button - Create and manipulate button widgets
$button = $parent->Button(?options?);
activeBackground cursor highlightThickness takeFocus
activeForeground disabledForeground image text
anchor font justify textVariable
background foreground padX underline
bitmap highlightColor padY wrapLength
borderWidth highlightBackground relief
See the ``options'' manual entry for details on the standard options.
- Name: command
- Class: Command
- Configure Option: -command
Specifies a Tcl command to associate with the button. This command
is typically invoked when mouse button 1 is released over the button
window.
- Name: height
- Class: Height
- Configure Option: -height
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 isn't specified, the button's desired height is computed
from the size of the image or bitmap or text being displayed in it.
- Name: state
- Class: State
- Configure Option: -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 disabledForeground and
background options determine how the button is displayed.
- Name: width
- Class: Width
- Configure Option: -width
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 text it is in characters.
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.
The button command creates a new window (given by the
$widget 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
$widget argument. At the time this command is invoked,
there must not exist a window named $widget, but
$widget'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 widget object whose
name is $widget. This
command may be used to invoke various
operations on the widget. It has the following general form:
$button->method(?arg arg ...?)
Option and the args
determine the exact behavior of the command. The following
commands are possible for button widgets:
- $button->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.
- $button->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 (see configure 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.
- $button->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 command was invoked.
This command is ignored if the button's state is disabled.
- $button->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
the following default behavior:
- A button activates whenever the mouse passes over it and deactivates
whenever the mouse leaves 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.
button, widget