1996-09-27 06:29:02 -04:00
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<HTML><HEAD><TITLE>Tk Built-In Commands - Tk:focus-next manual page</TITLE></HEAD>
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1998-04-10 06:59:06 -04:00
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<BR>
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1996-09-27 06:29:02 -04:00
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<BODY bgcolor = #c3ffc3>
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<H2><IMG ALIGN=BOTTOM SRC="./Img/ManPageGreen.gif"> Tk:focus-next, Tk:focus-prev, Tk:focus-follows-mouse, Tk:focus-on, Tk:focus-off</H2>
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<I>Utility procedures for managing the input focus.</I><P><IMG ALIGN=TOP SRC="./Img/line-red.gif">
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<H3><A NAME="M2">SYNOPSIS</A></H3>
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(<B>Tk:focus-next </B><I>window</I>)<BR>
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(<B>Tk:focus-prev </B><I>window</I>)<BR>
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(<B>Tk:focus-follows-mouse</B>)<BR>
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<H3><A NAME="M3">DESCRIPTION</A></H3>
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<B>Tk:focus-next</B> is a utility procedure used for keyboard traversal.
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It returns the ``next'' window after <I>window</I> in focus order.
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The focus order is determined by
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the stacking order of windows and the structure of the window hierarchy.
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Among siblings, the focus order is the same as the stacking order, with the
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lowest window being first.
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If a window has children, the window is visited first, followed by
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its children (recursively), followed by its next sibling.
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Top-level windows other than <I>window</I> are skipped, so that
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<B>Tk:focus-next</B> never returns a window in a different top-level
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from <I>window</I>.
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<P>
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After computing the next window, <B>Tk:focus-next</B> examines the
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window's <B>:takefocus</B> option to see whether it should be skipped.
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If so, <B>Tk:focus-next</B> continues on to the next window in the focus
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order, until it eventually finds a window that will accept the focus
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or returns back to <I>window</I>.
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<P>
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<B>Tk:focus-prev</B> is similar to <B>Tk:focus-next</B> except that it
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returns the window just before <I>window</I> in the focus order.
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<P>
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<B>Tk:focus-follows-mouse</B> changes the focus model for the application
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to an implicit one where the window under the mouse gets the focus.
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After this procedure is called, whenever the mouse enters a window
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Tk will automatically give it the input focus.
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The <B><A HREF="./focus.n.html">focus</A></B> command may be used to move the focus to a window
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other than the one under the mouse, but as soon as the mouse moves
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into a new window the focus will jump to that window.
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Note: at present there is no built-in support for returning the
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application to an explicit focus model; to do this you'll have
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to write a script that deletes the bindings created by
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<B>Tk:focus-follows-mouse</B>.
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<P>
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<B>Tk:focus-on</B> and <B>Tk:focus-off</B> are simpy defined as
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<PRE>(define Tk:focus-on (lambda (w) #t))
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(define Tk:focus-off (lambda (w) #f))</PRE>
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This procedures can be used by the focus traversal algorithm presented in the
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<B><A HREF="./options.n.html">options</A></B> manual page.
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<H3><A NAME="M4">SEE ALSO</A></H3>
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<B><A HREF="./focus.n.html">focus</A></B>, <B><A HREF="./toplevel.n.html">toplevel</A></B>
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1998-04-10 06:59:06 -04:00
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<P><IMG ALIGN=TOP SRC="./Img/line-red.gif"><P>
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1996-09-27 06:29:02 -04:00
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<A HREF=./STk-hlp.html><IMG ALIGN=BOTTOM SRC="./Img/RefBookGreen.gif"> Back to the <B>STk</B> main page</A>
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