<?php
/**
*ImageCode 生成包含验证码的GIF图片的函数
*@param $string 字符串
*@param $width 宽度
*@param $height 高度
**/
function ImageCode($string = '', $width = 75, $height = 25) {
    $authstr = $string ? $string : ((time() % 2 == 0) ? mt_rand(1000, 9999) : mt_rand(10000, 99999));
    $board_width = $width;
    $board_height = $height;
    // 生成一个32帧的GIF动画
    for ($i = 0; $i < 32; $i ++) {
        ob_start();
        $p_w_picpath = p_w_picpathcreate($board_width, $board_height);
        p_w_picpathcolorallocate($p_w_picpath, 0, 0, 0);
        // 设定文字颜色数组
        $colorList[] = ImageColorAllocate($p_w_picpath, 15, 73, 210);
        $colorList[] = ImageColorAllocate($p_w_picpath, 0, 64, 0);
        $colorList[] = ImageColorAllocate($p_w_picpath, 0, 0, 64);
        $colorList[] = ImageColorAllocate($p_w_picpath, 0, 128, 128);
        $colorList[] = ImageColorAllocate($p_w_picpath, 27, 52, 47);
        $colorList[] = ImageColorAllocate($p_w_picpath, 51, 0, 102);
        $colorList[] = ImageColorAllocate($p_w_picpath, 0, 0, 145);
        $colorList[] = ImageColorAllocate($p_w_picpath, 0, 0, 113);
        $colorList[] = ImageColorAllocate($p_w_picpath, 0, 51, 51);
        $colorList[] = ImageColorAllocate($p_w_picpath, 158, 180, 35);
        $colorList[] = ImageColorAllocate($p_w_picpath, 59, 59, 59);
        $colorList[] = ImageColorAllocate($p_w_picpath, 0, 0, 0);
        $colorList[] = ImageColorAllocate($p_w_picpath, 1, 128, 180);
        $colorList[] = ImageColorAllocate($p_w_picpath, 0, 153, 51);
        $colorList[] = ImageColorAllocate($p_w_picpath, 60, 131, 1);
        $colorList[] = ImageColorAllocate($p_w_picpath, 0, 0, 0);
        $fontcolor = ImageColorAllocate($p_w_picpath, 0, 0, 0);
        $gray = ImageColorAllocate($p_w_picpath, 245, 245, 245);
        $color = p_w_picpathcolorallocate($p_w_picpath, 255, 255, 255);
        $color2 = p_w_picpathcolorallocate($p_w_picpath, 255, 0, 0);
        p_w_picpathfill($p_w_picpath, 0, 0, $gray);
        $space = 15; // 字符间距
        if ($i > 0) { // 屏蔽第一帧
            $top = 0;
            for ($k = 0; $k < strlen($authstr); $k ++) {
                $colorRandom = mt_rand(0, sizeof($colorList) - 1);
                $float_top = rand(0, 4);
                $float_left = rand(0, 3);
                p_w_picpathstring($p_w_picpath, 6, $space * $k, $top + $float_top, substr($authstr, $k, 1), $colorList[$colorRandom]);
            }
        }
        for ($k = 0; $k < 20; $k ++) {
            $colorRandom = mt_rand(0, sizeof($colorList) - 1);
            p_w_picpathsetpixel($p_w_picpath, rand() % 70, rand() % 15, $colorList[$colorRandom]);
        }
        // 添加干扰线
        for ($k = 0; $k < 3; $k ++) {
            $colorRandom = mt_rand(0, sizeof($colorList) - 1);
            $todrawline = 1;
            if ($todrawline) {
                p_w_picpathline($p_w_picpath, mt_rand(0, $board_width), mt_rand(0, $board_height), mt_rand(0, $board_width), mt_rand(0, $board_height), $colorList[$colorRandom]);
            } else {
                $w = mt_rand(0, $board_width);
                $h = mt_rand(0, $board_width);
                p_w_picpatharc($p_w_picpath, $board_width - floor($w / 2), floor($h / 2), $w, $h, rand(90, 180), rand(180, 270), $colorList[$colorRandom]);
            }
        }
        p_w_picpathgif($p_w_picpath);
        p_w_picpathdestroy($p_w_picpath);
        $p_w_picpathdata[] = ob_get_contents();
        ob_clean();
