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Brian Manning
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Gtk3 - Perl interface to the 3.x series of the gtk+ toolkit


  use Gtk3 -init;
  my $window = Gtk3::Window->new ('toplevel');
  my $button = Gtk3::Button->new ('Quit');
  $button->signal_connect (clicked => sub { Gtk3::main_quit });
  $window->add ($button);


Perl bindings to the 3.x series of the gtk+ toolkit. This module allows you to write graphical user interfaces in a Perlish and object-oriented way, freeing you from the casting and memory management in C, yet remaining very close in spirit to original API.


The Gtk3 module allows a Perl developer to use the gtk+ graphical user interface library. Find out more about gtk+ at http://www.gtk.org.

The gtk+ reference manual is also a handy companion when writing Gtk3 programs in Perl: http://developer.gnome.org/gtk3/stable/. The Perl bindings follow the C API very closely, and the C reference documentation should be considered the canonical source. The principles underlying the mapping from C to Perl are explained in the documentation of Glib::Object::Introspection, on which Gtk3 is based.

Glib::Object::Introspection also comes with the perli11ndoc program which displays the API reference documentation of all installed libraries organized in accordance with these principles.

Wrapped libraries

Gtk3 automatically sets up the following correspondence between C libraries and Perl packages:

  Library       | Package
  Gtk-3.0       | Gtk3
  Gdk-3.0       | Gtk3::Gdk
  GdkPixbuf-2.0 | Gtk3::Gdk
  Pango-1.0     | Pango

Import arguments

When importing Gtk3, you can pass -init as in use Gtk3 -init; to have Gtk3::init automatically called. You can also pass a version number to require a certain version of Gtk3.

Customizations and overrides

In order to make things more Perlish or to make porting from Gtk2 to Gtk3 easier, Gtk3 customizes the API generated by Glib::Object::Introspection in a few spots:

  • The array ref normally returned by the following functions is flattened into a list:

  • The following functions normally return a boolean and additional out arguments, where the boolean indicates whether the out arguments are valid. They are altered such that when the boolean is true, only the additional out arguments are returned, and when the boolean is false, an empty list is returned.

  • Values of type Gtk3::ResponseType are converted to and from nick names if possible, while still allowing raw IDs, in the following places:

    - For Gtk3::Dialog and Gtk3::InfoBar: the signal response as well as the methods add_action_widget, add_button, add_buttons, response, set_default_response and set_response_sensitive.
    - For Gtk3::Dialog: the methods get_response_for_widget, get_widget_for_response, run and set_alternative_button_order.
  • Values of type Gtk3::IconSize are converted to and from nick names if possible, while still allowing raw IDs, in the following places:

    - Gtk3::Image: the constructors new_from_stock, new_from_icon_set, new_from_icon_name and new_from_gicon, the getters get_stock, get_icon_set, get_icon_name and get_gicon and the setters set_from_stock, set_from_icon_set, set_from_icon_name, set_from_gicon.
    - Gtk3::Widget: the method render_icon.
  • The constants Gtk3::EVENT_PROPAGATE and Gtk3::EVENT_STOP can be used in handlers for event signals like key-press-event to indicate whether or not the event should continue propagating through the widget hierarchy.

  • The records corresponding to the various Gtk3::Gdk::Event types, like expose or key-release, are represented as objects blessed into specific Perl packages, like Gtk3::Gdk::EventExpose or Gtk3::Gdk::EventKey, that all inherit from Gtk3::Gdk::Event. This allows you to seemlessly access type-specific fields as well as common fields, as in $event->window or $event->keyval.

  • Gtk3::Gdk::Atom has overloads for the == and != operators that check for equality of the underlying atoms.

  • For backwards compatibility, Gtk3::CHECK_VERSION, Gtk3::check_version, Gtk3::init, Gtk3::init_check, Gtk3::main, Gtk3::main_level and Gtk3::main_quit can be called as class-static or as normal functions: for example, Gtk3->main_quit and Gtk3::main_quit are both supported. Additionally, Gtk3::init and Gtk3::init_check automatically handle passing and updating @ARGV as appropriate.

  • A Perl reimplementation of Gtk3::show_about_dialog is provided.

  • Perl reimplementations of Gtk3::ActionGroup::add_actions, add_radio_actions and add_toggle_actions are provided.

  • Gtk3::Builder::add_objects_from_file and add_objects_from_string also accept a list of objects instead of an array ref.

  • Gtk3::Builder::add_objects_from_string and add_from_string don't take length arguments, as they are computed automatically.

  • A Perl reimplementation of Gtk3::Builder::connect_signals is provided.

  • The default new constructors of Gtk3::Button, Gtk3::CheckButton, Gtk3::ColorButton, Gtk3::FontButton and Gtk3::ToggleButton reroute to new_with_mnemonic if given an extra argument.

  • The default new constructor of Gtk3::CheckMenuItem reroutes to new_with_mnemonic if given an extra argument.

