'\"
'\" Copyright (c) 1990 The Regents of the University of California.
'\" Copyright (c) 1994-1995 Sun Microsystems, Inc.
'\" Copyright (c) 1996-1999 Christian Werner
'\"
'\" See the file "license.terms" for information on usage and redistribution
'\" of this file, and for a DISCLAIMER OF ALL WARRANTIES.
'\" 
.so man.macros
.TH listbox n 8.0 Ck "Ck Built-In Commands"
.BS
'\" Note:  do not modify the .SH NAME line immediately below!
.SH NAME
listbox \- Create and manipulate listbox widgets
.SH SYNOPSIS
\fBlistbox\fI \fIpathName \fR?\fIoptions\fR?
.SH "STANDARD OPTIONS"
.LP
.nf
.ta 4c 8c 12c
\fBactiveAttributes\fR	\fBattributes\fR	\fBselectAttributes\fR	\fBtakeFocus\fR
\fBactiveBackground\fR	\fBbackground\fR	\fBselectBackground\fR	\fBxScrollCommand\fR
\fBactiveForeground\fR	\fBforeground\fR	\fBselectForeground\fR	\fByScrollCommand\fR
.fi
.LP
See the ``options'' manual entry for details on the standard options.
.SH "WIDGET-SPECIFIC OPTIONS"
.ta 4c
.LP
.nf
Name:	\fBheight\fR
Class:	\fBHeight\fR
Command-Line Switch:	\fB\-height\fR
.fi
.IP
Specifies the desired height for the window, in lines.
If zero or less, then the desired height for the window is made just
large enough to hold all the elements in the listbox.
.LP
.nf
Name:	\fBselectMode\fR
Class:	\fBSelectMode\fR
Command-Line Switch:	\fB\-selectmode\fR
.fi
.IP
Specifies one of several styles for manipulating the selection.
The value of the option may be arbitrary, but the default bindings
expect it to be either \fBsingle\fR, \fBbrowse\fR or \fBmultiple\fR;
the default value is \fBbrowse\fR.
.LP
.nf
Name:	\fBwidth\fR
Class:	\fBWidth\fR
Command-Line Switch:	\fB\-width\fR
.fi
.IP
Specifies the desired width for the window in characters.
If zero or less, then the desired width for the window is made just
large enough to hold all the elements in the listbox.
.BE

.SH DESCRIPTION
.PP
The \fBlistbox\fR command creates a new window (given by the
\fIpathName\fR argument) and makes it into a listbox widget.
Additional options, described above, may be specified on the command line
or in the option database to configure aspects of the listbox such as its
colors, attributes and text. The \fBlistbox\fR command returns its
\fIpathName\fR argument.  At the time this command is invoked,
there must not exist a window named \fIpathName\fR, but
\fIpathName\fR's parent must exist.
.PP
A listbox is a widget that displays a list of strings, one per line.
When first created, a new listbox has no elements.
Elements may be added or deleted using widget commands described
below. In addition, one or more elements may be selected as described
below.
.PP
It is not necessary for all the elements to be
displayed in the listbox window at once;  commands described below
may be used to change the view in the window.  Listboxes allow
scrolling in both directions using the standard \fBxScrollCommand\fR
and \fByScrollCommand\fR options.

.SH "INDICES"
.PP
Many of the widget commands for listboxes take one or more indices
as arguments.
An index specifies a particular element of the listbox, in any of
the following ways:
.TP 12
\fInumber\fR
Specifies the element as a numerical index, where 0 corresponds
to the first element in the listbox.
.TP 12
\fBactive\fR
Indicates the element that has the location cursor.  This element
will be displayed with the \fBactiveAttributes\fR, \fBactiveBackground\fR,
and \fBactiveForeground\fR options if the keyboard focus is in the
listbox. The element is specified with the \fBactivate\fR
widget command.
.TP 12
\fBanchor\fR
Indicates the anchor point for the selection, which is set with the
\fBselection anchor\fR widget command.
.TP 12
\fBend\fR
Indicates the end of the listbox.
For some commands this means just after the last element;
for other commands it means the last element.
.TP 12
\fB@\fIx\fB,\fIy\fR
Indicates the element that covers the point in the listbox window
specified by \fIx\fR and \fIy\fR (in screen coordinates). If no
element covers that point, then the closest element to that
point is used.
.LP
In the widget command descriptions below, arguments named \fIindex\fR,
\fIfirst\fR, and \fIlast\fR always contain text indices in one of
the above forms.

