現在很多網站，比如淘寶，京東等都改用使用極驗拖動驗證碼實現登錄，這種方式比傳統的驗證碼方式有更好的體驗，減少用戶輸入的錯誤，也同樣能起到防盜刷的功能。現在很多極驗都是第三方的，也很多都是收費的。今天在這里給大家分享自己用原生php實現的一個極驗的代碼。用原生php的好處就是以后你要嵌套到什么框架，可以直接用核心代碼，改一改就好了。
?php
class TnCode
{
var $im = null;
var $im_fullbg = null;
var $im_bg = null;
var $im_slide = null;
var $bg_width = 240;
var $bg_height = 150;
var $mark_width = 50;
var $mark_height = 50;
var $bg_num = 6;
var $_x = 0;
var $_y = 0;
//容錯象素 越大體驗越好，越小破解難道越高
var $_fault = 3;
function __construct(){
//ini_set('display_errors','On');
//
error_reporting(0);
if(!isset($_SESSION)){
session_start();
}
}
function make(){
$this->_init();
$this->_createSlide();
$this->_createBg();
$this->_merge();
$this->_imgout();
$this->_destroy();
}
function check($offset=''){
if(!$_SESSION['tncode_r']){
return false;
}
if(!$offset){
$offset = $_REQUEST['tn_r'];
}
$ret = abs($_SESSION['tncode_r']-$offset)=$this->_fault;
if($ret){
unset($_SESSION['tncode_r']);
}else{
$_SESSION['tncode_err']++;
if($_SESSION['tncode_err']>10){//錯誤10次必須刷新
unset($_SESSION['tncode_r']);
}
}
return $ret;
}
private function _init(){
$bg = mt_rand(1,$this->bg_num);
$file_bg = dirname(__FILE__).'/bg/'.$bg.'.png';
$this->im_fullbg = imagecreatefrompng($file_bg);
$this->im_bg = imagecreatetruecolor($this->bg_width, $this->bg_height);
imagecopy($this->im_bg,$this->im_fullbg,0,0,0,0,$this->bg_width, $this->bg_height);
$this->im_slide = imagecreatetruecolor($this->mark_width, $this->bg_height);
$_SESSION['tncode_r'] = $this->_x = mt_rand(50,$this->bg_width-$this->mark_width-1);
$_SESSION['tncode_err'] = 0;
$this->_y = mt_rand(0,$this->bg_height-$this->mark_height-1);
}
private function _destroy(){
imagedestroy($this->im);
imagedestroy($this->im_fullbg);
imagedestroy($this->im_bg);
imagedestroy($this->im_slide);
}
private function _imgout(){
if(!$_GET['nowebp']function_exists('imagewebp')){//優先webp格式，超高壓縮率
$type = 'webp';
$quality = 40;//圖片質量 0-100
}else{
$type = 'png';
$quality = 7;//圖片質量 0-9
}
header('Content-Type: image/'.$type);
$func = "image".$type;
$func($this->im,null,$quality);
}
private function _merge(){
$this->im = imagecreatetruecolor($this->bg_width, $this->bg_height*3);
imagecopy($this->im, $this->im_bg,0, 0 , 0, 0, $this->bg_width, $this->bg_height);
imagecopy($this->im, $this->im_slide,0, $this->bg_height , 0, 0, $this->mark_width, $this->bg_height);
imagecopy($this->im, $this->im_fullbg,0, $this->bg_height*2 , 0, 0, $this->bg_width, $this->bg_height);
imagecolortransparent($this->im,0);//16777215
}
private function _createBg(){
$file_mark = dirname(__FILE__).'/img/mark.png';
$im = imagecreatefrompng($file_mark);
header('Content-Type: image/png');
//imagealphablending( $im, true);
imagecolortransparent($im,0);//16777215
//imagepng($im);exit;
imagecopy($this->im_bg, $im, $this->_x, $this->_y , 0 , 0 , $this->mark_width, $this->mark_height);
imagedestroy($im);
}
private function _createSlide(){
$file_mark = dirname(__FILE__).'/img/mark2.png';
$img_mark = imagecreatefrompng($file_mark);
imagecopy($this->im_slide, $this->im_fullbg,0, $this->_y , $this->_x, $this->_y, $this->mark_width, $this->mark_height);
imagecopy($this->im_slide, $img_mark,0, $this->_y , 0, 0, $this->mark_width, $this->mark_height);
imagecolortransparent($this->im_slide,0);//16777215
//header('Content-Type: image/png');
//imagepng($this->im_slide);exit;
imagedestroy($img_mark);
}
}
?>
更多關于PHP相關內容感興趣的讀者可查看本站專題：《PHP圖形與圖片操作技巧匯總》、《PHP數組(Array)操作技巧大全》、《PHP數據結構與算法教程》、《php程序設計算法總結》、《PHP數學運算技巧總結》、《php字符串(string)用法總結》及《php常見數據庫操作技巧匯總》
