public static function translucentWatermark($originalImage, $watermark, $saveFile = null, $outputFileTipe = 'jpg')
 {
     $tempFolder = "temp/";
     //$fileRandomValue = 0;
     $cache = $tempFolder . $saveFile . '.' . $outputFileTipe;
     // Load the stamp and the photo to apply the watermark to
     if (strstr($originalImage, '.jpg') !== false) {
         $im = imagecreatefromjpeg($originalImage);
     } elseif (strstr($originalImage, '.png') !== false) {
         $im = imagecreatefrompng($originalImage);
     }
     // First we create our stamp image manually from GD
     $stamp = imagecreatetruecolor(100, 70);
     imagefilledrectangle($stamp, 0, 0, 99, 69, 0xff);
     imagefilledrectangle($stamp, 9, 9, 90, 60, 0xffffff);
     //$im = imagecreatefromjpeg('photo.jpeg');
     imagestring($stamp, 5, 20, 20, 'libGD', 0xff);
     imagestring($stamp, 3, 20, 40, '(c) 2007-9', 0xff);
     // Set the margins for the stamp and get the height/width of the stamp image
     $marge_right = 10;
     $marge_bottom = 10;
     $sx = imagesx($stamp);
     $sy = imagesy($stamp);
     // Merge the stamp onto our photo with an opacity of 50%
     imagecopymerge($im, $stamp, imagesx($im) - $sx - $marge_right, imagesy($im) - $sy - $marge_bottom, 0, 0, imagesx($stamp), imagesy($stamp), 50);
     // Save the image to file and free memory
     imagepng($im, $cache);
     imagedestroy($im);
 }

function getCode($num, $w, $h)
{
    // 去掉了 0 1 O l 等
    $str = "23456789abcdefghijkmnpqrstuvwxyz";
    $code = '';
    for ($i = 0; $i < $num; $i++) {
        $code .= $str[mt_rand(0, strlen($str) - 1)];
    }
    //将生成的验证码写入session，备验证页面使用
    $_SESSION["my_checkcode"] = $code;
    //创建图片，定义颜色值
    Header("Content-type: image/PNG");
    $im = imagecreate($w, $h);
    $black = imagecolorallocate($im, mt_rand(0, 200), mt_rand(0, 120), mt_rand(0, 120));
    $gray = imagecolorallocate($im, 118, 151, 199);
    $bgcolor = imagecolorallocate($im, 235, 236, 237);
    //画背景
    imagefilledrectangle($im, 0, 0, $w, $h, $bgcolor);
    //画边框
    imagerectangle($im, 0, 0, $w - 1, $h - 1, $gray);
    //imagefill($im, 0, 0, $bgcolor);
    //在画布上随机生成大量点，起干扰作用;
    for ($i = 0; $i < 80; $i++) {
        imagesetpixel($im, rand(0, $w), rand(0, $h), $black);
    }
    //将字符随机显示在画布上,字符的水平间距和位置都按一定波动范围随机生成
    $strx = rand(5, 10);
    for ($i = 0; $i < $num; $i++) {
        $strpos = rand(1, 6);
        imagestring($im, 20, $strx, $strpos, substr($code, $i, 1), $black);
        $strx += $w / 5;
    }
    imagepng($im);
    imagedestroy($im);
}

 /**
  * Displays the captcha image
  *
  * @access  public
  * @param   int     $key    Captcha key
  * @return  mixed   Captcha raw image data
  */
 function image($key)
 {
     $value = Jaws_Utils::RandomText();
     $result = $this->update($key, $value);
     if (Jaws_Error::IsError($result)) {
         $value = '';
     }
     $bg = dirname(__FILE__) . '/resources/simple.bg.png';
     $im = imagecreatefrompng($bg);
     imagecolortransparent($im, imagecolorallocate($im, 255, 255, 255));
     // Write it in a random position..
     $darkgray = imagecolorallocate($im, 0x10, 0x70, 0x70);
     $x = 5;
     $y = 20;
     $text_length = strlen($value);
     for ($i = 0; $i < $text_length; $i++) {
         $fnt = rand(7, 10);
         $y = rand(6, 10);
         imagestring($im, $fnt, $x, $y, $value[$i], $darkgray);
         $x = $x + rand(15, 25);
     }
     header("Content-Type: image/png");
     ob_start();
     imagepng($im);
     $content = ob_get_contents();
     ob_end_clean();
     imagedestroy($im);
     return $content;
 }

