gdkKeymapTranslateKeyboardState {RGtk2} | R Documentation

## gdkKeymapTranslateKeyboardState

### Description

Translates the contents of a `GdkEventKey` into a keyval, effective group, and level. Modifiers that affected the translation and are thus unavailable for application use are returned in `consumed.modifiers`. See for an explanation of groups and levels. The `effective.group` is the group that was actually used for the translation; some keys such as Enter are not affected by the active keyboard group. The `level` is derived from `state`. For convenience, `GdkEventKey` already contains the translated keyval, so this function isn't as useful as you might think.

### Usage

    gdkKeymapTranslateKeyboardState(object, hardware.keycode, state,
        group)

### Arguments

``object`` | a `GdkKeymap`, or `NULL` to use the default. [ allow-none ]
``hardware.keycode`` | a keycode
``state`` | a modifier state
``group`` | active keyboard group

### Details

PLEASE NOTE: `consumed.modifiers` gives modifiers that should be masked out from `state` when comparing this key press to a hot key. For instance, on a US keyboard, the `plus` symbol is shifted, so when comparing a key press to a `<Control>plus` accelerator <Shift> should be masked out.

    # We want to ignore irrelevant modifiers like ScrollLock
    all_accels_mask <- GdkModifierType["control-mask"] |
    GdkModifierType["shift-mask"] | GdkModifierType["mod1-mask"]
    state <- gdkKeymapTranslateKeyboardState(keymap, event[["hardware_keycode"]],
                                             event[["state"]], event[["group"]])
    unconsumed <- all_accels_mask & event[["state"]] & !as.flag(state$consumed)
    if (state$keyval == .gdkPlus && unconsumed == GdkModifierType["control-mask"])
      print("Control was pressed")

An older interpretation `consumed.modifiers` was that it contained all modifiers that might affect the translation of the key; this allowed accelerators to be stored with irrelevant consumed modifiers, by doing:

    # XXX Don't do this XXX
    unconsumed <- all_accel_mask & event[["state"]] & !as.flag(state$consumed)
    if (state$keyval == accel_keyval &&
        unconsumed == accel_mods & !as.flag(state$consumed))
      print("Accellerator was pressed")

However, this did not work if multi-modifier combinations were used in the keymap, since, for instance, `<Control>` would be masked out even if only `<Control><Alt>` was used in the keymap. To support this usage as well as well as possible, all single modifier combinations that could affect the key for any combination of modifiers will be returned in `consumed.modifiers`; multi-modifier combinations are returned only when actually found in `state`. When you store accelerators, you should always store them with consumed modifiers removed. Store `<Control>plus`, not `<Control><Shift>plus`,

### Value

A list containing the following elements:

`retval` | [logical] `TRUE` if there was a keyval bound to the keycode/state/group
``keyval`` | return location for keyval, or `NULL`. [ out ][ allow-none ]
``effective.group`` | return location for effective group, or `NULL`. [ out ][ allow-none ]
``level`` | return location for level, or `NULL`. [ out ][ allow-none ]
``consumed.modifiers`` | return location for modifiers that were used to determine the group or level, or `NULL`. [ out ][ allow-none ]

### Note

`consumed.modifiers` gives modifiers that should be masked out from `state` when comparing this key press to a hot key. For instance, on a US keyboard, the `plus` symbol is shifted, so when comparing a key press to a `<Control>plus` accelerator <Shift> should be masked out.

An older interpretation `consumed.modifiers` was that it contained all modifiers that might affect the translation of the key; this allowed accelerators to be stored with irrelevant consumed modifiers, by doing: However, this did not work if multi-modifier combinations were used in the keymap, since, for instance, `<Control>` would be masked out even if only `<Control><Alt>` was used in the keymap. To support this usage as well as well as possible, all single modifier combinations that could affect the key for any combination of modifiers will be returned in `consumed.modifiers`; multi-modifier combinations are returned only when actually found in `state`. When you store accelerators, you should always store them with consumed modifiers removed. Store `<Control>plus`, not `<Control><Shift>plus`,

### Author(s)

Derived by RGtkGen from GTK+ documentation

[Package RGtk2 version 2.20.36.3 Index]