
     slider
        A slider lets the user choose a value  from  a  range  of
        integer or floating point values. Syntax:

        slider={ label=... value=... name=... action=...  min=...
        max=... format=... width=... height=... }

        A slider object has a label, a slider and  a  text  field
        that  displays the current slider value, and an "OK" but-
        ton to allow the user to trigger the slider's action.
        name defaults to "slider1", "slider2" etc. label  appears
        above  the  slider.   value is the starting value for the
        slider; defaults to  the  minimum.   action:  For  action
        types  SYSTEM  and  PRINT the action occurs when the "ok"
        button is pressed. For  action  type  STRING  the  action
        occurs when the slider position changes.

        Assigning a new value to  a  slider  changes  the  slider
        position  to match the new value. If the new value string
        is not a number (as interpreted by the routine  atof()  )
        the slider will be set to zero.

        min is the minimum value for the slider; defaults  to  0.
        max is the maximum value for the slider; defaults to 1.

        format is the format with which the slider label and  its
        internal  string  will  be  printed.  The slider value is
        stored internally as a floating point number; the default
        value  for format is %f, which prints the value with five
        decimal places.  You  can  specify  a  different  format,
        according  to the format specification for the C program-
        ming language. To obtain in integer-only  slider,  use  a
        format  of  %.0f  (the  0  indicates  no digits after the
        decimal point).

        width and height are the lengths of the major  and  minor
        axes of the slider. By default, sliders are oriented hor-
        izontally.  This can be changed by using the  orientation
        parameter described below in the MISCELLANEOUS PARAMETERS
        section.

        The OK button of a  slider  is  omitted  if  all  of  its
        actions  are  of  type  STRING  or  NONE. Actions of type
        STRING and NONE automatically  take  place  whenever  the
        slider  is  moved,  so there is no need for the button in
        these cases.

        example
        slider={  label=Velocity  min=1000  max=4000   value=2000
        format=%4.0f }

     scrollbar
        A scrollbar object is similar to a slider, except that it
        has no label or ok button. A scrollbar's actions are per-
        formed whenever the scrollbar is changed.  (This  may  be
        more  often than you would like. It may be better to sup-
        ply a separate button that acts based on the  scrollbar's
        value, rather than having the scrollbar act on its own.)

