NAME
XSetDeviceFocus, XGetDeviceFocus - control extension input device focus
SYNTAX
XSetDeviceFocus(_d_i_s_p_l_a_y, _d_e_v_i_c_e, _f_o_c_u_s, _r_e_v_e_r_t___t_o, _t_i_m_e)
Display *_d_i_s_p_l_a_y;
Display *_d_e_v_i_c_e;
Window _f_o_c_u_s;
int _r_e_v_e_r_t___t_o;
Time _t_i_m_e;
XGetDeviceFocus(_d_i_s_p_l_a_y, _d_e_v_i_c_e, _f_o_c_u_s___r_e_t_u_r_n,
_r_e_v_e_r_t___t_o___r_e_t_u_r_n, _t_i_m_e___r_e_t_u_r_n)
Display *_d_i_s_p_l_a_y;
Display *_d_e_v_i_c_e;
Window *_f_o_c_u_s___r_e_t_u_r_n;
int *_r_e_v_e_r_t___t_o___r_e_t_u_r_n;
int *_t_i_m_e___r_e_t_u_r_n;
ARGUMENTS
-
display
-
Specifies the connection to the X server.
-
device
-
Specifies the device whose focus is to be queried or changed.
-
focus
-
Specifies the window,
_P_o_i_n_t_e_r_R_o_o_t,
_F_o_l_l_o_w_K_e_y_b_o_a_r_d,
or
_N_o_n_e.
-
focus_return
-
Returns the focus window,
_P_o_i_n_t_e_r_R_o_o_t,
_F_o_l_l_o_w_K_e_y_b_o_a_r_d,
or
_N_o_n_e.
-
revert_to
-
Specifies where the input focus reverts to if the window becomes not
viewable.
You can pass
_R_e_v_e_r_t_T_o_P_a_r_e_n_t,
_R_e_v_e_r_t_T_o_P_o_i_n_t_e_r_R_o_o_t,
_R_e_v_e_r_t_T_o_F_o_l_l_o_w_K_e_y_b_o_a_r_d,
or
_R_e_v_e_r_t_T_o_N_o_n_e.
-
revert_to_return
-
Returns the current focus state
_R_e_v_e_r_t_T_o_P_a_r_e_n_t,
_R_e_v_e_r_t_T_o_P_o_i_n_t_e_r_R_o_o_t,
_R_e_v_e_r_t_T_o_F_o_l_l_o_w_K_e_y_b_o_a_r_d,
or
_R_e_v_e_r_t_T_o_N_o_n_e.
-
time_return
-
Returns the last_focus_time for the device.
-
time
-
Specifies the time.
You can pass either a timestamp or
_C_u_r_r_e_n_t_T_i_m_e.
DESCRIPTION
The _X_S_e_t_D_e_v_i_c_e_F_o_c_u_s
request changes the focus of the specified device and its last-focus-change
time.
It has no effect if the specified time is earlier than the current
last-focus-change time or is later than the current X server time.
Otherwise, the last-focus-change time is set to the specified time
_C_u_r_r_e_n_t_T_i_m_e
is replaced by the current X server time).
_X_S_e_t_D_e_v_i_c_e_F_o_c_u_s
causes the X server to generate
_D_e_v_i_c_e_F_o_c_u_s_I_n
and
_D_e_v_i_c_e_F_o_c_u_s_O_u_t
events.
Depending on the focus argument,
the following occurs:
-
·
If focus is
-
_N_o_n_e ,
all device events are discarded until a new focus window is set,
and the revert_to argument is ignored.
-
·
If focus is a window,
-
it becomes the device's focus window.
If a generated device event would normally be reported to this window
or one of its inferiors, the event is reported as usual.
Otherwise, the event is reported relative to the focus window.
-
·
If focus is
-
_P_o_i_n_t_e_r_R_o_o_t,
the focus window is dynamically taken to be the root window of whatever screen
the pointer is on at each event from the specified device.
In this case, the revert_to argument is ignored.
