Xkb Server Keyboard Mappingserver mapmapserver
The
server
field of the complete Xkb keyboard description (see section 6.1) is a pointer
to the Xkb server map.
Figure 16.1 shows the relationships between elements in the server map:
XkbServerMapRec
The Xkb server map contains the information the server needs to interpret key
events and is of type
XkbServerMapRec:
#define XkbNumVirtualMods 16
typedef struct { /* Server Map */
unsigned short num_acts; /* # of occupied entries in acts */
unsigned short size_acts; /* # of entries in acts */
XkbAction * acts; /* linear 2d tables of key actions,
1 per keycode */
XkbBehavior * behaviors; /* key behaviors, 1 per keycode */
unsigned short * key_acts; /* index into acts, 1 per keycode */
unsigned char * explicit; /* explicit overrides of core
remapping, 1 per key */
unsigned char vmods[XkbNumVirtualMods]; /* real mods bound
to virtual mods */
unsigned short * vmodmap; /* virtual mods bound to key,
1 per keycode */
} XkbServerMapRec, *XkbServerMapPtr;
The
num_acts,
size_acts,
acts,
and
key_acts
fields specify the key actions, defined in section 16.1. The
behaviors
field describes the behavior for each key and is defined in section 16.2. The
explicit
field describes the explicit components for a key and is defined in
section 16.3. The
vmods
and the
vmodmap
fields describe the virtual modifiers and the per-key virtual modifier mapping
and are defined in section 16.4.
Key Actions
A key action defines the effect key presses and releases have on the internal
state of the server. For example, the expected key action associated with
pressing the
Shift
key is to set the
Shift
modifier. There is zero or one key action associated with each keysym bound to
each key.
Just as the entire list of key symbols for the keyboard mapping is held in the
syms
field of the client map, the entire list of key actions for the keyboard
mapping is held in the
acts
array of the server map. The total size of
acts
is specified by
size_acts,
and the number of entries is specified by
num_acts.
The
key_acts
array, indexed by keycode, describes the actions associated with a key. The
key_acts
array has
min_key_code
unused entries at the start to allow direct indexing using a keycode. If a
key_acts
entry is
zero,
it means the key does not have any actions associated with it. If an entry is
not
zero,
the entry represents an index into the
acts
field of the server map, much as the
offset
field of a
KeySymMapRec
structure is an index into the
syms
field of the client map.
The reason the
acts
field is a linear list of
XkbActions
is to reduce the memory consumption associated with a keymap. Because Xkb
allows individual keys to have multiple shift levels and a different number of
groups per key, a single two-dimensional array of
KeySyms
would potentially be very large and sparse. Instead, Xkb provides a small
two-dimensional array of
XkbActions
for each key. To store all of these individual arrays, Xkb concatenates each
array together in the
acts
field of the server map.
The key action structures consist only of fields of type char or unsigned char.
This is done to optimize data transfer when the server sends bytes over the
wire. If the fields are anything but bytes, the server has to sift through all
of the actions and swap any nonbyte fields. Because they consist of nothing but
bytes, it can just copy them out.
Xkb provides the following macros, to simplify accessing information pertaining
to key actions:
XkbKeyHasActionsBool XkbKeyHasActionsXkbDescPtr xkbKeyCode keycodexkb
Xkb description of interest
keycode
keycode of interest
XkbKeyHasActions
returns
True
if the key corresponding to
keycode
has any actions associated with it; otherwise, it returns
False.
XkbKeyNumActionsint XkbKeyNumActionsXkbDescPtr xkbKeyCode keycodexkb
Xkb description of interest
keycode
keycode of interest
XkbKeyNumActions
computes the number of actions associated with the key corresponding to
keycode.
This should be the same value as the result of
XkbKeyNumSyms
(see section 15.3.3).
XkbKeyActionsPtrXkbKeyActionPtr XkbKeyActionsPtrXkbDescPtr xkbKeyCode keycodexkb
Xkb description of interest
keycode
keycode of interest
XkbKeyActionsPtr
returns a pointer to the two-dimensional array of key actions associated with
the key corresponding to
keycode.
Use
XkbKeyActionsPtr
only if the key actually has some actions associated with it, that is,
XkbKeyNumActions
(xkb, keycode) returns something greater than zero.
XkbKeyActionXkbAction XkbKeyActionXkbDescPtr xkbKeyCode keycodeint idxxkb
Xkb description of interest
keycode
keycode of interest
idx
index for group and shift level
XkbKeyAction
returns the key action indexed by
idx
in the two-dimensional array of key actions associated with the key
corresponding to
keycode.
idx
may be computed from the group and shift level of interest as follows:
idx = group_index * key_width + shift_level
XkbKeyActionEntryXkbAction XkbKeyActionEntryXkbDescPtr xkbKeyCode keycodeint shiftint grpxkb
Xkb description of interest
keycode
keycode of interest
shift
shift level within group
grp
group index for group of interest
XkbKeyActionEntry
returns the key action corresponding to group
grp
and shift level
shift
from the two-dimensional table of key actions associated with the key
corresponding to
keycode.
The XkbAction StructureXkbAction
The description for an action is held in an
XkbAction
structure, which is a union of all possible Xkb action types:
typedef union _XkbAction {
XkbAnyAction any;
XkbModAction mods;
XkbGroupAction group;
XkbISOAction iso;
XkbPtrAction ptr;
XkbPtrBtnAction btn;
XkbPtrDfltAction dflt;
XkbSwitchScreenAction screen;
XkbCtrlsAction ctrls;
XkbMessageAction msg;
XkbRedirectKeyAction redirect;
XkbDeviceBtnAction devbtn;
XkbDeviceValuatorAction devval;
unsigned char type;
} XkbAction;
The
type
field is provided for convenience and is the same as the type field in the
individual structures. The following sections describe the individual
structures for each action in detail.
The XkbAnyAction StructureXkbAnyAction
The
XkbAnyAction
structure is a convenience structure that refers to any of the actions:
#define XkbAnyActionDataSize 7
typedef struct _XkbAnyAction {
unsigned char type; /* type of action; determines interpretation for data */
unsigned char data[XkbAnyActionDataSize];
} XkbAnyAction;
The
data
field represents a structure for an action, and its interpretation depends on
the
type
field. The valid values for the
type
field, and the data structures associated with them are shown in
Table 16.1:
Action TypesTypeStructure for DataXkbAction Union MemberSectionXkbSA_NoActionXkbSA_NoAction
means the server does not perform an action for the key; this action does not
have an associated data structure.
anyXkbSA_SetModsXkbSA_LatchModsXkbSA_LockModsXkbModActionmods16.1.3XkbSA_SetGroupXkbSA_LatchGroupXkbSA_LockGroupXkbGroupActiongroup16.1.4XkbSA_MovePtrXkbPtrActionptr16.1.5XkbSA_PtrBtnXkbSA_LockPtrBtnXkbPtrBtnActionbtn16.1.6XkbSA_SetPtrDfltXkbPtrDfltActiondflt16.1.7XkbSA_ISOLockXkbISOActioniso16.1.8XkbSA_SwitchScreenXkbSwitchScreenActionscreen16.1.9XkbSA_SetControlsXkbSA_LockControlsXkbCtrlsActionctrls16.1.10XkbSA_ActionMessageXkbMessageActionmsg16.1.11XkbSA_RedirectKeyXkbRedirectKeyActionredirect16.1.12XkbSA_DeviceBtnXkbSA_LockDeviceBtnXkbDeviceBtnActiondevbtn16.1.13XkbSA_DeviceValuatorXkbDeviceValuatorActiondevval16.1.14
Actions for Changing Modifiers’ StateXkbModAction
Actions associated with the
XkbModAction
structure change the state of the modifiers when keys are pressed and released
(see for a discussion of modifiers):
typedef struct _XkbModAction {
unsigned char type; /* XkbSA_{Set|Latch|Lock}Mods */
unsigned char flags; /* with type, controls the effect
on modifiers */
unsigned char mask; /* same as mask field of
a modifier description */
unsigned char real_mods; /* same as real_mods field of
a modifier description */
unsigned char vmods1; /* derived from vmods field of
a modifier description */
unsigned char vmods2; /* derived from vmods field of
a modifier description */
} XkbModAction;
In the following description, the term
action modifiersaction modifiersmodifiersaction
means the real modifier bits associated with this action. Depending on the
value of
flags
(see Table 16.3),
these are designated either in the
mask
field of the
XkbModAction
structure itself or the real modifiers bound to the key for which the action
is being used. In the latter case, this is the client
map->modmap
[
keycode
] field.
