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NAME

button - Create and manipulate button widgets

SYNOPSIS

button pathName ? options ?

STANDARD OPTIONS

-activebackground -disabledcolor      -justify
-activeforeground -font               -relief
-anchor           -foreground         -takefocus
-background       -highlightcolor     -text
-bitmap           -highlightthickness -underline
-borderwidth      -image

WIDGET-SPECIFIC OPTIONS

-command tkcmd
Specifies a Tk command to associate with the button. This command is typically invoked when mouse button 1 is released over the button window.
-height dist
Specifies a desired height for the button. If this option isn't specified, the button's desired height is computed from the size of the image or bitmap or text being displayed in it.
-state state
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 background option determines how the button is displayed.
-width dist
Specifies a desired width for the button. If this option isn't specified, the button's desired width is computed from the size of the image or bitmap or text being displayed in it.

DESCRIPTION

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. to configure aspects of the button such as its colours, 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 .

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) 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. When a user invokes the button (by pressing mouse button 1 with the cursor over the button), then the Tk command specified in the -command option is invoked.

WIDGET COMMAND

The button command creates a new Tk 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 arg s determine the exact behaviour of the command. The following commands are possible for button widgets:

pathName 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 of all of the available options for pathName . 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 invoke
Invoke the Tk command associated with the button, if there is one. The return value is the return value from the Tk 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 .

DEFAULT BINDINGS

Tk automatically creates bindings for buttons that give them the following default behaviour:

[1]
A button activates whenever the mouse passes over it and deactivates whenever the mouse leaves the button.

[2]
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.

[3]
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.

[4]
If the Enter or Space key is pressed when the button has keyboard focus, the button is invoked.

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

The behaviour of buttons can be changed by defining new bindings for individual widgets.

SEE ALSO

checkbutton(9), choicebutton(9), options(9), radiobutton(9), types(9)

BUTTON(9) Rev:  Tue Jan 29 13:12:04 GMT 2008