PHP 生成动态GIF验证码

PHP 阅读量

生成一个有意思的动态gif验证码, 来自阿鸡的博客PHP动态gif验证码

效果

GIF

源码

主函数

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<?php

function ImageCode(
    $string = '',
    $frames = 60,
    $time = 1,
    $width = 75,
    $height = 25,
    $font = 6,
    $loops = 0
) {
    $auth_str = $string ?: (time() % 2 == 0)
        ? mt_rand(1000, 9999)
        : mt_rand(10000, 99999);

    $board_width  = $width;
    $board_height = $height;

    $delay = $time * 1000 / $frames;

    // 生成一个N帧的GIF动画
    for ($i = 0; $i < $frames; $i++) {
        ob_start();

        $image = imagecreate($board_width, $board_height);
        imagecolorallocate($image, 0, 0, 0);

        // 设定文字颜色数组
        $colorList[] = imagecolorallocate($image,15,73,210);
        $colorList[] = imagecolorallocate($image,0,64,0);
        $colorList[] = imagecolorallocate($image,0,0,64);
        $colorList[] = imagecolorallocate($image,0,128,128);
        $colorList[] = imagecolorallocate($image,27,52,47);
        $colorList[] = imagecolorallocate($image,51,0,102);
        $colorList[] = imagecolorallocate($image,0,0,145);
        $colorList[] = imagecolorallocate($image,0,0,113);
        $colorList[] = imagecolorallocate($image,0,51,51);
        $colorList[] = imagecolorallocate($image,158,180,35);
        $colorList[] = imagecolorallocate($image,59,59,59);
        $colorList[] = imagecolorallocate($image,0,0,0);
        $colorList[] = imagecolorallocate($image,1,128,180);
        $colorList[] = imagecolorallocate($image,0,153,51);
        $colorList[] = imagecolorallocate($image,60,131,1);
        $colorList[] = imagecolorallocate($image,0,0,0);

        $gray = imagecolorallocate($image, 245, 245, 245);
        imagefill($image, 0, 0, $gray);
        $space = $font * 0.65; // 字符间距

        $len = strlen($auth_str);
        for ($k = 0; $k < $len; $k++) {
            $colorRandom = mt_rand(0, sizeof($colorList) - 1);

            $float_top  = rand(0, 4);
            $float_left = rand(1, 4);

            imagettftext(
                $image, $font, 0,
                $space*$k + $float_left, $font + $float_top,
                $colorList[$colorRandom],
                './fonts/comic.ttf',
                substr($auth_str, $k, 1)
            );
        }

        for ($k = 0; $k < 20; $k++) {
            $colorRandom = mt_rand(0, sizeof($colorList) - 1);
            imagesetpixel($image, rand() % 70, rand() % 15, $colorList[$colorRandom]);
        }

        // 添加干扰线
        for ($k = 0; $k < 3; $k++) {
            $colorRandom = mt_rand(0, sizeof($colorList) - 1);
            $to_draw_line = 1;
            if ($to_draw_line) {
                imageline($image, 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_height);

                imagearc($image, $board_width - floor($w / 2), floor($h / 2), $w, $h, rand(90, 180), rand(180, 270), $colorList[$colorRandom]);
            }
        }

        imagegif($image);
        imagedestroy($image);
        $imageData[] = ob_get_contents();
        $delays[] = $delay;
        ob_clean();
    }

    return new AnimatedGif($imageData, $delays, $loops);
}

AnimatedGif类

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<?php

class AnimatedGif
{
    /**
     * The built gif image
     * @var resource
     */
    private $image = '';
    /**
     * The array of images to stack
     * @var array
     */
    private $buffer = Array();
    /**
     * How many times to loop? 0 = infinite
     * @var int
     */
    private $number_of_loops = 0;
    /**
     *
     * @var int
     */
    private $DIS = 2;
    /**
     * Which colour is transparent
     * @var int
     */
    private $transparent_colour = -1;
    /**
     * Is this the first frame
     * @var int
     */
    private $first_frame = TRUE;

    /**
     * Encode an animated gif
     * AnimatedGif constructor.
     * @param array $source_images
     * @param array $image_delays
     * @param $number_of_loops
     */
    function __construct(
        array $source_images,
        array $image_delays,
        $number_of_loops
    ) {
        /**
         * I have no idea what these even do, they appear to do nothing to the image so far
         */
        $transparent_colour_red = 0;
        $transparent_colour_green = 0;
        $transparent_colour_blue = 0;
        $this->number_of_loops = ( $number_of_loops > -1 ) ? $number_of_loops : 0;
        $this->set_transparent_colour($transparent_colour_red, $transparent_colour_green, $transparent_colour_blue);
        $this->buffer_images($source_images);
        $this->addHeader();
        for ($i = 0; $i < count($this->buffer); $i++) {
            $this->addFrame($i, $image_delays [$i]);
        }
    }

    /**
     * Set the transparent colour
     * @param int $red
     * @param int $green
     * @param int $blue
     */
    private function set_transparent_colour($red, $green, $blue){
        $this->transparent_colour = ( $red > -1 && $green > -1 && $blue > -1 ) ?
            ( $red | ( $green << 8 ) | ( $blue << 16 ) ) : -1;
    }

