PHP - ImageCreate（）錯誤

Question

我試圖做一個驗證碼，我在線閱讀一些教程。所以，我有複製/粘貼此功能：

create_image(); 
exit(); 

function create_image() { 
    //Let's generate a totally random string using md5 
    $md5_hash = md5(rand(0,999)); 
    //We don't need a 32 character long string so we trim it down to 5 
    $security_code = substr($md5_hash, 15, 5); 

    //Set the session to store the security code 
    $_SESSION["security_code"] = $security_code; 

    //Set the image width and height 
    $width = 100; 
    $height = 20; 

    //Create the image resource 
    $image = ImageCreate($width, $height); 

    //We are making three colors, white, black and gray 
    $white = ImageColorAllocate($image, 255, 255, 255); 
    $black = ImageColorAllocate($image, 0, 0, 0); 
    $grey = ImageColorAllocate($image, 204, 204, 204); 

    //Make the background black 
    ImageFill($image, 0, 0, $black); 

    //Add randomly generated string in white to the image 
    ImageString($image, 3, 30, 3, $security_code, $white); 

    //Throw in some lines to make it a little bit harder for any bots to break 
    ImageRectangle($image,0,0,$width-1,$height-1,$grey); 
    imageline($image, 0, $height/2, $width, $height/2, $grey); 
    imageline($image, $width/2, 0, $width/2, $height, $grey); 

    //Tell the browser what kind of file is come in 
    header("Content-Type: image/jpeg"); 

    //Output the newly created image in jpeg format 
    ImageJpeg($image); 

    //Free up resources 
    ImageDestroy($image); 
} 

但是，當我嘗試調用它，我得到這個錯誤：

致命錯誤：調用未定義功能ImageCreate（）在C：\ Program Files \ Apache Software Foundation \ Apache2.2 \ htdocs \ gtw \ registration \ createCaptcha.php on line 19

什麼問題？一些PHP庫？

Answer 1

php_gd2擴展未啓用。

它包含在Windows PHP發行版中，但必須在php.ini中啓用它。要做到這一點，只需打開php.ini並取消註釋（刪除前面的;）以下行：

extension=php_gd2.dll 

保存，重啓Apache，你應該罰款。

Answer 2

爲了能夠使用ImageCreate，您需要將GD Library作爲PHP安裝的一部分。

使用phpinfo（）函數檢查它是否已安裝。如果沒有，你需要添加這個。