 /**
  * Processes incoming text
  */
 public function action_index()
 {
     $this->request->headers['Content-type'] = 'image/png';
     // Grab text and styles
     $text = arr::get($_GET, 'text');
     $styles = $_GET;
     $hover = FALSE;
     try {
         // Create image
         $img = new PNGText($text, $styles);
         foreach ($styles as $key => $value) {
             if (substr($key, 0, 6) == 'hover-') {
                 // Grab hover associated styles and override existing styles
                 $hover = TRUE;
                 $styles[substr($key, 6)] = $value;
             }
         }
         if ($hover) {
             // Create new hover image and stack it
             $hover = new PNGText($text, $styles);
             $img->stack($hover);
         }
         echo $img->draw();
     } catch (Exception $e) {
         if (Kohana::config('pngtext.debug')) {
             // Dump error message in an image form
             $img = imagecreatetruecolor(strlen($e->getMessage()) * 6, 16);
             imagefill($img, 0, 0, imagecolorallocate($img, 255, 255, 255));
             imagestring($img, 2, 0, 0, $e->getMessage(), imagecolorallocate($img, 0, 0, 0));
             echo imagepng($img);
         }
     }
 }

 static function codeimage()
 {
     $image = imagecreatetruecolor(100, 30);
     $bgcolor = imagecolorallocate($image, 255, 255, 255);
     imagefill($image, 0, 0, $bgcolor);
     $code = '';
     for ($i = 0; $i < 4; $i++) {
         $fontsize = 6;
         $fontcolor = imagecolorallocate($image, rand(0, 120), rand(0, 120), rand(0, 120));
         $data = "abcdefghjkmnpqrstuvwxy3456789";
         $fontcontent = substr($data, rand(1, strlen($data) - 1), 1);
         $code .= $fontcontent;
         $x = $i * 100 / 4 + rand(5, 10);
         $y = rand(5, 10);
         imagestring($image, $fontsize, $x, $y, $fontcontent, $fontcolor);
     }
     for ($i = 0; $i < 200; $i++) {
         $pointcolor = imagecolorallocate($image, rand(50, 200), rand(50, 200), rand(50, 200));
         imagesetpixel($image, rand(1, 99), rand(1, 29), $pointcolor);
     }
     for ($i = 0; $i < 2; $i++) {
         $linecolor = imagecolorallocate($image, rand(80, 220), rand(80, 220), rand(80, 220));
         imageline($image, rand(1, 99), rand(1, 29), rand(1, 99), rand(1, 29), $linecolor);
     }
     $return['code'] = $code;
     $return['image'] = $image;
     return $return;
     //		header('content-type:image/png');
     //		imagepng($image);
 }

function imgcode($nums, $width, $high)
{
    //去除了數字0和1 字母小寫O和L，為了避免辨識不清楚
    //$str = "23456789abcdefghijkmnpqrstuvwxyzABCDEFGHIJKLMOPQRSTUBWXYZ";
    $str = "0123456789";
    $code = '';
    for ($i = 0; $i < $nums; $i++) {
        $code .= $str[mt_rand(0, strlen($str) - 1)];
    }
    $_SESSION['captcha'] = $code;
    //建立圖示，設置寬度及高度與顏色等等條件
    $image = imagecreate($width, $high);
    $black = imagecolorallocate($image, mt_rand(0, 200), mt_rand(0, 200), mt_rand(0, 200));
    $border_color = imagecolorallocate($image, 21, 106, 235);
    $background_color = imagecolorallocate($image, 235, 236, 237);
    //建立圖示背景
    imagefilledrectangle($image, 0, 0, $width, $high, $background_color);
    //建立圖示邊框
    imagerectangle($image, 0, 0, $width - 1, $high - 1, $border_color);
    //在圖示布上隨機產生大量躁點
    for ($i = 0; $i < 80; $i++) {
        imagesetpixel($image, rand(0, $width), rand(0, $high), $black);
    }
    $strx = rand(3, 8);
    for ($i = 0; $i < $nums; $i++) {
        $strpos = rand(1, 6);
        imagestring($image, 5, $strx, $strpos, substr($code, $i, 1), $black);
        $strx += rand(10, 30);
    }
    imagepng($image);
    imagedestroy($image);
}

