Tk (computing)

From Wikipedia, the free encyclopedia

Tk
Latest release: 8.4.14 / October 19, 2006
OS: Cross-platform
Use: 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 Tk Tile is due to be 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 still uses bitmap fonts and not the anti-aliased fonts, so applications have an '80s look to them.

Contents

[edit] History

Tk was developed by John Ousterhout as an extension for the Tcl scripting language. Bindings exist for several other languages, including Perl, Python, Ruby, and Common Lisp. Tk versioning was done separately from Tcl until version 8.0.

There are two ways to use Tk from Perl: the Tcl::Tk Perl module, which uses Tcl as a bridge (this approach provides more flexibility), and Perl/Tk, which has Tcl stripped away (only adopted Tcl/Tk extensions are available). The Python and Ruby bindings also use Tcl as a bridge for Tk.

[edit] 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 and since wish has been ported to multiple platforms, Tk can easily run on all those platforms without modification.
  • Customisable: Almost all of the features of a widget in Tk are customisable though options during the creation of the widget or later on through the configure command. Although the defaults are generally well chosen, a programmer can configure widgets to his/her heart's content.
  • Configurable: A lot of the options are can be stored in an option database making it very easy to parameterize the looks 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.

[edit] 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).

[edit] Some Examples

Hello, World! example:

button .b -text "Hello, World!" -command exit
pack .b

Button

button .b -text "Button" -command "exit"

Label

label .l -text "Label" -foreground Yellow -background Blue -font {-family times -size 24}

Check Buttons

checkbutton .c1 -text Bold -variable bold   -anchor w

Radio Buttons

radiobutton .r1 -text Helvetica -variable font -value helvetica

Entry

entry .e -width 40 -relief sunken -bd 2 -textvariable name

Canvas

canvas .c -width 250 -height 100

List Box

listbox .l -yscroll ".s set"

Scale

scale .scale -orient vertical -length 284 -from 0 -to 250 -tickinterval 50 -command "setHeight .canvas"

tk_messageBox

tk_messageBox -icon question -type yesno -title Message -parent . -message "Do you like me so far?"

tk_getOpenFile

tk_getOpenFile -filetypes $types -parent .

tk_chooseColor

tk_chooseColor -title "Choose a background color" -parent .

Text

text .t -yscrollcommand ".scroll set" -setgrid true -width 40 -height 10 -wrap word

Menu

menu .frame.file.m
.file.m add command -label "Exit" -command exit

menubutton

menubutton .file -text "File" -menu .frame.file.m

cursor

cursor ???

image

image create photo -file [file join images fun.gif]

bitmaps

bitmaps ???

[edit] See also

[edit] External links

[edit] Generic Tk and Tcl/Tk

[edit] Perl/Tk

[edit] Python/Tk

  • TkInter is a thin object-oriented layer on top of Tcl/Tk

[edit] Ruby/Tk

[edit] Common Lisp/Tk

  • LTK LTK, the Lisp ToolKit. Tk interface (through tcl) for Common Lisp
Retrieved from "http://en.wikipedia.org../../../t/k/_/Tk_%28computing%29.html"