There are two ways to make changes to map components: either change a local copy of the keyboard map and call XkbSetMap to send the modified map to the server, or, to reduce network traffic, use an XkbMapChangesRec structure and call XkbChangeMap.
Use XkbSetMap to send a complete new set of values for entire components (for example, all symbols, all actions, and so on) to the server. The which parameter specifies the components to be sent to the server, and is a bitwise inclusive OR of the masks listed in Table 1. The xkb parameter is a pointer to an XkbDescRec structure and contains the information to be copied to the server. For each bit set in the which parameter, XkbSetMap takes the corresponding structure values from the xkb parameter and sends it to the server specified by dpy.
If any components specified by which are not present in the xkb parameter, XkbSetMap returns False. Otherwise, it sends the update request to the server and returns True. XkbSetMap can generate BadAlloc, BadLength, and BadValue protocol errors.
Key types, symbol maps, and actions are all interrelated; changes in one require changes in the others. Xkb provides functions to make it easier to edit these components and handle the interdependencies. Table 1 lists these helper functions and provides a pointer to where they are defined.
Table 1 Xkb Mapping Component Masks | |
and Convenience Functions | |
Mask Value Map Fields Convenience | |
Functions | |
XkbKeyTypesMask | (1<<0) client T{ |
types | |
size_types | |
num_types | |
T} T{ | |
XkbGetKeyTypes | |
XkbResizeKeyType | |
XkbCopyKeyType | |
XkbCopyKeyTypes | |
T} | |
XkbKeySymsMask | (1<<1) client T{ |
syms | |
size_syms | |
num_syms | |
key_sym_map | |
T} T{ | |
XkbGetKeySyms | |
XkbResizeKeySyms | |
XkbChangeTypesOfKey | |
T} | |
XkbModifierMapMask | (1<<2) client modmap T{ |
XkbGetKeyModifierMap | |
T} | |
XkbExplicitComponentsMask | (1<<3) server T{ |
explicit | |
T} T{ | |
XkbGetKeyExplicitComponents | |
T} | |
XkbKeyActionsMask | (1<<4) server T{ |
key_acts | |
acts | |
num_acts | |
size_acts | |
T} T{ | |
XkbGetKeyActions | |
XkbResizeKeyActions | |
T} | |
XkbKeyBehaviorsMask | (1<<5) server T{ |
behaviors | |
T} T{ | |
XkbGetKeyBehaviors | |
T} | |
XkbVirtualModsMask | (1<<6) server T{ |
vmods | |
T} T{ | |
XkbGetVirtualMods | |
T} | |
XkbVirtualModMapMask | (1<<7) server T{ |
vmodmap | |
T} T{ | |
XkbGetVirtualModMap | |
T} |
The changed field identifies the map components that have changed in an XkbDescRec structure and may contain any of the bits in Table 1, which are also shown in Table 2. Every 1 bit in changed also identifies which other fields in the XkbMapChangesRec structure contain valid values, as indicated in Table 2. The min_key_code and max_key_code fields are for reference only; they are ignored on any requests sent to the server and are always updated by the server whenever it returns the data for an XkbMapChangesRec.
Table 2 XkbMapChangesRec Masks |
Valid |
Mask XkbMapChangesRec XkbDescRec Field Containing |
Fields Changed Data |
XkbKeyTypesMask first_type, map->type[first_type] .. |
num_types map->type[first_type + num_types - 1] |
XkbKeySymsMask first_key_sym, map->key_sym_map[first_key_sym] .. |
num_key_syms map->key_sym_map[first_key_sym + |
num_key_syms - 1] |
XkbModifierMapMask first_modmap_key, map->modmap[first_modmap_key] .. |
num_modmap_keys map->modmap[first_modmap_key + |
num_modmap_keys-1] |
XkbExplicitComponentsMask first_key_explicit, |
server->explicit[first_key_explicit] .. |
num_key_explicit server->explicit[first_key_explicit + |
num_key_explicit - 1] |
XkbKeyActionsMask first_key_act, server->key_acts[first_key_act] .. |
num_key_acts server->key_acts[first_key_act + |
num_key_acts - 1] |
XkbKeyBehaviorsMask first_key_behavior, |
server->behaviors[first_key_behavior] .. |
num_key_behaviors server->behaviors[first_key_behavior + |
num_key_behaviors - 1] |
XkbVirtualModsMask vmods server->vmods[*] |
XkbVirtualModMapMask first_vmodmap_key, |
server->vmodmap[first_vmodmap_key] |
num_vmodmap_keys .. |
server->vmodmap[first_vmodmap_key |
+ num_vmodmap_keys - 1] |
Use the XkbMapChangesRec structure to identify and
track partial modifications to the mapping components and to reduce the
amount of traffic between the server and clients.