The
type
field can have any of the values shown in
Table 16.2.
Modifier Action TypesTypeEffectXkbSA_SetMods
A key press adds any action modifiers to the keyboard’s base modifiers.
A key release clears any action modifiers in the keyboard’s base modifiers,
provided no other key affecting the same modifiers is logically down.
If no other keys are physically depressed when this key is released, and
XkbSA_ClearLocks
is set in the
flags
field, the key release unlocks any action modifiers.
XkbSA_LatchMods
Key press and key release events have the same effect as for
XkbSA_SetMods;
if no keys are physically depressed when this key is released, key release
events have the following additional effects:
Modifiers unlocked due to
XkbSA_ClearLocks
have no further effect.
If
XkbSA_LatchToLock
is set in the
flags
field, a key release locks and then unlatches any remaining action modifiers
that are already latched.
A key release latches any action modifiers not used by the
XkbSA_ClearLocks
and
XkbSA_LatchToLock
flags.
XkbSA_LockMods
A key press sets the base state of any action modifiers. If
XkbSA_LockNoLock
is set in the
flags
field, a key press also sets the locked state of any action modifiers.
A key release clears any action modifiers in the keyboard’s base modifiers,
provided no other key that affects the same modifiers is down. If
XkbSA_LockNoUnlock
is not set in the
flags
field, and any of the action modifiers were locked before the corresponding
key press occurred, a key release unlocks them.
The
flags
field is composed of the bitwise inclusive OR of the masks shown in
Table 16.3.
A general meaning is given in the table, but the exact meaning depends on
the action type.
Modifier Action FlagsFlagMeaningXkbSA_UseModMapMods
If set, the action modifiers are determined by the modifiers bound by the
modifier mapping of the key. Otherwise, the action modifiers are set to the
modifiers specified by the
mask,
real_mods,
vmods1,
and
vmods2
fields.
XkbSA_ClearLocks
If set and no keys are physically depressed when this key transition
occurs, the server unlocks any action modifiers.
XkbSA_LatchToLock
If set, and the action type is
XkbSA_LatchMods,
the server locks the action modifiers if they are already latched.
XkbSA_LockNoLock
If set, and the action type is
XkbSA_LockMods,
the server only unlocks the action modifiers.
XkbSA_LockNoUnlock
If set, and the action is
XkbSA_LockMods,
the server only locks the action modifiers.
If
XkbSA_UseModMapMods
is not set in the
flags
field, the
mask,
real_mods,
vmods1,
and
vmods2
fields are used to determine the action modifiers. Otherwise they are ignored
and the modifiers bound to the key (client
map->modmap
[
keycode
]) are used instead.
The
mask,
real_mods,
vmods1,
and
vmods2
fields represent the components of an Xkb modifier description
(see section 7.2). While the
mask
and
real_mods
fields correspond directly to the
mask
and
real_mods
fields of an Xkb modifier description, the
vmods1
and
vmods2
fields are combined to correspond to the
vmods
field of an Xkb modifier description. Xkb provides the following macros, to
convert between the two formats:
XkbModActionVModsunsigned short XkbModActionVModsXkbAction actact
action from which to extract virtual mods
XkbModActionVMods
returns the
vmods1
and
vmods2
fields of
act
converted to the
vmods
format of an Xkb modifier description.
XkbSetModActionVModsvoid XkbSetModActionVModsXkbAction actunsigned short vmodsact
action in which to set vmods
vmods
virtual mods to set
XkbSetModActionVMods
sets the
vmods1
and
vmods2
fields of
act
using the
vmods
format of an Xkb modifier description.
Despite the fact that the first parameter of these two macros is of
type XkbAction, these macros may be used only with Actions of type
XkbModAction
and
XkbISOAction.
Actions for Changing Group StateXkbGroupAction
Actions associated with the
XkbGroupAction
structure change the current group state when keys are pressed and released
(see for a description of groups and keyboard state):
typedef struct _XkbGroupAction {
unsigned char type; /* XkbSA_{Set|Latch|Lock}Group */
unsigned char flags; /* with type , controls the effect on groups */
char group_XXX; /* represents a group index or delta */
} XkbGroupAction;
The
type
field can have any of the following values:
Group Action TypesTypeEffectXkbSA_SetGroup
If the
XkbSA_GroupAbsolute
bit is set in the
flags
field, key press events change the base keyboard group to the group specified
by the
group_XXX
field. Otherwise, key press events change the base keyboard group by adding
the
group_XXX
field to the base keyboard group. In either case, the resulting effective
keyboard group is brought back into range depending on the value of the
groups_wrap
field of the controls structure (see section 10.7.1).
If a key with an
XkbSA_ISOLock
action (see section 16.1.8) is pressed while this key is down, the key release
of this key has no effect. Otherwise, the key release cancels the effects of
the key press.
If the
XkbSA_ClearLocks
bit is set in the flags field, and no keys are physically depressed when this
key is released, the key release also sets the locked keyboard group to
Group1.
XkbSA_LatchGroup
Key press and key release events have the same effect as for
XkbSA_SetGroup;
if no keys are physically depressed when this key is released, key release
events have the following additional effects.
If the
XkbSA_LatchToLock
bit is set in the
flags
field and the latched keyboard group index is nonzero, the key release adds
the delta applied by the corresponding key press to the locked keyboard group
and subtracts it from the latched keyboard group. The locked and effective
keyboard group are brought back into range according to the value of the
groups_wrap
field of the controls structure.
Otherwise, the key press adds the key press delta to the latched keyboard group.
XkbSA_LockGroup
If the
XkbSA_GroupAbsolute
is set in the
flags
field, key press events set the locked keyboard group to the group specified
by the
group_XXX
field. Otherwise, key press events add the group specified by the
group_XXX
field to the locked keyboard group. In either case, the resulting locked and
effective keyboard groups are brought back into range depending on the value of
the
groups_wrap
field of the controls structure.
A key release has no effect.
The
flags
field is composed of the bitwise inclusive OR of the masks shown in
Table 16.5.
A general meaning is given in the table, but the exact meaning depends on
the action
type.
Group Action FlagsFlagMeaningXkbSA_ClearLocks
If set and no keys are physically depressed when this key transition occurs,
the server sets the locked keyboard group to
Group1
on a key release.
XkbSA_LatchToLock
If set, and the action type is
XkbSA_LatchGroup,
the server locks the action group if it is already latched.
XkbSA_GroupAbsolute
If set, the
group_XXX
field represents an absolute group number. Otherwise, it represents a group
delta to be added to the current group to determine the new group number.
The
group_XXX
field represents a signed character. Xkb provides the following macros to
convert between a signed integer value and a signed character:
XkbSAGroupint XkbSAGroupXkbAction actact
action from which to extract group
XkbSAGroup
returns the
group_XXX
field of
act
converted to a signed int.
XkbSASetGroupvoid XkbSASetGroupXkbAction actint grpact
action from which to set group
grp
group index to set in group_XXXXkbSASetGroup
sets the
group_XXX
field of
act
from the group index
grp.
