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checkbutton - Create and manipulate checkbutton widgets
checkbutton pathName ?options?
|
-activebackground |
-cursor |
-highlightthickness-takefocus │ | ||
|
-activeforeground |
-disabledforeground-image-text │ |
|||
|
-anchor |
-font |
-justify |
-textvariable │ | |
|
-background |
-foreground |
-padx |
-underline │ | |
|
-bitmap |
-highlightbackground |
-pady-wraplength │ | ||
|
-borderwidth |
-highlightcolor |
-relief |
See the options manual entry for details on the standard options.
[-command 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. The button’s global variable
(-variable option) will be updated before the command
is invoked. [-height 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.
[-indicatoron indicatorOn] Specifies
whether or not the indicator │ should be
drawn. Must be a proper boolean value. If false, the
relief │ option is ignored and the
widget’s relief is always sunken if the
│ widget is selected and raised otherwise.
[-offvalue offValue] Specifies value to
store in the button’s associated variable whenever
this button is deselected. Defaults to
’’0’’.
[-onvalue onValue] Specifies value to
store in the button’s associated variable whenever
this button is selected. Defaults to
’’1’’.
[-selectcolor selectColor] Specifies a
background color to use when the │ button
is selected. If indicatorOn is true then the color
applicies to │ the indicator. If
indicatorOn is false, this color is used as the
│ background for the entire widget, in
place of background or │
activeBackground, whenever the widget is selected. If
specified as an │ empty string then no
special color is used for displaying when the
│ widget is selected.
[-selectimage selectImage] Specifies an
image to │ display (in place of the
image option) when the checkbutton is
│ selected. This option is ignored unless
the image option has been │
specified. [-state state] Specifies one
of three states for the checkbutton: normal,
active, or disabled. In normal state the
checkbutton is displayed using the foreground and
background options. The active state is typically
used when the pointer is over the checkbutton. In active
state the checkbutton is displayed using the
activeForeground and activeBackground options.
Disabled state means that the checkbutton 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 checkbutton is
displayed. [-variable variable] Specifies
name of global variable to set to indicate whether or not
this button is selected. Defaults to the name of the button
within its parent (i.e. the last element of the button
window’s path name). [-width 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.
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The checkbutton command creates a new window (given by the pathName argument) and makes it into a checkbutton widget. Additional options, described above, may be specified on the command line or in the option database to configure aspects of the checkbutton such as its colors, font, text, and initial relief. The checkbutton 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 checkbutton is a widget that displays a textual string, bitmap or │ image and a square called an indicator. 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. A checkbutton has all of the behavior of a simple button, including the following: 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; it can be made to flash; and it invokes a Tcl command whenever mouse button 1 is clicked over the checkbutton.
In addition, checkbuttons can be selected. If a checkbutton is │ selected then the indicator is normally drawn with a sunken relief and │ a special color, and a Tcl variable associated with the checkbutton is │ set to a particular value (normally 1). If the checkbutton is not │ selected, then the indicator is drawn with a raised relief and no │ special color, and the associated variable is set to a different value │ (typically 0). By default, the name of the variable associated with a │ checkbutton is the same as the name used to create the checkbutton. │ The variable name, and the ’’on’’ and ’’off’’ values stored in it, may │ be modified with options on the command line or in the option database. │ Configuration options may also be used to modify the way the indicator │ is displayed (or whether it is displayed at all). By default a checkbutton is configured to select and deselect itself on alternate button clicks. In addition, each checkbutton monitors its associated variable and automatically selects and deselects itself when the variables value changes to and from the button’s ’’on’’ value.
The checkbutton 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 checkbutton 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 │ checkbutton 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 checkbutton command.
pathName deselect
Deselects the checkbutton and sets the associated variable to its ’’off’’ value.
pathName flash
Flashes the checkbutton. This is accomplished by redisplaying the checkbutton several times, alternating between active and normal colors. At the end of the flash the checkbutton is left in the same normal/active state as when the command was invoked. This command is ignored if the checkbutton’s state is disabled.
pathName invoke
Does just what would have happened if the user invoked the checkbutton with the mouse: toggle the selection state of the button and invoke the Tcl command associated with the checkbutton, 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 checkbutton. This command is ignored if the checkbutton’s state is disabled.
pathName select
Selects the checkbutton and sets the associated variable to its ’’on’’ value.
pathName toggle
Toggles the selection state of the button, redisplaying it and modifying its associated variable to reflect the new state.
Tk automatically creates class bindings for checkbuttons that give them the following default behavior:
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[1] |
A checkbutton activates whenever the mouse passes over it and deactivates whenever the mouse leaves the checkbutton. | ||
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[2] |
When mouse button 1 is pressed over a checkbutton it is invoked │ (its selection state toggles and the command associated with the │ button is invoked, if there is one). │ |
[3] │
When a checkbutton has the input focus, the space key causes the │ checkbutton to be invoked.
If the checkbutton’s state is disabled then none of the above actions occur: the checkbutton is completely non-responsive.
The behavior of checkbuttons can be changed by defining new bindings for individual widgets or by redefining the class bindings.
checkbutton, widget