Highlevel printing API - proposal



On the summit owen and some people hacked up a proposal for a Gtk+
printing API. It is availible in libegg/libegg/print in cvs. Having
looked at various other APIs and platform requirements I have a
different idea of how such a highlevel API could look. 

Attached is a example implementation of the API ideas. Look at
testprint.c and testprintfileoperation.c to see how it is used.

The basic idea is that each time you want to print (i.e. when the user
selects File->Print) you create a new GtkPrintOperation, set various
information on it like:
* default page settings (size, orientation etc)
* initial printer settings (from last print)
* various settings controlling the print operation

Then you kick off the operation, with egg_print_operation_run(). We then
display a print dialog (if requested), and create a cairo context for
the correct printing backend. Then various signals are emitted on the
EggPrintOperation:
begin_print: emitted at start, here you can e.g. allocate resources
request_page_settings: emitted before page rendering, letting you change
                       the page settings on a per-page basis
draw_page: render the page nr given, return FALSE if no such page (you
           can hint on the nr of pages with
           egg_print_operation_set_nr_of_pages)
end_print: emitted at end, even if cancelled, here you can free  
           resources

When this is done the job is sent to the spooler, and the function
returns. We could add some form of feedback on the printing progress as
other signals on the object. At this point you should get the new
printer settings object and save that for the next print operation.

Another way to use this API is to subclass EggPrintOperation, like the
TestPrintFileOperation class in the example code.

Opinions on this?

=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=
 Alexander Larsson                                            Red Hat, Inc 
                   alexl redhat com    alla lysator liu se 
He's a bookish vegetarian stage actor moving from town to town, helping folk 
in trouble. She's a mentally unstable wisecracking museum curator with a 
flame-thrower. They fight crime! 

Attachment: print2.tar.bz2
Description: application/bzip-compressed-tar



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