Despite the fact that the first parameter of these two macros is of
type XkbAction, these macros may only be used with Actions of type
XkbGroupAction
and
XkbISOAction.
Actions for Moving the PointerXkbPtrAction
Actions associated with the
XkbPtrAction
structure move the pointer when keys are pressed and released:
typedef struct _XkbPtrAction {
unsigned char type; /* XkbSA_MovePtr */
unsigned char flags; /* determines type of pointer motion */
unsigned char high_XXX; /* x coordinate, high bits */
unsigned char low_XXX; /* y coordinate, low bits */
unsigned char high_YYY; /* x coordinate, high bits */
unsigned char low_YYY; /* y coordinate, low bits */
} XkbPtrAction;
If the
MouseKeys
control is not enabled (see section 10.5.1),
KeyPress
and
KeyRelease
events are treated as though the action is
XkbSA_NoAction.
If the
MouseKeys
control is enabled, a server action of type
XkbSA_MovePtr
instructs the server to generate core pointer
MotionNotify
events rather than the usual
KeyPress
event, and the corresponding
KeyRelease
event disables any mouse keys timers that were created as a result of handling
the
XkbSA_MovePtr
action.
The
type
field of the
XkbPtrAction
structure is always
XkbSA_MovePtr.
The
flags
field is a bitwise inclusive OR of the masks shown in
Table 16.6.
Pointer Action TypesAction TypeMeaningXkbSA_NoAcceleration
If not set, and the
MouseKeysAccel
control is enabled (see section 10.5.2), the
KeyPress
initiates a mouse keys timer for this key; every time the timer expires, the
cursor moves.
XkbSA_MoveAbsoluteXIf set, the X portion of the structure specifies the new pointer X
coordinate. Otherwise, the X portion is added to the current pointer X
coordinate to determine the new pointer X coordinate.
XkbSA_MoveAbsoluteY
If set, the Y portion of the structure specifies the new
pointer Y coordinate. Otherwise, the Y portion is added
to the current pointer Y coordinate to determine the new pointer Y coordinate.
Each of the X and Y coordinates of the
XkbPtrAction
structure is composed of two signed 16-bit values, that is, the X coordinate
is composed of
high_XXX
and
low_XXX,
and similarly for the Y coordinate. Xkb provides the following macros, to
convert between a signed integer and two signed 16-bit values in
XkbPtrAction
structures:
XkbPtrActionXint XkbPtrActionXXkbPtrAction actact
action from which to extract X
XkbPtrActionX
returns the
high_XXX
and
low_XXX
fields of
act
converted to a signed int.
XkbPtrActionYint XkbPtrActionYXkbPtrAction actact
action from which to extract Y
XkbPtrActionY
returns the
high_YYY
and
low_YYY
fields of
act
converted to a signed int.
XkbSetPtrActionXvoid XkbSetPtrActionXXkbPtrAction actint xact
action in which to set X
x
new value to set
XkbSetPtrActionX
sets the
high_XXX
and
low_XXX
fields of
act
from the signed integer value
x.
XkbSetPtrActionYvoid XkbSetPtrActionYXkbPtrAction actint yact
action in which to set Y
y
new value to set
XkbSetPtrActionX
sets the
high_YYY
and
low_YYY
fields of
act
from the signed integer value
y.
Actions for Simulating Pointer Button Press and ReleaseXkbPtrBtnAction
Actions associated with the
XkbPtrBtnAction
structure simulate the press and release of pointer buttons when keys are
pressed and released:
typedef struct _XkbPtrBtnAction {
unsigned char type; /* XkbSA_PtrBtn, XkbSA_LockPtrBtn */
unsigned char flags; /* with type, controls the effect
on pointer buttons */
unsigned char count; /* controls number of ButtonPress and
ButtonRelease events */
unsigned char button; /* pointer button to simulate */
} XkbPtrBtnAction;
If the
MouseKeys
(see section 10.5.1) control is not enabled,
KeyPress
and
KeyRelease
events are treated as though the action is
XkbSA_NoAction.
The
type
field can have any one of the values shown in
Table 16.7.
Pointer Button Action TypesTypeEffectXkbSA_PtrBtn
If
XkbSA_UseDfltButton
is set in the
flags
field, the event is generated for the pointer button specified by the
mk_dflt_btn
attribute of the
MouseKeys
control (see section 10.5.1). Otherwise, the event is generated for the button
specified by the
button
field.
If the mouse button specified for this action is logically down, the key press
and corresponding key release are ignored and have no effect. Otherwise, a key
press causes one or more core pointer button events instead of the usual
KeyPress
event. If
count
is
zero,
a key press generates a single
ButtonPress
event; if
count
is greater than
zero,
a key press generates
count
pairs of
ButtonPress
and
ButtonRelease
events.
If
count
is
zero,
a key release generates a core pointer
ButtonRelease
that matches the event generated by the corresponding
KeyPress;
if
count
is nonzero, a key release does not cause a
ButtonRelease
event. A key release never generates a key
KeyRelease
event.
XkbSA_LockPtrBtn
If the button specified by the
MouseKeys
default button
or
button
is not locked, a key press causes a
ButtonPress
event instead of a
KeyPress
event and locks the button. If the button is already locked or if
XkbSA_LockNoUnlock
is set in the
flags
field, a key press is ignored and has no effect.
If the corresponding key press was ignored, and if
XkbSA_LockNoLock
is not set in the
flags
field, a key release generates a
ButtonRelease
event instead of a
KeyRelease
event and unlocks the specified button. If the corresponding key press locked
a button, the key release is ignored and has no effect.
The
flags
field is composed of the bitwise inclusive OR of the masks shown in
Table 16.8.
A general meaning is given in the table, but the exact meaning depends on
the action
type:
Pointer Button Action FlagsFlagMeaningXkbSA_UseDfltButton
If set, the action uses the pointer button specified by the
mk_dflt_btn
attribute of the
MouseKeys
control (see section 10.5.1). Otherwise, the action uses the pointer button
specified by the
button
field.
XkbSA_LockNoLock
If set, and the action type is
XkbSA_LockPtrBtn,
the server only unlocks the pointer button.
XkbSA_LockNoUnlock
If set, and the action type is
XkbSA_LockPtrBtn,
the server only locks the pointer button.
Actions for Changing the Pointer Button SimulatedXkbPtrDfltAction
Actions associated with the
XkbPtrDfltAction
structure change the
mk_dflt_btn
attribute of the
MouseKeys
control (see section 10.5.1):
typedef struct _XkbPtrDfltAction {
unsigned char type; /* XkbSA_SetPtrDflt */
unsigned char flags; /* controls the pointer button number */
unsigned char affect; /* XkbSA_AffectDfltBtn */
char valueXXX; /* new default button member */
} XkbPtrDfltAction;
If the
MouseKeys
control is not enabled,
KeyPress
and
KeyRelease
events are treated as though the action is
XkbSA_NoAction.
Otherwise, this action changes the
mk_dflt_btn
attribute of the
MouseKeys
control.
The
type
field of the
XkbPtrDfltAction
structure should always be
XkbSA_SetPtrDflt.
The
flags
field is composed of the bitwise inclusive OR of the values shown in
Table 16.9
(currently there is only one value defined).
Pointer Default FlagsFlagMeaningXkbSA_DfltBtnAbsolute
If set, the
value
field represents an absolute pointer button. Otherwise, the
value
field represents the amount to be added to the current default button.
The
affect
field specifies what changes as a result of this action. The only valid value
for the
affect
field is XkbSA_AffectDfltBtn.
