### 3.2 Barmenus ¶

A `barmenu` displays a bar graph whose size can be adjusted using the mouse.

`(barmenu-create maxval initval barwidth`
`&optional title horizontal subtrackfn subtrackparms`
`parentw x y perm flat color)`

A value is selected by: `(barmenu-select m:barmenu &optional inside)`
If the `barmenu` is not `flat`, its window should be destroyed following the selection using `menu-destroy`.

The user must first click the mouse in the bar area; then the size of the displayed bar is adjusted as the user moves the mouse pointer. In addition, the `subtrackfn` is called with arguments of the size of the bar followed by the `subtrackparms`; this can be used, for example, to display a numeric value in addition to the bar size.