html or php to pdf whith pdflib?

Hello, somebody knows like turning a file HTML or php to pdf by means of pdflib but without having to write line to line? that is, a file already existing php or HTML, can be turned with pdflib? This I ask it because to where it studies pdflib, exit pdf is due to write line by line and coordinate by coordinate. A pdf already created can also be mattered and to combine it with the new exit. But what I did not find he is all this is the particularitity that I raise. I hope has explained to me correctly