2. EL 6 ELS
  3. tk
  4. scale(n)

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scale(n) Tk Built-In Commands scale(n) 





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


[-bigincrement 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
    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. [-digits
    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. [-from from] A real
    value corresponding to the left or top end of the scale.
    [-label 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. [-length
    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. [-resolution
    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).
    [-showvalue showValue] Specifies a
    boolean value indicating whether or not the current value of the scale is to
    be displayed. [-sliderlength
    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.
    [-sliderrelief sliderRelief] Specifies
    the relief to use when drawing the slider, such as raised or
    sunken. [-state 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 will not activate. If the scale is active, the slider
    is displayed using the color specified by the activeBackground
    option. [-tickinterval 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. [-to 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.
    [-variable 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. [-width 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:


  

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

  

  
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.

  

  
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.

  

  
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.

  

  
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 is
      not over one of these elements, an empty string is returned.

  

  
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







  

    4.1
    Tk