.SH "WIDGET COMMAND"
.PP
The \fBlistbox\fR command creates a new Tcl command whose
name is \fIpathName\fR.  This command may be used to invoke various
operations on the widget. It has the following general form:
.DS C
\fIpathName option \fR?\fIarg arg ...\fR?
.DE
\fIOption\fR and the \fIarg\fRs
determine the exact behavior of the command.  The following
commands are possible for listbox widgets:
.TP
\fIpathName \fBactivate\fR \fIindex\fR
Sets the active element to the one indicated by \fIindex\fR.
The active element is drawn with the \fBactiveAttributes\fR,
\fBactiveBackground\fR, and \fBactiveForeground\fR options
when the widget has the input focus, and its index may be retrieved
with the index \fBactive\fR.
.TP
\fIpathName \fBcget\fR \fIoption\fR
Returns the current value of the configuration option given
by \fIoption\fR.
\fIOption\fR may have any of the values accepted by the \fBlistbox\fR
command.
.TP
\fIpathName \fBconfigure\fR ?\fIoption\fR? ?\fIvalue option value ...\fR?
Query or modify the configuration options of the widget.
If no \fIoption\fR is specified, returns a list describing all of
the available options for \fIpathName\fR. If \fIoption\fR is specified
with no \fIvalue\fR, then the command returns a list describing the
one named option (this list will be identical to the corresponding
sublist of the value returned if no \fIoption\fR is specified).  If
one or more \fIoption\-value\fR pairs are specified, then the command
modifies the given widget option(s) to have the given value(s);  in
this case the command returns an empty string.
\fIOption\fR may have any of the values accepted by the \fBlistbox\fR
command.
.TP
\fIpathName \fBcurselection\fR
Returns a list containing the numerical indices of
all of the elements in the listbox that are currently selected.
If there are no elements selected in the listbox then an empty
string is returned.
.TP
\fIpathName \fBdelete \fIfirst \fR?\fIlast\fR?
Deletes one or more elements of the listbox.  \fIFirst\fR and \fIlast\fR
are indices specifying the first and last elements in the range
to delete.  If \fIlast\fR isn't specified it defaults to
\fIfirst\fR, i.e. a single element is deleted.
.TP
\fIpathName \fBget \fIfirst\fR ?\fIlast\fR?
If \fIlast\fR is omitted, returns the contents of the listbox
element indicated by \fIfirst\fR.
If \fIlast\fR is specified, the command returns a list whose elements
are all of the listbox elements between \fIfirst\fR and \fIlast\fR,
inclusive.
Both \fIfirst\fR and \fIlast\fR may have any of the standard
forms for indices.
.TP
\fIpathName \fBindex \fIindex\fR
Returns a decimal string giving the integer index value that
corresponds to \fIindex\fR.
.TP
\fIpathName \fBinsert \fIindex \fR?\fIelement element ...\fR?
Inserts zero or more new elements in the list just before the
element given by \fIindex\fR.  If \fIindex\fR is specified as
\fBend\fR then the new elements are added to the end of the
list.  Returns an empty string.
.TP
\fIpathName \fBnearest \fIy\fR
Given a y-coordinate within the listbox window, this command returns
the index of the (visible) listbox element nearest to that y-coordinate.
.TP
\fIpathName \fBsee \fIindex\fR
Adjust the view in the listbox so that the element given by \fIindex\fR
is visible.
If the element is already visible then the command has no effect;
if the element is near one edge of the window then the listbox
scrolls to bring the element into view at the edge;  otherwise
the listbox scrolls to center the element.
.TP
\fIpathName \fBselection \fIoption arg\fR
This command is used to adjust the selection within a listbox.  It
has several forms, depending on \fIoption\fR:
.RS
.TP
\fIpathName \fBselection anchor \fIindex\fR
Sets the selection anchor to the element given by \fIindex\fR.
The selection anchor is the end of the selection that is fixed
while dragging out a selection with the mouse.
The index \fBanchor\fR may be used to refer to the anchor
element.
.TP
\fIpathName \fBselection clear \fIfirst \fR?\fIlast\fR?
If any of the elements between \fIfirst\fR and \fIlast\fR
(inclusive) are selected, they are deselected.
The selection state is not changed for elements outside
this range.
.TP
\fIpathName \fBselection includes \fIindex\fR
Returns 1 if the element indicated by \fIindex\fR is currently
selected, 0 if it isn't.
.TP
\fIpathName \fBselection set \fIfirst \fR?\fIlast\fR?
Selects all of the elements in the range between
\fIfirst\fR and \fIlast\fR, inclusive, without affecting
the selection state of elements outside that range.
.RE
.TP
\fIpathName \fBsize\fR
Returns a decimal string indicating the total number of elements
in the listbox.
.TP
\fIpathName \fBxview \fIargs\fR
This command is used to query and change the horizontal position of the
information in the widget's window.  It can take any of the following
forms:
.RS
.TP
\fIpathName \fBxview\fR
Returns a list containing two elements.
Each element is a real fraction between 0 and 1;  together they describe
the horizontal span that is visible in the window.
For example, if the first element is .2 and the second element is .6,
20% of the listbox's text is off-screen to the left, the middle 40% is visible
in the window, and 40% of the text is off-screen to the right.
These are the same values passed to scrollbars via the \fB\-xscrollcommand\fR
option.
.TP
\fIpathName \fBxview\fR \fIindex\fR
Adjusts the view in the window so that the character position given by
\fIindex\fR is displayed at the left edge of the window.
Character positions are defined by the width of the character \fB0\fR.
.TP
\fIpathName \fBxview moveto\fI fraction\fR
Adjusts the view in the window so that \fIfraction\fR of the
total width of the listbox text is off-screen to the left.
\fIfraction\fR must be a fraction between 0 and 1.
.TP
\fIpathName \fBxview scroll \fInumber what\fR
This command shifts the view in the window left or right according to
\fInumber\fR and \fIwhat\fR.
\fINumber\fR must be an integer.
\fIWhat\fR must be either \fBunits\fR or \fBpages\fR or an abbreviation
of one of these.
If \fIwhat\fR is \fBunits\fR, the view adjusts left or right by
\fInumber\fR character units (the width of the \fB0\fR character)
on the display;  if it is \fBpages\fR then the view adjusts by
\fInumber\fR screenfuls.
If \fInumber\fR is negative then characters farther to the left
become visible;  if it is positive then characters farther to the right
become visible.
.RE
.TP
\fIpathName \fByview \fI?args\fR?
This command is used to query and change the vertical position of the
text in the widget's window.
It can take any of the following forms:
.RS
.TP
\fIpathName \fByview\fR
Returns a list containing two elements, both of which are real fractions
between 0 and 1.
The first element gives the position of the listbox element at the
top of the window, relative to the listbox as a whole (0.5 means
it is halfway through the listbox, for example).
The second element gives the position of the listbox element just after
the last one in the window, relative to the listbox as a whole.
These are the same values passed to scrollbars via the \fB\-yscrollcommand\fR
option.
.TP
\fIpathName \fByview\fR \fIindex\fR
Adjusts the view in the window so that the element given by
\fIindex\fR is displayed at the top of the window.
.TP
\fIpathName \fByview moveto\fI fraction\fR
Adjusts the view in the window so that the element given by \fIfraction\fR
appears at the top of the window.
\fIFraction\fR is a fraction between 0 and 1;  0 indicates the first
element in the listbox, 0.33 indicates the element one-third the
way through the listbox, and so on.
.TP
\fIpathName \fByview scroll \fInumber what\fR
This command adjusts the view in the window up or down according to
\fInumber\fR and \fIwhat\fR.
\fINumber\fR must be an integer.
\fIWhat\fR must be either \fBunits\fR or \fBpages\fR.
If \fIwhat\fR is \fBunits\fR, the view adjusts up or down by
\fInumber\fR lines;  if it is \fBpages\fR then
the view adjusts by \fInumber\fR screenfuls.
If \fInumber\fR is negative then earlier elements
become visible;  if it is positive then later elements
become visible.
.RE