 /**
  * Class constructor generates the CAPTCHA image.
  *
  * @return blob the image
  * @access public
  */
 function __construct()
 {
     session_start();
     $image = imagecreate($this->width, $this->height);
     $random_str = $this->gen_str($this->chars_nr);
     #md5( microtime() );						// md5 to generate the random string
     $result_str = substr($random_str, 0, $this->chars_nr);
     //trim $chars_nr digit
     $bg_color = imagecolorallocate($image, $this->background_color['red'], $this->background_color['green'], $this->background_color['blue']);
     // background color
     $tx_color = imagecolorallocate($image, $this->text_color['red'], $this->text_color['gree'], $this->text_color['blue']);
     // text color
     for ($i = 0; $i <= $this->lines; $i++) {
         $line_color = imagecolorallocate($image, rand(0, 255), rand(0, 255), rand(0, 255));
         //line color
         imageline($image, rand(rand(-10, 100), rand(-10, 100)), rand(rand(-10, 100), rand(-10, 100)), rand(rand(-10, 100), rand(-10, 100)), rand(rand(-10, 100), rand(-10, 100)), $line_color);
         // Create lines on image
     }
     imagestring($image, 5, 20, 10, $result_str, $tx_color);
     // Draw a random string horizontally
     $_SESSION['key'] = $result_str;
     // Carry the data through session
     header("Content-type: image/png");
     // Out out the image
     imagepng($image);
     // Output image to browser
 }

 public function generateCaptcha()
 {
     //make image
     $im = imagecreatetruecolor($this->width, $this->height);
     //set background
     $bg_color = imagecolorallocate($im, mt_rand($this->bg_color_min, $this->bg_color_max), mt_rand($this->bg_color_min, $this->bg_color_max), mt_rand($this->bg_color_min, $this->bg_color_max));
     //padding
     imagefill($im, 0, 0, $bg_color);
     //add lines
     for ($i = 0; $i < $this->lines; $i++) {
         //set color
         $line_color = imagecolorallocate($im, mt_rand($this->line_color_min, $this->line_color_max), mt_rand($this->line_color_min, $this->line_color_max), mt_rand($this->line_color_min, $this->line_color_max));
         //draw line
         imageline($im, mt_rand(0, $this->width), mt_rand(0, $this->height), mt_rand(0, $this->width), mt_rand(0, $this->height), $line_color);
     }
     //add pixels
     for ($i = 0; $i < $this->pixels; $i++) {
         //set color
         $pixels_color = imagecolorallocate($im, mt_rand($this->pixels_color_min, $this->pixels_color_max), mt_rand($this->pixels_color_min, $this->pixels_color_max), mt_rand($this->pixels_color_min, $this->pixels_color_max));
         //draw pixels
         imagesetpixel($im, mt_rand(0, $this->width), mt_rand(0, $this->height), $pixels_color);
     }
     //get captcha string
     $captcha = $this->generateString();
     //set color of font
     $str_color = imagecolorallocate($im, mt_rand($this->font_color_min, $this->font_color_max), mt_rand($this->font_color_min, $this->font_color_max), mt_rand($this->font_color_min, $this->font_color_max));
     //put string to picture
     imagestring($im, $this->font, ceil($this->width / 2) - 20, ceil($this->height / 2) - 10, $captcha, $str_color);
     //save or output
     imagepng($im);
     //destroy res
     imagedestroy($im);
 }

