A Scrollbar Widget's Arguments
The scrollbar 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 scrollbar widgets:
- 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 scrollbar
- pathName :get
- Returns a Tcl list containing four decimal values, which are
the current totalUnits, widnowUnits, firstUnit,
and lastUnit values for the scrollbar. These are the values
from the most recent set widget command on the scrollbar.
- pathName :set totalUnits windowUnits firstUnit lastUnit
- This command is invoked to give the scrollbar information about the
widget associated with the scrollbar. TotalUnits is an integer
value giving the total size of the object being displayed in the
associated widget. The meaning of one unit depends on the associated
widget; for example, in a text editor widget units might
correspond to lines of
text. WindowUnits indicates the total number of units that
can fit in the associated window at one time. FirstUnit
and lastUnit give the indices of the first and last units
currently visible in the associated window (zero corresponds to the
first unit of the object). This command should
be invoked by the associated widget whenever its object or window
changes size and whenever it changes the view in its window.