path: root/doc/ttk_scrollbar.n

'\"
'\" Copyright (c) 1994-1996 Sun Microsystems, Inc.
'\" Copyright (c) 2004 Joe English
'\"
'\" See the file "license.terms" for information on usage and redistribution
'\" of this file, and for a DISCLAIMER OF ALL WARRANTIES.
'\" 
'\" SOURCE: tk/doc/scrollbar.n, r1.4
'\" RCS: @(#) $Id: ttk_scrollbar.n,v 1.5 2007/10/23 15:44:36 dkf Exp $
'\" 
.so man.macros
.TH ttk_scrollbar n 8.5 Tk "Tk Themed Widget"
.BS
.\" Use _ instead of :: as the name becomes a filename on install
.SH NAME
ttk_scrollbar \- Control the viewport of a scrollable widget 
.SH SYNOPSIS
\fBttk::scrollbar\fR \fIpathName \fR?\fIoptions...\fR?
.BE

.SH DESCRIPTION
\fBttk::scrollbar\fR widgets are typically linked to an associated window that
displays a document of some sort, such as a file being edited or a drawing. A
scrollbar displays a \fIthumb\fR in the middle portion of the scrollbar, whose
position and size provides information about the portion of the document
visible in the associated window. The thumb may be dragged by the user to
control the visible region. Depending on the theme, two or more arrow buttons
may also be present; these are used to scroll the visible region in discrete
units.
.SO
\-class	\-cursor	\-style
\-takefocus
.SE
.SH "WIDGET-SPECIFIC OPTIONS"
.OP \-command command Command
A Tcl script prefix to evaluate to change the view in the widget associated
with the scrollbar. Additional arguments are appended to the value of this
option, as described in \fBSCROLLING COMMANDS\fR below, whenever the user
requests a view change by manipulating the scrollbar.
.RS
.PP
This option typically consists of a two-element list, containing the name of a
scrollable widget followed by either \fBxview\fR (for horizontal scrollbars)
or \fByview\fR (for vertical scrollbars).
.RE
.OP \-orient orient Orient
One of \fBhorizontal\fR or \fBvertical\fR. Specifies the orientation of the
scrollbar.
.BE
.SH "WIDGET COMMAND"
.TP
\fIpathName \fBcget\fR \fIoption\fR
.
Returns the current value of the specified \fIoption\fR; see
\fIttk_widget(n)\fR.
.TP
\fIpathName \fBconfigure\fR ?\fIoption\fR? ?\fIvalue option value ...\fR?
.
Modify or query widget options; see \fIttk_widget(n)\fR.
.TP
\fIpathName \fBget\fR
.
Returns the scrollbar settings in the form of a list whose elements are the
arguments to the most recent \fBset\fR widget command.
.TP
\fIpathName \fBinstate \fIstatespec\fR ?\fIscript\fR?
.
Test the widget state; see \fIttk_widget(n)\fR.
.TP
\fIpathName \fBset\fR \fIfirst last\fR
.
This command is normally invoked by the scrollbar's associated widget from an
\fB\-xscrollcommand\fR or \fB\-yscrollcommand\fR callback. Specifies the
visible range to be displayed. \fIfirst\fR and \fIlast\fR are real fractions
between 0 and 1.
.TP
\fIpathName \fBstate\fR ?\fIstateSpec\fR?
.
Modify or query the widget state; see \fIttk_widget(n)\fR.
.SH "INTERNAL COMMANDS"
The following widget commands are used internally by the TScrollbar widget
class bindings.
.TP
\fIpathName \fBdelta \fIdeltaX deltaY\fR
.
Returns a real number indicating the fractional change in the scrollbar
setting that corresponds to a given change in thumb position. For example, if
the scrollbar is horizontal, the result indicates how much the scrollbar
setting must change to move the thumb \fIdeltaX\fR pixels to the right
(\fIdeltaY\fR is ignored in this case). If the scrollbar is vertical, the
result indicates how much the scrollbar setting must change to move the thumb
\fIdeltaY\fR pixels down. The arguments and the result may be zero or
negative.
.TP
\fIpathName \fBfraction \fIx y\fR
.
Returns a real number between 0 and 1 indicating where the point given by
\fIx\fR and \fIy\fR lies in the trough area of the scrollbar, where 0.0
corresponds to the top or left of the trough and 1.0 corresponds to the bottom
or right. \fIX\fR and \fIy\fR are pixel coordinates relative to the scrollbar
widget. If \fIx\fR and \fIy\fR refer to a point outside the trough, the
closest point in the trough is used.
.TP
\fIpathName \fBidentify\fR \fIx y\fR
.
Returns the name of the element under the point given by \fIx\fR and \fIy\fR,
or an empty string if the point does not lie in any element of the scrollbar.
\fIX\fR and \fIy\fR are pixel coordinates relative to the scrollbar widget.
.SH "SCROLLING COMMANDS"
When the user interacts with the scrollbar, for example by dragging the thumb,
the scrollbar notifies the associated widget that it must change its view.
The scrollbar makes the notification by evaluating a Tcl command generated
from the scrollbar's \fB\-command\fR option. The command may take any of the
following forms. In each case, \fIprefix\fR is the contents of the
\fB\-command\fR option, which usually has a form like \fB.t yview\fR
.TP
\fIprefix \fBmoveto \fIfraction\fR
.
\fIFraction\fR is a real number between 0 and 1. The widget should adjust its
view so that the point given by \fIfraction\fR appears at the beginning of the
widget. If \fIfraction\fR is 0 it refers to the beginning of the document. 1.0
refers to the end of the document, 0.333 refers to a point one-third of the
way through the document, and so on.
.TP
\fIprefix \fBscroll \fInumber \fBunits\fR
.
The widget should adjust its view by \fInumber\fR units. The units are defined
in whatever way makes sense for the widget, such as characters or lines in a
text widget. \fINumber\fR is either 1, which means one unit should scroll off
the top or left of the window, or \-1, which means that one unit should scroll
off the bottom or right of the window.
.TP
\fIprefix \fBscroll \fInumber \fBpages\fR
.
The widget should adjust its view by \fInumber\fR pages. It is up to the
widget to define the meaning of a page; typically it is slightly less than
what fits in the window, so that there is a slight overlap between the old and
new views. \fINumber\fR is either 1, which means the next page should become
visible, or \-1, which means that the previous page should become visible.
.SH "WIDGET STATES"
The scrollbar automatically sets the \fBdisabled\fR state bit when the entire
range is visible (range is 0.0 to 1.0), and clears it otherwise. It also sets
the \fBactive\fR and \fBpressed\fR state flags of individual elements, based
on the position and state of the mouse pointer.
.SH EXAMPLE
.CS
set f [frame .f]
ttk::scrollbar $f.hsb -orient horizontal \e
        -command [list $f.t xview]
ttk::scrollbar $f.vsb -orient vertical \e
        -command [list $f.t yview]
text $f.t -xscrollcommand [list $f.hsb set] \e
        -yscrollcommand [list $f.vsb set]
grid $f.t -row 0 -column 0 -sticky nsew
grid $f.vsb -row 0 -column 1 -sticky nsew
grid $f.hsb -row 1 -column 0 -sticky nsew
grid columnconfigure $f 0 -weight 1
grid rowconfigure $f 0 -weight 1
.CE
.SH "SEE ALSO"
ttk_widget(n), scrollbar(n)
.SH KEYWORDS
scrollbar, widget