        ++ $i;
    }
    $gif = new GIFEncoder($p_w_picpathdata);
    Header('Content-type:p_w_picpath/gif');
    echo $gif->GetAnimation();
}
/**
 * *GIFEncoder类
 * *
 */
class GIFEncoder {
    var $GIF = "GIF89a"; /* GIF header 6 bytes */
    var $VER = "GIFEncoder V2.06"; /* Encoder version */
    var $BUF = Array();
    var $LOP = 0;
    var $DIS = 2;
    var $COL = - 1;
    var $IMG = - 1;
    var $ERR = Array(
            'ERR00' => "Does not supported function for only one p_w_picpath!",
            'ERR01' => "Source is not a GIF p_w_picpath!",
            'ERR02' => "Unintelligible flag ",
            'ERR03' => "Could not make animation from animated GIF source"
    );
    function GIFEncoder($GIF_src, $GIF_dly = 100, $GIF_lop = 0, $GIF_dis = 0, $GIF_red = 0, $GIF_grn = 0, $GIF_blu = 0, $GIF_mod = 'bin') {
        if (! is_array($GIF_src) && ! is_array($GIF_tim)) {
            printf("%s: %s", $this->VER, $this->ERR['ERR00']);
            exit(0);
        }
        $this->LOP = ($GIF_lop > - 1) ? $GIF_lop : 0;
        $this->DIS = ($GIF_dis > - 1) ? (($GIF_dis < 3) ? $GIF_dis : 3) : 2;
        $this->COL = ($GIF_red > - 1 && $GIF_grn > - 1 && $GIF_blu > - 1) ? ($GIF_red | ($GIF_grn << 8) | ($GIF_blu << 16)) : - 1;
        for ($i = 0, $src_count = count($GIF_src); $i < $src_count; $i ++) {
            if (strToLower($GIF_mod) == "url") {
                $this->BUF[] = fread(fopen($GIF_src[$i], "rb"), filesize($GIF_src[$i]));
            } elseif (strToLower($GIF_mod) == "bin") {
                $this->BUF[] = $GIF_src[$i];
            } else {
                printf("%s: %s(%s)!", $this->VER, $this->ERR['ERR02'], $GIF_mod);
                exit(0);
            }
            if (substr($this->BUF[$i], 0, 6) != "GIF87a" && substr($this->BUF[$i], 0, 6) != "GIF89a") {
                printf("%s: %d %s", $this->VER, $i, $this->ERR['ERR01']);
                exit(0);
            }
            for ($j = (13 + 3 * (2 << (ord($this->BUF[$i]{10}) & 0x07))), $k = TRUE; $k; $j ++) {
                switch ($this->BUF[$i]{$j}) {
                    case "!" :
                        if ((substr($this->BUF[$i], ($j + 3), 8)) == "NETSCAPE") {
                            printf("%s: %s(%s source)!", $this->VER, $this->ERR['ERR03'], ($i + 1));
                            exit(0);
                        }
                        break;
                    case ";" :
                        $k = FALSE;
                        break;
                }
            }
        }
        GIFEncoder::GIFAddHeader();
        for ($i = 0, $count_buf = count($this->BUF); $i < $count_buf; $i ++) {
            GIFEncoder::GIFAddFrames($i, $GIF_dly[$i]);
        }
        GIFEncoder::GIFAddFooter();
    }
    function GIFAddHeader() {
        $cmap = 0;
        if (ord($this->BUF[0]{10}) & 0x80) {
            $cmap = 3 * (2 << (ord($this->BUF[0]{10}) & 0x07));
            $this->GIF .= substr($this->BUF[0], 6, 7);
            $this->GIF .= substr($this->BUF[0], 13, $cmap);
            $this->GIF .= "!\377\13NETSCAPE2.0\3\1" . GIFEncoder::GIFWord($this->LOP) . "\0";
        }
    }
    function GIFAddFrames($i, $d) {
        $Locals_str = 13 + 3 * (2 << (ord($this->BUF[$i]{10}) & 0x07));
        $Locals_end = strlen($this->BUF[$i]) - $Locals_str - 1;
        $Locals_tmp = substr($this->BUF[$i], $Locals_str, $Locals_end);
        $Global_len = 2 << (ord($this->BUF[0]{10}) & 0x07);
