SO, you want to print the output of the procedure in pdf format? If so, you can try apex Report Query feature. You can find a number of examples for the same in this forum and in the internet:
Or, have a IR based on a collection; the collection based on a function returning query. And then, use the IR's generic download option to print reports.
For an easy understanding purpose i have created small procedure(EMP details).
My requirement is a procedure of nearly 500-600 line of code which has htp.p(''); stmts calling in Apex environment with PLSQL Dynamic Content.