The
valueXXX
field is a signed character that represents the new button value for the
mk_dflt_btn
attribute of the
MouseKeys
control (see section 10.5.1). If
XkbSA_DfltBtnAbsolute
is set in
flags,
valueXXX
specifies the button to be used; otherwise,
valueXXX
specifies the amount to be added to the current default button. In either
case, illegal button choices are wrapped back around into range. Xkb provides
the following macros, to convert between the integer and signed character
values in
XkbPtrDfltAction
structures:
XkbSAPtrDfltValueint XkbSAPtrDfltValueXkbAction actact
action from which to extract group
XkbSAPtrDfltValue
returns the
valueXXX
field of
act
converted to a signed int.
XkbSASetPtrDfltValuevoid XkbSASetPtrDfltValueXkbPtrDfltAction actint valact
action in which to set valueXXXval
value to set in valueXXXXkbSASetPtrDfltValue
sets the
valueXXX
field of
act
from
val.
Actions for Locking Modifiers and GroupXkbISOAction
Actions associated with the
XkbISOAction
structure lock modifiers and the group according to the ISO9995 specification.
Operated by itself, the
XkbISOAction
is just a caps lock. Operated simultaneously with another modifier key, it
transforms the other key into a locking key. For example, press
ISO_Lock,
press and release
Control_L,
release
ISO_Lock
ends up locking the
Control
modifier.
The default behavior is to convert:
{Set,Latch}Mods to: LockMods{Set,Latch}Group to: LockGroupSetPtrBtn to: LockPtrBtnSetControls to: LockControls
The
affects
field allows you to turn those effects on or off individually. Set
XkbSA_ISONoAffectMods
to disable the first,
XkbSA_ISONoAffectGroup
to disable the second, and so forth.
typedef struct _XkbISOAction {
unsigned char type; /* XkbSA_ISOLock */
unsigned char flags; /* controls changes to group or
modifier state */
unsigned char mask; /* same as mask field of
a modifier description */
unsigned char real_mods; /* same as real_mods field of
a modifier description */
char group_XXX; /* group index or delta group */
unsigned char affect; /* specifies whether to affect
mods, group, ptrbtn, or controls */
unsigned char vmods1; /* derived from vmods field of
a modifier description */
unsigned char vmods2; /* derived from vmods field of
a modifier description */
} XkbISOAction;
The
type
field of the
XkbISOAction
structure should always be
XkbSA_ISOLock.
The interpretation of the
flags
field depends on whether the
XkbSA_ISODfltIsGroup
is set in the
flags
field or not.
If the
XkbSA_ISODfltIsGroup
is set in the
flags
field, the action is used to change the group state. The remaining valid bits
of the
flags
field are composed of a bitwise inclusive OR using the masks shown in
Table 16.10.
ISO Action Flags when XkbSA_ISODfltIsGroup is SetFlagMeaningXkbSA_ISODfltIsGroup
If set, the action is used to change the base group state. Must be set for the
remaining bits in this table to carry their interpretations.
A key press sets the base group as specified by the
group_XXX
field and the
XkbSA_GroupAbsolute
bit of the
flags
field (see section Note). If no other actions are transformed by the
XkbSA_ISOLock
action, a key release locks the group. Otherwise, a key release clears group
set by the key press.
XkbSA_GroupAbsolute
If set, the
group_XXX
field represents an absolute group number. Otherwise, it represents a group
delta to be added to the current group to determine the new group number.
XkbSA_ISONoAffectMods
If not set, any
XkbSA_SetMods
or
XkbSA_LatchMods
actions that occur simultaneously with the
XkbSA_ISOLock
action are treated as
XkbSA_LockMods
actions instead.
XkbSA_ISONoAffectGroup
If not set, any
XkbSA_SetGroup
or
XkbSA_LatchGroup
actions that occur simultaneously with the
XkbSA_ISOLock
action are treated as
XkbSA_LockGroup
actions instead.
XkbSA_ISONoAffectPtr
If not set, any
XkbSA_PtrBtn
actions that occur simultaneously with the
XkbSA_ISOLock
action are treated as
XkbSA_LockPtrBtn
actions instead.
XkbSA_ISONoAffectCtrls
If not set, any
XkbSA_SetControls
actions that occur simultaneously with the
XkbSA_ISOLock
action are treated as
XkbSA_LockControls
actions instead.
If the
XkbSA_ISODfltIsGroup
is not set in the
flags
field, the action is used to change the modifier state and the remaining valid
bits of the
flags
field are composed of a bitwise inclusive OR using the masks shown in
Table 16.11.
ISO Action Flags when XkbSA_ISODfltIsGroup is Not SetFlagMeaningXkbSA_ISODfltIsGroup
If not set, action is used to change the base modifier state. Must not be set
for the remaining bits in this table to carry their interpretations.
A key press sets the action modifiers in the keyboard’s base modifiers using
the
mask,
real_mods,
vmods1,
and
vmods2
fields (see section 16.1.3). If no other actions are transformed by the
XkbSA_ISOLock
action, a key release locks the action modifiers. Otherwise, a key release
clears the base modifiers set by the key press.
XkbSA_UseModMapMods
If set, the action modifiers are determined by the modifiers bound by the
modifier mapping of the key. Otherwise, the action modifiers are set to the
modifiers specified by the
mask,
real_mods,
vmods1,
and
vmods2
fields.
XkbSA_LockNoLockIf set, the server only unlocks the action modifiers.XkbSA_LockNoUnlockIf set, the server only locks the action modifiers. XkbSA_ISONoAffectMods
If not set, any
XkbSA_SetMods
or
XkbSA_LatchMods
actions that occur simultaneously with the
XkbSA_ISOLock
action are treated as
XkbSA_LockMods
actions instead.
XkbSA_ISONoAffectGroup
If not set, any
XkbSA_SetGroup
or
XkbSA_LatchGroup
actions that occur simultaneously with the
XkbSA_ISOLock
action are treated as
XkbSA_LockGroup
actions instead.
XkbSA_ISONoAffectPtr
If not set, any
XkbSA_PtrBtn
actions that occur simultaneously with the
XkbSA_ISOLock
action are treated as
XkbSA_LockPtrBtn
actions instead.
XkbSA_ISONoAffectCtrls
If not set, any
XkbSA_SetControls
actions that occur simultaneously with the
XkbSA_ISOLock
action are treated as
XkbSA_LockControls
actions instead.
The
group_XXX
field represents a signed character. Xkb provides macros to convert between a
signed integer value and a signed character as shown in section Note.
The
mask,
real_mods,
vmods1,
and
vmods2
fields represent the components of an Xkb modifier description
(see section 7.2). While the
mask
and
real_mods
fields correspond directly to the
mask
and
real_mods
fields of an Xkb modifier description, the
vmods1
and
vmods2
fields are combined to correspond to the
vmods
field of an Xkb modifier description. Xkb provides macros to convert between
the two formats as shown in section 16.1.3.
The
affect
field is composed of a bitwise inclusive OR using the masks shown in
Table 16.11.
ISO Action Affect Field ValuesAffectMeaningXkbSA_ISONoAffectMods
If
XkbSA_ISONoAffectMods
is not set, any
SA_SetMods
or
SA_LatchMods
actions occurring simultaneously with the
XkbISOAction
are treated as
SA_LockMods
instead.
XkbSA_ISONoAffectGroup
If
XkbSA_ISONoAffectGroup
is not set, any
SA_SetGroup
or
SA_LatchGroup
actions occurring simultaneously with the
XkbISOAction
are treated as
SA_LockGroup
instead.
XkbSA_ISONoAffectPtr
If
XkbSA_ISONoAffectPtr
is not set, any
SA_PtrBtn
actions occurring simultaneously with the
XkbISOAction
are treated as
SA_LockPtrBtn
instead.
XkbSA_ISONoAffectCtrls
If
XkbSA_ISONoAffectCtrls
is not set, any
SA_SetControls
actions occurring simultaneously with the
XkbISOAction
are treated as
SA_LockControls
instead.
