really really good class.
and it worked like charm but i got problem there in one tree xml file, xml file is large then some problem happens and tree image doesnt generated
i have used your example code and it works in small tree's but not in large tree, xml file is company1.xml in that folder other file's are the same files in your code. only change is i give the company1.xml in test4.php xml file url variable.
can you find what's troubling because it was working fine in smaller tree but in large tree its not working.
xml is validated. it doesnt have any errors.
if you want to check the xml file and code then here is the code,