 /**
  * Makes a graphical captcha from the provided text string
  *
  * @param string $captcha_text string to make image captcha from
  * @return string $data_url a data url containing the obfuscated image
  */
 function makeGraphicalCaptcha($captcha_text)
 {
     $image = @imagecreatetruecolor(195, 35);
     // defines background color, random lines color and text color
     $bg_color = imagecolorallocate($image, mt_rand(0, 255), 255, 0);
     imagefill($image, 0, 0, $bg_color);
     $lines_color = imagecolorallocate($image, 0x99, 0xcc, 0x99);
     $text_color = imagecolorallocate($image, mt_rand(0, 255), 0, 255);
     // draws random lines
     for ($i = 0; $i < 4; $i++) {
         imageline($image, 0, rand(0, 35), 195, rand(0, 35), $lines_color);
     }
     $captcha_letter_array = str_split($captcha_text);
     foreach ($captcha_letter_array as $i => $captcha_letter) {
         imagesetthickness($image, 1);
         imagestring($image, 5, 5 + $i * 35, rand(2, 14), $captcha_letter, $text_color);
     }
     // creates image
     ob_start();
     imagejpeg($image);
     $image_data = ob_get_contents();
     ob_end_clean();
     $data_url = "data:image/jpeg;base64," . base64_encode($image_data);
     imagedestroy($image);
     return $data_url;
 }

function imagecharx($img, $char, $x0, $y0, $ylist)
{
    global $bk_color, $fg_color;
    $da = @imagecreate(10, 20) or die("Cannot Initialize new GD image stream");
    $background_color = imagecolorallocate($da, $bk_color[0], $bk_color[1], $bk_color[2]);
    $text_color = imagecolorallocate($da, $fg_color[0], $fg_color[1], $fg_color[2]);
    $color = imagecolorallocate($img, $fg_color[0], $fg_color[1], $fg_color[2]);
    $arg = rand(0, 18) / 100.0 * pi();
    imagestring($da, 18, 0, 0, $char, $text_color);
    for ($i = 0; $i < 200; $i++) {
        $y = @floor($i / 10);
        $x = $i % 10;
        $point_color = imagecolorat($da, $x, $y);
        if ($point_color == $text_color) {
            for ($j = 0; $j < 12; $j++) {
                $dx = 0;
                $dy = 0;
                $p = 6;
                for ($s = 0; $s < $p; $s++) {
                    $dx += rand(0, 1000 / $p) / 100;
                    $dy += rand(0, 1000 / $p) / 100;
                }
                $xx = $x * 5 + $dx - 25;
                $yy = $y * 5 + $dy - 50;
                $x1 = cos($arg) * $xx - sin($arg) * $yy + 25;
                $y1 = sin($arg) * $xx + cos($arg) * $yy + 50;
                imagesetpixel($img, $x0 + $x1, $y0 + $y1, $color);
            }
        }
    }
    imagedestroy($da);
}

function create_image()
{
    header("Content-Type: image/png");
    $image = imagecreatetruecolor(200, 50) or die("Cannot Initialize new GD image stream");
    $background_color = imagecolorallocate($image, 0, 0, 0);
    $text_color = imagecolorallocate($image, 122, 111, 255);
    $line_color = imagecolorallocate($image, 64, 64, 64);
    $pixel_color = imagecolorallocate($image, 0, 0, 255);
    imagefilledrectangle($image, 0, 0, 200, 50, $background_color);
    for ($i = 0; $i < 3; $i++) {
        imageline($image, 0, rand(0, 255) % 50, 200, rand(0, 255) % 50, $line_color);
    }
    for ($i = 0; $i < 1000; $i++) {
        imagesetpixel($image, rand() % 200, rand() % 50, $pixel_color);
    }
    $letters = 'ABCDEFGHIJKLMNOPQRSTUVWXYZ';
    $len = strlen($letters);
    $letter = $letters[rand(0, $len - 1)];
    # $text_color = imagecolorallocate($image, 0, 0, 0);
    $word = "";
    for ($i = 0; $i < 6; $i++) {
        $letter = $letters[rand(0, $len - 1)];
        imagestring($image, 7, 5 + $i * 30, 20, $letter, $text_color);
        $word .= $letter;
    }
    $_SESSION['solution'] = $word;
    imagepng($image);
    imagedestroy($image);
}

