Bindings

Bindings — Key bindings for individual widgets

Synopsis

#include <gtk/gtk.h>

struct              GtkBindingSet;
struct              GtkBindingEntry;
struct              GtkBindingSignal;
struct              GtkBindingArg;
void                gtk_binding_entry_add_signall       (GtkBindingSet *binding_set,
                                                         guint keyval,
                                                         GdkModifierType modifiers,
                                                         const gchar *signal_name,
                                                         GSList *binding_args);
GtkBindingSet *     gtk_binding_set_new                 (const gchar *set_name);
GtkBindingSet *     gtk_binding_set_by_class            (gpointer object_class);
GtkBindingSet *     gtk_binding_set_find                (const gchar *set_name);
gboolean            gtk_bindings_activate               (GObject *object,
                                                         guint keyval,
                                                         GdkModifierType modifiers);
gboolean            gtk_bindings_activate_event         (GObject *object,
                                                         GdkEventKey *event);
gboolean            gtk_binding_set_activate            (GtkBindingSet *binding_set,
                                                         guint keyval,
                                                         GdkModifierType modifiers,
                                                         GObject *object);
void                gtk_binding_entry_add_signal        (GtkBindingSet *binding_set,
                                                         guint keyval,
                                                         GdkModifierType modifiers,
                                                         const gchar *signal_name,
                                                         guint n_args,
                                                         ...);
GTokenType          gtk_binding_entry_add_signal_from_string
                                                        (GtkBindingSet *binding_set,
                                                         const gchar *signal_desc);
void                gtk_binding_entry_skip              (GtkBindingSet *binding_set,
                                                         guint keyval,
                                                         GdkModifierType modifiers);
void                gtk_binding_entry_remove            (GtkBindingSet *binding_set,
                                                         guint keyval,
                                                         GdkModifierType modifiers);
void                gtk_binding_set_add_path            (GtkBindingSet *binding_set,
                                                         GtkPathType path_type,
                                                         const gchar *path_pattern,
                                                         GtkPathPriorityType priority);

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.

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:

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@binding-set MoveCursor3
{
  bind "<Control>Right" { "move-cursor" (visual-positions, 3, 0) };
  bind "<Control>Left" { "move-cursor" (visual-positions, -3, 0) };
};
GtkEntry
{
  gtk-key-bindings: MoveCursor3
}


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.

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@binding-set MoveCursor3
{
  bind "<Control>Right" {  };
  bind "<Control>Left" {  };
};
GtkEntry
{
  gtk-key-bindings: MoveCursor3
}

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:

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@binding-set MoveCursor3
{
  unbind "<Control>Right";
  unbind "<Control>Left";
};
GtkEntry
{
  gtk-key-bindings: MoveCursor3
}

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.

Details

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.

gchar *set_name;

unique name of this binding set

gint priority;

unused

GSList *widget_path_pspecs;

unused

GSList *widget_class_pspecs;

unused

GSList *class_branch_pspecs;

unused

GtkBindingEntry *entries;

the key binding entries in this binding set

GtkBindingEntry *current;

implementation detail

guint parsed : 1;

whether this binding set stems from a CSS file and is reset upon theme changes

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.

guint keyval;

key value to match

GdkModifierType modifiers;

key modifiers to match

GtkBindingSet *binding_set;

binding set this entry belongs to

guint destroyed : 1;

implementation detail

guint in_emission : 1;

implementation detail

guint marks_unbound : 1;

implementation detail

GtkBindingEntry *set_next;

linked list of entries maintained by binding set

GtkBindingEntry *hash_next;

implementation detail

GtkBindingSignal *signals;

action signals of this entry

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.

GtkBindingSignal *next;

implementation detail

gchar *signal_name;

the action signal to be emitted

guint n_args;

number of arguments specified for the signal

GtkBindingArg *args;

the arguments specified for the signal

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.

GType arg_type;

implementation detail

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.

binding_set :

a GtkBindingSet to add a signal to

keyval :

key value

modifiers :

key modifier

signal_name :

signal name to be bound

binding_args :

list of GtkBindingArg signal arguments. [transfer none][element-type GtkBindingArg]

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.

set_name :

unique name of this binding set

Returns :

new binding set. [transfer full]

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.

object_class :

a valid GObject class

Returns :

the binding set corresponding to object_class. [transfer full]

gtk_binding_set_find ()

GtkBindingSet *     gtk_binding_set_find                (const gchar *set_name);

Find a binding set by its globally unique name.

The set_name can either be a name used for gtk_binding_set_new() or the type name of a class used in gtk_binding_set_by_class().

set_name :

unique binding set name

Returns :

NULL or the specified binding set. [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.

object :

object to activate when binding found

keyval :

key value of the binding

modifiers :

key modifier of the binding

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.

object :

a GObject (generally must be a widget)

event :

a GdkEventKey

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.

binding_set :

a GtkBindingSet set to activate

keyval :

key value of the binding

modifiers :

key modifier of the binding

object :

object to activate when binding found

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.

binding_set :

a GtkBindingSet to install an entry for

keyval :

key value of binding to install

modifiers :

key modifier of binding to install

signal_name :

signal to execute upon activation

n_args :

number of arguments to signal_name

... :

arguments to signal_name

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:

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bind "key" {
  "signalname" (param, ...)
  ...
}

Or they may also unbind a key combination:

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unbind "key"

Key combinations must be in a format that can be parsed by gtk_accelerator_parse().

binding_set :

a GtkBindingSet

signal_desc :

a signal description

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.

binding_set :

a GtkBindingSet to skip an entry of

keyval :

key value of binding to skip

modifiers :

key modifier of binding to skip

Since 2.12


gtk_binding_entry_remove ()

void                gtk_binding_entry_remove            (GtkBindingSet *binding_set,
                                                         guint keyval,
                                                         GdkModifierType modifiers);

Remove a binding previously installed via gtk_binding_entry_add_signal() on binding_set.

binding_set :

a GtkBindingSet to remove an entry of

keyval :

key value of binding to remove

modifiers :

key modifier of binding to remove

gtk_binding_set_add_path ()

void                gtk_binding_set_add_path            (GtkBindingSet *binding_set,
                                                         GtkPathType path_type,
                                                         const gchar *path_pattern,
                                                         GtkPathPriorityType priority);

Warning

gtk_binding_set_add_path is deprecated and should not be used in newly-written code. 3.0

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.

binding_set :

a GtkBindingSet to add a path to

path_type :

path type the pattern applies to

path_pattern :

the actual match pattern

priority :

binding priority

See Also

Keyboard Accelerators, Mnemonics, GtkCssProvider