g-object, common-lisp:standard-object, common-lisp:t

None

A gdk-keymap object defines the translation from keyboard state, including a hardware key, a modifier mask, and active keyboard group, to a keyval. This translation has two phases. The first phase is to determine the effective keyboard group and level for the keyboard state. The second phase is to look up the keycode/group/level triplet in the keymap and see what keyval it corresponds to.

Key values are the codes which are sent whenever a key is pressed or released. They appear in the keyval field of the gdk-event-key structure, which is passed to signal handlers for the "key-press-event" and "key-release-event" signals. The complete list of key values can be found in the gdk/gdkkeysyms.h header file.

Key values are regularly updated from the upstream X.org X11 implementation, so new values are added regularly. They will be prefixed with GDK_KEY_ rather than XF86XK_ or XK_ (for older symbols).

Key values can be converted into a string representation using the gdk-keyval-name function. The reverse function, converting a string to a key value, is provided by the gdk-keyval-from-name function.

The case of key values can be determined using the gdk-keyval-is-upper and gdk-keyval-is-lower functions. Key values can be converted to upper or lower case using the gdk-keyval-to-upper and gdk-keyval-to-lower functions.

When it makes sense, key values can be converted to and from Unicode characters with the gdk-keyval-to-unicode and gdk-unicode-to-keyval functions.

Groups

One gdk-keymap object exists for each user display. To obtain the keymap for the display, use the gdk-keymap-for-display function. A keymap is a mapping from a keycode, group, and level to key values. You can think of these values as a representation of a symbol printed on a physical keyboard key. That is, it contains three pieces of information. First, it contains the hardware keycode. This is an identifying number for a physical key. Second, it contains the "level" of the key. The level indicates which symbol on the key will be used, in a vertical direction. So on a standard US keyboard, the key with the number "1" on it also has the exclamation point "!" character on it. The level indicates whether to use the "1" or the "!" symbol. The letter keys are considered to have a lowercase letter at level 0, and an uppercase letter at level 1, though only the uppercase letter is printed. Third, there is the group. Groups are not used on standard US keyboards, but are used in many other countries. On a keyboard with groups, there can be 3 or 4 symbols printed on a single key. The group indicates movement in a horizontal direction. Usually groups are used for two different languages. In group 0, a key might have two English characters, and in group 1 it might have two Hebrew characters. The Hebrew characters will be printed on the key next to the English characters.

In order to use a keymap to interpret a key event, it is necessary to first convert the keyboard state into an effective group and level. This is done via a set of rules that varies widely according to type of keyboard and user configuration. The gdk-keymap-translate-keyboard-state function accepts a keyboard state - consisting of hardware keycode pressed, active modifiers, and active group - applies the appropriate rules, and returns the group/level to be used to index the keymap, along with the modifiers which did not affect the group and level, i.e. it returns "unconsumed modifiers". The keyboard group may differ from the effective group used for keymap lookups because some keys do not have multiple groups - e.g. the Enter key is always in group 0 regardless of keyboard state.

Note that the gdk-keymap-translate-keyboard-state function also returns the keyval, i.e. it goes ahead and performs the keymap lookup in addition to telling you which effective group/level values were used for the lookup. The gdk-event-key event already contains this keyval, however, so you do not normally need to call the gdk-keymap-translate-keyboard-state function just to get the keyval.

The "direction-changed" signal

 lambda (keymap)    :run-last      

The signal gets emitted when the direction of the keymap changes.

keymap

The gdk-keymap object on which the signal is emitted.

The "keys-changed" signal

 lambda (keymap)    :run-last      

The signal is emitted when the mapping represented by keymap changes.

keymap

The gdk-keymap object on which the signal is emitted.

The "state-changed" signal

 lambda (keymap)    :run-last      

The signal is emitted when the state of the keyboard changes, e.g. when Caps Lock is turned on or off. See the gdk-keymap-caps-lock-state function.

keymap

The gdk-keymap object on which the signal is emitted.