 protected function createImage($width, $height)
 {
     $im = imagecreate($width, $height);
     $text_color = imagecolorallocate($im, 233, 14, 91);
     imagestring($im, 1, 5, 5, "Простая Текстовая Строка", $text_color);
     imagepng($im, $this->tmpFile);
 }

function drawRating($rating, $max, $type)
{
    if ($type == 0) {
        $image = imagecreatetruecolor(102, 15);
        $back = ImageColorAllocate($image, 250, 250, 250);
        $border = ImageColorAllocate($image, 0, 0, 0);
        $fill = ImageColorAllocate($image, 0, 235, 0);
        ImageFilledRectangle($image, 0, 0, 101, 14, $back);
        ImageFilledRectangle($image, 1, 1, $rating / $max * 100, 14, $fill);
        ImageRectangle($image, 0, 0, 101, 14, $border);
        $textcolor = imagecolorallocate($image, 0, 0, 0);
        imagestring($image, 5, 35, 0, $rating / $max * 100 . '%', $textcolor);
    } else {
        if ($rating > $max) {
            $rating = $max;
        }
        $image = imagecreatetruecolor(10 * ($rating + 2) + 2, 15);
        $back = ImageColorAllocate($image, 250, 250, 250);
        $border = ImageColorAllocate($image, 0, 0, 0);
        $fill = ImageColorAllocate($image, 235, 0, 0);
        ImageFilledRectangle($image, 0, 0, 10 * ($rating + 2) + 1, 14, $back);
        ImageFilledRectangle($image, 1, 1, 10 * $rating, 14, $fill);
        ImageRectangle($image, 0, 0, 10 * $rating + 1, 14, $border);
        $textcolor = imagecolorallocate($image, 0, 0, 0);
        imagestring($image, 5, 10 * ($rating + 1), 0, $rating, $textcolor);
    }
    imagepng($image);
    imagedestroy($image);
}

function getCode($num, $w, $h)
{
    $code = "";
    for ($i = 0; $i < $num; $i++) {
        $code .= rand(0, 9);
    }
    //4位验证码也可以用rand(1000,9999)直接生成
    //将生成的验证码写入session，备验证页面使用
    $_SESSION['yzm'] = $code;
    //setcookie("mimi", md5($code), time()+1200);
    //创建图片，定义颜色值
    Header("Content-type: image/PNG");
    $im = imagecreate($w, $h);
    $black = imagecolorallocate($im, 255, 0, 63);
    $gray = imagecolorallocate($im, 200, 200, 200);
    $bgcolor = imagecolorallocate($im, 255, 255, 255);
    imagefill($im, 0, 0, $bgcolor);
    //画边框
    //imagerectangle($im, 0, 0, $w-1, $h-1, $black);
    //在画布上随机生成大量黑点，起干扰作用;
    for ($i = 0; $i < 10; $i++) {
        imagesetpixel($im, rand(0, $w), rand(0, $h), $black);
    }
    //将数字随机显示在画布上,字符的水平间距和位置都按一定波动范围随机生成
    $strx = rand(1, 3);
    for ($i = 0; $i < $num; $i++) {
        $strpos = rand(2, 6);
        imagestring($im, 5, $strx, $strpos, substr($code, $i, 1), $black);
        $strx += rand(8, 12);
    }
    imagepng($im);
    imagedestroy($im);
}