    /**
     * Buffer the images and check to make sure they are vaild
     * @param $source_images
     */
    private function buffer_images($source_images)
    {
        for ($i = 0; $i < count($source_images); $i++) {
            $this->buffer [] = $source_images [$i];
            if (substr($this->buffer [$i], 0, 6) != "GIF87a" && substr($this->buffer [$i], 0, 6) != "GIF89a") {
                throw new Exception('Image at position ' . $i. ' is not a gif');
            }
            for ($j = ( 13 + 3 * ( 2 << ( ord($this->buffer [$i] { 10 }) & 0x07 ) ) ), $k = TRUE; $k; $j++) {
                switch ($this->buffer [$i] { $j }) {
                    case "!":
                        if (( substr($this->buffer [$i], ( $j + 3), 8) ) == "NETSCAPE") {
                            throw new Exception('You cannot make an animation from an animated gif.');
                        }
                        break;
                    case ";":
                        $k = FALSE;
                        break;
                }
            }
        }
    }
    /**
     * Add the gif header to the image
     */
    private function addHeader()
    {
        $cmap = 0;
        $this->image = 'GIF89a';
        if (ord($this->buffer [0] { 10 }) & 0x80) {
            $cmap = 3 * ( 2 << ( ord($this->buffer [0] { 10 }) & 0x07 ) );
            $this->image .= substr($this->buffer [0], 6, 7);
            $this->image .= substr($this->buffer [0], 13, $cmap);
            $this->image .= "!\377\13NETSCAPE2.0\3\1" . $this->word($this->number_of_loops) . "\0";
        }
    }
    /**
     * Add a frame to the animation
     * @param int $frame The frame to be added
     * @param int $delay The delay associated with the frame
     */
    private function addFrame($frame, $delay)
    {
        $Locals_str = 13 + 3 * ( 2 << ( ord($this->buffer [$frame] { 10 }) & 0x07 ) );
        $Locals_end = strlen($this->buffer [$frame]) - $Locals_str - 1;
        $Locals_tmp = substr($this->buffer [$frame], $Locals_str, $Locals_end);
        $Global_len = 2 << ( ord($this->buffer [0] { 10 }) & 0x07 );
        $Locals_len = 2 << ( ord($this->buffer [$frame] { 10 }) & 0x07 );
        $Global_rgb = substr($this->buffer [0], 13, 3 * ( 2 << ( ord($this->buffer [0] { 10 }) & 0x07 ) ));
        $Locals_rgb = substr($this->buffer [$frame], 13, 3 * ( 2 << ( ord($this->buffer [$frame] { 10 }) & 0x07 ) ));
        $Locals_ext = "!\xF9\x04" . chr(( $this->DIS << 2 ) + 0) .
            chr(( $delay >> 0 ) & 0xFF) . chr(( $delay >> 8 ) & 0xFF) . "\x0\x0";
        if ($this->transparent_colour > -1 && ord($this->buffer [$frame] { 10 }) & 0x80) {
            for ($j = 0; $j < ( 2 << ( ord($this->buffer [$frame] { 10 }) & 0x07 ) ); $j++) {
                if (
                    ord($Locals_rgb { 3 * $j + 0 }) == ( ( $this->transparent_colour >> 16 ) & 0xFF ) &&
                    ord($Locals_rgb { 3 * $j + 1 }) == ( ( $this->transparent_colour >> 8 ) & 0xFF ) &&
                    ord($Locals_rgb { 3 * $j + 2 }) == ( ( $this->transparent_colour >> 0 ) & 0xFF )
                ) {
                    $Locals_ext = "!\xF9\x04" . chr(( $this->DIS << 2 ) + 1) .
                        chr(( $delay >> 0 ) & 0xFF) . chr(( $delay >> 8 ) & 0xFF) . chr($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->buffer [$frame] { 10 }) & 0x80 && $this->first_frame === FALSE) {
            if ($Global_len == $Locals_len) {
                if ($this->blockCompare($Global_rgb, $Locals_rgb, $Global_len)) {
                    $this->image .= ( $Locals_ext . $Locals_img . $Locals_tmp );
                } else {
                    $byte = ord($Locals_img { 9 });
                    $byte |= 0x80;
                    $byte &= 0xF8;
                    $byte |= ( ord($this->buffer [0] { 10 }) & 0x07 );
                    $Locals_img { 9 } = chr($byte);
                    $this->image .= ( $Locals_ext . $Locals_img . $Locals_rgb . $Locals_tmp );
                }
            } else {
                $byte = ord($Locals_img { 9 });
                $byte |= 0x80;
                $byte &= 0xF8;
                $byte |= ( ord($this->buffer [$frame] { 10 }) & 0x07 );
                $Locals_img { 9 } = chr($byte);
                $this->image .= ( $Locals_ext . $Locals_img . $Locals_rgb . $Locals_tmp );
            }
        } else {
            $this->image .= ( $Locals_ext . $Locals_img . $Locals_tmp );
        }
        $this->first_frame = FALSE;
    }
    /**
     * Add the gif footer
     */
    private function addFooter()
    {
        $this->image .= ";";
    }

    /**
     * Compare gif blocks? What is a block?
     * @param $GlobalBlock
     * @param $LocalBlock
     * @param $Len
     * @return int
     */
    private function blockCompare($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 );
    }
    /**
     * No clue
     * @param int $int
     * @return string the char you meant?
     */
    private function word($int)
    {
        return ( chr($int & 0xFF) . chr(( $int >> 8 ) & 0xFF) );
    }

    /**
     * Return the animated gif
     * @return resource
     */
    function getAnimation()
    {
        return $this->image;
    }
    /**
     * Return the animated gif
     * @echo image
     */
    function display()
    {
        //late footer add
        $this->addFooter();
        header('Content-type:image/gif');
        echo $this->image;
    }
}

使用示例代码:

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$str  = 'abcdefghijkmnpqrstuvwxy3456789';
$len  = strlen($str) - 1;
$text = '';

for ($i = 0; $i < 6; $i++) {
    $text .= $str[rand(0, $len)];
}

$gif = ImageCode($text, 8, 1, 100, 35, 23);

$gif->display();

参考

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