# scrlbar.tcl --## This file defines the default bindings for Tk scrollbar widgets.# It also provides procedures that help in implementing the bindings.## SCCS: @(#) scrlbar.tcl 1.26 96/11/30 17:19:16## Copyright (c) 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.##-------------------------------------------------------------------------# The code below creates the default class bindings for scrollbars.#-------------------------------------------------------------------------# Standard Motif bindings:if {($tcl_platform(platform) != "windows") &&    ($tcl_platform(platform) != "macintosh")} {bind Scrollbar <Enter> {    if $tk_strictMotif {	set tkPriv(activeBg) [%W cget -activebackground]	%W config -activebackground [%W cget -background]    }    %W activate [%W identify %x %y]}bind Scrollbar <Motion> {    %W activate [%W identify %x %y]}# The "info exists" command in the following binding handles the# situation where a Leave event occurs for a scrollbar without the Enter# event.  This seems to happen on some systems (such as Solaris 2.4) for# unknown reasons.bind Scrollbar <Leave> {    if {$tk_strictMotif && [info exists tkPriv(activeBg)]} {	%W config -activebackground $tkPriv(activeBg)    }    %W activate {}}bind Scrollbar <1> {    tkScrollButtonDown %W %x %y}bind Scrollbar <B1-Motion> {    tkScrollDrag %W %x %y}bind Scrollbar <B1-B2-Motion> {    tkScrollDrag %W %x %y}bind Scrollbar <ButtonRelease-1> {    tkScrollButtonUp %W %x %y}bind Scrollbar <B1-Leave> {    # Prevents <Leave> binding from being invoked.}bind Scrollbar <B1-Enter> {    # Prevents <Enter> binding from being invoked.}bind Scrollbar <2> {    tkScrollButton2Down %W %x %y}bind Scrollbar <B1-2> {    # Do nothing, since button 1 is already down.}bind Scrollbar <B2-1> {    # Do nothing, since button 2 is already down.}bind Scrollbar <B2-Motion> {    tkScrollDrag %W %x %y}bind Scrollbar <ButtonRelease-2> {    tkScrollButtonUp %W %x %y}bind Scrollbar <B1-ButtonRelease-2> {    # Do nothing:  B1 release will handle it.}bind Scrollbar <B2-ButtonRelease-1> {    # Do nothing:  B2 release will handle it.}bind Scrollbar <B2-Leave> {    # Prevents <Leave> binding from being invoked.}bind Scrollbar <B2-Enter> {    # Prevents <Enter> binding from being invoked.}bind Scrollbar <Control-1> {    tkScrollTopBottom %W %x %y}bind Scrollbar <Control-2> {    tkScrollTopBottom %W %x %y}bind Scrollbar <Up> {    tkScrollByUnits %W v -1}bind Scrollbar <Down> {    tkScrollByUnits %W v 1}bind Scrollbar <Control-Up> {    tkScrollByPages %W v -1}bind Scrollbar <Control-Down> {    tkScrollByPages %W v 1}bind Scrollbar <Left> {    tkScrollByUnits %W h -1}bind Scrollbar <Right> {    tkScrollByUnits %W h 1}bind Scrollbar <Control-Left> {    tkScrollByPages %W h -1}bind Scrollbar <Control-Right> {    tkScrollByPages %W h 1}bind Scrollbar <Prior> {    tkScrollByPages %W hv -1}bind Scrollbar <Next> {    tkScrollByPages %W hv 1}bind Scrollbar <Home> {    tkScrollToPos %W 0}bind Scrollbar <End> {    tkScrollToPos %W 1}}# tkScrollButtonDown --# This procedure is invoked when a button is pressed in a scrollbar.# It changes the way the scrollbar is displayed and takes actions# depending on where the mouse is.## Arguments:# w -		The scrollbar widget.# x, y -	Mouse coordinates.proc tkScrollButtonDown {w x y} {    global tkPriv    set tkPriv(relief) [$w cget -activerelief]    $w configure -activerelief sunken    set element [$w identify $x $y]    if {$element == "slider"} {	tkScrollStartDrag $w $x $y    } else {	tkScrollSelect $w $element initial    }}# tkScrollButtonUp --# This procedure is invoked when a button is released in a scrollbar.