Widget (n) - Linux Manuals

Widget: base class for mega-widgets within a frame


Widget - base class for mega-widgets within a frame


itk::Archetype <- itk::Widget


background  cursor

See the "options" manual entry for details on the standard options.


The Widget class inherits everything from the Archetype class, and adds a Tk frame called the "hull" component to represent the body of the mega-widget. The window class name for the hull is set to the most-specific class name for the mega-widget. The protected variable itk_interior contains the window path name for the "hull" component. Derived classes specialize this widget by packing other widget components into the hull.

Since the hull for the Widget class is implemented with a Tk frame, mega-widgets in the Widget class can be packed into other frames and toplevels.


Name:   hull
Class:  Frame
The "hull" component acts as the body for the entire mega-widget. Other components are packed into the hull to further specialize the widget.


The following example implements a simple TextDisplay mega-widget. It creates a read-only display of text with a text widget and a scrollbar.

option add *TextDisplay.wrap none widgetDefault
option add *TextDisplay.textBackground ivory widgetDefault
option add *TextDisplay.width 40 widgetDefault
option add *TextDisplay.height 10 widgetDefault

itcl::class TextDisplay {
    inherit itk::Widget

    constructor {args} {
        itk_component add text {
            text $itk_interior.info -state disabled                 -yscrollcommand [code $itk_interior.sbar set]
        } {
            keep -tabs -wrap -width -height
            rename -background -textbackground textBackground Background
        pack $itk_component(text) -side left -expand yes -fill both

        itk_component add scrollbar {
            scrollbar $itk_interior.sbar                 -command [code $itk_interior.info yview]
        pack $itk_component(scrollbar) -side right -fill y

        eval itk_initialize $args

    public method display {info}
    public method append {info}

itcl::body TextDisplay::display {info} {
    $itk_component(text) configure -state normal
    $itk_component(text) delete 1.0 end
    $itk_component(text) insert 1.0 $info
    $itk_component(text) configure -state disabled

itcl::body TextDisplay::append {info} {
    $itk_component(text) configure -state normal
    $itk_component(text) insert end $info
    $itk_component(text) configure -state disabled

itk::usual TextDisplay {
    keep -background -cursor -foreground -font
    keep -activebackground -activerelief
    keep -highlightcolor -highlightthickness
    keep -insertbackground -insertborderwidth -insertwidth
    keep -insertontime -insertofftime
    keep -selectbackground -selectborderwidth -selectforeground
    keep -textbackground -troughcolor

# EXAMPLE:  Display the /etc/passwd file
TextDisplay .file -background red
pack .file

.file display [exec cat /etc/passwd]


itk, Archetype, Widget, mega-widget