Actions for Changing the Active ScreenXkbSwitchScreenAction
Actions associated with the
XkbSwitchScreenAction
action structure change the active screen on a multiscreen display:
This action is optional. Servers are free to ignore the action or
any of its flags if they do not support the requested behavior. If the action
is ignored, it behaves like
XkbSA_NoAction.
Otherwise, key press and key release events do not generate an event.
typedef struct _XkbSwitchScreenAction {
unsigned char type; /* XkbSA_SwitchScreen */
unsigned char flags; /* controls screen switching */
char screenXXX; /* screen number or delta */
} XkbSwitchScreenAction;
The
type
field of the
XkbSwitchScreenAction
structure should always be
XkbSA_SwitchScreen.
The
flags
field is composed of the bitwise inclusive OR of the masks shown in
Table 16.13.
Switch Screen Action FlagsFlagMeaningXkbSA_SwitchAbsolute
If set, the
screenXXX
field represents the index of the new screen. Otherwise, it represents an
offset from the current screen to the new screen.
XkbSA_SwitchApplication
If not set, the action should switch to another screen on the same
server. Otherwise, it should switch to another X server or application that
shares the same physical display.
The
screenXXX
field is a signed character value that represents either the relative or
absolute screen index, depending on the state of the
XkbSA_SwitchAbsolute
bit in the
flags
field. Xkb provides the following macros to convert between the integer and
signed character value for screen numbers in
XkbSwitchScreenAction
structures:
XkbSAScreenint XkbSAScreenXkbSwitchScreenAction actact
action from which to extract screen
XkbSAScreen
returns the
screenXXX
field of
act
converted to a signed int.
XkbSASetScreenvoid XkbSASetScreenXkbSwitchScreenAction actint sact
action in which to set screenXXXs
value to set in screenXXXXkbSASetScreen
sets the
screenXXX
field of
act
from
s.
Actions for Changing Boolean Controls StateXkbCtrlsAction
Actions associated with the
XkbCtrlsAction
structure change the state of the boolean controls (see section 10.1):
typedef struct _XkbCtrlsAction {
unsigned char type; /* XkbSA_SetControls,
XkbSA_LockControls */
unsigned char flags; /* with type, controls enabling
and disabling of controls */
unsigned char ctrls3; /* ctrls0 through ctrls3
represent the boolean controls */
unsigned char ctrls2; /* ctrls0 through ctrls3
represent the boolean controls */
unsigned char ctrls1; /* ctrls0 through ctrls3
represent the boolean controls */
unsigned char ctrls0; /* ctrls0 through ctrls3
represent the boolean controls */
} XkbCtrlsAction;
The
type
field can have any one of the values shown in
Table 16.14.
Controls Action TypesTypeEffectXkbSA_SetControls
A key press enables any boolean controls specified in the
ctrls
fields that were not already enabled at the time of the key press.
A key release disables any controls enabled by the key press.
This action can cause
XkbControlsNotify
events (see section 10.1).
XkbSA_LockControls
If the
XkbSA_LockNoLock
bit is not set in the
flags
field, a key press enables any controls specified in the
ctrls
fields that were not already enabled at the time of the key press.
If the
XkbSA_LockNoUnlock
bit is not set in the
flags
field, a key release disables any controls specified in the
ctrls
fields that were not already disabled at the time of the key press.
This action can cause
XkbControlsNotify
events (see section 10.1).
The
flags
field is composed of the bitwise inclusive OR of the masks shown in
Table 16.15.
Control Action FlagsFlagMeaningXkbSA_LockNoLock
If set, and the action type is
XkbSA_LockControls,
the server only disables controls.
XkbSA_LockNoUnlock
If set, and the action type is
XkbSA_LockControls,
the server only enables controls.
The
XkbSA_SetControls
action implements a key that enables a boolean control when pressed and
disables it when released. The
XkbSA_LockControls
action is used to implement a key that toggles the state of a boolean control
each time it is pressed and released. The
XkbSA_LockNoLock
and
XkbSA_LockNoUnlock
flags allow modifying the toggling behavior to only unlock or only lock the
boolean control.
The
ctrls0,
ctrls1,
ctrls2,
and
ctrls3
fields represent the boolean controls in the
enabled_ctrls
field of the controls structure (see section 10.1). Xkb provides the following
macros, to convert between the two formats:
XkbActionCtrlsunsigned int XkbActionCtrlsXkbCtrlsAction actact
action from which to extract controls
XkbActionCtrls
returns the
ctrls
fields of
act
converted to an unsigned int.
XkbSAActionSetCtrlsvoid XkbSAActionSetCtrlsXkbCtrlsAction actunsigned int ctrlsact
action in which to set ctrls0-ctrls3
ctrls
value to set in ctrls0-ctrls3
XkbSAActionSetCtrls
sets the
ctrls0
through
ctrls3
fields of
act
from
ctrls.
Actions for Generating MessagesXkbMessageAction
Actions associated with the
XkbMessageAction
structure generate
XkbActionMessage
events:
#define XkbActionMessageLength 6
typedef struct _XkbMessageAction {
unsigned char type; /* XkbSA_ActionMessage */
unsigned char flags; /* controls event generation via
key presses and releases */
unsigned char message[XkbActionMessageLength]; /* message */
} XkbMessageAction;
The
type
field of the
XkbMessageAction
structure should always be
XkbSA_ActionMessage.
The
flags
field is composed of the bitwise inclusive OR of the masks shown in
Table 16.16.
Message Action FlagsFlagMeaningXkbSA_MessageOnPress
If set, key press events generate an
XkbActionMessage
event that reports the keycode, event type, and contents of the
message
field.
XkbSA_MessageOnRelease
If set, key release events generate an
XkbActionMessage
event that reports the keycode, event type, and contents of the
message
field.
XkbSA_MessageGenKeyEvent
If set, key press and key release events generate
KeyPress
and
KeyRelease
events, regardless of whether they generate
XkbActionMessage
events.
The
message
field is an array of
XkbActionMessageLength
unsigned characters and may be set to anything the keymap designer wishes.
Detecting Key Action MessageseventsXkbActionMessageXkbActionMessageEvent
To receive
XkbActionMessage
events by calling either
XkbSelectEvents
or
XkbSelectEventDetails
(see section 4.3).
To receive
XkbActionMessage
events under all possible conditions, use
XkbSelectEvents
and pass
XkbActionMessageMask
in both
bits_to_change
and
values_for_bits.
The
XkbActionMessage
event has no event details. However, you can call
XkbSelectEventDetails
using
XkbActionMessage
as the
event_type
and specifying
XkbAllActionMessagesMask
in
bits_to_change
and
values_for_bits.
This has the same effect as a call to
XkbSelectEvents.
The structure for the
XkbActionMessage
event is defined as follows:
typedef struct _XkbActionMessage {
int type; /* Xkb extension base event code */
unsigned long serial; /* X server serial number for event */
Bool send_event; /* True ⇒ synthetically generated */
Display * display; /* server connection where event generated */
Time time; /* server time when event generated */
int xkb_type; /* XkbActionMessage */
int device; /* Xkb device ID,
will not be XkbUseCoreKbd */
KeyCode keycode; /* keycode of key triggering event */
Bool press; /* True ⇒ key press,
False ⇒ release */
Bool key_event_follows;/* True ⇒ KeyPress/KeyRelease follows */
char message[XkbActionMessageLength+1]; /* message text */
} XkbActionMessageEvent;
The
keycode
is the keycode of the key that was pressed or released. The
press
field specifies whether the event was the result of a key press or key
release.
The
key_event_follows
specifies whether a
KeyPress
(if
press
is
True)
or
KeyRelease
(if
press
is
False)
event is also sent to the client. As with all other Xkb events,
XkbActionMessageEvents
are delivered to all clients requesting them, regardless of the current
keyboard focus. However, the
KeyPress
or
KeyRelease
event that conditionally follows an
XkbActionMessageEvent
is sent only to the client selected by the current keyboard focus.
key_event_follows
is
True
only for the client that is actually sent the following
KeyPress
or
KeyRelease
event.
