Ubuntu Manpage: scale - Create and manipulate scale widgets

NAME

       scale - Create and manipulate scale widgets

SYNOPSIS

       scale pathName ?options?

STANDARD OPTIONS

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

       See the options manual entry for details on the standard options.

WIDGET-SPECIFIC OPTIONS

Command-Line Name:-bigincrement
Database Name: bigIncrement
Database Class: 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.

Command-Line Name:-command
Database Name: command
Database Class: Command

Specifies the prefix of a Tcl command to invoke whenever the scale's value is changed via a widget
command. The actual command consists of this option followed by a space and a real number
indicating the new value of the scale.

Command-Line Name:-digits
Database Name: digits
Database Class: 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.

Command-Line Name:-from
Database Name: from
Database Class: From

A real value corresponding to the left or top end of the scale.

Command-Line Name:-label
Database Name: label
Database Class: 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.

Command-Line Name:-length
Database Name: length
Database Class: 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.

Command-Line Name:-resolution
Database Name: resolution
Database Class: 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).

Command-Line Name:-showvalue
Database Name: showValue
Database Class: ShowValue

Specifies a boolean value indicating whether or not the current value of the scale is to be
displayed.

Command-Line Name:-sliderlength
Database Name: sliderLength
Database Class: SliderLength

Specifies 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.

Command-Line Name:-sliderrelief
Database Name: sliderRelief
Database Class: SliderRelief

Specifies the relief to use when drawing the slider, such as raised or sunken.

Command-Line Name:-state
Database Name: state
Database Class: 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.

Command-Line Name:-tickinterval
Database Name: tickInterval
Database Class: 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.

Command-Line Name:-to
Database Name: to
Database Class: 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.

Command-Line Name:-variable
Database Name: variable
Database Class: 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.

Command-Line Name:-width
Database Name: width
Database Class: 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 command creates a new window (given by the pathName 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 pathName argument. At the time this command is invoked, there must not exist a window named
pathName, but pathName'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 COMMAND

The scale command creates a new Tcl command whose name is pathName. This command may be used to invoke
various operations on the widget. It has the following general form:
pathName option ?arg arg ...?
Option and the args determine the exact behavior of the command. The following commands are possible for
scale widgets:

pathName cget option
Returns the current value of the configuration option given by option. Option may have any of the
values accepted by the scale command.

pathName configure ?option? ?value option value ...?
Query or modify the configuration options of the widget. If no option is specified, returns a
list describing all of the available options for pathName (see Tk_ConfigureInfo for information on
the format of this list). If option is specified with no value, then the command returns a list
describing the one named option (this list will be identical to the corresponding sublist of the
value returned if no option is specified). If one or more option-value pairs are specified, then
the command modifies the given widget option(s) to have the given value(s); in this case the
command returns an empty string. Option may have any of the values accepted by the scale command.

pathName 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.

pathName 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.

pathName 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.

pathName 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

Tk                                                     4.1                                            scale(3tk)