Description
GtkBindingSet provides a mechanism for configuring GTK+ key bindings
through CSS 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.
In order for bindings to work in a custom widget implementation, the
widget’s “can-focus” and “has-focus” properties
must both be true. For example, by calling gtk_widget_set_can_focus()
in the widget’s initialisation function; and by calling
gtk_widget_grab_focus() when the widget is clicked.
Installing a key binding
A CSS file binding consists of a “binding-set” definition and a match
statement to apply the binding set to specific widget types. Details
on the matching mechanism are described under
Selectors
in the GtkCssProvider documentation. Inside the binding set
definition, key combinations are bound to one or more specific
signal emissions on the target widget. Key combinations are strings
consisting of an optional GdkModifierType name and
key names
such as those defined in gdk/gdkkeysyms.h
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 “move-cursor” signal (so
movement occurs in 3-character steps), the following binding can be
used:
Unbinding existing key bindings
GTK+ already defines a number of useful bindings for the widgets
it provides. Because custom bindings set up in CSS files take
precedence over the default bindings shipped with GTK+, overriding
existing bindings as demonstrated in
Installing a key binding
works as expected. The same mechanism can not be used to “unbind”
existing bindings, however.
The above example will not have the desired effect of causing
“<Control>Right” and “<Control>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 “<Control>Right” or
“<Control>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:
Now, GTK+ will find a match when looking up “<Control>Right” and
“<Control>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 entry’s parent widget, is now possible.
Functions
gtk_binding_entry_add_signall ()
void
gtk_binding_entry_add_signall (GtkBindingSet *binding_set,
guint keyval,
GdkModifierType modifiers,
const gchar *signal_name,
GSList *binding_args);
Override or install a new key binding for keyval
with modifiers
on
binding_set
.
gtk_binding_set_new ()
GtkBindingSet *
gtk_binding_set_new (const gchar *set_name);
GTK+ maintains a global list of binding sets. Each binding set has
a unique name which needs to be specified upon creation.
[skip]
Returns
new binding set.
[transfer none]
gtk_binding_set_by_class ()
GtkBindingSet *
gtk_binding_set_by_class (gpointer object_class);
This function returns the binding set named after the type name of
the passed in class structure. New binding sets are created on
demand by this function.
[skip]
Returns
the binding set corresponding to
object_class
.
[transfer none]
gtk_bindings_activate ()
gboolean
gtk_bindings_activate (GObject *object,
guint keyval,
GdkModifierType modifiers);
Find a key binding matching keyval
and modifiers
and activate the
binding on object
.
Returns
TRUE if a binding was found and activated
gtk_bindings_activate_event ()
gboolean
gtk_bindings_activate_event (GObject *object,
GdkEventKey *event);
Looks up key bindings for object
to find one matching
event
, and if one was found, activate it.
Returns
TRUE if a matching key binding was found
Since: 2.4
gtk_binding_set_activate ()
gboolean
gtk_binding_set_activate (GtkBindingSet *binding_set,
guint keyval,
GdkModifierType modifiers,
GObject *object);
Find a key binding matching keyval
and modifiers
within
binding_set
and activate the binding on object
.
Returns
TRUE if a binding was found and activated
gtk_binding_entry_add_signal ()
void
gtk_binding_entry_add_signal (GtkBindingSet *binding_set,
guint keyval,
GdkModifierType modifiers,
const gchar *signal_name,
guint n_args,
...);
Override or install a new key binding for keyval
with modifiers
on
binding_set
. When the binding is activated, signal_name
will be
emitted on the target widget, with n_args
Varargs
used as
arguments.
Each argument to the signal must be passed as a pair of varargs: the
GType of the argument, followed by the argument value (which must
be of the given type). There must be n_args
pairs in total.
gtk_binding_entry_add_signal_from_string ()
GTokenType
gtk_binding_entry_add_signal_from_string
(GtkBindingSet *binding_set,
const gchar *signal_desc);
Parses a signal description from signal_desc
and incorporates
it into binding_set
.
Signal descriptions may either bind a key combination to
one or more signals:
Or they may also unbind a key combination:
Key combinations must be in a format that can be parsed by
gtk_accelerator_parse().
Returns
G_TOKEN_NONE if the signal was successfully parsed and added,
the expected token otherwise
Since: 3.0
gtk_binding_entry_skip ()
void
gtk_binding_entry_skip (GtkBindingSet *binding_set,
guint keyval,
GdkModifierType modifiers);
Install a binding on binding_set
which causes key lookups
to be aborted, to prevent bindings from lower priority sets
to be activated.
Since: 2.12
gtk_binding_set_add_path ()
void
gtk_binding_set_add_path (GtkBindingSet *binding_set,
GtkPathType path_type,
const gchar *path_pattern,
GtkPathPriorityType priority);
gtk_binding_set_add_path has been deprecated since version 3.0 and should not be used in newly-written code.
This function was used internally by the GtkRC parsing mechanism
to assign match patterns to GtkBindingSet structures.
In GTK+ 3, these match patterns are unused.
Types and Values
struct GtkBindingSet
struct GtkBindingSet {
gchar *set_name;
gint priority;
GSList *widget_path_pspecs;
GSList *widget_class_pspecs;
GSList *class_branch_pspecs;
GtkBindingEntry *entries;
GtkBindingEntry *current;
guint parsed : 1;
};
A binding set maintains a list of activatable key bindings.
A single binding set can match multiple types of widgets.
Similar to style contexts, can be matched by any information contained
in a widgets GtkWidgetPath. 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.
struct GtkBindingEntry
struct GtkBindingEntry {
/* key portion */
guint keyval;
GdkModifierType modifiers;
GtkBindingSet *binding_set;
guint destroyed : 1;
guint in_emission : 1;
guint marks_unbound : 1;
GtkBindingEntry *set_next;
GtkBindingEntry *hash_next;
GtkBindingSignal *signals;
};
Each key binding element of a binding sets binding list is
represented by a GtkBindingEntry.
struct GtkBindingSignal
struct GtkBindingSignal {
GtkBindingSignal *next;
gchar *signal_name;
guint n_args;
GtkBindingArg *args;
};
A GtkBindingSignal stores the necessary information to
activate a widget in response to a key press via a signal
emission.
struct GtkBindingArg
struct GtkBindingArg {
GType arg_type;
union {
glong long_data;
gdouble double_data;
gchar *string_data;
} d;
};
A GtkBindingArg holds the data associated with
an argument for a key binding signal emission as
stored in GtkBindingSignal.