# scrlbar.tcl --

#

# This file defines the default bindings for Tk scrollbar widgets.

# It also provides procedures that help in implementing the bindings.

#

# RCS: @(#) $Id: scrlbar.tcl,v 1.10.2.1 2004/02/17 07:17:17 das Exp $

#

# 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 {[string equal [tk windowingsystem] "x11"]} {

bind Scrollbar <Enter> {

    if {$tk_strictMotif} {

	set tk::Priv(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 tk::Priv(activeBg)]} {

	%W config -activebackground $tk::Priv(activeBg)

    }

    %W activate {}

}

bind Scrollbar <1> {

    tk::ScrollButtonDown %W %x %y

}

bind Scrollbar <B1-Motion> {

    tk::ScrollDrag %W %x %y

}

bind Scrollbar <B1-B2-Motion> {

    tk::ScrollDrag %W %x %y

}

bind Scrollbar <ButtonRelease-1> {

    tk::ScrollButtonUp %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> {

    tk::ScrollButton2Down %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> {

    tk::ScrollDrag %W %x %y

}

bind Scrollbar <ButtonRelease-2> {

    tk::ScrollButtonUp %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> {

    tk::ScrollTopBottom %W %x %y

}

bind Scrollbar <Control-2> {

    tk::ScrollTopBottom %W %x %y

}

bind Scrollbar <Up> {

    tk::ScrollByUnits %W v -1

}

bind Scrollbar <Down> {

    tk::ScrollByUnits %W v 1

}

bind Scrollbar <Control-Up> {

    tk::ScrollByPages %W v -1

}

bind Scrollbar <Control-Down> {

    tk::ScrollByPages %W v 1

}

bind Scrollbar <Left> {

    tk::ScrollByUnits %W h -1

}

bind Scrollbar <Right> {

    tk::ScrollByUnits %W h 1

}

bind Scrollbar <Control-Left> {

    tk::ScrollByPages %W h -1

}

bind Scrollbar <Control-Right> {

    tk::ScrollByPages %W h 1

}

bind Scrollbar <Prior> {

    tk::ScrollByPages %W hv -1

}

bind Scrollbar <Next> {

    tk::ScrollByPages %W hv 1

}

bind Scrollbar <Home> {

    tk::ScrollToPos %W 0

}

bind Scrollbar <End> {

    tk::ScrollToPos %W 1

}

}

if {[string equal [tk windowingsystem] "classic"]

	|| [string equal [tk windowingsystem] "aqua"]} {

    bind Scrollbar <MouseWheel> {

        tk::ScrollByUnits %W v [expr {- (%D)}]

    }

    bind Scrollbar <Option-MouseWheel> {

        tk::ScrollByUnits %W v [expr {-10 * (%D)}]

    }

    bind Scrollbar <Shift-MouseWheel> {

        tk::ScrollByUnits %W h [expr {- (%D)}]

    }

    bind Scrollbar <Shift-Option-MouseWheel> {

        tk::ScrollByUnits %W h [expr {-10 * (%D)}]

    }

}

# tk::ScrollButtonDown --

# 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 tk::ScrollButtonDown {w x y} {

    variable ::tk::Priv

    set Priv(relief) [$w cget -activerelief]

    $w configure -activerelief sunken

    set element [$w identify $x $y]

    if {[string equal $element "slider"]} {

	ScrollStartDrag $w $x $y

    } else {

	ScrollSelect $w $element initial

    }

}

# ::tk::ScrollButtonUp --

# 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 ::tk::ScrollButtonUp {w x y} {

    variable ::tk::Priv

    tk::CancelRepeat

    if {[info exists Priv(relief)]} {

	# Avoid error due to spurious release events

	$w configure -activerelief $Priv(relief)

	ScrollEndDrag $w $x $y

	$w activate [$w identify $x $y]

    }

}

# ::tk::ScrollSelect --

# 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 ::tk::ScrollSelect {w element repeat} {

    variable ::tk::Priv

    if {![winfo exists $w]} return

    switch -- $element {

	"arrow1"	{ScrollByUnits $w hv -1}

	"trough1"	{ScrollByPages $w hv -1}

	"trough2"	{ScrollByPages $w hv 1}

	"arrow2"	{ScrollByUnits $w hv 1}

	default		{return}

    }

    if {[string equal $repeat "again"]} {

	set Priv(afterId) [after [$w cget -repeatinterval] \

		[list tk::ScrollSelect $w $element again]]

