button

Create and manipulate button widgets


SYNOPSIS

(button widget-name . options)

Standard options

activeBackground   cursor              highlightThickness  takeFocus 
activeForeground   disabledForeground  image               text 
anchor             font                justify             textVariable
background         foreground          padX                underline 
bitmap             highlightColor      padY                wrapLength 
borderWidth        highlightBackground relief


Widget-specific options

Name: procedure
Class: Command
Command-Line Switch: :procedure

Name: height
Class: Height
Command-Line Switch: :height

Name: state
Class: State
Command-Line Switch: :state

Name: width
Class: Width
Command-Line Switch: :width


DESCRIPTION

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


WIDGET COMMAND

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

Option and the args determine the exact behavior of the procedure. The following procedures are possible for button widgets:

(widget-name 'cget option)
Returns the current value of the configuration option given by option. Option may have any of the values accepted by the button procedure.

(widget-name '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 widget_name (see Tk_ConfigureInfo for information on the format of this list). If option is specified with no value, then the procedure 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 procedure modifies the given widget option(s) to have the given value(s); in this case the procedure returns an empty string. Option may have any of the values accepted by the button procedure.

(widget-name 'flash)
Flash the button. This is accomplished by redisplaying the button several times, alternating between active and normal colors. At the end of the flash the button is left in the same normal/active state as when the procedure was invoked. This procedure is ignored if the button's state is disabled.

(widget-name 'invoke)
Invoke the STk procedure associated with the button, if there is one. The return value is undefined.This procedure is ignored if the button's state is disabled.

DEFAULT BINDINGS

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

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.


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