Python and GObject-Introspection

Yuren Ju <yurenju@gmail.com>

About me

● http://about.me/yurenju ● Hacking Thursday● KaLUG● Twitter: @yurenju

GObject

D-BUS

VTE

notify

Glade GTK

GNOME platform

Library based on GObject

Binding

Use codegen to generate GTK C Wrapper for Python

gtk.c number of lines:

128,469

If GTK+ add APIs in new version,python-gtk also need to upgrade for new APIs.

Implement in Python,Also need to re-implement in Ruby, Perl, Java,

Javscript again.

GObject-Introspection

python-gobject

GTK+GTK+

metadata

Original

GTK+GTK+metadata

python-gobjectparser

GObject-Introspection

GTK+GTK+metadata

GTK+gstreamermetadata

GTK+...metadata

Same metadata format

python-gobjectparser

Parser + metadata = GObject-Introspection

tut-triangle

tut.triangle

+ get_color()+ set_color()+ get_centroid()+ get_centroidu()

Metadata

Comments in Source code

Gir XML file

Typelib binary file

g-ir-scanner

g-ir-compiler

Comments in Source code

http://live.gnome.org/GObjectIntrospection/Annotations

Gir XML file

Metadata

Comments in Source code

Gir XML file

Typelib binary file

g-ir-scanner

g-ir-compiler

libgirepository

python-gobjectPyGTK 2.24.0 has been released. This is a stable release supporting the GTK+ 2.24 API. New users wishing to develop Python applications using GTK+ are recommended to use the GObject-Introspection features available in PyGObject. Existing authors of PyGTK applications are also recommended to port their applications to PyGObject to take advantage of new features appearing in GTK-3 and beyond.

gtk.c number of lines:

128,469

How to use GI?from gi.repository import Gtk;

PEP-0302: New Import Hooks

Append finder to sys.meta_path,Use finder.find_module() dynamic to find module.

Load module

● find_module()● load_module()

● Create DynamicModule● Module._load()

– Create self._introspection_module● IntrospectionModule => repository.requre to load typelib

Objectfrom gi.repository import Gtk

Initial all items in Gtk

- Widget- Container- Window

...etc.Get info fromrepository.find_by_name()

If item is a object instance, Use a MetaClass“GobjectMeta” to create a class wrapper

Finally, you have a Python Class to create Object!

Method – relative easy

object.method()

Call info.invoke()

g_function_info_invoke

Summary

● GI Migrate metadata from language-binding to library

● python-gobject let you use GTK, GObject, Gstreamer, VTE, Dbus,...etc.

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