The
message
field is set to the message specified in the action and is guaranteed to be
NULL
-terminated; the Xkb extension forces a
NULL
into
message
[
XkbActionMessageLength
].
Actions for Generating a Different KeycodeXkbRedirectKeyAction
Actions associated with the
XkbRedirectKeyAction
structure generate
KeyPress
and
KeyRelease
events containing a keycode different from the key that was pressed or
released:
typedef struct _XkbRedirectKeyAction {
unsigned char type; /* XkbSA_RedirectKey */
unsigned char new_key; /* keycode to be put in event */
unsigned char mods_mask; /* mask of real mods to be reset */
unsigned char mods; /* mask of real mods to take values from */
unsigned char vmods_mask0; /* first half of mask of virtual mods
to be reset */
unsigned char vmods_mask1; /* other half of mask of virtual mods
to be reset */
unsigned char vmods0; /* first half of mask of virtual mods
to take values from */
unsigned char vmods1; /* other half of mask of virtual mods
to take values from */
} XkbRedirectKeyAction;
The
type
field for the
XkbRedirectKeyAction
structure should always be
XkbSA_RedirectKey.
Key presses cause a
KeyPress
event for the key specified by the
new_key
field instead of the actual key. The state reported in this event reports the
current effective modifiers changed as follows: any real modifiers selected by
the
mods_mask
field are set to corresponding values from the
mods
field. Any real modifiers bound to the virtual modifiers specified by the
vmods_mask0
and
vmods_mask1
fields are either set or cleared, depending on the corresponding values in the
vmods0
and
vmods1
fields. If the real and virtual modifier definitions specify conflicting
values for a single modifier, the real modifier definition has priority.
Key releases cause a
KeyRelease
event for the key specified by the
new_key
field instead of the actual key. The state for this event consists of the
effective keyboard modifiers at the time of the release, changed as described
previously.
The
XkbSA_RedirectKey
action normally redirects to another key on the same device as the key that
caused the event, unless that device does not belong to the input extension
KeyClass,
in which case this action causes an event on the core keyboard device. (The
input extension categorizes devices by breaking them into classes. Keyboards,
and other input devices with keys, are classified as KeyClass devices by the
input extension.)
The
vmods_mask0
and
vmods_mask1
fields actually represent one
vmods_mask
value, as described in . Xkb provides the following macros, to
convert between the two formats:
XkbSARedirectVModsMaskunsigned int XkbSARedirectVModsMaskXkbRedirectKeyAction actact
action from which to extract vmods
XkbSARedirectVModsMask
returns the
vmods_mask0
and
vmods_mask1
fields of
act
converted to an unsigned int.
XkbSARedirectSetVModsMaskvoid XkbSARedirectSetVModsMaskXkbRedirectKeyAction actunsigned int vmact
action in which to set vmods
vm
new value for virtual modifier mask
XkbSARedirectSetVModsMask
sets the
vmods_mask0
and
vmods_mask1
fields of
act
from
vm.
Similarly, the
vmods0
and
vmods1
fields actually represent one
vmods
value, as described in . To convert between the two formats, Xkb
provides the following convenience macros:
XkbSARedirectVModsunsigned int XkbSARedirectVModsXkbRedirectKeyAction actact
action from which to extract vmods
XkbSARedirectVModsMask returns the vmods0
and vmods1 fields of act
converted to an unsigned int.
XkbSARedirectSetVModsvoid XkbSARedirectSetVModsXkbRedirectKeyAction actunsigned int vact
action in which to set vmods
v
new value for virtual modifiers
XkbSARedirectSetVModsMask sets the vmods0
and vmods1 of act from v.
Actions for Generating DeviceButtonPress and DeviceButtonReleaseXkbDeviceBtnAction
Actions associated with
XkbDeviceBtnAction
structures generate
DeviceButtonPress
and
DeviceButtonRelease
events instead of normal
KeyPress
and
KeyRelease
events:
typedef struct _XkbDeviceBtnAction {
unsigned char type; /* XkbSA_DeviceBtn, XkbSA_LockDeviceBtn */
unsigned char flags; /* with type, specifies locking or unlocking */
unsigned char count; /* controls number of DeviceButtonPress
and Release events */
unsigned char button; /* index of button on device */
unsigned char device; /* device ID of an X input extension device */
} XkbDeviceBtnAction;
The
type
field can have any one of the values shown in
Table 16.17.
Device Button Action TypesTypeEffectXkbSA_DeviceBtn
If the button specified by this action is logically down, the key press and
corresponding release are ignored and have no effect. If the device or button
specified by this action are illegal, this action behaves like
XkbSA_NoAction.
Otherwise, key presses cause one or more input extension device events instead
of the usual key press event. If the
count
field is zero, a key press generates a single
DeviceButtonPress
event. If count is greater than zero, a key press event generates
count
pairs of
DeviceButtonPress
and
DeviceButtonRelease
events.
If
count
is zero, a key release generates an input extension
DeviceButtonRelease
event that matches the event generated by the corresponding key press. If
count
is nonzero, a key release does not cause a
DeviceButtonRelease
event. Key releases never cause
KeyRelease
events.
XkbSA_LockDeviceBtn
If the device or button specified by this action are illegal, this action
behaves like XkbSA_NoAction.
Otherwise, if the specified button is not locked and the
XkbSA_LockNoLock
bit is not set in the
flags
field, a key press generates an input extension
DeviceButtonPress
event instead of a
KeyPress
event and locks the button. If the button is already locked or if
XkbSA_LockNoLock
bit is set in the
flags
field, the key press is ignored and has no effect.
If the corresponding key press was ignored, and if the
XkbSA_LockNoUnlock
bit is not set in the
flags
field, a key release generates an input extension
DeviceButtonRelease
event instead of a
KeyRelease
event and unlocks the button. If the corresponding key press locked a button,
the key release is ignored and has no effect.
The
flags
field is composed of the bitwise inclusive OR of the masks shown in
Table 16.18.
Device Button Action FlagsFlagMeaningXkbSA_LockNoLock
If set, and the action type is
XkbSA_LockDeviceBtn,
the server only unlocks the button.
XkbSA_LockNoUnlock
If set, and the action type is
XkbSA_LockDeviceBtn,
the server only locks the button.
Actions for Simulating Events from Device ValuatorsXkbDeviceValuatorAction
A
valuatorvaluator
manipulates a range of values for some entity, like a mouse axis, a slider or
a dial. Actions associated with
XkbDeviceValuatorAction
structures are used to simulate events from one or two input extension device
valuators.
typedef struct _XkbDeviceValuatorAction {
unsigned char type; /* XkbSA_DeviceValuator */
unsigned char device; /* device ID */
unsigned char v1_what; /* determines how valuator is
to behave for valuator 1 */
unsigned char v1_ndx; /* specifies a real valuator */
unsigned char v1_value; /* the value for valuator 1 */
unsigned char v2_what; /* determines how valuator is
to behave for valuator 2 */
unsigned char v2_ndx; /* specifies a real valuator */
unsigned char v2_value; /* the value for valuator 1 */
} XkbDeviceValuatorAction;
If
device
is illegal or if neither
v1_ndx
nor
v2_ndx
specifies a legal valuator, this action behaves like
XkbSA_NoAction.
The low four bits of
v1_what
and
v2_what
specify the corresponding scale value (denoted
val<n>Scale
in Table 16.17), if needed.
The high four bits of
v1_what
and
v2_what
specify the operation to perform to set the values. The high four bits of
v1_what
and
v2_what
can have the values shown in Table 16.17;
the use of
val<n>Scale
is shown in that table also.
Device Valuator v<n>_what High Bits ValuesValue of high bitsEffectXkbSA_IgnoreValNo actionXkbSA_SetValMinv<n>_value is set to its minimum legal value.
