如何用PHP生成GIF動(dòng)畫來實(shí)現(xiàn)動(dòng)態(tài)圖片驗(yàn)證碼？相信您要在找答案，以下是實(shí)現(xiàn)過程。
    ImageCode函數(shù)通過GIFEncoder類實(shí)現(xiàn)的GIF動(dòng)畫的PHP源代碼，有興趣的朋友可以研究一下。
    有關(guān)GIFEncoder類。 具體代碼入如下：
    /**
    * ImageCode 生成GIF圖片驗(yàn)證
    * @param $string 字符串
    * @param $width 寬度
    * @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 = $height;
    // 生成一個(gè)32幀的GIF動(dòng)畫
    for($i = 0; $i < 32; $i++)
    {
    ob_start();
    $image = imagecreate($board_width, $board_height);
    imagecolorallocate($image, 0,0,0);
    // 設(shè)定文字顏色數(shù)組
    $colorList[] = ImageColorAllocate($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);
    $fontcolor = ImageColorAllocate($image, 0,0,0);
    $gray = ImageColorAllocate($image, 245,245,245);
    $color = imagecolorallocate($image, 255,255,255);
    $color2 = imagecolorallocate($image, 255,0,0);
    imagefill($image, 0, 0, $gray);
    $space = 15; // 字符間距
    if($i > 0) // 屏蔽第一幀
    {
    for ($k = 0; $k < strlen($authstr); $k++)
    {
    $colorRandom = mt_rand(0,sizeof($colorList)-1);
    $float_top = rand(0,4);
    $float_left = rand(0,3);
    imagestring($image, 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);
    imagesetpixel($image, rand()%70 , rand()%15 , $colorList[$colorRandom]);
    }
    // 添加干擾線
    for($k = 0; $k < 3; $k++)
    {
    $colorRandom = mt_rand(0, sizeof($colorList)-1);
    // $todrawline = rand(0,1);
    $todrawline = 1;
    if($todrawline)
    {
    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_width);
    imagearc($image, $board_width - floor($w / 2) , floor($h / 2), $w, $h, rand(90,180), rand(180,270), $colorList[$colorRandom]);
    }
    }
    imagegif($image);
    imagedestroy($image);
    $imagedata[] = ob_get_contents();
    ob_clean();
    ++$i;
    }
    $gif = new GIFEncoder($imagedata);
    Header ('Content-type:image/gif');
    echo $gif->GetAnimation();
    }
    /**
    * 調(diào)用示例
    * */
    session_start();
    $authstr = mt_rand(1000, 9999); // 生成隨機(jī)字符串
    $_SESSION['verify'] = $authstr; // 記錄session
    ImageCode($authstr, 60); // 顯示GIF動(dòng)畫