        $Locals_len = 2 << (ord($this->BUF[$i]{10}) & 0x07);
        $Global_rgb = substr($this->BUF[0], 13, 3 * (2 << (ord($this->BUF[0]{10}) & 0x07)));
        $Locals_rgb = substr($this->BUF[$i], 13, 3 * (2 << (ord($this->BUF[$i]{10}) & 0x07)));
        $Locals_ext = "!\xF9\x04" . chr(($this->DIS << 2) + 0) . chr(($d >> 0) & 0xFF) . chr(($d >> 8) & 0xFF) . "\x0\x0";
        if ($this->COL > - 1 && ord($this->BUF[$i]{10}) & 0x80) {
            for ($j = 0; $j < (2 << (ord($this->BUF[$i]{10}) & 0x07)); $j ++) {
                if (ord($Locals_rgb{3 * $j + 0}) == ($this->COL >> 0) & 0xFF && ord($Locals_rgb{3 * $j + 1}) == ($this->COL >> 8) & 0xFF && ord($Locals_rgb{3 * $j + 2}) == ($this->COL >> 16) & 0xFF) {
                    $Locals_ext = "!\xF9\x04" . chr(($this->DIS << 2) + 1) . chr(($d >> 0) & 0xFF) . chr(($d >> 8) & 0xFF) . chr($j) . "\x0";
                    break;
                }
            }
        }
        switch ($Locals_tmp{0}) {
            case "!" :
                $Locals_img = substr($Locals_tmp, 8, 10);
                $Locals_tmp = substr($Locals_tmp, 18, strlen($Locals_tmp) - 18);
                break;
            case "," :
                $Locals_img = substr($Locals_tmp, 0, 10);
                $Locals_tmp = substr($Locals_tmp, 10, strlen($Locals_tmp) - 10);
                break;
        }
        if (ord($this->BUF[$i]{10}) & 0x80 && $this->IMG > - 1) {
            if ($Global_len == $Locals_len) {
                if (GIFEncoder::GIFBlockCompare($Global_rgb, $Locals_rgb, $Global_len)) {
                    $this->GIF .= ($Locals_ext . $Locals_img . $Locals_tmp);
                } else {
                    $byte = ord($Locals_img{9});
                    $byte |= 0x80;
                    $byte &= 0xF8;
                    $byte |= (ord($this->BUF[0]{10}) & 0x07);
                    $Locals_img{9} = chr($byte);
                    $this->GIF .= ($Locals_ext . $Locals_img . $Locals_rgb . $Locals_tmp);
                }
            } else {
                $byte = ord($Locals_img{9});
                $byte |= 0x80;
                $byte &= 0xF8;
                $byte |= (ord($this->BUF[$i]{10}) & 0x07);
                $Locals_img{9} = chr($byte);
                $this->GIF .= ($Locals_ext . $Locals_img . $Locals_rgb . $Locals_tmp);
            }
        } else {
            $this->GIF .= ($Locals_ext . $Locals_img . $Locals_tmp);
        }
        $this->IMG = 1;
    }
    function GIFAddFooter() {
        $this->GIF .= ";";
    }
    function GIFBlockCompare($GlobalBlock, $LocalBlock, $Len) {
        for ($i = 0; $i < $Len; $i ++) {
            if ($GlobalBlock{3 * $i + 0} != $LocalBlock{3 * $i + 0} || $GlobalBlock{3 * $i + 1} != $LocalBlock{3 * $i + 1} || $GlobalBlock{3 * $i + 2} != $LocalBlock{3 * $i + 2}) {
                return (0);
            }
        }
        return (1);
    }
    function GIFWord($int) {
        return (chr($int & 0xFF) . chr(($int >> 8) & 0xFF));
    }
    function GetAnimation() {
        return ($this->GIF);
    }
}
/*-------------------------------------华丽的分割线----------------------------------*/
/* 调用示例 */
session_start();
$checkCode = '';
$chars = 'abcdefghjkmnpqrstuvwxyzABCDEFGHJKLMNPRSTUVWXYZ23456789';
for ($i = 0; $i < 4; $i ++) {
    $checkCode .= substr($chars, mt_rand(0, strlen($chars) - 1), 1);
}
$_SESSION['code'] = strtoupper($checkCode); // 记录session
ImageCode($checkCode, 60);// 显示GIF动画