check-box% : class?

superclass: object%

extends:  control<%>

A check box is a labeled box which is either checked or unchecked.

Whenever a check box is clicked by the user, the check box’s value is toggled and its callback procedure is invoked. A callback procedure is provided as an initialization argument when each check box is created.

(new check-box%   [label label]       [parent parent]      [ [callback callback]       [style style]       [value value]       [font font]       [enabled enabled]       [vert-margin vert-margin]       [horiz-margin horiz-margin]       [min-width min-width]       [min-height min-height]       [stretchable-width stretchable-width]       [stretchable-height stretchable-height]])

→ (is-a?/c check-box%)

label : (or/c label-string? (is-a?/c bitmap%))

parent   :   (or/c (is-a?/c frame%) (is-a?/c dialog%)       (is-a?/c panel%) (is-a?/c pane%))

callback   :   ((is-a?/c check-box%) (is-a?/c control-event%) . -> . any)       =   (lambda (c e) (void))

style : (listof (one-of/c 'deleted)) = null

value : any/c = #f

font : (is-a?/c font%) = (scheme normal-control-font)

enabled : any/c = #t

vert-margin : (integer-in 0 1000) = 2

horiz-margin : (integer-in 0 1000) = 2

min-width : (integer-in 0 10000) = graphical-minimum-width

min-height : (integer-in 0 10000) = graphical-minimum-height

stretchable-width : any/c = #f

stretchable-height : any/c = #f

Creates a check box with a string or bitmap label. If label is a bitmap, then the bitmap must be valid (see ok? in bitmap%) and not installed in a bitmap-dc% object; otherwise, an exn:fail:contract exception is raised. If the bitmap has a mask (see get-loaded-mask in bitmap%) that is the same size as the bitmap, then the mask is used for the label; furthermore, in contrast to the limitations of draw-bitmap in dc<%>, non-monochrome label masks work consistently on all platforms.

If & occurs in label (when label is a string), it is specially parsed as for button%.

The callback procedure is called (with the event type 'check-box) whenever the user clicks the check box.

If style includes 'deleted, then the check box is created as hidden, and it does not affect its parent’s geometry; the check box can be made active later by calling parent’s add-child method.

If value is true, it is passed to set-value so that the box is initially checked.

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<%>.

(send a-check-box get-value) → boolean?

Gets the state of the check box: #t if it is checked, #f otherwise.

(send a-check-box set-label label) → void?

label : (or/c label-string? (is-a?/c bitmap%))

Overrides set-label in window<%>.

The same as set-label in window<%> when label is a string.

Otherwise, sets the bitmap label for a bitmap check box. Since label is a bitmap, the bitmap must be valid (see ok? in bitmap%) and not installed in a bitmap-dc% object; otherwise, an exn:fail:contract exception is raised. If the bitmap has a mask (see get-loaded-mask in bitmap%) that is the same size as the bitmap, then the mask is used for the label; furthermore, in contrast to the limitations of draw-bitmap in dc<%>, non-monochrome label masks work consistently on all platforms. The bitmap label is installed only if the control was originally created with a bitmap label.

(send a-check-box set-value state) → void?

state : any/c

Sets the check box’s state. (The control’s callback procedure is not invoked.)

The check box’s state can be changed by the user clicking the control, and such changes do not go through this method; use the controlcallback procedure (provided as an initialization argument) to monitor state changes.

If state is #f, the box is unchecked, otherwise it is checked.