / 1024) . ' KB in size.';
        }

        // Try to delete the temporary screen shot image file
        @unlink($_FILES['screenshot']['tmp_name']);
      }
      else {
        echo'
Please enter all of the information to add your high score.
';
      }
    }
    else {
      echo'
Please enter the verification pass-phrase exactly as shown.
';
    }
  }
?>hr />formenctype="multipart/form-data"method="post"action="">inputtype="hidden"name="MAX_FILE_SIZE"value="" />labelfor="name">Name:label>inputtype="text"id="name"name="name"value="" />br />labelfor="score">Score:label>inputtype="text"id="score"name="score"value="" />br />labelfor="screenshot">Screen shot:label>inputtype="file"id="screenshot"name="screenshot" />br />labelfor="verify">Verification:label>inputtype="text"id="verify"name="verify"value="Enter the pass-phrase." />imgsrc="captcha.php"alt="Verification pass-phrase" />hr />inputtype="submit"value="Add"name="submit" />form>body>html>

').addClass('pre-numbering').hide(); $(this).addClass('has-numbering').parent().append($numbering); for (i = 1; i ').text(i)); }; $numbering.fadeIn(1700); }); });

以上就介绍了PHP绘图函数生成图片验证码，包括了方面的内容，希望对PHP教程有兴趣的朋友有所帮助。