Version 33 of What is a Megawidget

Updated 2005-11-03 19:56:09

Purpose: collect information and pointers to what megawidgets are, how to write them, etc.


Occasionally these have been called meta-widgets rather than megawidgets.


A mega widget is NOT an attempt to create new, unique, widgets. Instead, it is an effort to combine existing widgets in ways that are commonly needed (or at the very least interesting to the person who is writing the megawidget). - RS: Note that in contrast to megawatts or megabytes, a megawidget is not worth a million widgets ;-)

Not really knowing too much about the Tk side of things, is a megawidget analogous to a UIPattern? [L1 ]


See also Composite fields megawidgets.

See Adding User Data to Widgets the Megawidget Way.

Steve Uhler's 1996 Tcl workshop presentation slides on the search for the perfect megawidget can be found at http://www.usenix.org/publications/library/proceedings/tcl96/uhler.html

Chengye Mao mailto:[email protected] has a web page which discusses building combined widgets (aka mega widgets) in pure Tcl at http://www.geocities.com/%7Echengye/comb.html .

Creating a BWidget Widget talks about what it takes to write another Bwidget widget - sort of a similar topic. Also see Enhancing BWidget, which talks about how to get more bang out of using bwidget widgets.


escargo 16 Jan 2004 - In a recently modified page, A scrolled frame, it was mentioned that the scrolledframe megawidget, since its used the grid geometry manager, can only be within a parent that also uses the grid geometry manager. What are the ways that a megawidget can be queried to determine which geometry manager it can be used with? Is this an Introspection issue?

ulis, 2005-10-30. For most (all?) megawidgets the parent geometry manager doesn't matter. In the case you mention, a wrapper was built for a megawidget, adding scrollbars at the parent level and using the grid manager for that. This only works if the parent wasn't already using the pack manager. Hence the warning for the use of the wrapper, not for the use of the megawidget.

I think that most megawidgets are isolated inside a frame so you can use them as any normal widget without worring about the parent geometry manager.


Here are some megawidget frameworks (in other words, code designed to make it easier to build megawidgets). Please add to the following list.

 What: [incr Tk] Slate megawidget
 Where: http://ptolemy.eecs.berkeley.edu/%7Ejohnr/archives/code/slate/
 Description: The Slate is an [incr Tcl] megawidget layered over the Tcl/Tk
        canvas.  It contains visual hierarchy, symbolic item aspects and
        interaction support.  Release 3.0alpha supports
        Tcl 8.0 or [incr Tcl] 3.0.
 Updated: 07/1998
 Contact: mailto:[email protected] (John Reekie)
 What: Pmw
 Where: http://www.dscpl.com.au/pmw/
        ftp://ftp.dscpl.com.au/pub/pmw/Pmw.0.8.tar.gz
        http://www.dejanews.com/getdoc.xp?AN=423519318
        http://pmwcontribd.sourceforge.net/
 Description: A megawidget framework for constructing high-level
        compound widgets in Python 1.5.2 using Tk 8.x. Contains of a set of
        base classes for building megawidgets and a library of
        megawidgets such as ComboBox, Dialog, ButtonBox, etc. Also
        contains a python interface to BLT2.1's busy, graph and vector
        commands. The PmwContribD web site provides several Pmw based Tkinter
        widgets, including a ProgressMeter, basic TreeNavigator, and a GUI
        application framework for creating simple GUI apps quickly.
 Updated: 10/1999
 Contact: mailto:[email protected] (Greg McFarlane)
        mailto:[email protected] (Doug Hellmann)

Category GUI