


Tk:focus-next(n)       Tk Built-In Commands      Tk:focus-next(n)


NAME
       Tk:focus-next,   Tk:focus-prev,   Tk:focus-follows-mouse,  Tk:focus-on,
       Tk:focus-off - Utility procedures for managing the input focus.

SYNOPSIS
       (Tk:focus-next window)

       (Tk:focus-prev window)

       (Tk:focus-follows-mouse)


DESCRIPTION
       Tk:focus-next is a utility procedure used for keyboard  traversal.   It
       returns  the  ``next''  window  after window in focus order.  The focus
       order is determined by the stacking order of windows and the  structure
       of  the  window hierarchy.  Among siblings, the focus order is the same
       as the stacking order, with the lowest window being first.  If a window
       has  children,  the  window  is visited first, followed by its children
       (recursively), followed by its next sibling.  Top-level  windows  other
       than  window  are skipped, so that Tk:focus-next never returns a window
       in a different top-level from window.

       After computing the next window, Tk:focus-next  examines  the  window's
       :takefocus  option  to  see  whether  it  should  be  skipped.   If so,
       Tk:focus-next continues on to the next window in the focus order, until
       it eventually finds a window that will accept the focus or returns back
       to window.

       Tk:focus-prev is similar to Tk:focus-next except that  it  returns  the
       window just before window in the focus order.

       Tk:focus-follows-mouse  changes  the focus model for the application to
       an implicit one where the window under the mouse gets the focus.  After
       this  procedure  is  called, whenever the mouse enters a window Tk will
       automatically give it the input focus.  The focus command may  be  used
       to  move  the focus to a window other than the one under the mouse, but
       as soon as the mouse moves into a new window the  focus  will  jump  to
       that window.  Note: at present there is no built-in support for return-
       ing the application to an explicit focus model;  to do this you'll have
       to  write  a  script that deletes the bindings created by Tk:focus-fol-
       lows-mouse.


       Tk:focus-on and Tk:focus-off are simpy defined as  (define  Tk:focus-on
       (lambda  (w) #t)) (define Tk:focus-off (lambda (w) #f)) This procedures
       can be used by the focus traversal algorithm presented in  the  options
       manual page.

SEE ALSO
       focus, toplevel






STk                            3.1                              1


