Question

How to determine on what page(need a page number) will be each flowable after rendering to pdf. I was thinking to add a custom id attribute to flowable, so i will know what flowable is it. But how can i determine on what page it will be placed?
What is the best way to achieve this?

Answer 1

I ended with following solution. Addeda an custom id flo_id to every flowable. And override method handle_flowable in BaseDocTemplate, where was checking and saving id,

class SignDocTemplate(BaseDocTemplate):
   blocks_to_pages = {}
   def handle_flowable(self, flowables):
     f = flowables[0]
     BaseDocTemplate.handle_flowable(self, flowables)
     if hasattr(f,'flo_id'):
       if self.blocks_to_pages.has_key(self.canv._pageNumber):
          self.blocks_to_pages[self.canv._pageNumber].append(f.flo_id)
       else:
          self.blocks_to_pages[self.canv._pageNumber]= [f.flo_id,]

And after building a doc it will be available at document instance in blocks_to_pages variable.