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Scale(3)	      User Contributed Perl Documentation	      Scale(3)

NAME
       Tk::Scale - Create and manipulate Scale widgets

SYNOPSIS
       $scale =	$parent->Scale(?options?);

STANDARD OPTIONS
       -activebackground   -font     -highlightthickness -repeatinterval
       -background    -foreground    -orient   -takefocus
       -borderwidth   -highlightbackground     -relief	 -troughcolor
       -cursor	 -highlightcolor     -repeatdelay

       See Tk::options for details of the standard options.

WIDGET-SPECIFIC	OPTIONS
       Name:	 bigIncrement
       Class:	 BigIncrement
       Switch:	 -bigincrement
	   Some	interactions with the scale cause its value to change by
	   ``large'' increments;  this option specifies	the size of the	large
	   increments.	If specified as	0, the large increments	default	to
	   1/10	the range of the scale.

       Name:	 command
       Class:	 Command
       Switch:	 -command
	   Specifies the prefix	of a perl/Tk callback to invoke	whenever the
	   scale's value is changed via	a method.  The actual command consists
	   of this option followed by a	space and a real number	indicating the
	   new value of	the scale.

       Name:	 digits
       Class:	 Digits
       Switch:	 -digits
	   An integer specifying how many significant digits should be
	   retained when converting the	value of the scale to a	string.	 If
	   the number is less than or equal to zero, then the scale picks the
	   smallest value that guarantees that every possible slider position
	   prints as a different string.

       Name:	 from
       Class:	 From
       Switch:	 -from
	   A real value	corresponding to the left or top end of	the scale.

       Name:	 label
       Class:	 Label
       Switch:	 -label
	   A string to display as a label for the scale.  For vertical scales
	   the label is	displayed just to the right of the top end of the
	   scale.  For horizontal scales the label is displayed	just above the
	   left	end of the scale.  If the option is specified as an empty
	   string, no label is displayed.

       Name:	 length
       Class:	 Length
       Switch:	 -length
	   Specifies the desired long dimension	of the scale in	screen units
	   (i.e. any of	the forms acceptable to	Tk_GetPixels).	For vertical
	   scales this is the scale's height;  for horizontal scales it	is the
	   scale's width.

       Name:	 resolution
       Class:	 Resolution
       Switch:	 -resolution
	   A real value	specifying the resolution for the scale.  If this
	   value is greater than zero then the scale's value will always be
	   rounded to an even multiple of this value, as will tick marks and
	   the endpoints of the	scale.	If the value is	less than zero then no
	   rounding occurs.  Defaults to 1 (i.e., the value will be integral).

       Name:	 showValue
       Class:	 ShowValue
       Switch:	 -showvalue
	   Specifies a boolean value indicating	whether	or not the current
	   value of the	scale is to be displayed.

       Name:	 sliderLength
       Class:	 SliderLength
       Switch:	 -sliderlength
	   Specfies the	size of	the slider, measured in	screen units along the
	   slider's long dimension.  The value may be specified	in any of the
	   forms acceptable to Tk_GetPixels.

       Name:	 sliderRelief
       Class:	 SliderRelief
       Switch:	 -sliderrelief
	   Specifies the relief	to use when drawing the	slider,	such as	raised
	   or sunken.

       Name:	 state
       Class:	 State
       Switch:	 -state
	   Specifies one of three states for the scale:	 normal, active, or
	   disabled.  If the scale is disabled then the	value may not be
	   changed and the scale won't activate.  If the scale is active, the
	   slider is displayed using the color specified by the
	   activeBackground option.

       Name:	 tickInterval
       Class:	 TickInterval
       Switch:	 -tickinterval
	   Must	be a real value.  Determines the spacing between numerical
	   tick	marks displayed	below or to the	left of	the slider.  If	0, no
	   tick	marks will be displayed.

       Name:	 to
       Class:	 To
       Switch:	 -to
	   Specifies a real value corresponding	to the right or	bottom end of
	   the scale.  This value may be either	less than or greater than the
	   from	option.

       Name:	 variable
       Class:	 Variable
       Switch:	 -variable
	   Specifies the name of a global variable to link to the scale.
	   Whenever the	value of the variable changes, the scale will update
	   to reflect this value.  Whenever the	scale is manipulated
	   interactively, the variable will be modified	to reflect the scale's
	   new value.

       Name:	 width
       Class:	 Width
       Switch:	 -width
	   Specifies the desired narrow	dimension of the trough	in screen
	   units (i.e. any of the forms	acceptable to Tk_GetPixels).  For
	   vertical scales this	is the trough's	width;	for horizontal scales
	   this	is the trough's	height.

