A gauge is a horizontal or vertical bar for displaying the output
value of a bounded integer quantity. Each gauge has an adjustable
range, and the gauge’s current value is always between 0 and its
range, inclusive. Use set-value
to set the value
of the gauge.
If label is a string, it is used as the gauge label; otherwise
the gauge does not display a label.
If & occurs in label, it is specially parsed;
under Windows and X, the character
following & is underlined in the displayed control to
indicate a keyboard mnemonic. (Under Mac OS, mnemonic underlines are
not shown.) The mnemonic is meaningless for a gauge (as far as
on-traverse-char in top-level-window<%> is concerned),
but it is supported for consistency with other control types. A
programmer may assign a meaning to the mnemonic (e.g., by overriding
The range argument is an integer specifying the maximum value of
the gauge (inclusive). The minimum gauge value is always 0.
The style list must include either 'horizontal,
specifying a horizontal gauge, or 'vertical, specifying a vertical
gauge. If style includes 'vertical-label, then the gauge is
created with a label above the control; if style does not include
'vertical-label (and optionally includes 'horizontal-label), then the
label is created to the left of the gauge. If style includes 'deleted, then the gauge is created as hidden,
and it does not affect its parent’s geometry; the gauge can be made active later by calling
parent’s add-child method.
The font argument determines the font for the control. For information about the enabled argument, see window<%>. For information about the horiz-margin and vert-margin
arguments, see subarea<%>. For information about the
min-width, min-height, stretchable-width, and
stretchable-height arguments, see area<%>.
Returns the range (maximum value) of the gauge.
Returns the gauge’s current value.
Sets the range (maximum value) of the gauge.
Sets the gauge’s current value. If the specified value is larger than
the gauge’s range, an exn:fail:contract
exception is raised.