File: lib/captcha/captcha.php

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  Classes of Abed Nego Ragil Putra  >  Giga CMS  >  lib/captcha/captcha.php  >  Download  
File: lib/captcha/captcha.php
Role: Example script
Content type: text/plain
Description: Example script
Class: Giga CMS
Multi-user content management system
Author: By
Last change:
Date: 4 years ago
Size: 5,782 bytes
 

Contents

Class file image Download
<?php
function captcha($config = array()) {
    global
$set;

   
// Check for GD library
   
if( !function_exists('gd_info') ) {
        throw new
Exception('Required GD library is missing');
    }

   
// Default values
   
$captcha_config = array(
       
'code' => '',
       
'min_length' => 5,
       
'max_length' => 5,
       
'png_backgrounds' => array(dirname(__FILE__) . '/default.png'),
       
'fonts' => array(dirname(__FILE__) . '/times_new_yorker.ttf'),
       
'characters' => 'ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789',
       
'min_font_size' => 24,
       
'max_font_size' => 30,
       
'color' => '#000',
       
'angle_min' => 0,
       
'angle_max' => 15,
       
'shadow' => true,
       
'shadow_color' => '#CCC',
       
'shadow_offset_x' => -2,
       
'shadow_offset_y' => 2
   
);

   
// Overwrite defaults with custom config values
   
if( is_array($config) ) {
        foreach(
$config as $key => $value ) $captcha_config[$key] = $value;
    }

   
// Restrict certain values
   
if( $captcha_config['min_length'] < 1 ) $captcha_config['min_length'] = 1;
    if(
$captcha_config['angle_min'] < 0 ) $captcha_config['angle_min'] = 0;
    if(
$captcha_config['angle_max'] > 10 ) $captcha_config['angle_max'] = 10;
    if(
$captcha_config['angle_max'] < $captcha_config['angle_min'] ) $captcha_config['angle_max'] = $captcha_config['angle_min'];
    if(
$captcha_config['min_font_size'] < 10 ) $captcha_config['min_font_size'] = 10;
    if(
$captcha_config['max_font_size'] < $captcha_config['min_font_size'] ) $captcha_config['max_font_size'] = $captcha_config['min_font_size'];

   
// Use milliseconds instead of seconds
   
srand(microtime() * 100);

   
// Generate CAPTCHA code if not set by user
   
if( empty($captcha_config['code']) ) {
       
$captcha_config['code'] = '';
       
$length = rand($captcha_config['min_length'], $captcha_config['max_length']);
        while(
strlen($captcha_config['code']) < $length ) {
           
$captcha_config['code'] .= substr($captcha_config['characters'], rand() % (strlen($captcha_config['characters'])), 1);
        }
    }

   
// Generate image src
   
$image_src = $set->url . '/lib/captcha/captcha.php?_CAPTCHA&amp;t=' . urlencode(microtime());

   
$_SESSION['_CAPTCHA']['config'] = serialize($captcha_config);

    return array(
       
'code' => $captcha_config['code'],
       
'image_src' => $image_src
   
);

}


if( !
function_exists('hex2rgb') ) {
    function
hex2rgb($hex_str, $return_string = false, $separator = ',') {
       
$hex_str = preg_replace("/[^0-9A-Fa-f]/", '', $hex_str); // Gets a proper hex string
       
$rgb_array = array();
        if(
strlen($hex_str) == 6 ) {
           
$color_val = hexdec($hex_str);
           
$rgb_array['r'] = 0xFF & ($color_val >> 0x10);
           
$rgb_array['g'] = 0xFF & ($color_val >> 0x8);
           
$rgb_array['b'] = 0xFF & $color_val;
        } elseif(
strlen($hex_str) == 3 ) {
           
$rgb_array['r'] = hexdec(str_repeat(substr($hex_str, 0, 1), 2));
           
$rgb_array['g'] = hexdec(str_repeat(substr($hex_str, 1, 1), 2));
           
$rgb_array['b'] = hexdec(str_repeat(substr($hex_str, 2, 1), 2));
        } else {
            return
false;
        }
        return
$return_string ? implode($separator, $rgb_array) : $rgb_array;
    }
}


// Draw the image
if( isset($_GET['_CAPTCHA']) ) {

   
session_start();

   
$captcha_config = unserialize($_SESSION['_CAPTCHA']['config']);
    unset(
$_SESSION['_CAPTCHA']);

   
// Use milliseconds instead of seconds
   
srand(microtime() * 100);

   
// Pick random background, get info, and start captcha
   
$background = $captcha_config['png_backgrounds'][rand(0, count($captcha_config['png_backgrounds']) -1)];
    list(
$bg_width, $bg_height, $bg_type, $bg_attr) = getimagesize($background);

   
// Create captcha object
   
$captcha = imagecreatefrompng($background);
   
imagealphablending($captcha, true);
   
imagesavealpha($captcha , true);

   
$color = hex2rgb($captcha_config['color']);
   
$color = imagecolorallocate($captcha, $color['r'], $color['g'], $color['b']);

   
// Determine text angle
   
$angle = rand( $captcha_config['angle_min'], $captcha_config['angle_max'] ) * (rand(0, 1) == 1 ? -1 : 1);

   
// Select font randomly
   
$font = $captcha_config['fonts'][rand(0, count($captcha_config['fonts']) - 1)];

   
// Verify font file exists
   
if( !file_exists($font) ) throw new Exception('Font file not found: ' . $font);

   
//Set the font size.
   
$font_size = rand($captcha_config['min_font_size'], $captcha_config['max_font_size']);
   
$text_box_size = imagettfbbox($font_size, $angle, $font, $captcha_config['code']);

   
// Determine text position
   
$box_width = abs($text_box_size[6] - $text_box_size[2]);
   
$box_height = abs($text_box_size[5] - $text_box_size[1]);
   
$text_pos_x_min = 0;
   
$text_pos_x_max = ($bg_width) - ($box_width);
   
$text_pos_x = rand($text_pos_x_min, $text_pos_x_max);
   
$text_pos_y_min = $box_height;
   
$text_pos_y_max = ($bg_height) - ($box_height / 2);
   
$text_pos_y = rand($text_pos_y_min, $text_pos_y_max);

   
// Draw shadow
   
if( $captcha_config['shadow'] ){
       
$shadow_color = hex2rgb($captcha_config['shadow_color']);
       
$shadow_color = imagecolorallocate($captcha, $shadow_color['r'], $shadow_color['g'], $shadow_color['b']);
       
imagettftext($captcha, $font_size, $angle, $text_pos_x + $captcha_config['shadow_offset_x'], $text_pos_y + $captcha_config['shadow_offset_y'], $shadow_color, $font, $captcha_config['code']);
    }

   
// Draw text
   
imagettftext($captcha, $font_size, $angle, $text_pos_x, $text_pos_y, $color, $font, $captcha_config['code']);

   
// Output image
   
header("Content-type: image/png");
   
imagepng($captcha);

}

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