gtk2/docs/reference/gtk/tmpl/gtkbindings.sgml

<!-- ##### SECTION Title ##### -->
Bindings

<!-- ##### SECTION Short_Description ##### -->
Key bindings for individual widgets

<!-- ##### SECTION Long_Description ##### -->
<para>
GtkBinding provides a mechanism for configuring Gtk+ key bindings through RC files.
This eases key binding adjustments for application developers as well as users and
provides Gtk+ users or administrators with high key binding configurability which
requires no application or toolkit side changes.
</para>

<refsect2>
<anchor id="gtk-bindings-install"/>
<title>Installing a key binding</title>

<para>
A resource file binding consists of a 'binding' definition and a match statement to
apply the binding to specific widget types. Details on the matching mechanism are
described under <link linkend="gtkrc-pathnames-and-patterns">Pathnames and patterns</link>.
Inside the binding definition, key combinations are bound to specific signal emissions
on the target widget. Key combinations are strings consisting of an optional #GdkModifierType
name and <link linkend="gdk-Keyboard-Handling">key names</link> such as those defined in
<filename>&lt;gdk/gdkkeysyms.h&gt;</filename> or returned from gdk_keyval_name(), they have
to be parsable by gtk_accelerator_parse().
Specifications of signal emissions consist of a string identifying the signal name, and
a list of signal specific arguments in parenthesis.

For example for binding Control and the left or right cursor keys of a #GtkEntry widget to the
#GtkEntry::move-cursor signal, so movement occurs in 3 letter steps,
the following binding can be used:

<informalexample><programlisting>
binding "MoveCursor3" {
  bind "&lt;Control&gt;Right" {
    "move-cursor" (visual-positions, 3, 0)
  }
  bind "&lt;Control&gt;Left" {
    "move-cursor" (visual-positions, -3, 0)
  }
}
class "GtkEntry" binding "MoveCursor3"
</programlisting></informalexample>
</para>


<anchor id="gtk-bindings-unbind"/>
<title>Unbinding existing key bindings</title>
<para>
Gtk+ already defines a number of useful bindings for the widgets it provides.
Because custom bindings set up in RC files take precedence over the default bindings
shipped with Gtk+, overriding existing bindings as demonstrated in 
<link linkend="gtk-bindings-install">Installing a key binding</link>
works as expected. The same mechanism can not be used to "unbind" existing bindings,
however.

<informalexample><programlisting>
binding "MoveCursor3" {
  bind "&lt;Control&gt;Right" { }
  bind "&lt;Control&gt;Left" { }
}
class "GtkEntry" binding "MoveCursor3"
</programlisting></informalexample>

The above example will not have the desired effect of causing "&lt;Control&gt;Right"
and "&lt;Control&gt;Left" key presses to be ignored by Gtk+. Instead, it just causes
any existing bindings from the bindings set "MoveCursor3" to be deleted, so when
"&lt;Control&gt;Right" or "&lt;Control&gt;Left" are pressed, no binding for these keys
is found in binding set "MoveCursor3". Gtk+ will thus continue to search for matching
key bindings, and will eventually lookup and find the default Gtk+ bindings for entries
which implement word movement. To keep Gtk+ from activating its default bindings, the
"unbind" keyword can be used like this:

<informalexample><programlisting>
binding "MoveCursor3" {
  unbind "&lt;Control&gt;Right"
  unbind "&lt;Control&gt;Left"
}
class "GtkEntry" binding "MoveCursor3"
</programlisting></informalexample>

Now, Gtk+ will find a match when looking up "&lt;Control&gt;Right" and "&lt;Control&gt;Left"
key presses before it resorts to its default bindings, and the match instructs it to abort
("unbind") the search, so the key presses are not consumed by this widget. 
As usual, further processing of the key presses, e.g. by an entries parent widget,
is now possible.

</para>

</refsect2>

<!-- ##### SECTION See_Also ##### -->
<para>
<variablelist>

<varlistentry>
<term><link linkend="gtk-keyboard-accelerators">Keyboard Accelerators</link>
</term>
<listitem><para>installing and using keyboard short-cuts.</para></listitem>
</varlistentry>

<varlistentry>
<term><link linkend="Resource-Files">Resource Files</link>
</term>
<listitem><para>Gtk+ Resource Files - behavior and style definitions.</para></listitem>
</varlistentry>

</variablelist>
</para>

<!-- ##### SECTION Stability_Level ##### -->


<!-- ##### STRUCT GtkBindingSet ##### -->
<para>
A binding set maintains a list of activatable key bindings.
A single binding set can match multiple types of widgets.
Similar to styles, widgets can be mapped by widget name paths, widget class paths or widget class types.
When a binding within a set is matched upon activation, an action signal is emitted on
the target widget to carry out the actual activation.
</para>

@set_name: 		unique binding set name
@priority: 		unused
@widget_path_pspecs: 	widgets matched by path that this binding set applies to
@widget_class_pspecs: 	widgets matched by class path that this binding set applies to
@class_branch_pspecs: 	widgets matched by class that this binding set applies to
@entries: 		the key binding entries in this binding set
@current: 		implementation detail
@parsed: 		whether this binding set stems from an RC file and is reset upon theme changes

<!-- ##### STRUCT GtkBindingEntry ##### -->
<para>
Each key binding element of a binding sets binding list is represented by a #GtkBindingEntry.
</para>

@keyval: 	key value to match
@modifiers: 	key modifier to match
@binding_set: 	binding set this entry belongs to
@destroyed:  	implementation detail
@in_emission: 	implementation detail
@set_next: 	linked list of entries maintained by binding set
@hash_next:	implementation detail
@signals: 	action signals of this entry

<!-- ##### STRUCT GtkBindingSignal ##### -->
<para>
A #GtkBindingSignal stores the necessary information to activate a widget
in response to a key press via a signal emission.
</para>

@next: 		implementation detail
@signal_name: 	the action signal to be emitted
@n_args: 	number of arguments specified for the signal
@args: 		the arguments specified for the signal

<!-- ##### STRUCT GtkBindingArg ##### -->
<para>
A #GtkBindingArg holds the data associated with an argument for a
key binding signal emission as stored in #GtkBindingSignal.
</para>

@arg_type: implementation detail


<!-- ##### FUNCTION gtk_bindings_activate_event ##### -->
<para>
<!-- documented inline -->
</para>

@object: 
@event: 
@Returns: 


<!-- ##### MACRO gtk_binding_entry_add ##### -->
<para>
Deprecated.
</para>