.SH "DEFAULT BINDINGS"
.PP
Ck automatically creates class bindings for listboxes. Much of the
behavior of a listbox is determined by its \fBselectMode\fR option,
which selects one of three ways of dealing with the selection.
.PP
If the selection mode is \fBsingle\fR or \fBbrowse\fR, at most one
element can be selected in the listbox at once.
In both modes, clicking button 1 on an element selects
it and deselects any other selected item.
.PP
If the selection mode is \fBmultiple\fR, any number of elements may
be selected at once, including discontiguous ranges.
Clicking button 1 on an element toggles its selection state without
affecting any other elements.
.PP
Most people will probably want to use \fBbrowse\fR mode for
single selections and \fBmultiple\fR mode for multiple selections.
.PP
In addition to the above behavior, the following additional behavior
is defined by the default bindings:
.IP [1]
If the Up or Down key is pressed, the location cursor (active
element) moves up or down one element.
If the selection mode is \fBbrowse\fR then the
new active element is also selected and all other elements are
deselected.
.IP [2]
The Left and Right keys scroll the listbox view left and right
by the one column.
.IP [3]
The Prior and Next keys scroll the listbox view up and down
by one page (the height of the window).
.IP [4]
The Home and End keys scroll the listbox horizontally to
the left and right edges, respectively.
.IP [5]
The space and Select keys make a selection at the location cursor
(active element) just as if mouse button 1 had been pressed over
this element.
.PP
The behavior of listboxes can be changed by defining new bindings for
individual widgets or by redefining the class bindings.

.SH KEYWORDS
listbox, widget