| Chapter 20. Printing | ||
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| Chapter 20. Printing | ||
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Table of Contents
At the application development level, gtkmm's printing API provides dialogs that are consistent across applications and allows use of Cairo's common drawing API, with Pango-driven text rendering. In the implementation of this common API, platform-specific backends and printer-specific drivers are used.
The primary object is Gtk::PrintOperation, allocated
for each print operation. To handle page drawing connect to its signals,
or inherit from it and override the default virtual signal handlers.
PrintOperation automatically handles all the settings
affecting the print loop.
The PrintOperation::run() method starts the print loop,
during which various signals are emitted:
begin_print:
You must handle this signal, because this is where you
create and set up a Pango::Layout using the
provided Gtk::PrintContext, and break up your
printing output into pages.
paginate: Pagination is potentially slow so if you
need to monitor it you can call the
PrintOperation::set_show_progress() method and
handle this signal.
For each page that needs to be rendered, the following signals are emitted:
request_page_setup: Provides a
PrintContext, page number and
Gtk::PageSetup. Handle this signal if you
need to modify page setup on a per-page basis.
draw_page: You must handle this signal, which provides a
PrintContext and a page number.
The PrintContext should be used
to create a Cairo::Context into which
the provided page should be drawn. To render text, iterate over
the Pango::Layout you created in the
begin_print handler.
end_print: A handler for it is a safe place to free
any resources related to a PrintOperation.
If you have your custom class that inherits from
PrintOperation, it is naturally simpler to do it
in the destructor.
done: This signal is emitted when printing is finished, meaning when the
print data is spooled. Note that the provided
Gtk::PrintOperationResult may indicate that
an error occurred. In any case you probably want to notify the user
about the final status.
status_changed: Emitted whenever a print job's
status changes, until it is finished. Call the
PrintOperation::set_track_print_status() method to
monitor the job status after spooling. To see the status, use
get_status() or
get_status_string().
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| Examples |  |
Page setup |