我找到了字节
http://bytes.com/topic/php/answers/4833-gd-could-not-find-open-font-font-problem的答案
设置gdfontpath可能会有所帮助
$fontpath = realpath('.'); //replace . with a different directory if needed
putenv('GDFONTPATH='.$fontpath);
$font = 't.otf';
...
$Box = imagettfbBox($size,$font,$text);