  • Gtk3::Container::get_focus_chain returns a list of widgets, or an empty list.

  • Gtk3::Container::set_focus_chain also accepts a list of widgets.

  • Gtk3::CssProvider::load_from_data also accepts a string.

  • For Gtk3::Dialog and Gtk3::InfoBar, a Perl implementaion of add_buttons is provided.

  • Gtk3::Dialog::new can optionally be called as Gtk3::Dialog->new (TITLE, PARENT, FLAGS, ...) where ... is a series of button text and response id pairs.

  • A Perl implementation of Gtk3::Dialog::new_with_buttons is provided.

  • The length argument of Gtk3::Editable::insert_text is optional.

  • A Perl implementation of Gtk3::FileChooserDialog::new is provided.

  • Gtk3::HBox::new uses the defaults homogeneous = FALSE and spacing = 5.

  • The default new constructor of Gtk3::ImageMenuItem reroutes to new_with_mnemonic if given an extra argument.

  • Gtk3::InfoBar::new can optionally be called as Gtk3::InfoBar->new (...) where ... is a series of button text and response id pairs.

  • A Perl reimplementation of Gtk3::InfoBar::new_with_buttons is provided.

  • The default new constructor of Gtk3::LinkButton reroutes to new_with_label if given an extra argument.

  • Gtk3::ListStore::new also accepts a list of type names.

  • Gtk3::ListStore has a get method that calls Gtk3::TreeModel::get instead of Glib::Object::get.

  • Gtk3::ListStore::insert_with_values also accepts a list of column => value pairs and reroutes to insert_with_valuesv.

  • Gtk3::ListStore::set also accepts a list of column => value pairs.

  • Gtk3::Menu::popup reroutes to popup_for_device for better callback handling.

  • Gtk3::Menu::popup_for_device allows the given menu position func to return only x and y coordinates, defaulting push_in to FALSE.

  • The default new constructor of Gtk3::MenuItem reroutes to new_with_mnemonic if given an extra argument.

  • A Perl reimplementation of Gtk3::MessageDialog::new is provided.

  • The group handling in the constructors and accessors of Gtk3::RadioAction, Gtk3::RadioButton, Gtk3::RadioMenuItem and Gtk3::RadioToolButton is amended to work correctly when given array refs of group members or single group members.

  • Perl reimplementations of Gtk3::RecentChooserDialog::new and new_for_manager are provided.

  • Redirects are provided from Gtk3::Stock::[function] to Gtk3::stock_[function] for add, add_static, list_ids, lookup and set_translate_func.

  • A Perl reimplementation of Gtk3::TextBuffer::create_tag is provided.

  • The length arguments of Gtk3::TextBuffer::insert, insert_at_cursor, insert_interactive, insert_interactive_at_cursor, insert_markup and set_text are optional.

  • Perl reimplementations of Gtk3::TextBuffer::insert_with_tags and insert_with_tags_by_name are provided which do not require a length argument.

  • A Perl reimplementation of Gtk3::TreeModel::get is provided.

  • A redirect is added from Gtk3::TreeModelFilter::new to <Gtk3::TreeModel::filter_new> so that Gtk3::TreeModelFilter objects can be constructed normally.

  • Gtk3::TreeModelFilter has a get method that calls Gtk3::TreeModel::get instead of Glib::Object::get.

  • A redirect is added from Gtk3::TreeModelSort::new_with_model to <Gtk3::TreeModel::sort_new_with_model> so that Gtk3::TreeModelSort objects can be constructed normally.

  • Gtk3::TreeModelSort has a get method that calls Gtk3::TreeModel::get instead of Glib::Object::get.

  • Gtk3::TreePath::new redirects to new_from_string if an additional argument is given.

  • A Perl reimplementation of Gtk3::TreePath::new_from_indices is provided.

  • Gtk3::TreeStore::new also accepts a list of type names.

  • Gtk3::TreeStore has a get method that calls Gtk3::TreeModel::get instead of Glib::Object::get.

  • Gtk3::TreeStore::insert_with_values also accepts a list of column => value pairs.

  • Gtk3::TreeStore::set also accepts a list of column => value pairs.

  • Gtk3::TreeView::new redirects to new_with_model if an additional argument is given.

  • A Perl reimplementation of Gtk3::TreeView::insert_column_with_attributes is provided.

  • A Perl reimplementation of Gtk3::TreeViewColumn::new_with_attributes is provided.

  • Perl reimplementations of Gtk3::TreeViewColumn::set_attributes and Gtk3::CellLayout::set_attributes are provided.

  • Gtk3::UIManager::add_ui_from_string takes no length argument.

  • Gtk3::VBox::new uses the defaults homogeneous = FALSE and spacing = 5.

  • Gtk3::Window::new uses the default type = 'toplevel'.