XkbSA_SetValCenterv<n>_valueis centered (to (max-min)/2).
XkbSA_SetValMaxv<n>_value is set to its maximum legal value.
XkbSA_SetValRelativev<n>_value * (2
val<n>Scale) is added to
v<n>_value.
XkbSA_SetValAbsolutev<n>_value
is set to (2 val<n>Scale).
Illegal values for
XkbSA_SetValRelative
or
XkbSA_SetValAbsolute
are clamped into range. Note that all of these possibilities are legal for
absolute valuators. For relative valuators, only
XkbSA_SetValRelative
is permitted. Part of the input extension description of a device is the range
of legal values for all absolute valuators, whence the maximum and minimum
legal values shown in Table 16.17.
The following two masks are provided as a convenience to select either portion
of
v1_what
or
v2_what:
#define XkbSA_ValOpMask (0x70)
#define XkbSA_ValScaleMask (0x07)
v1_ndx
and
v2_ndx
specify valuators that actually exists. For example, most mice have two
valuators (x and y axes) so the only legal values for a mouse would be 0 and 1.
For a dial box with eight dials, any value in the range 0..7 would be correct.
Obtaining Key Actions for Keys from the Server
To update the actions (the
key_acts
array) for a subset of the keys in a keyboard description, use
XkbGetKeyActions.
XkbGetKeyActionsStatus XkbGetKeyActionsDisplay *dpyunsigned int firstunsigned int numXkbDescPtr xkbdpy
connection to X server
first
keycode of first key of interest
num
number of keys desired
xkb
pointer to keyboard description where result is stored
XkbGetKeyActions
sends a request to the server to obtain the actions for
num
keys on the keyboard starting with key
first.
It waits for a reply and returns the actions in the
server->key_acts
field of
xkb.
If successful,
XkbGetKeyActions
returns
Success.
The
xkb
parameter must be a pointer to a valid Xkb keyboard description.
If the
server
map in the
xkb
parameter has not been allocated,
XkbGetKeyActions
allocates and initializes it before obtaining the actions.
If the server does not have a compatible version of Xkb, or the Xkb extension
has not been properly initialized,
XkbGetKeyActions
returns
BadAccess.
If
num
is less than 1 or greater than
XkbMaxKeyCount,
XkbGetKeyActions
returns
BadValue.
If any allocation errors occur,
XkbGetKeyActions
returns
BadAlloc.
Changing the Number of Actions Bound to a Key
To change the number of actions bound to a key, use
XkbResizeKeyActions.
XkbResizeKeyActionsXkbAction *XkbResizeKeyActionsXkbDescRec *xkbint keyint neededxkb
keyboard description to change
key
keycode of key to change
needed
new number of actions required
The
xkb
parameter points to the keyboard description containing the
key
whose number of actions is to be changed. The
key
parameter is the keycode of the key to change, and
needed
specifies the new number of actions required for the key.
XkbResizeKeyActions
reserves the space needed for the actions and returns a pointer to the
beginning of the new array that holds the actions. It can change the
acts,
num_acts,
and
size_acts
fields of
xkb->server
if it is necessary to reallocate the
acts
array.
If
needed
is greater than the current number of keysyms for the key,
XkbResizeKeyActions
initializes all new actions in the array to
NoAction.
Because the number of actions needed by a key is normally computed as width *
number of groups, and
XkbResizeKeyActions
does not modify either the width or number of groups for the key, a
discrepancy exists on return from
XkbResizeKeyActions
between the space allocated for the actions and the number required. The
unused entries in the list of actions returned by
XkbResizeKeyActions
are not preserved across future calls to any of the map editing functions, so
you must update the key actions (which updates the width and number of groups
for the key) before calling another allocator function. A call to
XkbChangeTypesOfKey
updates these.
If any allocation errors occur while resizing the number of actions bound to
the key,
XkbResizeKeyActions
returns
NULL.
A change to the number of actions bound to a key should be
accompanied by a change in the number of symbols bound to a key. Refer to
section 15.3.7 for more information on changing the number of symbols bound to
a key.Key Behavior
Key behavior refers to the demeanor of a key. For example, the expected
behavior of the
CapsLock
key is that it logically locks when pressed, and then logically unlocks when
pressed again.
Radio Groups
Keys that belong to the same radio group have the
XkbKB_RadioGroup
type in the
type
field and the radio group index specified in the
data
field in the
XkbBehavior
structure. If the radio group has a name in the
XkbNamesRec
structure, the radio group index is the index into the
radio_group
array in the
XkbNamesRec
structure. A radio group key when pressed stays logically down until another
key in the radio group is pressed, when the first key becomes logically up and
the new key becomes logically down. Setting the
XkbKB_RGAllowNone
bit in the behavior for all of the keys of the radio group means that pressing
the logically down member of the radio group causes it to logically release, in
which case none of the keys of the radio group would be logically down. If
XkbKB_RGAllowNone
is not set, there is no way to release the logically down member of the group.
The low five bits of the
data
field of the
XkbBehavior
structure are the group number, the high three bits are flags. The only flag
currently defined is:
#define XkbKB_RGAllowNone 0x80
The XkbBehavior StructureXkbBehavior
The
behaviors
field of the server map is an array of
XkbBehavior
structures, indexed by keycode, and contains the behavior for each key. The
XkbBehavior
structure is defined as follows:
typedef struct _XkbBehavior {
unsigned char type; /* behavior type + optional
XkbKB_Permanent bit */
unsigned char data;
} XkbBehavior;
The
type
field specifies the Xkb behavior, and the value of the
data
field depends on the
type.
Xkb supports the key behaviors shown in
Table 16.20.
Key BehaviorsTypeEffectXkbKB_Default
Press and release events are processed normally. The
data
field is unused.
XkbKB_Lock
If a key is logically up (that is, the corresponding bit of the core key map is
cleared) when it is pressed, the key press is processed normally and the
corresponding release is ignored. If the key is logically down when pressed,
the key press is ignored but the corresponding release is processed normally.
The
data
field is unused.
XkbKB_RadioGroup
If another member of the radio group is logically down (all members of the
radio group have the same index, specified in
data)
when a key is pressed, the server synthesizes a key release for the member
that is logically down and then processes the new key press event normally.
If the key itself is logically down when pressed, the key press event is
ignored, but the processing of the corresponding key release depends on the
value of the
XkbKB_RGAllowNone
bit in
flags.
If it is set, the key release is processed normally; otherwise, the key
release is also ignored.
All other key release events are ignored.
XkbKB_Overlay1
If the
Overlay1
control is enabled (see section 10.4),
data
is interpreted as a keycode, and events from this key are reported as if they
came from
data’s
keycode. Otherwise, press and release events are processed normally.
XkbKB_Overlay2
If the
Overlay2
control is enabled (see section 10.4),
data
is interpreted as a keycode, and events from this key are reported as if they
came from
data’s
keycode. Otherwise, press and release events are processed normally.
Xkb also provides the mask,
XkbKB_Permanent
to specify whether the key behavior type should be simulated by Xkb or whether
the key behavior describes an unalterable physical, electrical, or software
aspect of the keyboard. If the
XkbKB_Permanent
bit is not set in the
type
field, Xkb simulates the behavior in software. Otherwise, Xkb relies upon the
keyboard to implement the behavior.
Obtaining Key Behaviors for Keys from the Server
To obtain the behaviors (the
behaviors
array) for a subset of the keys in a keyboard description from the server, use
XkbGetKeyBehaviors:
XkbGetKeyBehaviorsStatus XkbGetKeyBehaviorsDisplay *dpyunsigned int firstunsigned int numXkbDescPtr xkbdpy
connection to server
first
keycode of first key to get
num
number of keys for which behaviors are desired
xkb
Xkb description to contain the result
XkbGetKeyBehaviors
sends a request to the server to obtain the behaviors for
num
keys on the keyboard starting with the key whose keycode is
first.
