Help with gs source code

[Suma Kuriakose]

Sir,
   We are a group working on modifying ghostscript with the intent of 
adding a search facility to gv. We have been debugging the source code of gs 
using ddd and have not been able to understand how gs extracts words that 
appear on the output screen from the postscript file.

  Could you please guide  us by specifying which structure holds the  final 
text to be displayed and also how it positions the words on the screen?

 Hoping to receive a prompt reply.