Emitted after the begin_print signal, but before the actual rendering starts.
It keeps getting emitted until a connected signal handler returns true.
The paginate signal is intended to be used for paginating a document in small chunks, to avoid blocking the user interface for a long time. The signal handler should update the number of pages using set_n_pages, and return true if the document has been completely paginated.
If you don't need to do pagination in chunks, you can simply do it all in the begin_print handler, and set the number of pages from there.
the PrintContext for the current operation
true if pagination is complete