It waits for a reply and returns the behaviors in the
server->behaviors
field of
xkb.
If successful,
XkbGetKeyBehaviors
returns
Success.
If the
server
map in the
xkb
parameter has not been allocated,
XkbGetKeyBehaviors
allocates and initializes it before obtaining the actions.
If the server does not have a compatible version of Xkb, or the Xkb extension
has not been properly initialized,
XkbGetKeyBehaviors
returns
BadAccess.
If
num
is less than 1 or greater than
XkbMaxKeyCount,
XkbGetKeyBehaviors
returns
BadValue.
If any allocation errors occur,
XkbGetKeyBehaviors
returns
BadAlloc.
Explicit Components—Avoiding Automatic Remapping by the Server
Whenever a client remaps the keyboard using core protocol requests, Xkb
examines the map to determine likely default values for the components that
cannot be specified using the core protocol (see section 17.1.2 for more
information on how Xkb chooses the default values).
This automatic remapping might replace definitions explicitly requested by an
application, so the Xkb keyboard description defines an explicit components
mask for each key. Any aspects of the automatic remapping listed in the
explicit components mask for a key are not changed by the automatic keyboard
mapping.
The explicit components masks are held in the
explicit
field of the server map, which is an array indexed by keycode. Each entry in
this array is a mask that is a bitwise inclusive OR of the values shown in
Table 16.21.
Explicit Component MasksBit in Explicit MaskValueProtects AgainstExplicitKeyType1(1<<0)
Automatic determination of the key type associated with
Group1.
ExplicitKeyType2(1<<1)
Automatic determination of the key type associated with
Group2.
ExplicitKeyType3(1<<2)
Automatic determination of the key type associated with
Group3.
ExplicitKeyType4(1<<3)
Automatic determination of the key type associated with
Group4.
ExplicitInterpret(1<<4)
Application of any of the fields of a symbol interpretation to the
key in question.
ExplicitAutoRepeat(1<<5)Automatic determination of auto-repeat status for the key, as
specified in a symbol interpretation.ExplicitBehavior(1<<6)
Automatic assignment of the
XkbKB_Lock
behavior to the key, if the
XkbSI_LockingKey
flag is set in a symbol interpretation.
ExplicitVModMap(1<<7)
Automatic determination of the virtual modifier map for the key
based on the actions assigned to the key and the symbol interpretations that
match the key.
Obtaining Explicit Components for Keys from the Server
To obtain the explicit components (the
explicit
array) for a subset of the keys in a keyboard description, use
XkbGetKeyExplicitComponents.
XkbGetKeyExplicitComponentsStatus XkbGetKeyExplicitComponentsDisplay *dpyunsigned int firstunsigned int numXkbDescPtr xkbdpy
connection to server
first
keycode of first key to fetch
num
number of keys for which to get explicit info
xkb
Xkb description in which to put results
XkbGetKeyExplicitComponents
sends a request to the server to obtain the explicit components for
num
keys on the keyboard starting with key
first.
It waits for a reply and returns the explicit components in the
server->explicit
array of
xkb.
If successful,
XkbGetKeyExplicitComponents
returns
Success.
The
xkb
parameter must be a pointer to a valid Xkb keyboard description.
If the
server
map in the
xkb
parameter has not been allocated,
XkbGetKeyExplicitComponents
allocates and initializes it before obtaining the actions.
If the server does not have a compatible version of Xkb, or the Xkb extension
has not been properly initialized,
XkbGetKeyExplicitComponents
returns
BadMatch.
If
num
is less than 1 or greater than
XkbMaxKeyCount,
XkbGetKeyExplicitComponents
returns
BadValue.
If any allocation errors occur,
XkbGetKeyExplicitComponents
returns
BadAlloc.
Virtual Modifier Mapping
The
vmods
member of the server map is a fixed-length array containing
XkbNumVirtualMods
entries. Each entry corresponds to a virtual modifier and provides the binding
of the virtual modifier to the real modifier bits. Each entry in the
vmods
array is a bitwise inclusive OR of the legal modifier masks:
ShiftMaskLockMaskControlMaskMod1MaskMod2MaskMod3MaskMod4MaskMod5Mask
The
vmodmap
member of the server map is similar to the
modmap
array of the client map (see section 15.4), but is used to define the virtual
modifier mapping for each key. Like the
modmap
member, it is indexed by keycode, and each entry is a mask representing the
virtual modifiers bound to the corresponding key:
Each of the bits in a
vmodmap
entry represents an index into the
vmods
member. That is, bit 0 of a
vmodmap
entry refers to index 0 of the
vmods
array, bit 1 refers to index 1, and so on.
If a bit is set in the
vmodmap
entry for a key, that key is bound to the corresponding virtual modifier in
the
vmods
array.
The
vmodmap
and
vmods
members of the server map are the master virtual modifier definitions. Xkb
automatically propagates any changes to these fields to all other fields that
use virtual modifier mappings.
The overall relationship of fields dealing with virtual modifiers in an Xkb
keyboard description are shown in Figure 16.2.
Obtaining Virtual Modifier Bindings from the Server
To obtain a subset of the virtual modifier bindings (the
vmods
array) in a keyboard description, use
XkbGetVirtualMods:
XkbGetVirtualModsStatus XkbGetVirtualModsDisplay *dpyunsigned int whichXkbDescPtr xkbdpy
connection to server
which
mask indicating virtual modifier bindings to get
xkb
Xkb description where results will be placed
XkbGetVirtualMods
sends a request to the server to obtain the
vmods
entries for the virtual modifiers specified in the mask,
which,
and waits for a reply. See section 7.1 for a description of how to determine
the virtual modifier mask. For each bit set in
which,
XkbGetVirtualMods
updates the corresponding virtual modifier definition in the
server->vmods
array of
xkb.
The
xkb
parameter must be a pointer to a valid Xkb keyboard description. If
successful,
XkbGetVirtualMods
returns
Success.
If the
server
map has not been allocated in the
xkb
parameter,
XkbGetVirtualMods
allocates and initializes it before obtaining the virtual modifier bindings.
If the server does not have a compatible version of Xkb, or the Xkb extension
has not been properly initialized,
XkbGetVirtualMods
returns
BadMatch.
Any errors in allocation cause
XkbGetVirtualMods
to return
BadAlloc.
Obtaining Per-Key Virtual Modifier Mappings from the Server
To obtain the virtual modifier map (the
vmodmap
array) for a subset of the keys in a keyboard description, use
XkbGetKeyVirtualModMap:
XkbGetKeyVirtualModMapStatus XkbGetKeyVirtualModMapDisplay *dpyunsigned int firstunsigned int numXkbDescPtr xkbdpy
connection to server
first
keycode of first key to fetch
num
# keys for which virtual mod maps are desired
xkb
Xkb description where results will be placed
XkbGetKeyVirtualModmap
sends a request to the server to obtain the virtual modifier mappings for
num
keys on the keyboard starting with key
first.
It waits for a reply and returns the virtual modifier mappings in the
server->vmodmap
array of
xkb.
If successful,
XkbGetKeyVirtualModMap
returns
Success.
The
xkb
parameter must be a pointer to a valid Xkb keyboard description
If the
server
map in the
xkb
parameter has not been allocated,
XkbGetKeyVirtualModMap
allocates and initializes it before obtaining the virtual modifier mappings.
If the server does not have a compatible version of Xkb, or the Xkb extension
has not been properly initialized,
XkbGetKeyVirtualModMap
returns
BadMatch.
If
num
is less than 1 or greater than
XkbMaxKeyCount,
XkbGetKeyVirtualModMap
returns
BadValue.
If any allocation errors occur,
XkbGetKeyVirtualModMap
returns
BadAlloc.