function create_image()
{
    // *** Generate a passcode using md5
    //	(it will be all lowercase hex letters and numbers ***
    $md5 = md5(rand(0, 9999));
    $pass = substr($md5, 10, 5);
    // *** Set the session cookie so we know what the passcode is ***
    $_SESSION["pass"] = $pass;
    // *** Create the image resource ***
    $image = ImageCreatetruecolor(100, 20);
    // *** We are making two colors, white and black ***
    $clr_white = ImageColorAllocate($image, 255, 255, 255);
    $clr_black = ImageColorAllocate($image, 0, 0, 0);
    // *** Make the background black ***
    imagefill($image, 0, 0, $clr_black);
    // *** Set the image height and width ***
    imagefontheight(15);
    imagefontwidth(15);
    // *** Add the passcode in white to the image ***
    imagestring($image, 5, 30, 3, $pass, $clr_white);
    // *** Throw in some lines to trick those cheeky bots! ***
    imageline($image, 5, 1, 50, 20, $clr_white);
    imageline($image, 60, 1, 96, 20, $clr_white);
    // *** Return the newly created image in jpeg format ***
    return imagejpeg($image);
    // *** Just in case... ***
    imagedestroy($image);
}

function create_captcha($width = 60, $height = 32)
{
    session_start();
    //生成验证码图片
    Header("Content-type: image/PNG");
    $im = imagecreate($width, $height);
    // width and height of image
    $back = ImageColorAllocate($im, 245, 245, 245);
    // specify background color
    imagefill($im, 0, 0, $back);
    // fill the background color into image
    $vcodes = "";
    srand((double) microtime() * 1000000);
    //生成4位数字
    for ($i = 0; $i < 4; $i++) {
        $font = ImageColorAllocate($im, rand(100, 255), rand(0, 100), rand(100, 255));
        // 生成随机颜色
        $authnum = rand(1, 9);
        $vcodes .= $authnum;
        imagestring($im, 5, 2 + $i * 10, 1, $authnum, $font);
    }
    for ($i = 0; $i < 100; $i++) {
        // interuppting
        $randcolor = ImageColorallocate($im, rand(0, 255), rand(0, 255), rand(0, 255));
        imagesetpixel($im, rand() % 70, rand() % 30, $randcolor);
        // 画像素点函数
    }
    ImagePNG($im);
    ImageDestroy($im);
    $_SESSION['captcha'] = $vcodes;
}

function create_image()
{
    $image = imagecreatetruecolor(200, 50);
    $background_color = imagecolorallocate($image, 255, 255, 255);
    imagefilledrectangle($image, 0, 0, 200, 50, $background_color);
    $line_color = imagecolorallocate($image, 255, 0, 255);
    for ($i = 0; $i < 10; $i++) {
        imageline($image, 0, rand() % 50, 200, rand() % 25, $line_color);
    }
    $pixel_color = imagecolorallocate($image, 255, 0, 255);
    for ($i = 0; $i < 1000; $i++) {
        imagesetpixel($image, rand() % 200, rand() % 50, $pixel_color);
    }
    $letters = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz";
    $len = strlen($letters);
    $letter = $letters[rand(0, $len - 1)];
    $text_color = imagecolorallocate($image, 0, 0, 0);
    $word = "";
    for ($i = 0; $i < 6; $i++) {
        $letter = $letters[rand(0, $len - 1)];
        imagestring($image, 5, 5 + $i * 30, 20, $letter, $text_color);
        $word .= $letter;
    }
    $_SESSION['security_key'] = $word;
    imagepng($image);
}

