PHP - ImageCreate() 错误

Question

我正在尝试制作一个验证码，并且我在网上阅读了一些教程。所以，我复制/粘贴了这个函数:

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); 
}

但是当我尝试调用它时，出现了这个错误:

fatal error :在第 19 行调用 C:\Program Files\Apache Software Foundation\Apache2.2\htdocs\gtw\registration\createCaptcha.php 中未定义的函数 ImageCreate()

有什么问题？一些 PHP 库？

Answer 1

未启用 php_gd2 扩展。

它包含在 Windows PHP 发行版中，但您必须在 php.ini 中启用它。为此，只需打开 php.ini 并取消注释(删除前导 ;)以下行:

extension=php_gd2.dll

保存，重启 Apache，你应该没问题。