'\"'\" Copyright (c) 1990-1994 The Regents of the University of California.'\" Copyright (c) 1994-1996 Sun Microsystems, Inc.'\"'\" See the file "license.terms" for information on usage and redistribution'\" of this file, and for a DISCLAIMER OF ALL WARRANTIES.'\" '\" SCCS: @(#) scrollbar.n 1.33 97/10/31 12:58:52'\" .so man.macros.TH scrollbar n 4.1 Tk "Tk Built-In Commands".BS'\" Note:  do not modify the .SH NAME line immediately below!.SH NAMEscrollbar \- Create and manipulate scrollbar widgets.SH SYNOPSIS\fBscrollbar\fR \fIpathName \fR?\fIoptions\fR?.SO\-activebackground	\-highlightbackground	\-orient	\-takefocus\-background	\-highlightcolor	\-relief	\-troughcolor\-borderwidth	\-highlightthickness	\-repeatdelay\-cursor	\-jump	\-repeatinterval.SE.SH "WIDGET-SPECIFIC OPTIONS".OP \-activerelief activeRelief ActiveReliefSpecifies the relief to use when displaying the element that isactive, if any.Elements other than the active element are always displayed witha raised relief..OP \-command command CommandSpecifies the prefix of a Tcl command to invoke to change the viewin the widget associated with the scrollbar.  When a user requestsa view change by manipulating the scrollbar, a Tcl command isinvoked.  The actual command consists of this option followed byadditional information as described later.  This option almost always hasa value such as \fB.t xview\fR or \fB.t yview\fR, consisting of thename of a widget and either \fBxview\fR (if the scrollbar is forhorizontal scrolling) or \fByview\fR (for vertical scrolling).All scrollable widgets have \fBxview\fR and \fByview\fR commandsthat take exactly the additional arguments appended by the scrollbaras described in SCROLLING COMMANDS below..OP \-elementborderwidth elementBorderWidth BorderWidthSpecifies the width of borders drawn around the internal elementsof the scrollbar (the two arrows and the slider).  The value mayhave any of the forms acceptable to \fBTk_GetPixels\fR.If this value is less than zero, the value of the \fBborderWidth\fRoption is used in its place..OP \-width width WidthSpecifies the desired narrow dimension of the scrollbar window,not including 3-D border, if any.  For verticalscrollbars this will be the width and for horizontal scrollbarsthis will be the height.The value may have any of the forms acceptable to \fBTk_GetPixels\fR..BE.SH DESCRIPTION.PPThe \fBscrollbar\fR command creates a new window (given by the\fIpathName\fR argument) and makes it into a scrollbar widget.Additional options, described above, may be specified on the commandline or in the option database to configure aspects of the scrollbarsuch as its colors, orientation, and relief.The \fBscrollbar\fR command returns its \fIpathName\fR argument.At the time this command is invoked, there must not exist a windownamed \fIpathName\fR, but \fIpathName\fR's parent must exist..PPA scrollbar is a widget that displays two arrows, one at each end ofthe scrollbar, and a \fIslider\fR in the middle portion of thescrollbar.It provides information about what is visible in an \fIassociated window\fRthat displays an document of some sort (such as a file being edited ora drawing).The position and size of the slider indicate which portion of thedocument is visible in the associated window.  For example, if theslider in a vertical scrollbar covers the top third of the areabetween the two arrows, it means that the associated window displaysthe top third of its document..PPScrollbars can be used to adjust the view in the associated windowby clicking or dragging with the mouse.  See the BINDINGS sectionbelow for details..SH "ELEMENTS".PPA scrollbar displays five elements, which are referred to in thewidget commands for the scrollbar:.TP 10\fBarrow1\fRThe top or left arrow in the scrollbar..TP 10\fBtrough1\fRThe region between the slider and \fBarrow1\fR..TP 10\fBslider\fRThe rectangle that indicates what is visible in the associated widget..TP 10\fBtrough2\fRThe region between the slider and \fBarrow2\fR..TP 10\fBarrow2\fRThe bottom or right arrow in the scrollbar..SH "WIDGET COMMAND".PPThe \fBscrollbar\fR command creates a new Tcl command whosename is \fIpathName\fR.  Thiscommand may be used to invoke variousoperations on the widget.  It has the following general form:.CS\fIpathName option \fR?\fIarg arg ...\fR?.CE\fIOption\fR and the \fIarg\fRsdetermine the exact behavior of the command.  The followingcommands are possible for scrollbar widgets:.TP\fIpathName \fBactivate \fR?