# It cancels scans and auto-repeats that were in progress, and restores# the way the active element is displayed.## Arguments:# w -		The scrollbar widget.# x, y -	Mouse coordinates.proc tkScrollButtonUp {w x y} {    global tkPriv    tkCancelRepeat    $w configure -activerelief $tkPriv(relief)    tkScrollEndDrag $w $x $y    $w activate [$w identify $x $y]}# tkScrollSelect --# This procedure is invoked when a button is pressed over the scrollbar.# It invokes one of several scrolling actions depending on where in# the scrollbar the button was pressed.## Arguments:# w -		The scrollbar widget.# element -	The element of the scrollbar that was selected, such#		as "arrow1" or "trough2".  Shouldn't be "slider".# repeat -	Whether and how to auto-repeat the action:  "noRepeat"#		means don't auto-repeat, "initial" means this is the#		first action in an auto-repeat sequence, and "again"#		means this is the second repetition or later.proc tkScrollSelect {w element repeat} {    global tkPriv    if {![winfo exists $w]} return    if {$element == "arrow1"} {	tkScrollByUnits $w hv -1    } elseif {$element == "trough1"} {	tkScrollByPages $w hv -1    } elseif {$element == "trough2"} {	tkScrollByPages $w hv 1    } elseif {$element == "arrow2"} {	tkScrollByUnits $w hv 1    } else {	return    }    if {$repeat == "again"} {	set tkPriv(afterId) [after [$w cget -repeatinterval] \		tkScrollSelect $w $element again]    } elseif {$repeat == "initial"} {	set delay [$w cget -repeatdelay]	if {$delay > 0} {	    set tkPriv(afterId) [after $delay tkScrollSelect $w $element again]	}    }}# tkScrollStartDrag --# This procedure is called to initiate a drag of the slider.  It just# remembers the starting position of the mouse and slider.## Arguments:# w -		The scrollbar widget.# x, y -	The mouse position at the start of the drag operation.proc tkScrollStartDrag {w x y} {    global tkPriv    if {[$w cget -command] == ""} {	return    }    set tkPriv(pressX) $x    set tkPriv(pressY) $y    set tkPriv(initValues) [$w get]    set iv0 [lindex $tkPriv(initValues) 0]    if {[llength $tkPriv(initValues)] == 2} {	set tkPriv(initPos) $iv0    } else {	if {$iv0 == 0} {	    set tkPriv(initPos) 0.0	} else {	    set tkPriv(initPos) [expr (double([lindex $tkPriv(initValues) 2])) \		    / [lindex $tkPriv(initValues) 0]]	}    }}# tkScrollDrag --# This procedure is called for each mouse motion even when the slider# is being dragged.  It notifies the associated widget if we're not# jump scrolling, and it just updates the scrollbar if we are jump# scrolling.## Arguments:# w -		The scrollbar widget.# x, y -	The current mouse position.proc tkScrollDrag {w x y} {    global tkPriv    if {$tkPriv(initPos) == ""} {	return    }    set delta [$w delta [expr $x - $tkPriv(pressX)] [expr $y - $tkPriv(pressY)]]    if [$w cget -jump] {	if {[llength $tkPriv(initValues)] == 2} {	    $w set [expr [lindex $tkPriv(initValues) 0] + $delta] \		    [expr [lindex $tkPriv(initValues) 1] + $delta]	} else {	    set delta [expr round($delta * [lindex $tkPriv(initValues) 0])]	    eval $w set [lreplace $tkPriv(initValues) 2 3 \		    [expr [lindex $tkPriv(initValues) 2] + $delta] \		    [expr [lindex $tkPriv(initValues) 3] + $delta]]	}    } else {	tkScrollToPos $w [expr $tkPriv(initPos) + $delta]    }}# tkScrollEndDrag --# This procedure is called to end an interactive drag of the slider.# It scrolls the window if we're in jump mode, otherwise it does nothing.## Arguments:# w -		The scrollbar widget.