 /**
  * +----------------------------------------------------------
  * 图片上传的处理函数
  * +----------------------------------------------------------
  */
 function create_captcha()
 {
     $word = $this->create_word();
     // 把验证码字符串写入session
     $_SESSION['captcha'] = md5($word . DOU_SHELL);
     // 绘制基本框架
     $im = imagecreatetruecolor($this->captcha_width, $this->captcha_height);
     $bg_color = imagecolorallocate($im, 235, 236, 237);
     imagefilledrectangle($im, 0, 0, $this->captcha_width, $this->captcha_height, $bg_color);
     $border_color = imagecolorallocate($im, 118, 151, 199);
     imagerectangle($im, 0, 0, $this->captcha_width - 1, $this->captcha_height - 1, $border_color);
     // 添加干扰
     for ($i = 0; $i < 5; $i++) {
         $rand_color = imagecolorallocate($im, mt_rand(0, 255), mt_rand(0, 255), mt_rand(0, 255));
         imagearc($im, mt_rand(-$this->captcha_width, $this->captcha_width), mt_rand(-$this->captcha_height, $this->captcha_height), mt_rand(30, $this->captcha_width * 2), mt_rand(20, $this->captcha_height * 2), mt_rand(0, 360), mt_rand(0, 360), $rand_color);
     }
     for ($i = 0; $i < 50; $i++) {
         $rand_color = imagecolorallocate($im, mt_rand(0, 255), mt_rand(0, 255), mt_rand(0, 255));
         imagesetpixel($im, mt_rand(0, $this->captcha_width), mt_rand(0, $this->captcha_height), $rand_color);
     }
     // 生成验证码图片
     $text_color = imagecolorallocate($im, mt_rand(0, 200), mt_rand(0, 120), mt_rand(0, 120));
     imagestring($im, 6, 18, 5, $word, $text_color);
     // header
     header("Cache-Control: max-age=1, s-maxage=1, no-cache, must-revalidate");
     header("Content-type: image/png;charset=utf-8");
     /* 绘图结束 */
     imagepng($im);
     imagedestroy($im);
     return true;
 }

 public function index()
 {
     header("content-type:image/gif");
     $this->load->library('session');
     $width = 60;
     $height = 30;
     $img = imagecreatetruecolor($width, $height);
     $white = imagecolorallocate($img, 255, 255, 255);
     $color = imagecolorallocate($img, rand(0, 255), rand(0, 255), rand(0, 255));
     $str = "123456789abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ";
     $code = "";
     for ($i = 0; $i < 5; $i++) {
         $code .= $str[rand(0, strlen($str) - 1)];
     }
     $this->session->set_userdata(array('myCode' => strtolower($code)));
     imagefilledrectangle($img, 0, 0, 60, 30, $color);
     for ($i = 0; $i < 100; $i++) {
         imagesetpixel($img, rand(0, 60), rand(0, 30), imagecolorallocate($img, rand(0, 255), rand(0, 255), rand(0, 255)));
     }
     for ($i = 0; $i < 10; $i++) {
         imageline($img, rand(0, 60), rand(0, 30), rand(0, 60), rand(0, 30), imagecolorallocate($img, rand(0, 255), rand(0, 255), rand(0, 255)));
     }
     imagestring($img, 5, 10, 5, $code, $white);
     return imagegif($img);
     //imagedestroy($img);
 }

function getCode($w, $h)
{
    $im = imagecreate($w, $h);
    //imagecolorallocate($im, 14, 114, 180); // background color
    $red = imagecolorallocate($im, 255, 0, 0);
    $white = imagecolorallocate($im, 255, 255, 255);
    $num1 = rand(1, 20);
    $num2 = rand(1, 20);
    $_SESSION['helloweba_math'] = $num1 + $num2;
    $gray = imagecolorallocate($im, 118, 151, 199);
    $black = imagecolorallocate($im, mt_rand(0, 100), mt_rand(0, 100), mt_rand(0, 100));
    //画背景
    imagefilledrectangle($im, 0, 0, 100, 24, $black);
    //在画布上随机生成大量点，起干扰作用;
    for ($i = 0; $i < 80; $i++) {
        imagesetpixel($im, rand(0, $w), rand(0, $h), $gray);
    }
    imagestring($im, 5, 5, 4, $num1, $red);
    imagestring($im, 5, 30, 3, "+", $red);
    imagestring($im, 5, 45, 4, $num2, $red);
    imagestring($im, 5, 70, 3, "=", $red);
    imagestring($im, 5, 80, 2, "?", $white);
    header("Content-type: image/png");
    imagepng($im);
    imagedestroy($im);
}