\fIelement\fR?Marks the element indicated by \fIelement\fR as active, whichcauses it to be displayed as specified by the \fBactiveBackground\fRand \fBactiveRelief\fR options.The only element values understood by this command are \fBarrow1\fR,\fBslider\fR, or \fBarrow2\fR.If any other value is specified then no element of the scrollbarwill be active.If \fIelement\fR is not specified, the command returnsthe name of the element that is currently active, or an empty stringif no element is active..TP\fIpathName \fBcget\fR \fIoption\fRReturns the current value of the configuration option givenby \fIoption\fR.\fIOption\fR may have any of the values accepted by the \fBscrollbar\fRcommand..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 ofthe available options for \fIpathName\fR (see \fBTk_ConfigureInfo\fR forinformation on the format of this list).  If \fIoption\fR is specifiedwith no \fIvalue\fR, then the command returns a list describing theone named option (this list will be identical to the correspondingsublist of the value returned if no \fIoption\fR is specified).  Ifone or more \fIoption\-value\fR pairs are specified, then the commandmodifies the given widget option(s) to have the given value(s);  inthis case the command returns an empty string.\fIOption\fR may have any of the values accepted by the \fBscrollbar\fRcommand..TP\fIpathName \fBdelta \fIdeltaX deltaY\fRReturns a real number indicating the fractional change inthe scrollbar setting that corresponds to a given changein slider position.  For example, if the scrollbar is horizontal,the result indicates how much the scrollbar setting must changeto move the slider \fIdeltaX\fR pixels to the right (\fIdeltaY\fR isignored in this case).If the scrollbar is vertical, the result indicates how much thescrollbar setting must change to move the slider \fIdeltaY\fR pixelsdown.  The arguments and the result may be zero or negative..TP\fIpathName \fBfraction \fIx y\fRReturns a real number between 0 and 1 indicating where the pointgiven by \fIx\fR and \fIy\fR lies in the trough area of the scrollbar.The value 0 corresponds to the top or left of the trough, thevalue 1 corresponds to the bottom or right, 0.5 corresponds tothe middle, and so on.\fIX\fR and \fIy\fR must be pixel coordinates relative to the scrollbarwidget.If \fIx\fR and \fIy\fR refer to a point outside the trough, the closestpoint in the trough is used..TP\fIpathName \fBget\fRReturns the scrollbar settings in the form of a list whoseelements are the arguments to the most recent \fBset\fR widget command..TP\fIpathName \fBidentify\fR \fIx y\fRReturns the name of the element under the point given by \fIx\fR and\fIy\fR (such as \fBarrow1\fR), or an empty string if the point doesnot lie in any element of the scrollbar.\fIX\fR and \fIy\fR must be pixel coordinates relative to the scrollbarwidget..TP\fIpathName \fBset\fR \fIfirst last\fRThis command is invoked by the scrollbar's associated widget totell the scrollbar about the current view in the widget.The command takes two arguments, each of which is a real fractionbetween 0 and 1.The fractions describe the range of the document that is visible inthe associated widget.For example, if \fIfirst\fR is 0.2 and \fIlast\fR is 0.4, it meansthat the first part of the document visible in the window is 20%of the way through the document, and the last visible part is 40%of the way through..SH "SCROLLING COMMANDS".PPWhen the user interacts with the scrollbar, for example by draggingthe slider, the scrollbar notifies the associated widget that itmust change its view.The scrollbar makes the notification by evaluating a Tcl commandgenerated 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 givenby \fIfraction\fR appears at the beginning of the widget.If \fIfraction\fR is 0 it refers to the beginning of thedocument.  1.0 refers to the end of the document, 0.333refers to a point one-third of the way through the document,and so on..TP\fIprefix \fBscroll \fInumber \fBunits\fRThe 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 offthe top or left of the window, or \-1, which means that one unitshould scroll off the bottom or right of the window..TP\fIprefix \fBscroll \fInumber \fBpages\fRThe widget should adjust its view by \fInumber\fR pages.It is up to the widget to define the meaning of a page;  typicallyit is slightly less than what fits in the window, so that thereis a slight overlap between the old and new views.\fINumber\fR is either 1, which means the next page shouldbecome visible, or \-1, which means that the previous page shouldbecome visible..SH "OLD COMMAND SYNTAX".PPIn versions of Tk before 4.0, the \fBset\fR and \fBget\fR widgetcommands used a different form.This form is still supported for backward compatibility, but itis deprecated.In the old command syntax, the \fBset\fR widget command has thefollowing form:.TP\fIpathName \fBset\fR \fItotalUnits windowUnits firstUnit lastUnit\fRIn this form the arguments are all integers.