3.39  radio-box%

Implements: control<%>

A radio-box% control allows the user to select one of number of mutually exclusive items. The items are displayed as a vertical column or horizontal row of labelled radio buttons. Unlike a list-control<%>, the set of items in a radio-box% cannot be changed dynamically.

Whenever the user changes the selected radio button, the radio box's callback procedure is invoked. A callback procedure is provided as an initialization argument when each radio box is created.

• (new radio-box% (label _) (choices _) (parent _) [(callback _)] [(style _)] [(selection _)] [(font _)] [(enabled _)] [(vert-margin _)] [(horiz-margin _)] [(min-width _)] [(min-height _)] [(stretchable-width _)] [(stretchable-height _)]) -> radio-box% object
     label : string (up to 200 characters) or #f
   choices : list of strings (up to 200 characters each) or bitmap% objects
     parent : frame%, dialog%, panel%, or pane% object
     callback = (lambda (rb e) (void)) : procedure of two arguments: a radio-box% object and a control-event% object
     style = '(vertical) : list of symbols in '(horizontal vertical vertical-label horizontal-label deleted)
   selection = 0 : exact non-negative integer
     font = normal-control-font : font% object
     enabled = #t : boolean
     vert-margin = 2 : exact integer in [0, 1000]
     horiz-margin = 2 : exact integer in [0, 1000]
     min-width = graphical minimum width : exact integer in [0, 10000]
     min-height = graphical minimum height : exact integer in [0, 10000]
     stretchable-width = #f : boolean
     stretchable-height = #f : boolean

  Creates a radio button set with string or bitmap labels. The choices list specifies the radio button labels; the list of choices must be homogeneous, either all strings or all bitmaps.

  If an ampersand (``&'') occurs in label, it is specially parsed; under Windows and X, the character following an ampersand is underlined in the displayed control to indicate a keyboard mnemonic. (Under Mac OS X, mnemonic underlines are not shown.) The underlined mnemonic character must be a letter or a digit. The user can move the keyboard focus to the radio box by typing the mnemonic when the control's top-level-window contains the keyboard focus. The user must also hold down the Meta or Alt key if the keyboard focus is currently in a control that handles normal alphanumeric input. The ampersand itself is removed from label before it is displayed for the control; a double-ampersand in label is converted to a single ampersand (with no mnemonic underlining). Under Mac OS X, a parenthesized mnemonic character is removed (along with any surrounding space) before the label is displayed, since a parenthesized mnemonic is often used for non-Roman languages. Finally, any text after a tab character is removed on all platforms. Mnemonic keyboard events are handled by on-traverse-char (but not under Mac OS X).

  Each string in choices can also contain an ampersand, which creates a mnemonic for clicking the corresponding radio button. As for label, a double ampersand is converted to a single ampersand.

  If choices is a list of bitmaps, then the bitmaps 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 label is a string, it is used as the label for the radio box. Otherwise, the radio box does not display its label.

  The callback procedure is called (with the event type 'radio-box) when the user changes the radio button selection.

  The style argument must include either 'vertical for a collection of radio buttons vertically arranged, or 'horizontal for a horizontal arrangement. If style includes 'vertical-label, then the radio box 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 radio box. If style includes 'deleted, then the radio box is created as hidden, and it does not affect its parent's geometry; the radio box can be made active later by calling parent's add-child method.

  By default, the first radio button is initially selected. If selection is positive, it is passed to set-selection to set the initial radio button selection.

  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<%>.

  
  

Methods
    enable
    get-item-label
    get-item-plain-label
    get-number
    get-selection
    is-enabled?
    set-selection

All Methods
    accept-drop-files from window<%>
    client->screen from window<%>
    command from control<%>
    enable from radio-box%
        overrides enable from window<%>
    focus from window<%>
    get-client-size from window<%>
    get-cursor from window<%>
    get-font from control<%>
    get-graphical-min-size from area<%>
    get-handle from window<%>
    get-height from window<%>
    get-item-label from radio-box%
    get-item-plain-label from radio-box%
    get-label from window<%>
    get-number from radio-box%
    get-parent from area<%>
    get-plain-label from window<%>
    get-selection from radio-box%
    get-size from window<%>
    get-top-level-window from area<%>
    get-width from window<%>
    get-x from window<%>
    get-y from window<%>
    has-focus? from window<%>
    horiz-margin from subarea<%>
    is-enabled? from radio-box%
        overrides is-enabled? from window<%>
    is-shown? from window<%>
    min-height from area<%>
    min-width from area<%>
    on-drop-file from window<%>
    on-focus from window<%>
    on-move from window<%>
    on-size from window<%>
    on-subwindow-char from window<%>
    on-subwindow-event from window<%>
    on-superwindow-enable from window<%>
    on-superwindow-show from window<%>
    popup-menu from window<%>
    refresh from window<%>
    screen->client from window<%>
    set-cursor from window<%>
    set-label from window<%>
    set-selection from radio-box%
    show from window<%>
    stretchable-height from area<%>
    stretchable-width from area<%>
    vert-margin from subarea<%>