    } elseif {[string equal $repeat "initial"]} {

	set delay [$w cget -repeatdelay]

	if {$delay > 0} {

	    set Priv(afterId) [after $delay \

		    [list tk::ScrollSelect $w $element again]]

	}

    }

}

# ::tk::ScrollStartDrag --

# 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 ::tk::ScrollStartDrag {w x y} {

    variable ::tk::Priv

    if {[string equal [$w cget -command] ""]} {

	return

    }

    set Priv(pressX) $x

    set Priv(pressY) $y

    set Priv(initValues) [$w get]

    set iv0 [lindex $Priv(initValues) 0]

    if {[llength $Priv(initValues)] == 2} {

	set Priv(initPos) $iv0

    } elseif {$iv0 == 0} {

	set Priv(initPos) 0.0

    } else {

	set Priv(initPos) [expr {(double([lindex $Priv(initValues) 2])) \

		/ [lindex $Priv(initValues) 0]}]

    }

}

# ::tk::ScrollDrag --

# 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 ::tk::ScrollDrag {w x y} {

    variable ::tk::Priv

    if {[string equal $Priv(initPos) ""]} {

	return

    }

    set delta [$w delta [expr {$x - $Priv(pressX)}] [expr {$y - $Priv(pressY)}]]

    if {[$w cget -jump]} {

	if {[llength $Priv(initValues)] == 2} {

	    $w set [expr {[lindex $Priv(initValues) 0] + $delta}] \

		    [expr {[lindex $Priv(initValues) 1] + $delta}]

	} else {

	    set delta [expr {round($delta * [lindex $Priv(initValues) 0])}]

	    eval [list $w] set [lreplace $Priv(initValues) 2 3 \

		    [expr {[lindex $Priv(initValues) 2] + $delta}] \

		    [expr {[lindex $Priv(initValues) 3] + $delta}]]

	}

    } else {

	ScrollToPos $w [expr {$Priv(initPos) + $delta}]

    }

}

# ::tk::ScrollEndDrag --

# 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 ::tk::ScrollEndDrag {w x y} {

    variable ::tk::Priv

    if {[string equal $Priv(initPos) ""]} {

	return

    }

    if {[$w cget -jump]} {

	set delta [$w delta [expr {$x - $Priv(pressX)}] \

		[expr {$y - $Priv(pressY)}]]

	ScrollToPos $w [expr {$Priv(initPos) + $delta}]

    }

    set Priv(initPos) ""

}

# ::tk::ScrollByUnits --

# 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 ::tk::ScrollByUnits {w orient amount} {

    set cmd [$w cget -command]

    if {[string equal $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}]

    }

}

# ::tk::ScrollByPages --

# 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 ::tk::ScrollByPages {w orient amount} {

    set cmd [$w cget -command]

    if {[string equal $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)}]

    }

}

# ::tk::ScrollToPos --

# 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 ::tk::ScrollToPos {w pos} {

    set cmd [$w cget -command]

    if {[string equal $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)}]

    }

}

# ::tk::ScrollTopBottom

# 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 ::tk::ScrollTopBottom {w x y} {

    variable ::tk::Priv

    set element [$w identify $x $y]

    if {[string match *1 $element]} {

	ScrollToPos $w 0

    } elseif {[string match *2 $element]} {

	ScrollToPos $w 1

    }

    # Set Priv(relief), since it's needed by tk::ScrollButtonUp.

    set Priv(relief) [$w cget -activerelief]

}

# ::tk::ScrollButton2Down

# 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 ::tk::ScrollButton2Down {w x y} {

    variable ::tk::Priv

    set element [$w identify $x $y]

    if {[string match {arrow[12]} $element]} {

	ScrollButtonDown $w $x $y

	return

    }

    ScrollToPos $w [$w fraction $x $y]

    set Priv(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

    ScrollStartDrag $w $x $y

}