\fITotalUnits\fR gives the total size of the object being displayed in theassociated widget.  The meaning of one unit depends on the associatedwidget;  for example, in a text editor widget units mightcorrespond to lines oftext.  \fIWindowUnits\fR indicates the total number of units thatcan fit in the associated window at one time.  \fIFirstUnit\fRand \fIlastUnit\fR give the indices of the first and last unitscurrently visible in the associated window (zero corresponds to thefirst unit of the object)..LPUnder the old syntax the \fBget\fR widget command returns a listof four integers, consisting of the \fItotalUnits\fR, \fIwindowUnits\fR,\fIfirstUnit\fR, and \fIlastUnit\fR values from the last \fBset\fRwidget command..PPThe commands generated by scrollbars also have a different formwhen the old syntax is being used:.TP\fIprefix\fR \fIunit\fR\fIUnit\fR is an integer that indicates what should appear atthe top or left of the associated widget's window.It has the same meaning as the \fIfirstUnit\fR and \fIlastUnit\fRarguments to the \fBset\fR widget command..LPThe most recent \fBset\fR widget command determines whether or notto use the old syntax.If it is given two real arguments then the new syntax will beused in the future, and if it is given four integer arguments thenthe old syntax will be used..SH BINDINGSTk automatically creates class bindings for scrollbars that give themthe following default behavior.If the behavior is different for vertical and horizontal scrollbars,the horizontal behavior is described in parentheses..IP [1]Pressing button 1 over \fBarrow1\fR causes the view in theassociated widget to shift up (left) by one unit so that thedocument appears to move down (right) one unit.If the button is held down, the action auto-repeats..IP [2]Pressing button 1 over \fBtrough1\fR causes the view in theassociated widget to shift up (left) by one screenful so that thedocument appears to move down (right) one screenful.If the button is held down, the action auto-repeats..IP [3]Pressing button 1 over the slider and dragging causes the viewto drag with the slider.If the \fBjump\fR option is true, then the view doesn't drag alongwith the slider;  it changes only when the mouse button is released..IP [4]Pressing button 1 over \fBtrough2\fR causes the view in theassociated widget to shift down (right) by one screenful so that thedocument appears to move up (left) one screenful.If the button is held down, the action auto-repeats..IP [5]Pressing button 1 over \fBarrow2\fR causes the view in theassociated widget to shift down (right) by one unit so that thedocument appears to move up (left) one unit.If the button is held down, the action auto-repeats..IP [6]If button 2 is pressed over the trough or the slider, it setsthe view to correspond to the mouse position;  dragging themouse with button 2 down causes the view to drag with the mouse.If button 2 is pressed over one of the arrows, it causes thesame behavior as pressing button 1..IP [7]If button 1 is pressed with the Control key down, then if themouse is over \fBarrow1\fR or \fBtrough1\fR the view changesto the very top (left) of the document;  if the mouse is over\fBarrow2\fR or \fBtrough2\fR the view changesto the very bottom (right) of the document;  if the mouse isanywhere else then the button press has no effect..IP [8]In vertical scrollbars the Up and Down keys have the same behavioras mouse clicks over \fBarrow1\fR and \fBarrow2\fR, respectively.In horizontal scrollbars these keys have no effect..IP [9]In vertical scrollbars Control-Up and Control-Down have the samebehavior as mouse clicks over \fBtrough1\fR and \fBtrough2\fR, respectively.In horizontal scrollbars these keys have no effect..IP [10]In horizontal scrollbars the Up and Down keys have the same behavioras mouse clicks over \fBarrow1\fR and \fBarrow2\fR, respectively.In vertical scrollbars these keys have no effect..IP [11]In horizontal scrollbars Control-Up and Control-Down have the samebehavior as mouse clicks over \fBtrough1\fR and \fBtrough2\fR, respectively.In vertical scrollbars these keys have no effect..IP [12]The Prior and Next keys have the same behavioras mouse clicks over \fBtrough1\fR and \fBtrough2\fR, respectively..IP [13]The Home key adjusts the view to the top (left edge) of the document..IP [14]The End key adjusts the view to the bottom (right edge) of the document..SH KEYWORDSscrollbar, widget