gdk-Keyboard-Handling         package:RGtk2         R Documentation

_K_e_y _V_a_l_u_e_s

_D_e_s_c_r_i_p_t_i_o_n:

     Functions for manipulating keyboard codes

_M_e_t_h_o_d_s _a_n_d _F_u_n_c_t_i_o_n_s:

     'gdkKeymapGetDefault()'
      'gdkKeymapGetForDisplay(display)'
      'gdkKeymapLookupKey(object, key)'
      'gdkKeymapTranslateKeyboardState(object, hardware.keycode, state,
     group)'
      'gdkKeymapGetEntriesForKeyval(object, keyval)'
      'gdkKeymapGetEntriesForKeycode(object, hardware.keycode)'
      'gdkKeymapGetDirection(object)'
      'gdkKeymapHaveBidiLayouts(object)'
      'gdkKeyvalName(keyval)'
      'gdkKeyvalFromName(keyval.name)'
      'gdkKeyvalConvertCase(symbol)'
      'gdkKeyvalToUpper(keyval)'
      'gdkKeyvalToLower(keyval)'
      'gdkKeyvalIsUpper(keyval)'
      'gdkKeyvalIsLower(keyval)'
      'gdkKeyvalToUnicode(keyval)'
      'gdkUnicodeToKeyval(wc)'

_H_i_e_r_a_r_c_h_y:

     GObject
        +----GdkKeymap 

_D_e_t_a_i_l_e_d _D_e_s_c_r_i_p_t_i_o_n:

     Key values are the codes which are sent whenever a key is pressed
     or released. They appear in the 'keyval' field of the
     'GdkEventKey' 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. '<gdk/gdkkeysyms.h>' is not
     included in '<gtk/gtk.h>',  it must be included independently,
     because the file is quite large.

     Key values can be converted into a string representation using
     'gdkKeyvalName'. The reverse function, converting a string to a
     key value, is provided by 'gdkKeyvalFromName'.

     The case of key values can be determined using 'gdkKeyvalIsUpper'
     and 'gdkKeyvalIsLower'. Key values can be converted to upper or
     lower case using 'gdkKeyvalToUpper' and 'gdkKeyvalToLower'.

     When it makes sense, key values can be converted to and from 
     Unicode characters with 'gdkKeyvalToUnicode' and
     'gdkUnicodeToKeyval'.

     One 'GdkKeymap' object exists for each user display.
     'gdkKeymapGetDefault'  returns the 'GdkKeymap' for the default
     display; to obtain keymaps for other  displays, use
     'gdkKeymapGetForDisplay'. A keymap is a mapping from
     'GdkKeymapKey' to key values. You can think of a 'GdkKeymapKey' 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, the 'GdkKeymapKey' contains a 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's 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 function
     'gdkKeymapTranslateKeyboardState' 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
     don't have multiple groups - e.g. the Enter key is always in group
     0 regardless of keyboard state.

     Note that 'gdkKeymapTranslateKeyboardState' 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.  'GdkEventKey' already contains this keyval,
     however, so you don't normally need to call
     'gdkKeymapTranslateKeyboardState' just to get the keyval.

_S_t_r_u_c_t_u_r_e_s:


     '_G_d_k_K_e_y_m_a_p' A 'GdkKeymap' 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.


     '_G_d_k_K_e_y_m_a_p_K_e_y' A 'GdkKeymapKey' is a hardware key that can  be
          mapped to a keyval. *'GdkKeymapKey' is a transparent-type.*

          '_k_e_y_c_o_d_e' [numeric] the hardware keycode. This is an
               identifying number for a  physical key.

          '_g_r_o_u_p' [integer] 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.

          '_l_e_v_e_l' [integer] 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.


_S_i_g_n_a_l_s:


     '_d_i_r_e_c_t_i_o_n-_c_h_a_n_g_e_d(_k_e_y_m_a_p, _u_s_e_r._d_a_t_a)' The ::direction_changed
          signal gets emitted when the direction of the keymap changes.            

          Since  2.0

          '_k_e_y_m_a_p' ['GdkKeymap']  the object on which the signal is
               emitted

          '_u_s_e_r._d_a_t_a' [R object] user data set when the signal handler
               was connected.


     '_k_e_y_s-_c_h_a_n_g_e_d(_k_e_y_m_a_p, _u_s_e_r._d_a_t_a)' The ::keys_changed signal is
          emitted when the mapping represented by 'keymap' changes.  

          Since  2.2

          '_k_e_y_m_a_p' ['GdkKeymap']  the object on which the signal is
               emitted

          '_u_s_e_r._d_a_t_a' [R object] user data set when the signal handler
               was connected.


_N_o_t_e:

     The keyval constants exist in RGtk2 as .gdkKeyvalName, so
     '.gdkPlus' for 'plus'.

_A_u_t_h_o_r(_s):

     Derived by RGtkGen from GTK+ documentation

_R_e_f_e_r_e_n_c_e_s:

     <URL:
     http://developer.gnome.org/doc/API/2.0/gdk/gdk-Keyboard-Handling.html>