DESCRIPTION
       The Scale method	creates	a new window (given by the $widget argument)
       and makes it into a scale widget.  Additional options, described	above,
       may be specified	on the command line or in the option database to
       configure aspects of the	scale such as its colors, orientation, and
       relief.	The scale command returns its $widget argument.	 At the	time
       this command is invoked,	there must not exist a window named $widget,
       but $widget's parent must exist.

       A scale is a widget that	displays a rectangular trough and a small
       slider.	The trough corresponds to a range of real values (determined
       by the from, to,	and resolution options), and the position of the
       slider selects a	particular real	value.	The slider's position (and
       hence the scale's value)	may be adjusted	with the mouse or keyboard as
       described in the	"BINDINGS" section below.  Whenever the	scale's	value
       is changed, a Tcl command is invoked (using the command option) to
       notify other interested widgets of the change.  In addition, the	value
       of the scale can	be linked to a Tcl variable (using the variable
       option),	so that	changes	in either are reflected	in the other.

       Three annotations may be	displayed in a scale widget:  a	label
       appearing at the	top right of the widget	(top left for horizontal
       scales),	a number displayed just	to the left of the slider (just	above
       the slider for horizontal scales), and a	collection of numerical	tick
       marks just to the left of the current value (just below the trough for
       horizontal scales).  Each of these three	annotations may	be enabled or
       disabled	using the configuration	options.

WIDGET METHODS
       The Scale method	creates	a widget object.  This object supports the
       configure and cget methods described in Tk::options which can be	used
       to enquire and modify the options described above.  The widget also
       inherits	all the	methods	provided by the	generic	Tk::Widget class.

       The following additional	methods	are available for scale	widgets:

       $scale->coords(?value?)
	   Returns a list whose	elements are the x and y coordinates of	the
	   point along the centerline of the trough that corresponds to	value.
	   If value is omitted then the	scale's	current	value is used.

       $scale->get(?x, y?)
	   If x	and y are omitted, returns the current value of	the scale.  If
	   x and y are specified, they give pixel coordinates within the
	   widget;  the	command	returns	the scale value	corresponding to the
	   given pixel.	 Only one of x or y is used:  for horizontal scales y
	   is ignored, and for vertical	scales x is ignored.

       $scale->identify(x, y)
	   Returns a string indicating what part of the	scale lies under the
	   coordinates given by	x and y.  A return value of slider means that
	   the point is	over the slider;  trough1 means	that the point is over
	   the portion of the slider above  or to the left of the slider; and
	   trough2 means that the point	is over	the portion of the slider
	   below or to the right of the	slider.	 If the	point isn't over one
	   of these elements, an empty string is returned.

       $scale->set(value)
	   This	command	is invoked to change the current value of the scale,
	   and hence the position at which the slider is displayed.  Value
	   gives the new value for the scale.  The command has no effect if
	   the scale is	disabled.

BINDINGS
       Tk automatically	creates	class bindings for scales that give them the
       following default behavior.  Where the behavior is different for
       vertical	and horizontal scales, the horizontal behavior is described in
       parentheses.

       [1] If button 1 is pressed in the trough, the scale's value will	be
	   incremented or decremented by the value of the resolution option so
	   that	the slider moves in the	direction of the cursor.  If the
	   button is held down,	the action auto-repeats.

       [2] If button 1 is pressed over the slider, the slider can be dragged
	   with	the mouse.

       [3] If button 1 is pressed in the trough	with the Control key down, the
	   slider moves	all the	way to the end of its range, in	the direction
	   towards the mouse cursor.

       [4] If button 2 is pressed, the scale's value is	set to the mouse
	   position.  If the mouse is dragged with button 2 down, the scale's
	   value changes with the drag.

       [5] The Up and Left keys	move the slider	up (left) by the value of the
	   resolution option.

       [6] The Down and	Right keys move	the slider down	(right)	by the value
	   of the resolution option.

       [7] Control-Up and Control-Left move the	slider up (left) by the	value
	   of the bigIncrement option.

       [8] Control-Down	and Control-Right move the slider down (right) by the
	   value of the	bigIncrement option.

       [9] Home	moves the slider to the	top (left) end of its range.

       [10]
	   End moves the slider	to the bottom (right) end of its range.

	   If the scale	is disabled using the state option then	none of	the
	   above bindings have any effect.

	   The behavior	of scales can be changed by defining new bindings for
	   individual widgets or by redefining the class bindings.

KEYWORDS
       scale, slider, trough, widget

perl v5.24.1			  2015-01-31			      Scale(3)

NAME | SYNOPSIS | STANDARD OPTIONS | WIDGET-SPECIFIC OPTIONS | DESCRIPTION | WIDGET METHODS | BINDINGS | KEYWORDS

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