Re: [gedit-list] First pass hack of gedit and gtksourceview port to gtkprintoperation

["John (J5) Palmieri" <johnp redhat com>]

On Mon, 2006-05-08 at 17:18 +0200, Paolo Maggi wrote:
> Hi,
> 
> > 
> > Adding a specific "print current selection" feature should be quite
> > easy, although it will require some work to implement the win32 side i
> > think. However, how do you propose a generic mechanism for this would
> > work? (That also would work in the native print dialogs on win32 and
> > OSX.)
> 
> I have started working on the implementation, but looking at the code of
> gtkprintoperation.c I have seen that the real problem is not pagination,
> but the fact the printing is always mostly a sync operation also when
> gtk_print_operation_run_async is used.
> 
> What I mean is that the real printing is done in the print_pages
> function. In that function a "draw_page" signal is emitted for each page
> and in order to not block the UI the "while (gtk_events_pending ())
> gtk_main_iteration ();" trick is used (may be it is me, but I don't like
> very much the main loop iteration stuff )
> 
> What about modifying the print_page function in order to install a "idle
> handler" that prints a single page and remove the handler when there are
> no more pages to print?
> 
> In this way we could also implement "print canceling" (at least in the
> async way).

Doing this in an idle handler doesn't sound like a bad idea.  

> Ciao,
> Paolo
> 
> P.S. It is not clear to me how the "request_page_setup" signal is
> supposed to be used.
> 
> P.P.S. May be "draw_page" should return a boolean so we can print
> without knowing a priori the number of pages. 

I wonder why we didn't do this in the first place.  The drawback is that
we won't be able to display printing page x of x. 

-- 
John (J5) Palmieri <johnp redhat com>