SCALE(9)                                                 SCALE(9)

     NAME
          scale - Create and manipulate scale widgets

     SYNOPSIS
          scale pathName ?options?

     STANDARD OPTIONS
          -activebackground -font               -orient
          -background       -foreground         -relief
          -borderwidth      -highlightcolor     -takefocus
          -disabledcolor    -highlightthickness

     WIDGET-SPECIFIC OPTIONS
          -bigincrement dist
               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 Tk 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.

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

          -height dist
               Specifies a desired height for the scale.  If this
               option isn't specified, the scale is given a default
               height.

          -label string
               A string to display as a label for the scale. If the
               option is specified as an empty string, no label is
               displayed.

          -resolution frac
               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 inte-
               gral).

     SCALE(9)                                                 SCALE(9)

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

          -sliderlength dist
               Specfies the size of the slider along the slider's long
               dimension..

          -sliderrelief relief
               Specifies the relief to use when drawing the slider.

          -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 won't activate.
               If the scale is active, the slider is displayed using
               the colour specified by the activebackground option.

          -tickinterval frac
               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 frac
               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.

          -width dist
               Specifies a desired width for the scale.  If this
               option isn't specified, the scale is given a default
               width.

     DESCRIPTION
          The scale command creates a new window (given by the path-
          Name argument) and makes it into a scale widget.  Additional
          options, described above, may be specified on the command
          line to configure aspects of the scale such as its colours,
          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.

          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 Tk command is invoked (using the command option)
          to notify other interested widgets of the change.

     SCALE(9)                                                 SCALE(9)

          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 right
          of the trough (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 Tk command whose name is
          pathName.  This command may be used to invoke various opera-
          tions on the widget.  It has the following general form:
               pathName option ?arg arg ...?
          Option and the args determine the exact behaviour of the
          command.  The following commands are possible for scale wid-
          gets:

          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 wid-
               get.  If no option is specified, returns a list of all
               of the available options for pathName.  If one or more
               option-value pairs are specified, then the command mod-
               ifies 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 coordi-
               nates of the point along the centreline 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;

     SCALE(9)                                                 SCALE(9)

               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 bindings for scales that give them
          the following default behaviour.  Where the behaviour is
          different for vertical and horizontal scales, the horizontal
          behaviour 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
               bigincrement 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 the widget receives Up-arrow or Left-arrow key
               events, the scale's value will be incremented or decre-
               mented so as to adjust the value towards the fromvalue.

          [4]  If the widget receives Down-arrow or Right-arrow key
               events, the scale's value will be incremented or decre-
               mented so as to adjust the value towards the tovalue.

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

          The behaviour of scales can be changed by defining new bind-
          ings for individual widgets.

     SEE ALSO
          options(9), types(9)