-
·
If focus is
-
_F_o_l_l_o_w_K_e_y_b_o_a_r_d,
the focus window is dynamically taken to be the window to which the X keyboard
focus is set at each input event.
The specified focus window must be viewable at the time
_X_S_e_t_D_e_v_i_c_e_F_o_c_u_s
is called,
or a
_B_a_d_M_a_t_c_h
error results.
If the focus window later becomes not viewable,
the X server
evaluates the revert_to argument to determine the new focus window as follows:
-
·
If revert_to is
-
_R_e_v_e_r_t_T_o_P_a_r_e_n_t,
the focus reverts to the parent (or the closest viewable ancestor),
and the new revert_to value is taken to be
_R_e_v_e_r_t_T_o_N_o_n_e.
-
·
If revert_to is
-
_R_e_v_e_r_t_T_o_P_o_i_n_t_e_r_R_o_o_t,
_R_e_v_e_r_t_T_o_F_o_l_l_o_w_K_e_y_b_o_a_r_d,
or
_R_e_v_e_r_t_T_o_N_o_n_e,
the focus reverts to
_P_o_i_n_t_e_r_R_o_o_t,
_F_o_l_l_o_w_K_e_y_b_o_a_r_d,
or
_N_o_n_e,
respectively.
When the focus reverts,
the X server generates
_D_e_v_i_c_e_F_o_c_u_s_I_n
and
_D_e_v_i_c_e_F_o_c_u_s_O_u_t
events, but the last-focus-change time is not affected.
Input extension devices are not required to support the ability to be focused.
Attempting to set the focus of a device that does not support this request
will result in a _B_a_d_M_a_t_c_h error. Whether or not given device can
support this request can be determined by the information returned by
_X_O_p_e_n_D_e_v_i_c_e.
For those devices that
support focus, _X_O_p_e_n_D_e_v_i_c_e will return an
_X_I_n_p_u_t_C_l_a_s_s_I_n_f_o structure with the input_class field
equal to the constant _F_o_c_u_s_C_l_a_s_s (defined in the file _X_I_._h).
_X_S_e_t_D_e_v_i_c_e_F_o_c_u_s
can generate
_B_a_d_D_e_v_i_c_e,
_B_a_d_M_a_t_c_h,
_B_a_d_V_a_l_u_e,
and
_B_a_d_W_i_n_d_o_w
errors.
The
_X_G_e_t_D_e_v_i_c_e_F_o_c_u_s
request returns the focus window and the current focus state.
Not all input extension devices can be focused. Attempting to query the
focus state of a device that can't be focused results in a _B_a_d_M_a_t_c_h
error. A device that can be focused returns information for input Class
Focus when an _X_O_p_e_n_D_e_v_i_c_e request is made.
_X_G_e_t_D_e_v_i_c_e_F_o_c_u_s can generate _B_a_d_D_e_v_i_c_e,
and _B_a_d_M_a_t_c_h errors.
DIAGNOSTICS
-
_B_a_d_D_e_v_i_c_e
-
An invalid device was specified. The specified device does not exist or has
not been opened by this client via _X_O_p_e_n_I_n_p_u_t_D_e_v_i_c_e. This error may
also occur if the specified device is the X keyboard or X pointer device.
-
_B_a_d_V_a_l_u_e
-
Some numeric value falls outside the range of values accepted by the request.
Unless a specific range is specified for an argument, the full range defined
by the argument's type is accepted. Any argument defined as a set of
alternatives can generate this error.
-
_B_a_d_W_i_n_d_o_w
-
A value for a Window argument does not name a defined Window.
-
_B_a_d_M_a_t_c_h
-
This error may occur if an _X_G_e_t_D_e_v_i_c_e_F_o_c_u_s or _X_S_e_t_D_e_v_i_c_e_F_o_c_u_s
request was made specifying a device that the server implementation does not
allow to be focused.
SEE ALSO
_P_r_o_g_r_a_m_m_i_n_g _w_i_t_h _X_l_i_b