typedef struct _XkbMapChanges { unsigned short changed; /* identifies valid components in structure */ KeyCode min_key_code; /* lowest numbered keycode for device */ KeyCode max_key_code; /* highest numbered keycode for device */ unsigned char first_type; /* index of first key type modified */ unsigned char num_types; /* # types modified */ KeyCode first_key_sym; /* first key whose key_sym_map changed */ unsigned char num_key_syms; /* # key_sym_map entries changed */ KeyCode first_key_act; /* first key whose key_acts entry changed */ unsigned char num_key_acts; /* # key_acts entries changed */ KeyCode first_key_behavior; /* first key whose behaviors changed */ unsigned char num_key_behaviors; /* # behaviors entries changed */ KeyCode first_key_explicit; /* first key whose explicit entry changed */ unsigned char num_key_explicit; /* # explicit entries changed */ KeyCode first_modmap_key; /* first key whose modmap entry changed */ unsigned char num_modmap_keys; /* # modmap entries changed */ KeyCode first_vmodmap_key; /* first key whose vmodmap changed */ unsigned char num_vmodmap_keys; /* # vmodmap entries changed */ unsigned char pad1; /* reserved */ unsigned short vmods; /* mask indicating which vmods changed */ } XkbMapChangesRec,*XkbMapChangesPtr;
The complete description of an Xkb keyboard is given by an XkbDescRec. The component structures in the XkbDescRec represent the major Xkb components.
typedef struct { struct _XDisplay * display; /* connection to X server */ unsigned short flags; /* private to Xkb, do not modify */ unsigned short device_spec; /* device of interest */ KeyCode min_key_code; /* minimum keycode for device */ KeyCode max_key_code; /* maximum keycode for device */ XkbControlsPtr ctrls; /* controls */ XkbServerMapPtr server; /* server keymap */ XkbClientMapPtr map; /* client keymap */ XkbIndicatorPtr indicators; /* indicator map */ XkbNamesPtr names; /* names for all components */ XkbCompatMapPtr compat; /* compatibility map */ XkbGeometryPtr geom; /* physical geometry of keyboard */ } XkbDescRec, *XkbDescPtr;The display field points to an X display structure. The flags field is private to the library: modifying flags may yield unpredictable results. The device_spec field specifies the device identifier of the keyboard input device, or XkbUseCoreKeyboard, which specifies the core keyboard device. The min_key_code and max_key_code fields specify the least and greatest keycode that can be returned by the keyboard.
Each structure component has a corresponding mask bit that is used in function calls to indicate that the structure should be manipulated in some manner, such as allocating it or freeing it. These masks and their relationships to the fields in the XkbDescRec are shown in Table 3.
Table 3 Mask Bits for XkbDescRec |
Mask Bit XkbDescRec Field Value |
XkbControlsMask ctrls (1L<<0) |
XkbServerMapMask server (1L<<1) |
XkbIClientMapMask map (1L<<2) |
XkbIndicatorMapMask indicators (1L<<3) |
XkbNamesMask names (1L<<4) |
XkbCompatMapMask compat (1L<<5) |
XkbGeometryMask geom (1L<<6) |
XkbAllComponentsMask All Fields (0x7f) |