# x, y -	The mouse position at the end of the drag operation.proc tkScrollEndDrag {w x y} {    global tkPriv    if {$tkPriv(initPos) == ""} {	return    }    if [$w cget -jump] {	set delta [$w delta [expr $x - $tkPriv(pressX)] \		[expr $y - $tkPriv(pressY)]]	tkScrollToPos $w [expr $tkPriv(initPos) + $delta]    }    set tkPriv(initPos) ""}# tkScrollByUnits --# This procedure tells the scrollbar's associated widget to scroll up# or down by a given number of units.  It notifies the associated widget# in different ways for old and new command syntaxes.## Arguments:# w -		The scrollbar widget.# orient -	Which kinds of scrollbars this applies to:  "h" for#		horizontal, "v" for vertical, "hv" for both.# amount -	How many units to scroll:  typically 1 or -1.proc tkScrollByUnits {w orient amount} {    set cmd [$w cget -command]    if {($cmd == "") || ([string first \	    [string index [$w cget -orient] 0] $orient] < 0)} {	return    }    set info [$w get]    if {[llength $info] == 2} {	uplevel #0 $cmd scroll $amount units    } else {	uplevel #0 $cmd [expr [lindex $info 2] + $amount]    }}# tkScrollByPages --# This procedure tells the scrollbar's associated widget to scroll up# or down by a given number of screenfuls.  It notifies the associated# widget in different ways for old and new command syntaxes.## Arguments:# w -		The scrollbar widget.# orient -	Which kinds of scrollbars this applies to:  "h" for#		horizontal, "v" for vertical, "hv" for both.# amount -	How many screens to scroll:  typically 1 or -1.proc tkScrollByPages {w orient amount} {    set cmd [$w cget -command]    if {($cmd == "") || ([string first \	    [string index [$w cget -orient] 0] $orient] < 0)} {	return    }    set info [$w get]    if {[llength $info] == 2} {	uplevel #0 $cmd scroll $amount pages    } else {	uplevel #0 $cmd [expr [lindex $info 2] + $amount*([lindex $info 1] - 1)]    }}# tkScrollToPos --# This procedure tells the scrollbar's associated widget to scroll to# a particular location, given by a fraction between 0 and 1.  It notifies# the associated widget in different ways for old and new command syntaxes.## Arguments:# w -		The scrollbar widget.# pos -		A fraction between 0 and 1 indicating a desired position#		in the document.proc tkScrollToPos {w pos} {    set cmd [$w cget -command]    if {($cmd == "")} {	return    }    set info [$w get]    if {[llength $info] == 2} {	uplevel #0 $cmd moveto $pos    } else {	uplevel #0 $cmd [expr round([lindex $info 0]*$pos)]    }}# tkScrollTopBottom# Scroll to the top or bottom of the document, depending on the mouse# position.## Arguments:# w -		The scrollbar widget.# x, y -	Mouse coordinates within the widget.proc tkScrollTopBottom {w x y} {    global tkPriv    set element [$w identify $x $y]    if [string match *1 $element] {	tkScrollToPos $w 0    } elseif [string match *2 $element] {	tkScrollToPos $w 1    }    # Set tkPriv(relief), since it's needed by tkScrollButtonUp.    set tkPriv(relief) [$w cget -activerelief]}# tkScrollButton2Down# This procedure is invoked when button 2 is pressed over a scrollbar.# If the button is over the trough or slider, it sets the scrollbar to# the mouse position and starts a slider drag.  Otherwise it just# behaves the same as button 1.## Arguments:# w -		The scrollbar widget.# x, y -	Mouse coordinates within the widget.proc tkScrollButton2Down {w x y} {    global tkPriv    set element [$w identify $x $y]    if {($element == "arrow1") || ($element == "arrow2")} {	tkScrollButtonDown $w $x $y	return    }    tkScrollToPos $w [$w fraction $x $y]    set tkPriv(relief) [$w cget -activerelief]    # Need the "update idletasks" below so that the widget calls us    # back to reset the actual scrollbar position before we start the    # slider drag.    update idletasks    $w configure -activerelief sunken    $w activate slider    tkScrollStartDrag $w $x $y}