button − Create and manipulate ’button’ action widgets


button pathName ?options?




























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


Command-Line Name:−command

Database Name:


Database Class:


Specifies a Tcl command to associate with the button. This command is typically invoked when mouse button 1 is released over the button window.

Command-Line Name:−default

Database Name:


Database Class:


Specifies one of three states for the default ring: normal, active, or disabled. In active state, the button is drawn with the platform specific appearance for a default button. In normal state, the button is drawn with the platform specific appearance for a non-default button, leaving enough space to draw the default button appearance. The normal and active states will result in buttons of the same size. In disabled state, the button is drawn with the non-default button appearance without leaving space for the default appearance. The disabled state may result in a smaller button than the active state.

Command-Line Name:−height

Database Name:


Database Class:


Specifies a desired height for the button. If an image or bitmap is being displayed in the button then the value is in screen units (i.e. any of the forms acceptable to Tk_GetPixels); for text it is in lines of text. If this option is not specified, the button’s desired height is computed from the size of the image or bitmap or text being displayed in it.

Command-Line Name:−overrelief

Database Name:


Database Class:


Specifies an alternative relief for the button, to be used when the mouse cursor is over the widget. This option can be used to make toolbar buttons, by configuring −relief flat −overrelief raised. If the value of this option is the empty string, then no alternative relief is used when the mouse cursor is over the button. The empty string is the default value.

Command-Line Name:−state

Database Name:


Database Class:


Specifies one of three states for the button: normal, active, or disabled. In normal state the button is displayed using the −foreground and −background options. The active state is typically used when the pointer is over the button. In active state the button is displayed using the −activeforeground and −activebackground options. Disabled state means that the button should be insensitive: the default bindings will refuse to activate the widget and will ignore mouse button presses. In this state the −disabledforeground and −background options determine how the button is displayed.

Command-Line Name:−width

Database Name:


Database Class:


Specifies a desired width for the button. If an image or bitmap is being displayed in the button then the value is in screen units (i.e. any of the forms acceptable to Tk_GetPixels). For a text button (no image or with −compound none) then the width specifies how much space in characters to allocate for the text label. If the width is negative then this specifies a minimum width. If this option is not specified, the button’s desired width is computed from the size of the image or bitmap or text being displayed in it. ___________________________


The button command creates a new window (given by the pathName argument) and makes it into a button widget. Additional options, described above, may be specified on the command line or in the option database to configure aspects of the button such as its colors, font, text, and initial relief. The button command returns its pathName argument. At the time this command is invoked, there must not exist a window named pathName, but pathName’s parent must exist.

A button is a widget that displays a textual string, bitmap or image. If text is displayed, it must all be in a single font, but it can occupy multiple lines on the screen (if it contains newlines or if wrapping occurs because of the −wraplength option) and one of the characters may optionally be underlined using the −underline option. It can display itself in either of three different ways, according to the −state option; it can be made to appear raised, sunken, or flat; and it can be made to flash. When a user invokes the button (by pressing mouse button 1 with the cursor over the button), then the Tcl command specified in the −command option is invoked.


The button command creates a new Tcl command whose name is pathName. This command may be used to invoke various operations on the widget. It has the following general form:

pathName option ?arg arg ...?

Option and the args determine the exact behavior of the command. The following commands are possible for button widgets:
cget option

Returns the current value of the configuration option given by option. Option may have any of the values accepted by the button command.

pathName configure ?option? ?value option value ...?

Query or modify the configuration options of the widget. If no option is specified, returns a list describing all of the available options for pathName (see Tk_ConfigureInfo for information on the format of this list). If option is specified with no value, then the command returns a list describing the one named option (this list will be identical to the corresponding sublist of the value returned if no option is specified). If one or more option−value pairs are specified, then the command modifies the given widget option(s) to have the given value(s); in this case the command returns an empty string. Option may have any of the values accepted by the button command.

pathName flash

Flash the button. This is accomplished by redisplaying the button several times, alternating between the configured activebackground and background colors. At the end of the flash the button is left in the same normal/active state as when the command was invoked. This command is ignored if the button’s state is disabled.

pathName invoke

Invoke the Tcl command associated with the button, if there is one. The return value is the return value from the Tcl command, or an empty string if there is no command associated with the button. This command is ignored if the button’s state is disabled.


Tk automatically creates class bindings for buttons that give them default behavior:


A button activates whenever the mouse passes over it and deactivates whenever the mouse leaves the button. Under Windows, this binding is only active when mouse button 1 has been pressed over the button.


A button’s relief is changed to sunken whenever mouse button 1 is pressed over the button, and the relief is restored to its original value when button 1 is later released.


If mouse button 1 is pressed over a button and later released over the button, the button is invoked. However, if the mouse is not over the button when button 1 is released, then no invocation occurs.


When a button has the input focus, the space key causes the button to be invoked.

If the button’s state is disabled then none of the above actions occur: the button is completely non-responsive.

The behavior of buttons can be changed by defining new bindings for individual widgets or by redefining the class bindings.


On Aqua/Mac OS X, some configuration options are ignored for the purpose of drawing of the widget because they would otherwise conflict with platform guidelines. The configure and cget subcommands can still manipulate the values, but do not cause any variation to the look of the widget. The options affected notably include −background and −relief.


This is the classic Tk “Hello, World!” demonstration:

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

This example demonstrates how to handle button accelerators:

button .b1 −text Hello −underline 0
.b2 −text World −underline 0
bind . <Key−h> {.b1 flash; .b1 invoke}
bind . <Key−w> {.b2 flash; .b2 invoke}
pack .b1 .b2




button, widget


Personal Opportunity - Free software gives you access to billions of dollars of software at no cost. Use this software for your business, personal use or to develop a profitable skill. Access to source code provides access to a level of capabilities/information that companies protect though copyrights. Open source is a core component of the Internet and it is available to you. Leverage the billions of dollars in resources and capabilities to build a career, establish a business or change the world. The potential is endless for those who understand the opportunity.

Business Opportunity - Goldman Sachs, IBM and countless large corporations are leveraging open source to reduce costs, develop products and increase their bottom lines. Learn what these companies know about open source and how open source can give you the advantage.

Free Software

Free Software provides computer programs and capabilities at no cost but more importantly, it provides the freedom to run, edit, contribute to, and share the software. The importance of free software is a matter of access, not price. Software at no cost is a benefit but ownership rights to the software and source code is far more significant.

Free Office Software - The Libre Office suite provides top desktop productivity tools for free. This includes, a word processor, spreadsheet, presentation engine, drawing and flowcharting, database and math applications. Libre Office is available for Linux or Windows.

Free Books

The Free Books Library is a collection of thousands of the most popular public domain books in an online readable format. The collection includes great classical literature and more recent works where the U.S. copyright has expired. These books are yours to read and use without restrictions.

Source Code - Want to change a program or know how it works? Open Source provides the source code for its programs so that anyone can use, modify or learn how to write those programs themselves. Visit the GNU source code repositories to download the source.


Study at Harvard, Stanford or MIT - Open edX provides free online courses from Harvard, MIT, Columbia, UC Berkeley and other top Universities. Hundreds of courses for almost all major subjects and course levels. Open edx also offers some paid courses and selected certifications.

Linux Manual Pages - A man or manual page is a form of software documentation found on Linux/Unix operating systems. Topics covered include computer programs (including library and system calls), formal standards and conventions, and even abstract concepts.