Tk (framework)

Infobox Software
name = Tk



caption =
developer =
latest release version = 8.5.4
latest release date = release date|2008|08|15
latest preview version =
latest preview date =
operating system = Cross-platform
platform = Cross-platform
genre = widget toolkit
license = open source
website = http://www.tcl.tk

Tk is an open source, cross-platform widget toolkit, that is, a library of basic elements for building a graphical user interface (GUI).

Tk provides a number of widgets commonly needed to develop desktop applications such as button, menu, canvas, text, frame, label etc. Tk has been ported to run on most flavors of Linux, Apple Macintosh, Unix, and Windows. Since Tcl/Tk 8, it offers "native look and feel" (for instance, menus and buttons are displayed in the manner of "native" software for any given platform). Also, there are several extensions to provide external drag-and-drop, non-rectangular windows, and native widgets. A new theming engine called [http://tktable.sourceforge.net/tile/ Tk Tile] is included in the 8.5 release. Like Tcl, Tk supports Unicode within the Basic Multilingual Plane but it has not yet been extended to handle 32-bit Unicode. On *nix systems, Tk 8.4 and below still use bitmap fonts, but Tk 8.5 uses anti-aliased fonts.

History

Tk was developed by John Ousterhout as an extension for the Tcl scripting language. Bindings exist for several other languages, including Ada (called [http://tcladashell.sourceforge.net/ TASH] ), Perl, Python, Ruby, and Common Lisp. Tk versioning was done separately from Tcl until version 8.0.

There are several ways to use Tk from Perl: the Tcl::Tk and Tkx Perl modules, both of which use Tcl as a bridge to access Tk, and Perl/Tk, which provides native Perl access to Tk structures. The Python and Ruby bindings use Tcl as a bridge to Tk.

Architecture

Tk is a platform independent GUI framework for Tcl. Although Tk can be loaded from Tcl shell (tclsh) by a package require Tk command, it is common to invoke it from the wish (Windowing Shell). It has the following characteristics:

* Platform independent: Like Tcl, Tk is interpreted. It has been ported to multiple platforms and can easily run on all of them without modification.

* Customizable: Almost all of the features of a widget in Tk are customizable though options during the creation of the widget or later on through the configure command.

* Configurable: A lot of the options can be stored in an option database making it very easy to parameterize the look of an application (such as the color scheme). This also means that storing the application-specific options is only a matter of saving the option add commands and executing them on loading the application.

Features

Tk provides the following widgets:
*button
*canvas
*checkbutton
*entry
*frame
*label
*labelframe
*listbox
*menu
*menubutton
*message
*tk_optionMenu
*panedwindow
*radiobutton
*scale
*scrollbar
*spinbox
*text

as well as the following top-level windows:
*tk_chooseColor - pops up a dialog box for the user to select a color.
*tk_chooseDirectory - pops up a dialog box for the user to select a directory.
*tk_dialog - Create modal dialog and wait for response
*tk_getOpenFile - pop up a dialog box for the user to select a file to open or save.
*tk_messageBox - pops up a message window and waits for user response.
*tk_popup - Post a popup menu
*toplevel - Create and manipulate toplevel widgets

Tk also provides three geometry managers:

*place - which positions widgets at absolute locations
*grid - which arranges widgets in a grid
*pack - which packs widgets into a cavity

The most unusual and versatile features of Tk are its canvas and text widgets, which provide capabilities found in few if any other widget toolkits.

Object oriented widgets are available with incr Tk and Iwidgets. There are many other useful widgets built on top of Tk such as TkTreeCtrl, BLT (toolkit), Tix Mega-Widgets and TSIPP (a 3D Graphics Toolkit).

See also

* Expect
* Widget toolkit
* Tkinter - a Tk binding for Python
* Itk
* Itcl
* GTK+ - The GIMP Toolkit
* Qt
* wxWidgets

External links

* [http://www.tcl.tk/ Tcl and Tk website]
* [http://aspn.activestate.com/ASPN/docs/ActiveTcl/8.4/tcl/tk_contents.htm Tk 8.4 manual]
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