Bindings

## Bindings Bindings — Key bindings for individual widgets |

## Includes

    #include <gtk/gtk.h>

## Description

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.

### Installing a key binding

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 Pathnames and patterns. 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 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 letter steps, the following binding can be used:

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    binding "MoveCursor3" {
      bind "<Control>Right" {
        "move-cursor" (visual-positions, 3, 0)
      }
      bind "<Control>Left" {
        "move-cursor" (visual-positions, -3, 0)
      }
    }
    class "GtkEntry" binding "MoveCursor3"

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 Installing a key binding works as expected. The same mechanism can not be used to "unbind" existing bindings, however.

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    binding "MoveCursor3" {
      bind "<Control>Right" { }
      bind "<Control>Left" { }
    }
    class "GtkEntry" binding "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 "MoveCursor3" {
      unbind "<Control>Right"
      unbind "<Control>Left"
    }
    class "GtkEntry" binding "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.

The "unbind" functionality has been introduced in GTK+ 2.12.

## Functions

## Types and Values

## See Also

Keyboard Accelerators | installing and using keyboard short-cuts.
Resource Files | GTK+ Resource Files - behavior and style definitions.