Mega-widgets are high-level widgets that are constructed using Tk widgets as component parts, usually without any C code. A fileselectionbox, for example, may have a few listboxes, some entry widgets and some control buttons. These individual widgets are put together in a way that makes them act like one big widget. A fileselectionbox mega-widget can be created with a command like:
fileselectionbox .fsb -background blue -foreground whiteOnce it has been created, it can be reconfigured with a command like:
.fsb configure -background green -foreground blackand all of its internal components will change color. Each mega-widget has a set of methods that can be used to manipulate it. For example, the current selection can be queried from a fileselectionbox like this:
set fileName [.fsb get]In effect, a mega-widget looks and acts exactly like a Tk widget, but is considerably easier to implement.
[incr Tk] is a framework for building mega-widgets. It uses [incr Tcl] to support the object paradigm, and adds base classes which provide default widget behaviors.
All [incr Tk] widgets are derived from the Archetype base class. This class manages internal component widgets, and provides methods like "configure" and "cget" to access configuration options.
The Widget base class inherits everything from Archetype, and adds a Tk frame which acts as a container for the mega-widget. It is used to build mega-widgets that sit inside of other frames and toplevels. Derived classes create other internal components and pack them into the "hull" frame created by the Widget base class.
The Toplevel base class inherits everything from Archetype, but adds a Tk toplevel which acts as a container for the mega-widget. It is used to build mega-widgets, such as dialog boxes, that have their own toplevel window. Derived classes create other internal components and pack them into the "hull" toplevel created by the Toplevel base class.
[incr Widgets] is a mega-widget library built using [incr Tk]. It can be used right out of the box, and contains more than 30 different widget classes, including:
The catalog demo in the "iwidgets/demos" directory shows all of the available widgets in action. Each widget class has its own man page describing the features available.