  • A constructor Gtk3::Gdk::RGBA::new is provided that can be called as Gtk3::Gdk::RGBA->new (r, g, b, a).

  • Gtk3::Gdk::RGBA::parse can be called as a function returning a new instance ($rgba = Gtk3::Gdk::RGBA::parse ($spec)) or as a method ($rgba->parse ($spec)).

  • Gtk3::Gdk::Window::new optionally computes the attr_mask automatically from the given attr.

  • Gtk3::Gdk::Pixbuf::get_pixels returns a byte string.

  • Gtk3::Gdk::Pixbuf::new_from_data is reimplemented in terms of new_from_inline for correct memory management. No destroy_fn and destroy_fn_data arguments are needed.

  • Gtk3::Gdk::Pixbuf::new_from_inline does not take a copy_pixels argument. It is always set to TRUE for correct memory management.

  • Gtk3::Gdk::Pixbuf::new_from_xpm_data also accepts a list of XPM lines.

  • Gtk3::Gdk::Pixbuf::save, save_to_buffer and save_to_callback also accept key => value pairs and invoke the correct C function as appropriate for the current gdk-pixbuf version.

  • Pango::Layout::set_text takes no length argument.

Perl compatibility

As of 5.20.0, perl does not automatically re-check the locale environment for changes. If a function thus changes the locale behind perl's back, problems might arise whenever numbers are formatted, for example when checking versions. To ensure perl's assumption about the locale are up-to-date, the functions Gtk3::init, init_check, init_with_args and parse_args are amended to let perl know of any changes.

Porting from Gtk2 to Gtk3

The majority of the API has not changed, so as a first approximation you can run s/Gtk2/Gtk3/ on your application. A big exception to this rule is APIs that were deprecated in gtk+ 2.x -- these were all removed from gtk+ 3.0 and thus from Gtk3. The migration guide at http://developer.gnome.org/gtk3/stable/migrating.html describes what to use instead. Apart from this, here is a list of some other incompatible differences between Gtk2 and Gtk3:

  • The call syntax for class-static methods is now always Gtk3::Stock::lookup instead of Gtk3::Stock->lookup.

  • The %Gtk2::Gdk::Keysyms hash is gone; instead of Gtk2::Gdk::Keysyms{XYZ}, use Gtk3::Gdk::KEY_XYZ.

  • The Gtk2::Pango compatibility wrapper was not carried over; simply use the namespace "Pango" everywhere. It gets set up automatically when loading Gtk3.

  • The types Gtk3::Allocation and Gtk3::Gdk::Rectangle are now aliases for Cairo::RectangleInt, and as such they are represented as plain hashes with keys 'width', 'height', 'x' and 'y'.

  • Gtk3::Editable: Callbacks connected to the "insert-text" signal do not have as many options anymore as they had in Gtk2. Changes to arguments will not be propagated to the next signal handler, and only the updated position can and must be returned.

  • Gtk3::Menu: In gtk+ < 3.16, the position callback passed to popup() does not receive x and y parameters.

  • Gtk3::RadioAction: The constructor now follows the C API.

  • Gtk3::TreeModel: iter_next() is now a method that is modifying the iter directly, instead of returning a new one. rows_reordered() and the "rows-reordered" signal are currently unusable.

  • Gtk3::TreeSelection: get_selected_rows() now returns two values: an array ref containing the selected paths, and the model. get_user_data() is not available currently.

  • Gtk3::TreeSortable: get_sort_column_id() has an additional boolean return value.

  • Gtk3::TreeStore, Gtk3::ListStore: reorder() is currently unusable.

  • Gtk3::Gdk::Atom: The constructor new() is not provided anymore, and the class function intern() must now be called as Gtk3::Gdk::Atom::intern (name, only_if_exists).

  • Implementations of Gtk3::TreeModel: Gtk3::TreeIter now has a constructor called new() expecting key => value pairs; new_from_arrayref() does not exist anymore. To access the contents of Gtk3::TreeIter, use stamp(), user_data(), user_data2() and user_data3(); to_arrayref() does not exist anymore. GET_ITER(), ITER_CHILDREN(), ITER_NTH_CHILD() and ITER_PARENT() must return an additional boolean value. ITER_NEXT() must modify the iter and return a boolean rather than return a new iter. GET_VALUE() must return the value wrapped with Glib::Object::Introspection::GValueWrapper->new.

  • Implementations of Gtk3::CellLayout: GET_CELLS() now needs to return an array ref instead of a list.

Note also that Gtk3::CHECK_VERSION will always fail when passed 2.y.z, so if you have any existing version checks in your code, you will most likely need to remove them.



Torsten Schönfeld <kaffeetisch@gmx.de>


Copyright (C) 2011-2015 by Torsten Schoenfeld <kaffeetisch@gmx.de>

This library is free software; you can redistribute it and/or modify it under the terms of the GNU Library General Public License as published by the Free Software Foundation; either version 2.1 of the License, or (at your option) any later version.