php imagettftext函数有什么用

array imagettftext ( resource $image , float $size , float $angle , int $x , int $y , int $color , string $fontfile , string $text )

<?php

     $image = imagecreate(400,300);
     $blue = imagecolorallocate($image, 0, 0, 255);
     $white = ImageColorAllocate($image, 255,255,255);                                           
     imagettftext($image, 44, 15, 50, 200, $white,"ARIAL", "java2s.com");
     // Set the content-type
     header("content-type: image/png");
     imagepng($image);
     imagedestroy($image);
?>