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IRIX Base Documentation 1998 November
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IRIX 6.5.2 Base Documentation November 1998.img
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catman
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Tk
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focus.z
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focus
Wrap
Text File
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1998-10-30
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8KB
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133 lines
ffffooooccccuuuussss((((3333TTTTkkkk)))) ffffooooccccuuuussss((((3333TTTTkkkk))))
NNNNAAAAMMMMEEEE
focus - Manage the input focus
SSSSYYYYNNNNOOOOPPPPSSSSIIIISSSS
ffffooooccccuuuussss
ffffooooccccuuuussss _w_i_n_d_o_w
ffffooooccccuuuussss _o_p_t_i_o_n ?_a_r_g _a_r_g ...?
DDDDEEEESSSSCCCCRRRRIIIIPPPPTTTTIIIIOOOONNNN
The ffffooooccccuuuussss command is used to manage the Tk input focus. At any given |
time, one window on each display is designated as the _f_o_c_u_s _w_i_n_d_o_w; any |
key press or key release events for the display are sent to that window. |
It is normally up to the window manager to redirect the focus among the |
top-level windows of a display. For example, some window managers |
automatically set the input focus to a top-level window whenever the |
mouse enters it; others redirect the input focus only when the user |
clicks on a window. Usually the window manager will set the focus only |
to top-level windows, leaving it up to the application to redirect the |
focus among the children of the top-level. |
Tk remembers one focus window for each top-level (the most recent |
descendant of that top-level to receive the focus); when the window |
manager gives the focus to a top-level, Tk automatically redirects it to |
the remembered window. Within a top-level Tk uses an _e_x_p_l_i_c_i_t focus |
model by default. Moving the mouse within a top-level does not normally |
change the focus; the focus changes only when a widget decides |
explicitly to claim the focus (e.g., because of a button click), or when |
the user types a key such as Tab that moves the focus. |
The Tcl procedure ttttkkkk____ffffooooccccuuuussssFFFFoooolllllllloooowwwwssssMMMMoooouuuusssseeee may be invoked to create an |
_i_m_p_l_i_c_i_t focus model: it reconfigures Tk so that the focus is set to a |
window whenever the mouse enters it. The Tcl procedures ttttkkkk____ffffooooccccuuuussssNNNNeeeexxxxtttt and|
ttttkkkk____ffffooooccccuuuussssPPPPrrrreeeevvvv implement a focus order among the windows of a top-level; |
they are used in the default bindings for Tab and Shift-Tab, among other |
things. |
The ffffooooccccuuuussss command can take any of the following forms: |
ffffooooccccuuuussss ||
Returns the path name of the focus window on the display containing |
the application's main window, or an empty string if no window in |
this application has the focus on that display. Note: it is |
better to specify the display explicitly using ----ddddiiiissssppppllllaaaayyyyooooffff (see |
below) so that the code will work in applications using multiple |
displays. |
ffffooooccccuuuussss _w_i_n_d_o_w ||
If the application currently has the input focus on _w_i_n_d_o_w's |
display, this command resets the input focus for _w_i_n_d_o_w's display to|
_w_i_n_d_o_w and returns an empty string. If the application doesn't |
currently have the input focus on _w_i_n_d_o_w's display, _w_i_n_d_o_w will be |
PPPPaaaaggggeeee 1111
ffffooooccccuuuussss((((3333TTTTkkkk)))) ffffooooccccuuuussss((((3333TTTTkkkk))))
remembered as the focus for its top-level; the next time the focus |
arrives at the top-level, Tk will redirect it to _w_i_n_d_o_w. If _w_i_n_d_o_w |
is an empty string then the command does nothing. |
ffffooooccccuuuussss ----ddddiiiissssppppllllaaaayyyyooooffff _w_i_n_d_o_w ||
Returns the name of the focus window on the display containing |
_w_i_n_d_o_w. If the focus window for _w_i_n_d_o_w's display isn't in this |
application, the return value is an empty string. |
ffffooooccccuuuussss ----ffffoooorrrrcccceeee _w_i_n_d_o_w ||
Sets the focus of _w_i_n_d_o_w's display to _w_i_n_d_o_w, even if the |
application doesn't currently have the input focus for the display. |
This command should be used sparingly, if at all. In normal usage, |
an application should not claim the focus for itself; instead, it |
should wait for the window manager to give it the focus. If _w_i_n_d_o_w |
is an empty string then the command does nothing. |
ffffooooccccuuuussss ----llllaaaassssttttffffoooorrrr _w_i_n_d_o_w ||
Returns the name of the most recent window to have the input focus |
among all the windows in the same top-level as _w_i_n_d_o_w. If no window|
in that top-level has ever had the input focus, or if the most |
recent focus window has been deleted, then the name of the top-level|
is returned. The return value is the window that will receive the |
input focus the next time the window manager gives the focus to the |
top-level. |
QQQQUUUUIIIIRRRRKKKKSSSS ||||
When an internal window receives the input focus, Tk doesn't actually set|
the X focus to that window; as far as X is concerned, the focus will |
stay on the top-level window containing the window with the focus. |
However, Tk generates FocusIn and FocusOut events just as if the X focus |
were on the internal window. This approach gets around a number of |
problems that would occur if the X focus were actually moved; the fact |
that the X focus is on the top-level is invisible unless you use C code |
to query the X server directly.
KKKKEEEEYYYYWWWWOOOORRRRDDDDSSSS
events, focus, keyboard, top-level, window manager
PPPPaaaaggggeeee 2222